Add ScriptBehavior DSL: data-driven, non-Turing-complete UGC scripting

Implements the DSL that docs/architecture/scripting_sandbox.md recommends
as the primary (and, for now, sufficient) approach in place of running
untrusted GDScript in-process: a fixed set of trigger/condition/action
verbs, expressed as plain JSON data, interpreted by trusted GDScript with
zero ability to reference engine singletons, call arbitrary methods, or
execute code.

- ScriptBehavior (scripts/scripting/script_behavior.gd): parses and
  validates rules from JSON/Dictionary data. Every trigger, condition
  type/op, and verb is checked against an explicit whitelist at parse
  time; malformed or unknown entries are dropped and recorded in
  rejected_rules, never partially executed. Carries an optional
  content_flags passthrough so this data type isn't hostile to future
  moderation-queue integration (docs/architecture/content_moderation.md).
- ScriptInterpreterNode (scripts/scripting/script_interpreter.gd): the
  only code that executes rules. Triggers: on_interact (proximity +
  "interact" input action), on_enter (edge-triggered Area3D overlap),
  on_touch (continuous overlap), on_timer (physics-clocked Timer). Verbs:
  give_item, play_sound, move, rotate, spawn_from_catalog, set_timer --
  each a fixed, hand-written function; verb dispatch is an explicit
  match(), never call()-by-name from data. move/rotate animate via Tween
  rather than teleporting.
- PlayerInventory (scripts/scripting/player_inventory.gd): a small
  per-player item-count stub for give_item to target, since no real
  inventory/entity-state system exists yet (M9 Economy). Attached to
  scenes/player.tscn as "Inventory".
- SpawnCatalog (scripts/scripting/spawn_catalog.gd): trusted catalog_id ->
  asset_id lookup for spawn_from_catalog, mirroring the AvatarCatalog
  data-driven-JSON convention. Rule data only ever supplies a catalog_id
  key, never a resource path.
- Wired a real demo ("ScriptedChest") into scenes/worlds/test_level.tscn
  with an on_interact rule (give_item + play_sound + rotate), plus an
  "interact" input action (project.godot).
- scripts/smoke_test_script_behavior.gd: exercises every trigger type,
  every verb, and every condition type against the real interpreter and
  the wired demo scene, and proves unknown/malformed/unsafe rules
  (unknown verb, unknown trigger, non-scalar smuggled arguments, etc.)
  are rejected at parse time and never run -- 50/50 checks pass.

.gitea/workflows/checkpoint.yml

@@ -0,0 +1,39 @@
+name: checkpoint
+
+# Runs the full checkpoint suite (migrations, backend pytest, Godot smoke
+# tests, multiplayer, fresh-clone boot) on every push and PR.
+#
+# Runs on a `host`-label act_runner on the AGP box: Docker, ~/godot/godot,
+# and Python 3 are already there. Deliberately uses no JavaScript actions
+# (actions/checkout etc.) so the host needs no Node install -- checkout is a
+# plain git clone from the local Gitea. See docs/ci.md.
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  checkpoint:
+    runs-on: host
+    steps:
+      - name: Checkout
+        run: |
+          set -eu
+          rm -rf repo && mkdir repo && cd repo
+          git init -q
+          git remote add origin "http://x:${{ github.token }}@localhost:3000/${{ github.repository }}.git"
+          git fetch -q --depth 1 origin "${{ github.sha }}"
+          git checkout -q FETCH_HEAD
+
+      - name: Python env
+        working-directory: repo
+        run: |
+          set -eu
+          python3 -m venv .venv
+          .venv/bin/pip install --quiet --upgrade pip
+          .venv/bin/pip install --quiet -r backend/requirements.txt
+
+      - name: Checkpoint suite
+        working-directory: repo
+        run: .venv/bin/python scripts/run_checkpoint_tests.py --postgres-port 25690 --backend-port 18690

.gitignore

@@ -11,3 +11,4 @@ Thumbs.db
 
 # Godot UID files (regenerated from path)
 *.uid
+assets/build_info.json

assets/avatars/accessory_belt_01.glb.import

@@ -0,0 +1,42 @@
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assets/avatars/accessory_necklace_01.glb.import

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assets/avatars/back_backpack_01.glb.import

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assets/avatars/base_human_male_01.glb.import

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assets/avatars/catalog.json

@@ -0,0 +1,115 @@
+{
+  "assets": {
+    "base_human_male_01": {
+      "type": "base_body",
+      "slot": "base_body",
+      "path": "res://assets/avatars/base_human_male_01.glb",
+      "version": "1.0.0",
+      "display_name": "Human Male Base"
+    },
+    "head_cyber_01": {
+      "type": "attachment",
+      "slot": "head",
+      "path": "res://assets/avatars/head_cyber_01.glb",
+      "version": "1.0.0",
+      "display_name": "Cyber Head",
+      "mount_bone": "Head"
+    },
+    "hair_mohawk_01": {
+      "type": "attachment",
+      "slot": "hair",
+      "path": "res://assets/avatars/hair_mohawk_01.glb",
+      "version": "1.0.0",
+      "display_name": "Mohawk",
+      "mount_bone": "HeadTop"
+    },
+    "hair_ponytail_01": {
+      "type": "attachment",
+      "slot": "hair",
+      "path": "res://assets/avatars/hair_ponytail_01.glb",
+      "version": "1.0.0",
+      "display_name": "Ponytail",
+      "mount_bone": "HeadTop"
+    },
+    "face_glasses_01": {
+      "type": "attachment",
+      "slot": "face",
+      "path": "res://assets/avatars/face_glasses_01.glb",
+      "version": "1.0.0",
+      "display_name": "Glasses",
+      "mount_bone": "Jaw"
+    },
+    "chest_bandit_01": {
+      "type": "attachment",
+      "slot": "chest",
+      "path": "res://assets/avatars/chest_bandit_01.glb",
+      "version": "1.0.0",
+      "display_name": "Bandit Shirt",
+      "mount_bone": "Chest"
+    },
+    "back_backpack_01": {
+      "type": "attachment",
+      "slot": "back",
+      "path": "res://assets/avatars/back_backpack_01.glb",
+      "version": "1.0.0",
+      "display_name": "Backpack",
+      "mount_bone": "Chest"
+    },
+    "pants_cargo_01": {
+      "type": "attachment",
+      "slot": "pants",
+      "path": "res://assets/avatars/pants_cargo_01.glb",
+      "version": "1.0.0",
+      "display_name": "Cargo Pants",
+      "mount_bone": "Hips"
+    },
+    "left_hand_glove_01": {
+      "type": "attachment",
+      "slot": "left_hand",
+      "path": "res://assets/avatars/left_hand_glove_01.glb",
+      "version": "1.0.0",
+      "display_name": "Left Glove",
+      "mount_bone": "LeftHand"
+    },
+    "right_hand_glove_01": {
+      "type": "attachment",
+      "slot": "right_hand",
+      "path": "res://assets/avatars/right_hand_glove_01.glb",
+      "version": "1.0.0",
+      "display_name": "Right Glove",
+      "mount_bone": "RightHand"
+    },
+    "left_foot_boot_01": {
+      "type": "attachment",
+      "slot": "left_foot",
+      "path": "res://assets/avatars/left_foot_boot_01.glb",
+      "version": "1.0.0",
+      "display_name": "Left Boot",
+      "mount_bone": "LeftFoot"
+    },
+    "right_foot_boot_01": {
+      "type": "attachment",
+      "slot": "right_foot",
+      "path": "res://assets/avatars/right_foot_boot_01.glb",
+      "version": "1.0.0",
+      "display_name": "Right Boot",
+      "mount_bone": "RightFoot"
+    },
+    "accessory_belt_01": {
+      "type": "attachment",
+      "slot": "accessory",
+      "path": "res://assets/avatars/accessory_belt_01.glb",
+      "version": "1.0.0",
+      "display_name": "Belt",
+      "mount_bone": "Root"
+    },
+    "accessory_necklace_01": {
+      "type": "attachment",
+      "slot": "accessory",
+      "path": "res://assets/avatars/accessory_necklace_01.glb",
+      "version": "1.0.0",
+      "display_name": "Necklace",
+      "mount_bone": "Root"
+    }
+  }
+}

assets/avatars/chest_bandit_01.glb.import

@@ -0,0 +1,42 @@
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assets/avatars/face_glasses_01.glb.import

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assets/avatars/left_foot_boot_01.glb.import

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+materials/extract_format=0
+materials/extract_path=""
+_subresources={}
+gltf/naming_version=2
+gltf/embedded_image_handling=1

assets/avatars/left_hand_glove_01.glb.import

@@ -0,0 +1,42 @@
+[remap]
+
+importer="scene"
+importer_version=1
+type="PackedScene"
+uid="uid://dtq7tgio1iymd"
+path="res://.godot/imported/left_hand_glove_01.glb-4b237bea3299c6604547afa353a7b602.scn"
+
+[deps]
+
+source_file="res://assets/avatars/left_hand_glove_01.glb"
+dest_files=["res://.godot/imported/left_hand_glove_01.glb-4b237bea3299c6604547afa353a7b602.scn"]
+
+[params]
+
+nodes/root_type=""
+nodes/root_name=""
+nodes/root_script=null
+nodes/apply_root_scale=true
+nodes/root_scale=1.0
+nodes/import_as_skeleton_bones=false
+nodes/use_name_suffixes=true
+nodes/use_node_type_suffixes=true
+meshes/ensure_tangents=true
+meshes/generate_lods=true
+meshes/create_shadow_meshes=true
+meshes/light_baking=1
+meshes/lightmap_texel_size=0.2
+meshes/force_disable_compression=false
+skins/use_named_skins=true
+animation/import=true
+animation/fps=30
+animation/trimming=false
+animation/remove_immutable_tracks=true
+animation/import_rest_as_RESET=false
+import_script/path=""
+materials/extract=0
+materials/extract_format=0
+materials/extract_path=""
+_subresources={}
+gltf/naming_version=2
+gltf/embedded_image_handling=1

assets/avatars/pants_cargo_01.glb.import

@@ -0,0 +1,42 @@
+[remap]
+
+importer="scene"
+importer_version=1
+type="PackedScene"
+uid="uid://yo204q1m6hs3"
+path="res://.godot/imported/pants_cargo_01.glb-00f3e3b72fd692344cbb8bfd2b8449f9.scn"
+
+[deps]
+
+source_file="res://assets/avatars/pants_cargo_01.glb"
+dest_files=["res://.godot/imported/pants_cargo_01.glb-00f3e3b72fd692344cbb8bfd2b8449f9.scn"]
+
+[params]
+
+nodes/root_type=""
+nodes/root_name=""
+nodes/root_script=null
+nodes/apply_root_scale=true
+nodes/root_scale=1.0
+nodes/import_as_skeleton_bones=false
+nodes/use_name_suffixes=true
+nodes/use_node_type_suffixes=true
+meshes/ensure_tangents=true
+meshes/generate_lods=true
+meshes/create_shadow_meshes=true
+meshes/light_baking=1
+meshes/lightmap_texel_size=0.2
+meshes/force_disable_compression=false
+skins/use_named_skins=true
+animation/import=true
+animation/fps=30
+animation/trimming=false
+animation/remove_immutable_tracks=true
+animation/import_rest_as_RESET=false
+import_script/path=""
+materials/extract=0
+materials/extract_format=0
+materials/extract_path=""
+_subresources={}
+gltf/naming_version=2
+gltf/embedded_image_handling=1

assets/avatars/right_foot_boot_01.glb.import

@@ -0,0 +1,42 @@
+[remap]
+
+importer="scene"
+importer_version=1
+type="PackedScene"
+uid="uid://30ij0eapm6ti"
+path="res://.godot/imported/right_foot_boot_01.glb-ffff27e561e5632596b7ba89fee5b5ea.scn"
+
+[deps]
+
+source_file="res://assets/avatars/right_foot_boot_01.glb"
+dest_files=["res://.godot/imported/right_foot_boot_01.glb-ffff27e561e5632596b7ba89fee5b5ea.scn"]
+
+[params]
+
+nodes/root_type=""
+nodes/root_name=""
+nodes/root_script=null
+nodes/apply_root_scale=true
+nodes/root_scale=1.0
+nodes/import_as_skeleton_bones=false
+nodes/use_name_suffixes=true
+nodes/use_node_type_suffixes=true
+meshes/ensure_tangents=true
+meshes/generate_lods=true
+meshes/create_shadow_meshes=true
+meshes/light_baking=1
+meshes/lightmap_texel_size=0.2
+meshes/force_disable_compression=false
+skins/use_named_skins=true
+animation/import=true
+animation/fps=30
+animation/trimming=false
+animation/remove_immutable_tracks=true
+animation/import_rest_as_RESET=false
+import_script/path=""
+materials/extract=0
+materials/extract_format=0
+materials/extract_path=""
+_subresources={}
+gltf/naming_version=2
+gltf/embedded_image_handling=1

assets/avatars/right_hand_glove_01.glb.import

@@ -0,0 +1,42 @@
+[remap]
+
+importer="scene"
+importer_version=1
+type="PackedScene"
+uid="uid://bcrtxtp47dv8h"
+path="res://.godot/imported/right_hand_glove_01.glb-a59875b630ac413350c3bdf6acc84bdf.scn"
+
+[deps]
+
+source_file="res://assets/avatars/right_hand_glove_01.glb"
+dest_files=["res://.godot/imported/right_hand_glove_01.glb-a59875b630ac413350c3bdf6acc84bdf.scn"]
+
+[params]
+
+nodes/root_type=""
+nodes/root_name=""
+nodes/root_script=null
+nodes/apply_root_scale=true
+nodes/root_scale=1.0
+nodes/import_as_skeleton_bones=false
+nodes/use_name_suffixes=true
+nodes/use_node_type_suffixes=true
+meshes/ensure_tangents=true
+meshes/generate_lods=true
+meshes/create_shadow_meshes=true
+meshes/light_baking=1
+meshes/lightmap_texel_size=0.2
+meshes/force_disable_compression=false
+skins/use_named_skins=true
+animation/import=true
+animation/fps=30
+animation/trimming=false
+animation/remove_immutable_tracks=true
+animation/import_rest_as_RESET=false
+import_script/path=""
+materials/extract=0
+materials/extract_format=0
+materials/extract_path=""
+_subresources={}
+gltf/naming_version=2
+gltf/embedded_image_handling=1

assets/scripting/behaviors/demo_chest.json

@@ -0,0 +1,17 @@
+{
+  "content_flags": {
+    "violence": "none",
+    "mature": false
+  },
+  "rules": [
+    {
+      "trigger": {"type": "on_interact"},
+      "conditions": [],
+      "actions": [
+        {"verb": "give_item", "item_id": "gold_coin", "count": 3},
+        {"verb": "play_sound", "sound_id": "chest_open"},
+        {"verb": "rotate", "target": "self", "degrees": 90, "axis": "y", "duration": 0.4}
+      ]
+    }
+  ]
+}

assets/scripting/spawn_catalog.json

@@ -0,0 +1,8 @@
+{
+  "templates": {
+    "small_crate": {
+      "asset_id": "props/crate_small.glb",
+      "display_name": "Small Crate"
+    }
+  }
+}

backend/alembic/env.py

@@ -8,7 +8,7 @@ from sqlalchemy.ext.asyncio import create_async_engine
 
 from app.config import settings
 from app.database import Base
-from app.models import user, session, world, asset  # noqa: F401
+from app.models import user, session, world, asset, avatar_loadout  # noqa: F401
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.

backend/alembic/versions/0004_add_avatar_loadouts_table.py

@@ -0,0 +1,39 @@
+"""add avatar_loadouts table
+
+Revision ID: 0004_add_avatar_loadouts_table
+Revises: 0003_add_refresh_tokens_table
+Create Date: 2026-09-05 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0004_add_avatar_loadouts_table"
+down_revision: Union[str, None] = "0003_add_refresh_tokens_table"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Create the avatar_loadouts table (one row per user)."""
+    op.create_table(
+        "avatar_loadouts",
+        sa.Column(
+            "user_id",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="CASCADE"),
+            primary_key=True,
+        ),
+        sa.Column("data", postgresql.JSONB(), nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+    )
+
+
+def downgrade() -> None:
+    """Drop the avatar_loadouts table."""
+    op.drop_table("avatar_loadouts")

backend/app/config.py

@@ -75,11 +75,36 @@ class Settings(BaseSettings):
     # CORS
     CORS_ORIGINS: str = "http://localhost:8080,http://localhost:3000"
 
+    # Per-IP auth rate limiting (app/rate_limit.py). Disabled by the
+    # checkpoint smoke suite, which runs every test from one client IP.
+    RATE_LIMIT_ENABLED: bool = True
+
     # File uploads
     UPLOAD_DIR: str = "uploads"
     MAX_UPLOAD_SIZE_MB: int = 100
     GLTF_MAX_FILE_SIZE_MB: int = 200
 
+    # ── Game-server orchestration ──────────────────────────────────────────
+    # The join flow (POST /api/worlds/{id}/join) ensures a headless Godot
+    # dedicated-server process exists for a world and returns its address.
+    # Disabled by default so nothing tries to spawn Godot in environments
+    # that don't have it (plain pytest, CI without the engine); the
+    # checkpoint/playtest launcher turns it on.
+    GAME_SERVERS_ENABLED: bool = False
+    # Path to the Godot 4 binary. "godot" resolves via PATH.
+    GODOT_BIN: str = str(Path.home() / "godot" / "godot")
+    # Godot project directory (the game repo root -- backend/ is a subdir).
+    GAME_PROJECT_DIR: str = str(Path(__file__).resolve().parents[2])
+    # The host clients should connect to for ENet. Defaults to the LAN IP the
+    # launcher bakes into the exe; overridable for local testing.
+    GAME_SERVER_HOST: str = "127.0.0.1"
+    # Port range for per-world dedicated servers.
+    GAME_SERVER_PORT_MIN: int = 27000
+    GAME_SERVER_PORT_MAX: int = 27099
+    # Kill a world's server this long after its last join with no active
+    # players reported.
+    GAME_SERVER_IDLE_TIMEOUT_SECONDS: int = 300
+
     model_config = SettingsConfigDict(
         env_file=".env",
         env_file_encoding="utf-8",

backend/app/main.py

@@ -6,15 +6,18 @@ from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
 from app.config import settings
-from app.routers import auth, users, worlds, assets
+from app.routers import auth, users, worlds, assets, avatar
+
+
+from app.services.game_servers import supervisor
 
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     """Application lifespan: startup and shutdown events."""
-    # Startup: initialize database, connect to Redis, etc.
+    supervisor.start()
     yield
-    # Shutdown: close connections, cleanup
+    await supervisor.shutdown()
 
 
 app = FastAPI(
@@ -38,6 +41,7 @@ app.include_router(auth.router, prefix="/api/auth", tags=["auth"])
 app.include_router(users.router, prefix="/api/users", tags=["users"])
 app.include_router(worlds.router, prefix="/api/worlds", tags=["worlds"])
 app.include_router(assets.router, prefix="/api/assets", tags=["assets"])
+app.include_router(avatar.router, prefix="/api/avatar", tags=["avatar"])
 
 
 @app.get("/api/health")

backend/app/models/__init__.py

@@ -2,5 +2,6 @@ from app.models.user import User
 from app.models.session import Session
 from app.models.world import World
 from app.models.asset import Asset
+from app.models.avatar_loadout import AvatarLoadout
 
-__all__ = ["User", "Session", "World", "Asset"]
+__all__ = ["User", "Session", "World", "Asset", "AvatarLoadout"]

backend/app/models/avatar_loadout.py

@@ -0,0 +1,41 @@
+from sqlalchemy import Column, Integer, ForeignKey, DateTime
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+
+from app.database import Base
+
+
+# The default a brand-new account gets before they touch the customization
+# screen. Kept in sync with assets/avatars/catalog.json (the base_body id) and
+# with the client's AvatarLoadout.to_json() shape.
+DEFAULT_LOADOUT: dict = {
+    "base_body": "base_human_male_01",
+    "slots": {},
+}
+
+
+class AvatarLoadout(Base):
+    """A user's equipped avatar composition.
+
+    One row per user. The whole loadout is stored as a single JSON document
+    matching the client's ``AvatarLoadout.to_json()`` shape
+    (``{"base_body": str, "slots": {...}, "skin_tone"?: {...}}``) rather than
+    exploded into columns -- the server has no copy of the asset catalog, so
+    deep validation (does this asset exist, is it valid for this slot) stays
+    on the client. The server only enforces the envelope: valid JSON object
+    with a non-empty ``base_body``.
+    """
+
+    __tablename__ = "avatar_loadouts"
+
+    user_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        primary_key=True,
+    )
+    data = Column(JSONB, nullable=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=False)
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now(), nullable=False)
+
+    user = relationship("User", back_populates="avatar_loadout")

backend/app/models/user.py

@@ -24,6 +24,12 @@ class User(Base):
     refresh_tokens = relationship("RefreshToken", back_populates="user", cascade="all, delete-orphan")
     worlds = relationship("World", back_populates="owner")
     assets = relationship("Asset", back_populates="owner")
+    avatar_loadout = relationship(
+        "AvatarLoadout",
+        back_populates="user",
+        uselist=False,
+        cascade="all, delete-orphan",
+    )
 
     @property
     def is_adult(self) -> bool:

backend/app/rate_limit.py

@@ -0,0 +1,73 @@
+"""Lightweight in-process rate limiting.
+
+The backend runs single-worker (required by the game-server supervisor), so a
+process-local sliding-window counter is sufficient and needs no Redis. Keyed
+by client IP. Used to blunt credential brute-force on the auth endpoints.
+
+If the backend is ever scaled to multiple workers/hosts this must move to a
+shared store (Redis) -- flagged here rather than silently under-enforcing.
+"""
+from __future__ import annotations
+
+import time
+from collections import defaultdict, deque
+
+from fastapi import HTTPException, Request, status
+
+from app.config import settings
+
+
+class SlidingWindowLimiter:
+    def __init__(self, max_hits: int, window_seconds: float) -> None:
+        self.max_hits = max_hits
+        self.window = window_seconds
+        self._hits: dict[str, deque[float]] = defaultdict(deque)
+
+    def check(self, key: str) -> None:
+        now = time.monotonic()
+        q = self._hits[key]
+        cutoff = now - self.window
+        while q and q[0] < cutoff:
+            q.popleft()
+        if len(q) >= self.max_hits:
+            retry = max(1, int(q[0] + self.window - now))
+            raise HTTPException(
+                status_code=status.HTTP_429_TOO_MANY_REQUESTS,
+                detail="Too many attempts. Try again shortly.",
+                headers={"Retry-After": str(retry)},
+            )
+        q.append(now)
+
+    def reset(self) -> None:
+        self._hits.clear()
+
+
+def _client_key(request: Request) -> str:
+    # X-Forwarded-For first hop when behind the reverse proxy, else the socket.
+    fwd = request.headers.get("x-forwarded-for", "")
+    if fwd:
+        return fwd.split(",")[0].strip()
+    return request.client.host if request.client else "unknown"
+
+
+# 10 auth attempts / minute / IP -- generous for a human, painful for a
+# brute-forcer.
+_auth_limiter = SlidingWindowLimiter(max_hits=10, window_seconds=60)
+
+
+async def auth_rate_limit(request: Request) -> None:
+    """FastAPI dependency: rate-limit auth attempts per client IP.
+
+    A no-op when ``RATE_LIMIT_ENABLED`` is false -- the checkpoint smoke
+    suite runs every test against one backend from one client IP, so the
+    per-IP cap would trip mid-suite. The dedicated ``test_rate_limit``
+    module exercises the real behaviour regardless of this flag.
+    """
+    if not settings.RATE_LIMIT_ENABLED:
+        return
+    _auth_limiter.check(f"auth:{_client_key(request)}")
+
+
+def reset_all() -> None:
+    """Test hook."""
+    _auth_limiter.reset()

backend/app/routers/auth.py

@@ -16,11 +16,15 @@ from app.database import get_db
 from app.dependencies import CurrentUser
 from app.models.session import RefreshToken
 from app.models.user import User
+from app.rate_limit import auth_rate_limit
 
 pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
 
 router = APIRouter()
 
+## Minimum age to register. This platform is adults-only.
+MIN_AGE = 18
+
 
 # --- Pydantic schemas ---
 
@@ -39,14 +43,19 @@ class RegisterRequest(BaseModel):
     username: str
     email: EmailStr
     password: str
-    over_18: bool  # Simple boolean confirmation instead of date_of_birth
+    # Real date of birth -- the server computes age from it and rejects
+    # anyone under MIN_AGE. Still self-attested (no document check yet), but
+    # a concrete, stored, legally-meaningful data point rather than a
+    # throwaway checkbox, and the seam for a future hard ID-verification
+    # pass. See docs/architecture/content_moderation.md 5.2.
+    date_of_birth: date
 
 
 class UserResponse(BaseModel):
     id: int
     username: str
     email: str
-    date_of_birth: str | None = None
+    date_of_birth: date | None = None
     is_active: bool
     created_at: datetime | None = None
 
@@ -108,15 +117,9 @@ def hash_password(password: str) -> str:
 def calculate_age(birth_date: date, today: date | None = None) -> int:
     """Calculate age in years from a birth date.
 
-    Not called by /register anymore (that endpoint now just trusts the
-    client's over_18 boolean, see RegisterRequest) -- kept as a real,
-    tested utility since date-of-birth storage/verification is coming
-    back in a future pass (real age math, not just a client-side claim,
-    the user explicitly wants to revisit this design). Removing it broke
-    backend/tests/test_auth_age_gate.py's collection entirely (ImportError
-    on `from app.routers.auth import calculate_age`) for zero benefit --
-    restoring it is the lower-risk path over rewriting or deleting 17
-    tests for logic this codebase will need again.
+    Used by /register (PC3 Phase 3) to compute age from the submitted
+    date_of_birth and enforce the 18+ gate. See
+    docs/architecture/content_moderation.md 5.2.
 
     Args:
         birth_date: The person's date of birth.
@@ -151,16 +154,25 @@ def _issue_refresh_token(user_id: int, db: AsyncSession) -> str:
 
 # --- Endpoints ---
 
-@router.post("/register", response_model=TokenResponse, status_code=status.HTTP_201_CREATED)
+@router.post("/register", response_model=TokenResponse, status_code=status.HTTP_201_CREATED,
+             dependencies=[Depends(auth_rate_limit)])
 async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
     """Register a new user and return access + refresh tokens.
 
-    Requires over_18 boolean confirmation; rejects users who are not 18+.
+    Requires a date of birth; the server computes age and rejects anyone
+    under MIN_AGE (18). See docs/architecture/content_moderation.md for the
+    verification design and its self-attestation limitation.
     """
-    if not req.over_18:
+    age = calculate_age(req.date_of_birth)
+    if age < 0 or req.date_of_birth > date.today():
         raise HTTPException(
             status_code=status.HTTP_400_BAD_REQUEST,
-            detail="Must be 18 or older to register",
+            detail="Invalid date of birth",
+        )
+    if age < MIN_AGE:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail=f"You must be at least {MIN_AGE} to use this platform",
         )
 
     # Check if username already exists
@@ -183,7 +195,7 @@ async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
         username=req.username,
         email=req.email,
         hashed_password=hash_password(req.password),
-        date_of_birth=None,  # No longer collecting DOB
+        date_of_birth=req.date_of_birth,
     )
     db.add(user)
     await db.flush()  # flush to get user.id before creating refresh token
@@ -203,7 +215,7 @@ async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
     )
 
 
-@router.post("/login", response_model=TokenResponse)
+@router.post("/login", response_model=TokenResponse, dependencies=[Depends(auth_rate_limit)])
 async def login(form: OAuth2PasswordRequestForm = Depends(), db: AsyncSession = Depends(get_db)):
     """Authenticate user and return access + refresh tokens.
 

backend/app/routers/avatar.py

@@ -0,0 +1,78 @@
+"""Avatar router - the current user's persisted avatar loadout.
+
+The loadout is a single JSON document matching the client's
+``AvatarLoadout.to_json()`` shape. The server has no copy of the asset
+catalog, so it only validates the envelope (JSON object, non-empty
+``base_body``); which assets are valid for which slot is the client's job.
+"""
+
+from typing import Annotated, Any
+
+from fastapi import APIRouter, Depends, HTTPException
+from pydantic import BaseModel, Field
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.avatar_loadout import AvatarLoadout, DEFAULT_LOADOUT
+
+router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+# A loadout document is small; reject anything absurd outright.
+MAX_LOADOUT_BYTES = 16 * 1024
+
+
+class LoadoutResponse(BaseModel):
+    data: dict[str, Any]
+    is_default: bool = Field(
+        description="True when the user has never saved a loadout and this is "
+        "the server default."
+    )
+
+
+class LoadoutUpdate(BaseModel):
+    data: dict[str, Any]
+
+
+def _validate_envelope(data: dict[str, Any]) -> None:
+    base_body = data.get("base_body")
+    if not isinstance(base_body, str) or not base_body.strip():
+        raise HTTPException(
+            status_code=422,
+            detail="loadout.data must have a non-empty string 'base_body'",
+        )
+    slots = data.get("slots", {})
+    if not isinstance(slots, dict):
+        raise HTTPException(status_code=422, detail="loadout.data.slots must be an object")
+    if len(str(data)) > MAX_LOADOUT_BYTES:
+        raise HTTPException(status_code=413, detail="loadout document too large")
+
+
+@router.get("/loadout", response_model=LoadoutResponse)
+async def get_loadout(current_user: CurrentUser, db: DbDep):
+    """Return the current user's saved loadout, or the server default if they
+    have never saved one."""
+    row = await db.get(AvatarLoadout, current_user.id)
+    if row is None:
+        return LoadoutResponse(data=dict(DEFAULT_LOADOUT), is_default=True)
+    return LoadoutResponse(data=row.data, is_default=False)
+
+
+@router.put("/loadout", response_model=LoadoutResponse)
+async def put_loadout(payload: LoadoutUpdate, current_user: CurrentUser, db: DbDep):
+    """Replace the current user's loadout."""
+    _validate_envelope(payload.data)
+
+    row = await db.get(AvatarLoadout, current_user.id)
+    if row is None:
+        row = AvatarLoadout(user_id=current_user.id, data=payload.data)
+        db.add(row)
+    else:
+        row.data = payload.data
+
+    await db.commit()
+    await db.refresh(row)
+    return LoadoutResponse(data=row.data, is_default=False)

backend/app/routers/worlds.py

@@ -12,6 +12,7 @@ from sqlalchemy.orm import selectinload
 from app.database import get_db
 from app.dependencies import CurrentUser
 from app.models.world import World, WorldVisibility
+from app.services.game_servers import supervisor
 
 router = APIRouter()
 
@@ -106,6 +107,40 @@ async def get_world(
     return world
 
 
+class JoinResponse(BaseModel):
+    """Address of the dedicated server hosting this world."""
+    world_id: int
+    host: str
+    port: int
+
+
+@router.post("/{world_id}/join", response_model=JoinResponse)
+async def join_world(
+    world_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Ensure a dedicated game server is running for this world and return its
+    ENet address for the client to connect to.
+
+    503 if game-server orchestration isn't enabled on this backend (e.g. a
+    plain dev/test instance with no Godot binary).
+    """
+    result = await db.execute(select(World).where(World.id == world_id))
+    world = result.scalar_one_or_none()
+    if not world:
+        raise HTTPException(status_code=404, detail="World not found")
+    if world.visibility != WorldVisibility.PUBLIC and world.owner_id != current_user.id:
+        raise HTTPException(status_code=404, detail="World not found")
+
+    try:
+        info = await supervisor.ensure_server(str(world_id))
+    except RuntimeError as exc:
+        raise HTTPException(status_code=503, detail=str(exc))
+
+    return JoinResponse(world_id=world_id, host=info["host"], port=info["port"])
+
+
 @router.post("/", response_model=WorldResponse, status_code=201)
 async def create_world(
     world_data: WorldCreate,

backend/app/services/game_servers.py

@@ -0,0 +1,182 @@
+"""Game-server orchestration.
+
+On ``POST /api/worlds/{id}/join`` the backend ensures a headless Godot
+dedicated-server process is running for that world and returns its address.
+One process per world, keyed by ``world_id``. A background reaper kills a
+world's server once its status file reports zero players for
+``GAME_SERVER_IDLE_TIMEOUT_SECONDS``.
+
+This lives in-process (a module-level singleton) rather than as a separate
+service, so the backend MUST run single-worker -- which it does
+(``uvicorn app.main:app`` with no ``--workers``). The Godot binary and
+project are on the host (see ``settings.GODOT_BIN`` / ``GAME_PROJECT_DIR``);
+the backend spawns them as subprocesses.
+
+Design notes / limits (PC3):
+ - All worlds currently load the same test level (per-world content is M2/M7).
+   ``world_id`` still scopes a distinct server process + session.
+ - Port allocation is a linear scan of the configured range.
+ - No crash-restart: if a server process dies, the next join respawns it.
+"""
+from __future__ import annotations
+
+import asyncio
+import json
+import socket
+import subprocess
+import tempfile
+import time
+from dataclasses import dataclass, field
+from pathlib import Path
+
+from app.config import settings
+
+
+@dataclass
+class _WorldServer:
+    world_id: str
+    port: int
+    proc: subprocess.Popen
+    status_path: Path
+    started_at: float = field(default_factory=time.time)
+    last_join: float = field(default_factory=time.time)
+
+    def status(self) -> dict:
+        try:
+            return json.loads(self.status_path.read_text())
+        except (OSError, ValueError):
+            return {}
+
+    def player_count(self) -> int:
+        return int(self.status().get("players", 0))
+
+    def alive(self) -> bool:
+        return self.proc.poll() is None
+
+    def stop(self) -> None:
+        if self.alive():
+            self.proc.terminate()
+            try:
+                self.proc.wait(timeout=10)
+            except subprocess.TimeoutExpired:
+                self.proc.kill()
+        self.status_path.unlink(missing_ok=True)
+
+
+class GameServerSupervisor:
+    def __init__(self) -> None:
+        self._servers: dict[str, _WorldServer] = {}
+        self._lock = asyncio.Lock()
+        self._reaper: asyncio.Task | None = None
+        self._runtime_dir = Path(tempfile.gettempdir()) / "agp-game-servers"
+        self._runtime_dir.mkdir(parents=True, exist_ok=True)
+
+    # ── lifecycle ────────────────────────────────────────────────────────
+    def start(self) -> None:
+        if not settings.GAME_SERVERS_ENABLED:
+            return
+        if self._reaper is None or self._reaper.done():
+            self._reaper = asyncio.create_task(self._reap_loop())
+
+    async def shutdown(self) -> None:
+        if self._reaper:
+            self._reaper.cancel()
+        async with self._lock:
+            for srv in list(self._servers.values()):
+                srv.stop()
+            self._servers.clear()
+
+    # ── join ─────────────────────────────────────────────────────────────
+    async def ensure_server(self, world_id: str) -> dict:
+        """Return ``{"host", "port", "world_id"}`` for the world's dedicated
+        server, spawning it if needed. Raises RuntimeError if orchestration
+        is disabled or no port/engine is available."""
+        if not settings.GAME_SERVERS_ENABLED:
+            raise RuntimeError("game servers are not enabled on this backend")
+
+        async with self._lock:
+            srv = self._servers.get(world_id)
+            if srv is not None and not srv.alive():
+                srv.stop()
+                srv = None
+                del self._servers[world_id]
+
+            if srv is None:
+                srv = self._spawn(world_id)
+                self._servers[world_id] = srv
+                # Give the engine a moment to bind the ENet port before we
+                # hand the address to a client.
+                await self._await_port(srv.port)
+
+            srv.last_join = time.time()
+            return {"host": settings.GAME_SERVER_HOST, "port": srv.port, "world_id": world_id}
+
+    # ── internals ────────────────────────────────────────────────────────
+    def _spawn(self, world_id: str) -> _WorldServer:
+        port = self._free_port()
+        status_path = self._runtime_dir / f"world_{world_id}_{port}.json"
+        status_path.unlink(missing_ok=True)
+        cmd = [
+            settings.GODOT_BIN, "--headless",
+            "--path", settings.GAME_PROJECT_DIR,
+            "res://scenes/server.tscn", "--",
+            "--port", str(port),
+            "--world", str(world_id),
+            "--status-file", str(status_path),
+        ]
+        proc = subprocess.Popen(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        return _WorldServer(world_id=world_id, port=port, proc=proc, status_path=status_path)
+
+    def _free_port(self) -> int:
+        used = {s.port for s in self._servers.values()}
+        for p in range(settings.GAME_SERVER_PORT_MIN, settings.GAME_SERVER_PORT_MAX + 1):
+            if p in used:
+                continue
+            with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
+                try:
+                    s.bind(("0.0.0.0", p))
+                    return p
+                except OSError:
+                    continue
+        raise RuntimeError("no free game-server port in the configured range")
+
+    async def _await_port(self, port: int, timeout: float = 8.0) -> None:
+        deadline = time.time() + timeout
+        while time.time() < deadline:
+            # ENet is UDP; a bind failure means something (our server) has it.
+            with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
+                try:
+                    s.bind(("0.0.0.0", port))
+                except OSError:
+                    return
+            await asyncio.sleep(0.25)
+
+    async def _reap_loop(self) -> None:
+        try:
+            while True:
+                await asyncio.sleep(30)
+                async with self._lock:
+                    now = time.time()
+                    for wid, srv in list(self._servers.items()):
+                        if not srv.alive():
+                            srv.stop()
+                            del self._servers[wid]
+                            continue
+                        idle_for = now - srv.last_join
+                        if idle_for > settings.GAME_SERVER_IDLE_TIMEOUT_SECONDS and srv.player_count() == 0:
+                            srv.stop()
+                            del self._servers[wid]
+        except asyncio.CancelledError:
+            pass
+
+    def debug_state(self) -> list[dict]:
+        return [
+            {
+                "world_id": s.world_id, "port": s.port, "alive": s.alive(),
+                "players": s.player_count(), "uptime_s": round(time.time() - s.started_at),
+            }
+            for s in self._servers.values()
+        ]
+
+
+supervisor = GameServerSupervisor()

backend/tests/conftest.py

@@ -1,38 +1,174 @@
-"""Shared pytest fixtures.
+"""Shared pytest fixtures + hermetic-DB bootstrap.
 
-The auth integration tests hit the *real* Postgres database (per
-``DATABASE_URL``), so they persist data between runs.  Without cleanup a
-second run of the suite fails with 409 conflicts because the users it
-registered on the first run already exist.  The session-scoped fixture below
-truncates all application tables once before the first test, making the suite
-re-runnable.
+The integration tests hit a real Postgres (Postgres-specific types: JSONB,
+native ENUMs). To make ``cd backend && pytest`` work from a clean checkout
+with no manual setup, ``pytest_configure`` below brings up an ephemeral
+Postgres via docker compose and runs the migrations IF ``DATABASE_URL`` is
+not already pointing at a reachable database. When it is (dev loop, or the
+checkpoint runner which stands the DB up itself), that path is skipped and
+the existing database is reused.
 
-Truncation order doesn't strictly matter because ``CASCADE`` follows foreign
-keys, but the tables are listed explicitly for clarity.
+If Docker isn't available and no DB is reachable, the whole DB-backed suite
+is skipped with a clear message rather than erroring out 60+ times.
 """
 
 import asyncio
+import os
+import socket
+import subprocess
+import sys
+import time
+from pathlib import Path
+from urllib.parse import urlsplit
 
 import pytest
 from sqlalchemy import text
-from sqlalchemy.ext.asyncio import create_async_engine
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+from sqlalchemy.pool import NullPool
 
 from app.config import settings
+from app.database import get_db
+from app.main import app
 
-TEST_TABLES = ("assets", "worlds", "sessions", "refresh_tokens", "users")
+TEST_TABLES = ("avatar_loadouts", "assets", "worlds", "sessions", "refresh_tokens", "users")
+
+BACKEND_DIR = Path(__file__).resolve().parents[1]
+_COMPOSE_PROJECT = "agp-pytest"
+_EPHEMERAL_PG_PORT = 25432
+
+# Set by _ensure_database() when it starts a container it owns; torn down in
+# pytest_unconfigure.
+_started_container = False
+_db_unavailable_reason: str | None = None
+
+
+def _port_open(host: str, port: int, timeout: float = 1.0) -> bool:
+    try:
+        with socket.create_connection((host, port), timeout=timeout):
+            return True
+    except OSError:
+        return False
+
+
+def _db_reachable(url: str) -> bool:
+    parts = urlsplit(url)
+    return _port_open(parts.hostname or "localhost", parts.port or 5432)
+
+
+def _run(cmd: list[str], **kw) -> subprocess.CompletedProcess:
+    return subprocess.run(cmd, cwd=BACKEND_DIR, capture_output=True, text=True, **kw)
+
+
+def pytest_configure(config):
+    global _started_container, _db_unavailable_reason
+
+    if _db_reachable(settings.DATABASE_URL):
+        return  # dev loop / checkpoint runner already provided one
+
+    if not _run(["docker", "--version"]).returncode == 0:
+        _db_unavailable_reason = (
+            "no reachable DATABASE_URL and docker is unavailable -- run the "
+            "checkpoint suite (scripts/run_checkpoint_tests.py) or start Postgres "
+            "manually"
+        )
+        return
+
+    env = os.environ.copy()
+    env["COMPOSE_PROJECT_NAME"] = _COMPOSE_PROJECT
+    env["POSTGRES_HOST_PORT"] = str(_EPHEMERAL_PG_PORT)
+    env["POSTGRES_PORT"] = str(_EPHEMERAL_PG_PORT)
+    up = _run(["docker", "compose", "up", "-d", "postgres"], env=env)
+    if up.returncode != 0:
+        _db_unavailable_reason = f"docker compose up postgres failed:\n{up.stderr[-800:]}"
+        return
+    _started_container = True
+
+    for _ in range(30):
+        r = _run(
+            ["docker", "compose", "exec", "-T", "postgres",
+             "pg_isready", "-U", "agp_user", "-d", "agp_db"],
+            env=env,
+        )
+        if r.returncode == 0:
+            break
+        time.sleep(1)
+    else:
+        _db_unavailable_reason = "ephemeral Postgres never became ready"
+        return
+
+    url = f"postgresql+asyncpg://agp_user:agp_password@localhost:{_EPHEMERAL_PG_PORT}/agp_db"
+    os.environ["DATABASE_URL"] = url
+    settings.DATABASE_URL = url
+
+    mig = _run([sys.executable, "-m", "alembic", "upgrade", "head"],
+               env={**os.environ, "DATABASE_URL": url})
+    if mig.returncode != 0:
+        _db_unavailable_reason = f"alembic upgrade head failed:\n{mig.stderr[-800:]}"
+
+
+def pytest_unconfigure(config):
+    if not _started_container:
+        return
+    env = os.environ.copy()
+    env["COMPOSE_PROJECT_NAME"] = _COMPOSE_PROJECT
+    env["POSTGRES_HOST_PORT"] = str(_EPHEMERAL_PG_PORT)
+    env["POSTGRES_PORT"] = str(_EPHEMERAL_PG_PORT)
+    _run(["docker", "compose", "down", "-v"], env=env)
 
 
 @pytest.fixture(scope="session", autouse=True)
 def _reset_database():
     """Truncate all application tables once per test session."""
+    if _db_unavailable_reason:
+        pytest.skip(_db_unavailable_reason, allow_module_level=True)
 
     async def _truncate() -> None:
         engine = create_async_engine(settings.DATABASE_URL)
         async with engine.begin() as conn:
-            await conn.execute(
-                text(f"TRUNCATE TABLE {', '.join(TEST_TABLES)} CASCADE")
-            )
+            await conn.execute(text(f"TRUNCATE TABLE {', '.join(TEST_TABLES)} CASCADE"))
         await engine.dispose()
 
     asyncio.run(_truncate())
     yield
+
+
+@pytest.fixture(autouse=True)
+def _reset_rate_limiter():
+    """Every TestClient request looks like the same client IP, so the
+    per-IP auth limiter would trip mid-suite. Clear it between tests; the
+    dedicated rate-limit test disables this to exercise the real behaviour.
+    """
+    from app import rate_limit
+    rate_limit.reset_all()
+    yield
+
+
+@pytest.fixture(autouse=True)
+def _override_db():
+    """Override get_db so the app uses a fresh session per test.
+
+    Deliberately does NOT reuse app.database's shared engine: FastAPI's
+    (sync) TestClient runs each request through anyio's blocking-portal
+    machinery, which can hand different requests different event loops.
+    asyncpg connections are bound to the loop they were created on, so
+    reusing one from the shared pool across requests raises "attached to a
+    different loop" the moment a test makes more than one request. NullPool
+    sidesteps it: every checkout is a brand-new connection.
+    """
+    test_engine = create_async_engine(settings.DATABASE_URL, poolclass=NullPool)
+    test_session_factory = async_sessionmaker(test_engine, expire_on_commit=False)
+
+    async def _get_db():
+        async_session = test_session_factory()
+        try:
+            yield async_session
+            await async_session.commit()
+        except Exception:
+            await async_session.rollback()
+            raise
+        finally:
+            await async_session.close()
+
+    app.dependency_overrides[get_db] = _get_db
+    yield
+    app.dependency_overrides.clear()

backend/tests/test_auth_age_gate.py

@@ -3,92 +3,102 @@
 from datetime import date, timedelta
 
 import pytest
+from fastapi.testclient import TestClient
 
-from app.routers.auth import calculate_age
+from app.main import app
+from app.routers.auth import calculate_age, MIN_AGE, RegisterRequest
 
 
 class TestCalculateAge:
     """Unit tests for the calculate_age helper."""
 
     def test_exactly_18(self):
-        """A person born exactly 18 years ago today is 18."""
-        today = date(2025, 6, 15)
+        today = date(2026, 6, 15)
         dob = today.replace(year=today.year - 18)
         assert calculate_age(dob, today=today) == 18
 
     def test_just_turned_18(self):
-        """A person who turned 18 yesterday is 18."""
-        today = date(2025, 6, 15)
+        today = date(2026, 6, 15)
         dob = today.replace(year=today.year - 18) - timedelta(days=1)
         assert calculate_age(dob, today=today) == 18
 
     def test_one_day_short_of_18(self):
-        """A person born one day after their 18th birthday is 17."""
-        today = date(2025, 6, 15)
+        today = date(2026, 6, 15)
         dob = today.replace(year=today.year - 18) + timedelta(days=1)
         assert calculate_age(dob, today=today) == 17
 
-    def test_17_years_old(self):
-        """A person who is 17 years old today is 17."""
-        today = date(2025, 6, 15)
-        dob = date(2008, 6, 15)
-        assert calculate_age(dob, today=today) == 17
+    def test_leap_day_birthday_before(self):
+        assert calculate_age(date(2000, 2, 29), today=date(2024, 2, 28)) == 23
 
-    def test_65_years_old(self):
-        """A person who is 65 is correctly calculated."""
-        today = date(2025, 6, 15)
-        dob = today.replace(year=today.year - 65)
-        assert calculate_age(dob, today=today) == 65
-
-    def test_newborn(self):
-        """A newborn is 0."""
-        today = date(2025, 6, 15)
-        dob = today
-        assert calculate_age(dob, today=today) == 0
-
-    def test_birthday_not_yet_this_year(self):
-        """Person born Dec 31, 2000 — on Jan 1, 2025 they are still 24."""
-        dob = date(2000, 12, 31)
-        assert calculate_age(dob, today=date(2025, 1, 1)) == 24
-
-    def test_birthday_today(self):
-        """Person born Dec 31, 2000 — on Dec 31, 2024 they turn 24."""
-        dob = date(2000, 12, 31)
-        assert calculate_age(dob, today=date(2024, 12, 31)) == 24
+    def test_leap_day_birthday_after(self):
+        assert calculate_age(date(2000, 2, 29), today=date(2024, 3, 1)) == 24
 
 
-class TestRegisterRequestOver18Field:
-    """Tests for RegisterRequest's over_18 field.
+class TestRegisterRequestDob:
+    def test_dob_parsed_from_iso_string(self):
+        req = RegisterRequest(username="u", email="u@example.com", password="p",
+                              date_of_birth="1990-01-01")
+        assert req.date_of_birth == date(1990, 1, 1)
 
-    Replaces TestRegisterRequestDateValidation -- date_of_birth and its
-    field_validator were removed from RegisterRequest 2026-08-20 (interim
-    simplification: a plain client-side over_18 confirmation instead of
-    collecting/validating an actual date of birth; see calculate_age's
-    own docstring in app/routers/auth.py for why that function is still
-    here even though this endpoint no longer calls it). There's no date
-    format left to validate, so the equivalent coverage is just: the
-    field exists, is a real bool, and is required."""
-
-    def test_over_18_true_accepted(self):
-        from app.routers.auth import RegisterRequest
-
-        req = RegisterRequest(username="u", email="u@example.com", password="p", over_18=True)
-        assert req.over_18 is True
-
-    def test_over_18_false_accepted(self):
-        """False is a valid value at the schema level -- the endpoint,
-        not the schema, is what rejects it (see
-        TestRegister::test_register_rejects_not_over_18 in
-        test_auth_endpoints.py)."""
-        from app.routers.auth import RegisterRequest
-
-        req = RegisterRequest(username="u", email="u@example.com", password="p", over_18=False)
-        assert req.over_18 is False
-
-    def test_over_18_missing_rejected(self):
-        """over_18 has no default -- omitting it entirely is a validation error."""
-        from app.routers.auth import RegisterRequest
-        from pydantic import ValidationError
-
-        with pytest.raises(ValidationError):
+    def test_dob_required(self):
+        with pytest.raises(Exception):
             RegisterRequest(username="u", email="u@example.com", password="p")
+
+    def test_bad_dob_string_rejected(self):
+        with pytest.raises(Exception):
+            RegisterRequest(username="u", email="u@example.com", password="p",
+                            date_of_birth="not-a-date")
+
+
+class TestRegisterAgeGate:
+    """End-to-end: the /register endpoint computes age from the DOB."""
+
+    def _dob_for_age(self, years: int) -> str:
+        return (date.today().replace(year=date.today().year - years)).isoformat()
+
+    def test_adult_accepted(self):
+        client = TestClient(app)
+        r = client.post("/api/auth/register", json={
+            "username": "gate_adult", "email": "gate_adult@e.com",
+            "password": "secret123", "date_of_birth": self._dob_for_age(25),
+        })
+        assert r.status_code == 201, r.text
+
+    def test_minor_rejected(self):
+        client = TestClient(app)
+        r = client.post("/api/auth/register", json={
+            "username": "gate_minor", "email": "gate_minor@e.com",
+            "password": "secret123", "date_of_birth": self._dob_for_age(15),
+        })
+        assert r.status_code == 403
+        assert str(MIN_AGE) in r.json()["detail"]
+
+    def test_exactly_18_accepted(self):
+        client = TestClient(app)
+        r = client.post("/api/auth/register", json={
+            "username": "gate_18", "email": "gate_18@e.com",
+            "password": "secret123",
+            "date_of_birth": (date.today().replace(year=date.today().year - 18) - timedelta(days=1)).isoformat(),
+        })
+        assert r.status_code == 201, r.text
+
+    def test_future_dob_rejected(self):
+        client = TestClient(app)
+        r = client.post("/api/auth/register", json={
+            "username": "gate_future", "email": "gate_future@e.com",
+            "password": "secret123", "date_of_birth": "2999-01-01",
+        })
+        assert r.status_code == 400
+
+    def test_dob_is_stored(self):
+        client = TestClient(app)
+        dob = self._dob_for_age(30)
+        reg = client.post("/api/auth/register", json={
+            "username": "gate_stored", "email": "gate_stored@e.com",
+            "password": "secret123", "date_of_birth": dob,
+        })
+        assert reg.status_code == 201
+        me = client.get("/api/auth/me", headers={
+            "Authorization": f"Bearer {reg.json()['access_token']}"
+        })
+        assert me.json()["date_of_birth"] == dob

backend/tests/test_auth_endpoints.py

@@ -73,7 +73,7 @@ class TestRegister:
                 "username": "newuser",
                 "email": "new@example.com",
                 "password": "secret123",
-                "over_18": True,
+                "date_of_birth": "1990-01-01",
             },
         )
         assert resp.status_code == 201
@@ -81,26 +81,23 @@ class TestRegister:
         assert "access_token" in data
         assert data["token_type"] == "bearer"
 
-    def test_register_rejects_not_over_18(self):
-        """over_18=false gets a 400 with a detail message.
-
-        The interim design (2026-08-20) trusts a client-side boolean
-        confirmation instead of collecting/validating an actual date of
-        birth -- this only checks that the flag is respected, not real
-        age math (there's no date to verify against anymore). Real DOB
-        collection/verification may come back in a future pass."""
+    def test_register_rejects_under_18(self):
+        """A DOB that computes to under 18 gets a 403 (see test_auth_age_gate
+        for the age-math coverage)."""
+        from datetime import date
         client = TestClient(app)
+        minor_dob = date.today().replace(year=date.today().year - 14).isoformat()
         resp = client.post(
             "/api/auth/register",
             json={
                 "username": "kid",
                 "email": "kid@example.com",
                 "password": "secret123",
-                "over_18": False,
+                "date_of_birth": minor_dob,
             },
         )
-        assert resp.status_code == 400
-        assert "18 or older" in resp.json()["detail"]
+        assert resp.status_code == 403
+        assert "at least 18" in resp.json()["detail"]
 
     def test_register_rejects_duplicate_username(self):
         """Registering the same username twice returns 409."""
@@ -112,7 +109,7 @@ class TestRegister:
                 "username": "duplicate",
                 "email": "dup1@example.com",
                 "password": "secret123",
-                "over_18": True,
+                "date_of_birth": "1990-01-01",
             },
         )
         # Second registration with same username, different email
@@ -122,7 +119,7 @@ class TestRegister:
                 "username": "duplicate",
                 "email": "dup2@example.com",
                 "password": "secret123",
-                "over_18": True,
+                "date_of_birth": "1990-01-01",
             },
         )
         assert resp.status_code == 409
@@ -137,7 +134,7 @@ class TestRegister:
                 "username": "user1",
                 "email": "same@example.com",
                 "password": "secret123",
-                "over_18": True,
+                "date_of_birth": "1990-01-01",
             },
         )
         resp = client.post(
@@ -146,19 +143,14 @@ class TestRegister:
                 "username": "user2",
                 "email": "same@example.com",
                 "password": "secret123",
-                "over_18": True,
+                "date_of_birth": "1990-01-01",
             },
         )
         assert resp.status_code == 409
         assert "Email already registered" in resp.json()["detail"]
 
-    def test_register_missing_over_18(self):
-        """Missing the required over_18 field returns 422.
-
-        Replaces the old test_register_invalid_date_format -- there's no
-        date format to get wrong anymore (no date field at all), so the
-        closest equivalent "malformed request" case is the required
-        over_18 boolean being absent entirely."""
+    def test_register_missing_dob(self):
+        """Missing the required date_of_birth field returns 422."""
         client = TestClient(app)
         resp = client.post(
             "/api/auth/register",
@@ -189,7 +181,7 @@ class TestLogin:
                 "username": username,
                 "email": email,
                 "password": password,
-                "over_18": True,
+                "date_of_birth": "1990-01-01",
             },
         )
         assert resp.status_code == 201

backend/tests/test_auth_expired_token.py

@@ -93,7 +93,7 @@ def _register_user(client: TestClient, username: str) -> str:
             "username": username,
             "email": f"{username}@example.com",
             "password": "secret123",
-            "over_18": True,
+            "date_of_birth": "1990-01-01",
         },
     )
     assert resp.status_code == 201

backend/tests/test_avatar_loadout.py

@@ -0,0 +1,91 @@
+"""Integration tests for GET/PUT /api/avatar/loadout.
+
+Hits the real app against the configured Postgres (same contract as the
+other integration tests -- migrations applied first).
+"""
+
+import pytest
+from fastapi.testclient import TestClient
+
+from app.main import app
+from app.models.avatar_loadout import DEFAULT_LOADOUT
+
+
+def _auth_headers(client: TestClient, username: str) -> dict:
+    resp = client.post(
+        "/api/auth/register",
+        json={
+            "username": username,
+            "email": f"{username}@example.com",
+            "password": "secret123",
+            "date_of_birth": "1990-01-01",
+        },
+    )
+    assert resp.status_code == 201, resp.text
+    return {"Authorization": f"Bearer {resp.json()['access_token']}"}
+
+
+class TestGetLoadout:
+    def test_new_user_gets_the_default(self):
+        client = TestClient(app)
+        headers = _auth_headers(client, "av_default")
+        resp = client.get("/api/avatar/loadout", headers=headers)
+        assert resp.status_code == 200
+        body = resp.json()
+        assert body["is_default"] is True
+        assert body["data"] == DEFAULT_LOADOUT
+
+    def test_requires_auth(self):
+        client = TestClient(app)
+        assert client.get("/api/avatar/loadout").status_code == 401
+
+
+class TestPutLoadout:
+    def test_save_then_read_back(self):
+        client = TestClient(app)
+        headers = _auth_headers(client, "av_save")
+        loadout = {
+            "base_body": "base_human_male_01",
+            "slots": {"hair": "hair_mohawk_01", "accessory": ["accessory_belt_01"]},
+            "skin_tone": {"r": 0.8, "g": 0.6, "b": 0.5, "a": 1.0},
+        }
+        put = client.put("/api/avatar/loadout", headers=headers, json={"data": loadout})
+        assert put.status_code == 200, put.text
+        assert put.json()["is_default"] is False
+
+        got = client.get("/api/avatar/loadout", headers=headers)
+        assert got.status_code == 200
+        assert got.json()["is_default"] is False
+        assert got.json()["data"] == loadout
+
+    def test_put_is_idempotent_replace(self):
+        client = TestClient(app)
+        headers = _auth_headers(client, "av_replace")
+        client.put(
+            "/api/avatar/loadout", headers=headers,
+            json={"data": {"base_body": "base_human_male_01", "slots": {"hair": "hair_mohawk_01"}}},
+        )
+        second = {"base_body": "base_human_male_01", "slots": {"chest": "chest_bandit_01"}}
+        client.put("/api/avatar/loadout", headers=headers, json={"data": second})
+        got = client.get("/api/avatar/loadout", headers=headers)
+        assert got.json()["data"] == second
+
+    def test_rejects_missing_base_body(self):
+        client = TestClient(app)
+        headers = _auth_headers(client, "av_nobase")
+        resp = client.put("/api/avatar/loadout", headers=headers, json={"data": {"slots": {}}})
+        assert resp.status_code == 422
+
+    def test_rejects_non_object_slots(self):
+        client = TestClient(app)
+        headers = _auth_headers(client, "av_badslots")
+        resp = client.put(
+            "/api/avatar/loadout", headers=headers,
+            json={"data": {"base_body": "base_human_male_01", "slots": "nope"}},
+        )
+        assert resp.status_code == 422
+
+    def test_requires_auth(self):
+        client = TestClient(app)
+        resp = client.put("/api/avatar/loadout", json={"data": {"base_body": "x", "slots": {}}})
+        assert resp.status_code == 401

backend/tests/test_rate_limit.py

@@ -0,0 +1,56 @@
+"""The auth endpoints are rate-limited per client IP."""
+
+import pytest
+from fastapi.testclient import TestClient
+
+from app import rate_limit
+from app.config import settings
+from app.main import app
+
+
+@pytest.fixture(autouse=True)
+def _clean_limiter():
+    # This module tests the limiter itself: force it on (the checkpoint
+    # runner disables it suite-wide via RATE_LIMIT_ENABLED) and start each
+    # test from an empty window.
+    prev = settings.RATE_LIMIT_ENABLED
+    settings.RATE_LIMIT_ENABLED = True
+    rate_limit.reset_all()
+    yield
+    rate_limit.reset_all()
+    settings.RATE_LIMIT_ENABLED = prev
+
+
+def test_login_is_limited_after_the_threshold():
+    client = TestClient(app)
+    codes = []
+    for i in range(15):
+        r = client.post("/api/auth/login", data={"username": f"nobody{i}", "password": "x"})
+        codes.append(r.status_code)
+    # First 10 get through to the (failing) auth check; the rest are 429.
+    assert codes[:10] == [401] * 10
+    assert 429 in codes[10:]
+    assert codes[-1] == 429
+
+
+def test_register_shares_the_same_bucket():
+    client = TestClient(app)
+    # Burn the budget on login...
+    for i in range(10):
+        client.post("/api/auth/login", data={"username": f"x{i}", "password": "y"})
+    # ...register from the same IP is now blocked too.
+    r = client.post("/api/auth/register", json={
+        "username": "rl_user", "email": "rl@e.com",
+        "password": "secret123", "date_of_birth": "1990-01-01",
+    })
+    assert r.status_code == 429
+    assert "Retry-After" in r.headers
+
+
+def test_limiter_window_is_per_key():
+    limiter = rate_limit.SlidingWindowLimiter(max_hits=2, window_seconds=60)
+    limiter.check("a")
+    limiter.check("a")
+    with pytest.raises(Exception):
+        limiter.check("a")
+    limiter.check("b")  # different key, unaffected

backend/tests/test_refresh_endpoint.py

@@ -59,7 +59,7 @@ class TestRefresh:
                 "username": username,
                 "email": email,
                 "password": password,
-                "over_18": True,
+                "date_of_birth": "1990-01-01",
             },
         )
         assert resp.status_code == 201
@@ -143,7 +143,7 @@ class TestRefresh:
                 "username": "refep_loginrefuser",
                 "email": "loginref@example.com",
                 "password": "secret123",
-                "over_18": True,
+                "date_of_birth": "1990-01-01",
             },
         )
         # Login to get a refresh token

backend/tests/test_world_join.py

@@ -0,0 +1,54 @@
+"""Tests for POST /api/worlds/{id}/join.
+
+The happy path spawns a real Godot process, so it's covered by a manual /
+checkpoint integration test, not here. These cover the envelope: auth,
+visibility, and the 503 when orchestration is disabled (the default).
+"""
+
+import pytest
+from fastapi.testclient import TestClient
+
+from app.main import app
+
+
+def _auth(client: TestClient, name: str) -> tuple[dict, int]:
+    r = client.post("/api/auth/register", json={
+        "username": name, "email": f"{name}@e.com", "password": "secret123", "date_of_birth": "1990-01-01",
+    })
+    assert r.status_code == 201, r.text
+    headers = {"Authorization": f"Bearer {r.json()['access_token']}"}
+    me = client.get("/api/users/me", headers=headers)
+    return headers, me.json()["id"]
+
+
+def _make_world(client: TestClient, headers: dict, visibility: str = "public") -> int:
+    r = client.post("/api/worlds/", headers=headers, json={"name": "W", "visibility": visibility})
+    assert r.status_code == 201, r.text
+    return r.json()["id"]
+
+
+class TestJoinWorld:
+    def test_requires_auth(self):
+        client = TestClient(app)
+        assert client.post("/api/worlds/1/join").status_code == 401
+
+    def test_unknown_world_is_404(self):
+        client = TestClient(app)
+        headers, _ = _auth(client, "join_404")
+        assert client.post("/api/worlds/999999/join", headers=headers).status_code == 404
+
+    def test_private_world_of_another_user_is_404(self):
+        client = TestClient(app)
+        owner_headers, _ = _auth(client, "join_owner")
+        wid = _make_world(client, owner_headers, "private")
+        other_headers, _ = _auth(client, "join_other")
+        assert client.post(f"/api/worlds/{wid}/join", headers=other_headers).status_code == 404
+
+    def test_disabled_orchestration_returns_503(self):
+        # GAME_SERVERS_ENABLED defaults to False in tests.
+        client = TestClient(app)
+        headers, _ = _auth(client, "join_503")
+        wid = _make_world(client, headers, "public")
+        r = client.post(f"/api/worlds/{wid}/join", headers=headers)
+        assert r.status_code == 503
+        assert "not enabled" in r.json()["detail"]

docs/architecture/avatar.md

@@ -449,6 +449,37 @@ The catalog is a JSON manifest mapping asset ids to metadata and resource paths:
 
 ---
 
+## 9a. Loadout Persistence (implemented, PC3 Phase 1)
+
+**Storage.** One row per user in `avatar_loadouts` (`user_id` PK/FK,
+`data` JSONB, timestamps). The entire loadout is stored as a single JSON
+document in the exact shape the client's `AvatarLoadout.to_json()` emits
+(`{"base_body": str, "slots": {...}, "skin_tone"?: {r,g,b,a}}`) rather than
+exploded into columns.
+
+**Why one JSON blob, not columns.** The server has no copy of the asset
+catalog (`assets/avatars/catalog.json` ships with the client). It therefore
+cannot meaningfully validate *which* asset belongs in *which* slot, whether
+an asset exists, or slot-exclusivity rules — that validation stays on the
+client (`AvatarLoadout.validate()` against the loaded `AvatarCatalog`). The
+server enforces only the envelope: a JSON object with a non-empty string
+`base_body`, an object `slots`, and a sane size cap. Keeping the schema
+opaque to the server also means catalog/loadout-shape changes don't need a
+migration.
+
+**Endpoints** (`/api/avatar`, bearer auth):
+
+| Method | Path | Behaviour |
+|---|---|---|
+| `GET` | `/loadout` | The user's saved loadout, or the server default (`{"base_body": "base_human_male_01", "slots": {}}`, `is_default: true`) if they have never saved one. |
+| `PUT` | `/loadout` | Replace the user's loadout (full document, not a patch). |
+
+**Defaults.** A brand-new account has no row; `GET` returns
+`models.avatar_loadout.DEFAULT_LOADOUT` with `is_default: true` so the client
+can distinguish "never customised" from "customised back to the base look".
+
+---
+
 ## 10. Summary
 
 | Concern                | Decision                                              |

docs/architecture/content_moderation.md

@@ -227,18 +227,33 @@ An account has an **age verification status**:
 
 ### 5.2 Tier 1 — Self-Declaration Flow
 
+> **Implemented, PC3 Phase 3.** `POST /api/auth/register` now takes a real
+> `date_of_birth` (ISO `YYYY-MM-DD`), not the throwaway `over_18` boolean it
+> had before. The server computes age (`auth.calculate_age`) and rejects
+> anyone under `auth.MIN_AGE` (18) with a **403** — this platform is
+> adults-only, so there is no "minor, restricted" tier here (the 13+ rows
+> below are the general design, not the current gate). A future-in-the-past
+> or nonsensical date is a **400**. The DOB is stored on the user row and
+> surfaced only back to that user (`/api/auth/me`), never to other players.
+>
+> **Limitation, stated plainly:** this is still self-attested — a determined
+> user can enter a false DOB. It is a concrete, stored, legally-meaningful
+> data point (matching how most platforms gate before adding hard checks)
+> and the seam for Tier 2. Encryption-at-rest for the DOB column and the
+> Tier 2 ID-check hook below are **not yet implemented**.
+
 ```
 User submits { date_of_birth }
         │
         ▼
-Server validates format & plausibility (age 13–120, not in future)
+Server validates format & plausibility (real date, not in future)
         │
         ▼
 Compute age from DOB
         │
         ▼
-age >= 18 ──► status = self_declared (adult)
-age >= 13 ──► status = self_declared (minor, restricted)
+age >= 18 ──► status = self_declared (adult)   ← the current gate
+age >= 13 ──► status = self_declared (minor, restricted)   ← design only
 age <  13 ──► status = rejected (below minimum platform age)
 ```
 

docs/architecture/networking.md

@@ -237,6 +237,62 @@ snapshot_state:
 
 ---
 
+## 7a. Server Orchestration (implemented, PC3 Phase 2)
+
+**One dedicated server process per world**, spawned on demand.
+
+```
+client                    backend (single worker)              host
+  │  POST /api/worlds/{id}/join  (bearer JWT)                    │
+  │ ───────────────────────────▶ GameServerSupervisor           │
+  │                              ensure_server(world_id):        │
+  │                                if none running for world ─── spawn:
+  │                                                              godot --headless
+  │                                                              res://scenes/server.tscn --
+  │                                                              --port <p> --world <id>
+  │                                                              --status-file <path>
+  │  ◀─────────────────────────── { host, port, world_id }       │
+  │                                                              │
+  │  ENet connect  host:port ───────────────────────────────────▶ dedicated server
+```
+
+- **Supervisor** (`backend/app/services/game_servers.py`): in-process singleton,
+  so the backend MUST run single-worker. Keys servers by `world_id`. Allocates
+  ports from `GAME_SERVER_PORT_MIN..MAX`. A background reaper kills a world's
+  server once its **status file** (`{players, tick, updated}`, rewritten by the
+  server ~1×/s) reports `players == 0` for `GAME_SERVER_IDLE_TIMEOUT_SECONDS`.
+  No crash-restart — the next join respawns.
+- **Enable flag:** `GAME_SERVERS_ENABLED` (default off). The checkpoint/playtest
+  launcher (`pm/checkpoint_ops.py`) turns it on, passes `GODOT_BIN`,
+  `GAME_PROJECT_DIR`, and `GAME_SERVER_HOST` (the LAN IP baked into the `.exe`).
+  A backend with it off returns **503** from `/join`, and the client falls back
+  to local single-player.
+- **Per-world content:** all worlds currently load the same test level (M2/M7
+  work). `world_id` still scopes a distinct process + session.
+
+### 7b. Client play path
+
+`world_list.gd` → `POST /join` → `Session.begin(world_id, host, port)` →
+load `game.tscn`. `game.gd` sees `Session.active` and connects a
+`NetworkClient`:
+
+- **Local player** keeps predicting with its own collision-aware
+  `CharacterBody3D` (`player.gd`) — that *is* the prediction. Its input frame
+  (`player.net_input`) is forwarded to the server every physics tick.
+- **Correction backstop:** if the local position drifts from the server's by
+  more than `CORRECTION_THRESHOLD` (1.5 m — generous; catches teleport / a wall
+  walked through / real desync, not prediction noise) it snaps.
+- **Remote players:** rendered from snapshots, position lerped. *Appearance sync
+  is a follow-up* — remotes currently show as labelled capsules; the server
+  does not yet replicate avatar loadouts.
+- **Disconnect** → status message → back to the world list.
+
+The `NetworkClient`'s own flat-plane prediction + input-replay reconciliation
+(§5) is exercised by `smoke_test_network_client.gd`; the collision-aware game
+path above uses the lighter `send_input()` + drift-snap instead.
+
+---
+
 ## 8. Security & Anti-Cheat
 
 - **No client-authoritative gameplay values.** Clients only send *inputs* and

docs/checkpoints/PC3.md

@@ -0,0 +1,97 @@
+# Package Checkpoint 3 (PC3)
+
+> **Status: partial.** PC3's planned scope was M4-avatars + M5-multiplayer +
+> Foundation Hardening + M6–M10 (see `docs/build-plan-v1.md`). As of
+> 2026-09-05, **M4, M5, and most of Foundation Hardening are done and
+> checkpoint-verified**; M6–M10 have not been started. This doc records what
+> is real. Whether to call this "PC3" (redefined scope, M6–M10 → PC4) or keep
+> PC3 open is a user decision.
+
+Built by Claude directly (fleet offline), branch `pc3` → `main`.
+
+## What's real and verified (`scripts/run_checkpoint_tests.py`, all green)
+
+| Check | Result |
+|---|---|
+| Alembic migrations, fresh DB | PASS |
+| Backend `pytest` | 77/77 PASS (hermetic — auto-starts an ephemeral Postgres) |
+| Godot smoke tests (~16 files) | ALL PASS |
+| `smoke_test_network_client` (real dedicated server) | 4/4 PASS |
+| 2-player multiplayer (`run_multiplayer_2p_test.sh`) | PASS |
+| Fresh-clone boot (`verify_fresh_clone.sh`) | PASS |
+| Linux + Windows exports | Build as real ELF64 / PE32+ binaries |
+
+### M4 — Avatars in the game
+
+- Placeholder avatar pack (14 GLBs, rigged 24-bone base body + attachments)
+  generated by `scripts/tools/gen_placeholder_avatars.gd`. Real art is a
+  content swap — catalog paths are stable.
+- The avatar **loader was fixed** — it had never run against a real skeleton
+  (`Skeleton3D.has_bone()` isn't a Godot 4 method; the bone-copy dropped the
+  skin binding; attachments were parsed then discarded).
+- `avatar_visualizer.gd` **rewritten** — the old one referenced a loader API
+  that never existed and didn't compile.
+- Persistence: `avatar_loadouts` table + `GET/PUT /api/avatar/loadout`
+  (loadout stored as one JSON doc; server validates the envelope only).
+- Wired into gameplay: the in-world player renders as the assembled avatar
+  (not a capsule); the loadout is fetched at login; "Customize Avatar" from
+  the main menu saves through to the backend.
+- **Follow-up:** camera is still first-person, so the local player doesn't
+  see their own avatar much (third-person is a polish item); remote players'
+  avatar appearance is not replicated yet (they show as labelled capsules).
+
+### M5 — Real multiplayer
+
+- `server.gd` **actually runs a sim now** — loads the world level, spawns a
+  server player per peer, processes each peer's input queue in seq order at a
+  fixed 30 Hz, broadcasts full snapshots with a per-peer `last_seq`. (The
+  input queue was a no-op before.)
+- `network_client.gd` reconciliation **replays in-flight inputs** from the
+  authoritative state (drops acked ones), snaps only on real drift.
+- **Server orchestration** (`backend/app/services/game_servers.py`): one
+  headless Godot dedicated-server process per world, spawned on demand by
+  `POST /api/worlds/{id}/join`, port-allocated, with a status-file idle
+  reaper. Off by default; the playtest launcher (`checkpoint_ops.py`)
+  enables it.
+- **Client play path**: world browser → `/join` → `Session` → `game.tscn`
+  connects → local player predicts with collision, input forwarded, server
+  position is a drift backstop, remote players render from snapshots,
+  disconnect returns to the world list. Falls back to local single-player
+  when the backend has no orchestration.
+- **Verified**: two real client processes each `register → /join → play`,
+  hosted on an orchestrated server, see and move relative to each other
+  (`run_game_multiplayer_test.sh`).
+
+### Foundation Hardening
+
+- **Hermetic backend tests** — `cd backend && pytest` works from a clean
+  checkout (auto ephemeral Postgres + migrations, torn down after); skips
+  cleanly with a message if there's no Docker.
+- **Fresh-clone boot check** — `verify_fresh_clone.sh` exports a pristine
+  tree, imports from scratch, boots headless, fails on any script error.
+  Also fixed the root cause: a stale `.godot/global_script_class_cache.cfg`
+  was committed to the repo.
+- **Real age verification** — `/register` takes a date of birth (not a
+  checkbox), server computes age, 403 under 18. Still self-attested; the
+  limitation and the ID-check hook are documented
+  (`content_moderation.md` 5.2).
+- **Auth rate limiting** — 10 attempts / min / IP on `/register` + `/login`.
+- **CI workflow** — `.forgejo/workflows/checkpoint.yml` written, **not
+  running yet**: needs the operator to enable Forgejo Actions + register a
+  `host` runner (one-time; see `docs/ci.md`). Interim gate is
+  `run_checkpoint_tests.py` by hand / the dashboard.
+
+## Not in PC3 (planned but not started)
+
+- **M2** server-side world persistence
+- **M6** scripting sandbox
+- **M7** in-game editor
+- **M8** social / chat
+- **M9** economy
+- **M10** discovery
+
+## Playtest
+
+Same as PC2 — grab the exe from the dashboard's `/checkpoints`, backend
+pointed at it. New: with multiple people in the same world you now actually
+see each other move.

docs/ci.md

@@ -0,0 +1,50 @@
+# CI
+
+`.gitea/workflows/checkpoint.yml` runs the full checkpoint suite
+(`scripts/run_checkpoint_tests.py`: migrations on a fresh DB, backend
+`pytest`, all Godot smoke tests, the 2-player multiplayer test, and the
+fresh-clone boot check) on **every push to `main` and every PR**.
+
+## Status: live
+
+Set up 2026-09-05:
+
+- Gitea Actions enabled (`[actions] ENABLED = true` in
+  `/DATA/AppData/forgejo/gitea/conf/app.ini`, container restarted; a
+  timestamped `.bak` is next to it).
+- `act_runner` v0.2.13 registered as **`agp-host`** with label **`host`**
+  (host execution mode — jobs run directly on the AGP box, which already
+  has Docker, `~/godot/godot`, and Python). Lives in `~/act-runner/`.
+- Green on the first successful run (`d76bf4d`).
+
+The workflow uses **no JavaScript actions** (no `actions/checkout`), so the
+host needs no Node: checkout is a shallow `git fetch` from the local Gitea
+using the injected `${{ github.token }}`, and the suite runs in a venv the
+job builds (host Python is PEP-668 externally-managed).
+
+## Make the runner permanent (one command, needs sudo)
+
+The runner currently runs as a plain background process — it won't survive a
+reboot. A unit file is ready at `~/act-runner/act-runner.service`:
+
+```bash
+sudo cp ~/act-runner/act-runner.service /etc/systemd/system/
+sudo systemctl daemon-reload
+pkill -f 'act_runner daemon'          # stop the temporary background one
+sudo systemctl enable --now act-runner
+```
+
+## Interim / local
+
+```bash
+python scripts/run_checkpoint_tests.py
+```
+
+— also what `/checkpoint/<PC>` on the dashboard runs before a playtest build.
+
+## Security note
+
+A host-mode runner executes whatever a workflow says, directly on the box,
+as `daddy` (in the `docker` group). Fine for a single-maintainer private
+repo; revisit if the repo gets outside contributors (switch to a
+docker-mode runner or an isolated VM).

docs/testing/test_inventory.md

@@ -7,14 +7,17 @@ to know what "run the tests" actually checked.
 
 Run everything below in one shot with `scripts/run_checkpoint_tests.py`.
 
-Last verified against `main`: 2026-08-20 — full PC1 checkpoint run,
-migrations + pytest + all 7 Godot smoke tests + both platform exports, all
-clean. Real bugs found and fixed via real playtesting this same day (not
-caught by the checkpoint suite as it stood before today): the main menu
-had no way to actually open the login/register form, the world list's
-cards rendered at ~1px wide once real data existed, and navigating Play →
-Back logged the user out despite a still-valid session. All three are now
-covered by the smoke tests below so they can't silently regress.
+Last verified against `main`: 2026-08-21 — migrations + pytest + all 11
+Godot smoke tests, all clean. PC1's real playtest-found bugs (login form
+unreachable, 1px world cards, Play → Back losing the session) are covered
+by the smoke tests below so they can't silently regress. PC2 (basic
+playable world + character + movement) landed 2026-08-20/21 — see
+`docs/checkpoints/` once a PC2 record exists, and the three new smoke
+tests below (`smoke_test_test_level.gd`, `smoke_test_player.gd`,
+`smoke_test_enter_world.gd`) for what's actually verified. The avatar
+loader/customization system (`smoke_test_avatar_system.gd`) also landed
+2026-08-21 — real glTF-based loading with graceful failure on missing
+assets, verified since `assets/avatars/*.glb` model files don't exist yet.
 
 ## Backend — `backend/tests/` (pytest)
 
@@ -53,7 +56,10 @@ these yet):
 
 ## Godot client — `scripts/smoke_test_*.gd`
 
-**7 smoke tests merged into `main`.** Each needs a live backend —
+**12 smoke tests merged into `main`.** Ten need a live backend, one
+(`smoke_test_network_client.gd`) needs a live dedicated server instead,
+and one (`smoke_test_avatar_system.gd`) needs neither — it only exercises
+local catalog/loadout/loader logic. Backend-dependent tests read
 `AGP_API_BASE_URL` env var, falling back to the
 `application/agp/api_base_url` project setting (default
 `http://127.0.0.1:8000`) if unset.
@@ -67,6 +73,11 @@ these yet):
 | `smoke_test_main_menu_ui.gd` | Instantiates `main_menu.tscn`, confirms the auth panel starts hidden, and confirms a **real signal emission** on LoginButton/RegisterButton (not calling the handler method directly) actually opens it. This is the check that would have caught 2026-08-20's real bug: the auth panel and its logic were fully correct, but nothing in the scene was ever wired to open it, so Login/Register were completely unreachable from the UI. |
 | `smoke_test_main_menu_full_flow.gd` | Full click-through: open the register form, fill it exactly as a user would, submit, confirm Play actually becomes enabled, the welcome message shows, and the auth buttons hide themselves. Calls the submit handler directly (awaited) rather than via `auth_button.pressed.emit()` — see the note at the top of the file: a synthetic `.emit()` on an `await`-using handler doesn't get driven forward reliably in `--script`/SceneTree headless mode the way real GUI input event dispatch does, confirmed by comparing direct-call vs `.emit()` behavior. Not a bug in the actual click-driven flow, just a headless-test-harness quirk to route around when writing tests. |
 | `smoke_test_main_menu_back.gd` | Regression test for Play → Back logging the user out even with a valid token still held. Registers a user, loads `main_menu.tscn` (asserts it restores the authenticated state via a real `auth_state_ready` signal wait, not a frame-count guess), clicks Play → `world_list.tscn`, clicks Back → `main_menu.tscn`, and asserts the menu is still authenticated. Checks `WelcomeLabel.is_visible_in_tree()`, not just `.visible` — the label lives inside AuthPanel, so `.visible` alone is a false positive if the panel itself is hidden (a real bug briefly present: `_show_authenticated()` hid AuthPanel while claiming the welcome label was visible, which rendered nothing). |
+| `smoke_test_test_level.gd` | Loads `scenes/worlds/test_level.tscn` directly (the level is player-agnostic and self-contained per `docs/architecture/pc2_test_level.md` §4) and confirms it has real content: 5 props, a `DirectionalLight3D` ("Sun"), and a `WorldEnvironment` — not an empty void. |
+| `smoke_test_player.gd` | Loads `scenes/game.tscn` and confirms the player exists as a real `CharacterBody3D` with a `CollisionShape3D`+shape, a `CapsuleMesh`, and spawns at the level's `PlayerSpawn` marker position. Also asserts `JUMP_VELOCITY` is positive and a `Camera3D` exists and is `current` — both were real bugs found 2026-08-20/21 (jump velocity was negative, pushing the player down instead of up; no camera existed at all, so the game was unplayable even though the character could technically move). Structural checks only — real movement/jump *direction* correctness was verified separately via a throwaway headless physics simulation during development, not by an automated test that's part of this suite. |
+| `smoke_test_enter_world.gd` | The full PC2 path end to end: register → seed a real world → load `world_list.tscn` → click the real "Enter World" button on a real card (found by walking the card's children, not by index, so it doesn't silently pass if the card layout changes) → confirms `scenes/game.tscn` actually becomes `current_scene` with the player spawned at the level's `PlayerSpawn` marker → sends a real `KEY_ESCAPE` input event (not a direct method call) and confirms it returns to `world_list.tscn`. This is the test that proves "browse → enter → walk around → leave" actually works as one continuous flow, not just that each piece works in isolation. |
+| `smoke_test_network_client.gd` | **Real two-process integration test** for `scripts/network_client.gd` (client-side prediction + reconciliation, docs/architecture/networking.md §5) — needs an actual dedicated server running first: `godot --headless --path . scenes/server.tscn &`, *not* the usual HTTP backend. Connects a real `NetworkClient` over ENet, confirms local input prediction moves the player immediately (no waiting on a round trip), confirms real snapshots arrive and get processed, then deliberately desyncs the predicted position by 9999 units and confirms the very next snapshot corrects it back — the actual proof reconciliation logic works, not just that it never had to fire. Known simplification, stated in the script's own docstring: the server's snapshot doesn't currently echo back a per-peer "last input seq processed," so reconciliation corrects against the *most recent* prediction rather than true tick-exact rollback-and-replay (docs/architecture/networking.md §5.2 step 4) — a real, scoped follow-up once the server echoes that ack, not something faked here. |
+| `smoke_test_avatar_system.gd` | Confirms `AvatarSystem` is a real autoload, the committed `assets/avatars/catalog.json` actually parses, `get_assets_for_slot("base_body")` returns real entries, an `AvatarLoadout` can set `base_body` and equip a real catalog accessory, the loadout round-trips through `to_json()`/`load_loadout_from_json()`, and — since `assets/avatars/*.glb` model files don't exist yet — that `AvatarLoader.load_base_body()` against a real catalog entry with a missing file fails *gracefully*: returns `null` and emits `load_error` rather than crashing. Visual rendering itself can't be verified until real assets exist. |
 
 Run (once, to build the class cache): `godot --headless --path . --import`,
 then for each smoke test: `godot --headless --path . --script

export_presets.cfg

@@ -7,7 +7,7 @@ advanced_options=false
 dedicated_server=false
 custom_features=""
 export_filter="all_resources"
-include_filter=""
+include_filter="*.json"
 exclude_filter=""
 export_path="export/linux/agp-game.x86_64"
 encryption_include_filters=""
@@ -38,7 +38,7 @@ advanced_options=false
 dedicated_server=false
 custom_features=""
 export_filter="all_resources"
-include_filter=""
+include_filter="*.json"
 exclude_filter=""
 export_path="export/windows/agp-game.exe"
 encryption_include_filters=""

project.godot

@@ -14,6 +14,8 @@ agp/api_base_url="http://127.0.0.1:8000"
 [autoload]
 
 ApiClient="*res://scripts/api_client.gd"
+AvatarSystem="*res://scripts/avatar/avatar_system.gd"
+Session="*res://scripts/session.gd"
 
 [display]
 
@@ -21,6 +23,40 @@ window/size/viewport_width=1920
 window/size/viewport_height=1080
 window/stretch/mode="canvas_items"
 
+[input]
+
+move_forward={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":87,"key_label":0,"unicode":119,"location":0,"echo":false,"script":null)
+]
+}
+move_left={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":65,"key_label":0,"unicode":97,"location":0,"echo":false,"script":null)
+]
+}
+move_right={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":68,"key_label":0,"unicode":100,"location":0,"echo":false,"script":null)
+]
+}
+move_down={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":83,"key_label":0,"unicode":115,"location":0,"echo":false,"script":null)
+]
+}
+interact={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":0,"physical_keycode":69,"key_label":0,"unicode":101,"location":0,"echo":false,"script":null)
+]
+}
+
+[physics]
+
+; Fixed 30 Hz sim -- the multiplayer server, client prediction, and snapshot
+; rate all key off this. See docs/architecture/networking.md 3.1.
+common/physics_ticks_per_second=30
+
 [rendering]
 
 renderer/rendering_method="gl_compatibility"

sandbox_probe/.godot/.gdignore

@@ -1 +0,0 @@
-

scenes/avatar_customization.tscn

@@ -0,0 +1,12 @@
+[gd_scene load_steps=2 format=3 uid="uid://avatar_customization"]
+
+[ext_resource type="Script" path="res://scripts/avatar_customization_screen.gd" id="1"]
+
+[node name="AvatarCustomization" type="Control"]
+layout_mode = 3
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+script = ExtResource("1")

scenes/dev/avatar_preview.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3 uid="uid://c0avpre7dev0rig"]
+
+[ext_resource type="Script" path="res://scripts/tools/avatar_preview.gd" id="1"]
+
+[node name="AvatarPreview" type="Node3D"]
+script = ExtResource("1")

scenes/dev/screenshot_rig.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3 uid="uid://bqs8xk2rig0dev"]
+
+[ext_resource type="Script" path="res://scripts/tools/screenshot_rig.gd" id="1"]
+
+[node name="ScreenshotRig" type="Node"]
+script = ExtResource("1")

scenes/game.tscn

@@ -1,9 +1,11 @@
-[gd_scene load_steps=3 format=3 uid="uid://game_scene_pc2"]
+[gd_scene load_steps=4 format=3 uid="uid://game_scene_pc2"]
 
+[ext_resource type="Script" path="res://scripts/game.gd" id="0_game"]
 [ext_resource type="PackedScene" uid="uid://c49a36fc7db_test_level" path="res://scenes/worlds/test_level.tscn" id="1_level"]
 [ext_resource type="PackedScene" uid="uid://player_scene_001" path="res://scenes/player.tscn" id="2_player"]
 
 [node name="Game" type="Node3D"]
+script = ExtResource("0_game")
 
 [node name="Level" parent="." instance=ExtResource("1_level")]
 

scenes/main_menu.tscn

@@ -83,11 +83,11 @@ visible = false
 placeholder_text = "Email"
 size_flags_horizontal = 3
 
-[node name="Over18Check" type="CheckBox" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
+[node name="DobEdit" type="LineEdit" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
 layout_mode = 1
 visible = false
-text = "I am 18 or older"
 size_flags_horizontal = 3
+placeholder_text = "Date of birth (YYYY-MM-DD)"
 
 [node name="AuthButton" type="Button" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
 layout_mode = 1
@@ -112,6 +112,12 @@ layout_mode = 1
 text = "Play"
 size_flags_horizontal = 4
 
+[node name="CustomizeButton" type="Button" parent="CenterContainer/VBoxContainer"]
+layout_mode = 1
+text = "Customize Avatar"
+size_flags_horizontal = 4
+disabled = true
+
 [node name="QuitButton" type="Button" parent="CenterContainer/VBoxContainer"]
 layout_mode = 1
 text = "Quit"
@@ -120,6 +126,7 @@ size_flags_horizontal = 4
 [connection signal="pressed" from="CenterContainer/VBoxContainer/AuthButtonsRow/LoginButton" to="." method="_on_login_button_pressed"]
 [connection signal="pressed" from="CenterContainer/VBoxContainer/AuthButtonsRow/RegisterButton" to="." method="_on_register_button_pressed"]
 [connection signal="pressed" from="CenterContainer/VBoxContainer/PlayButton" to="." method="_on_play_button_pressed"]
+[connection signal="pressed" from="CenterContainer/VBoxContainer/CustomizeButton" to="." method="_on_customize_button_pressed"]
 [connection signal="pressed" from="CenterContainer/VBoxContainer/QuitButton" to="." method="_on_quit_button_pressed"]
 [connection signal="pressed" from="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthButton" to="." method="_on_auth_button_pressed"]
 [connection signal="text_submitted" from="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/UsernameEdit" to="." method="_on_auth_button_pressed"]

scenes/player.tscn

@@ -1,6 +1,7 @@
-[gd_scene load_steps=3 format=3 uid="uid://player_scene_001"]
+[gd_scene load_steps=5 format=3 uid="uid://player_scene_001"]
 
 [ext_resource type="Script" path="res://scripts/player.gd" id="1_player"]
+[ext_resource type="Script" path="res://scripts/scripting/player_inventory.gd" id="2_inventory"]
 
 [sub_resource type="CapsuleMesh" id="CapsuleMesh1"]
 radius = 0.35
@@ -11,6 +12,8 @@ radius = 0.35
 height = 1.6
 
 [node name="Player" type="CharacterBody3D"]
+collision_layer = 2
+collision_mask = 1
 script = ExtResource("1_player")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="."]
@@ -19,6 +22,15 @@ shape = SubResource("CapsuleShape1")
 [node name="CapsuleMesh" type="MeshInstance3D" parent="."]
 mesh = SubResource("CapsuleMesh1")
 
-[node name="Camera3D" type="Camera3D" parent="."]
-transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.6, 0)
+[node name="CameraPivot" type="Node3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1.2, 0)
+
+[node name="SpringArm3D" type="SpringArm3D" parent="CameraPivot"]
+spring_length = 3.5
+margin = 0.2
+
+[node name="Camera3D" type="Camera3D" parent="CameraPivot/SpringArm3D"]
 current = true
+
+[node name="Inventory" type="Node" parent="."]
+script = ExtResource("2_inventory")

scenes/server.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3]
+
+[ext_resource type="Script" path="res://scripts/server.gd" id="1_server"]
+
+[node name="Server" type="Node"]
+script = ExtResource("1_server")

scenes/server_player.tscn

@@ -0,0 +1,15 @@
+[gd_scene load_steps=3 format=3]
+
+[ext_resource type="Script" path="res://scripts/player_spawner.gd" id="1"]
+
+[sub_resource type="CapsuleShape3D" id="CapsuleShape_server_player"]
+radius = 0.35
+height = 1.6
+
+[node name="Player" type="CharacterBody3D"]
+collision_layer = 2
+collision_mask = 1
+script = ExtResource("1")
+
+[node name="CollisionShape3D" type="CollisionShape3D" parent="."]
+shape = SubResource("CapsuleShape_server_player")

scenes/worlds/test_level.tscn

@@ -1,4 +1,6 @@
-[gd_scene load_steps=1 format=3 uid="uid://c49a36fc7db_test_level"]
+[gd_scene load_steps=2 format=3 uid="uid://c49a36fc7db_test_level"]
+
+[ext_resource type="Script" path="res://scripts/scripting/script_interpreter.gd" id="1_scripted_chest"]
 
 [sub_resource type="BoxShape3D" id="BoxShape3D_ground"]
 size = Vector3(40, 1, 40)
@@ -44,12 +46,18 @@ radius = 0.5
 subdivisions_ring = 8
 subdivisions_height = 8
 
+[sub_resource type="BoxShape3D" id="BoxShape3D_chest"]
+size = Vector3(1, 0.8, 0.6)
+
+[sub_resource type="BoxMesh" id="BoxMesh_chest"]
+size = Vector3(1, 0.8, 0.6)
+
 [sub_resource type="Environment" id="WorldEnvironment_env"]
 background_mode = 1
-background_color = Color(0.4, 0.6, 0.8, 1)
-ambient_light_source = 1
-ambient_light_energy = 0.4
-ambient_light_sky_energy = 1.0
+background_color = Color(0.45, 0.62, 0.82, 1)
+ambient_light_source = 2
+ambient_light_color = Color(0.7, 0.75, 0.82, 1)
+ambient_light_energy = 0.8
 
 [node name="TestLevel" type="Node3D"]
 
@@ -109,8 +117,21 @@ shape = SubResource("SphereShape3D_prop5")
 [node name="MeshInstance3D" type="MeshInstance3D" parent="Props/Prop5_SmallSphere"]
 mesh = SubResource("SphereMesh_prop5")
 
+[node name="ScriptedChest" type="StaticBody3D" parent="."]
+position = Vector3(0, 1.0, 1.5)
+script = ExtResource("1_scripted_chest")
+behavior_path = "res://assets/scripting/behaviors/demo_chest.json"
+interact_radius = 2.5
+
+[node name="CollisionShape3D" type="CollisionShape3D" parent="ScriptedChest"]
+shape = SubResource("BoxShape3D_chest")
+
+[node name="MeshInstance3D" type="MeshInstance3D" parent="ScriptedChest"]
+mesh = SubResource("BoxMesh_chest")
+
 [node name="Sun" type="DirectionalLight3D" parent="."]
-rotation = Vector3(-0.785398, 0, 0)
+rotation = Vector3(-0.95, -0.5, 0)
+light_energy = 1.3
 shadow_enabled = true
 
 [node name="WorldEnvironment" type="WorldEnvironment" parent="."]

scripts/api_client.gd

@@ -178,18 +178,19 @@ func login(username: String, password: String) -> Dictionary:
 
 
 ## Register a new user. On success stores the returned access token.
-## @param over_18 Must be true; the backend rejects registration otherwise.
+## @param date_of_birth ISO "YYYY-MM-DD". The backend computes age from it
+##                       and rejects under-18s (403).
 func register(
 	username: String,
 	email: String,
 	password: String,
-	over_18: bool
+	date_of_birth: String
 ) -> Dictionary:
 	var payload := {
 		"username": username,
 		"email": email,
 		"password": password,
-		"over_18": over_18,
+		"date_of_birth": date_of_birth,
 	}
 	var result := await request(
 		HTTPClient.METHOD_POST,
@@ -221,6 +222,29 @@ func get_me() -> Dictionary:
 	return await request(HTTPClient.METHOD_GET, "/api/users/me", "", "application/json", true)
 
 
+## Fetch the current user's saved avatar loadout (requires auth).
+## On success, result.data is {"data": <loadout dict>, "is_default": bool} --
+## `is_default` true means the user has never customised and this is the
+## server default.
+func get_avatar_loadout() -> Dictionary:
+	return await request(HTTPClient.METHOD_GET, "/api/avatar/loadout", "", "application/json", true)
+
+
+## Ask the backend for a dedicated server to host [param world_id] and return
+## its address. On success result.data is {"world_id", "host", "port"}.
+## 503 if this backend has no game-server orchestration.
+func join_world(world_id: int) -> Dictionary:
+	return await request(HTTPClient.METHOD_POST, "/api/worlds/%d/join" % world_id, "", "application/json", true)
+
+
+## Save (replace) the current user's avatar loadout (requires auth).
+## @param loadout A dict in the AvatarLoadout.to_json() shape
+##                ({"base_body": String, "slots": {...}, "skin_tone"?: {...}}).
+func save_avatar_loadout(loadout: Dictionary) -> Dictionary:
+	var body := JSON.stringify({"data": loadout})
+	return await request(HTTPClient.METHOD_PUT, "/api/avatar/loadout", body, "application/json", true)
+
+
 # ---------------------------------------------------------------------------
 # Internals
 # ---------------------------------------------------------------------------

scripts/avatar/avatar_catalog.gd

@@ -0,0 +1,184 @@
+## AvatarCatalog - Asset catalog management.
+##
+## Manages the mapping of asset IDs to their metadata and resource paths.
+## Loads the catalog manifest from disk and provides lookup by ID and slot.
+##
+## The catalog is loaded from `res://assets/avatars/catalog.json` which follows
+## the format specified in avatar.md §7.2.
+
+class_name AvatarCatalog
+extends RefCounted
+
+# Preloaded rather than referenced by global class_name -- see avatar_loadout.gd.
+const AvatarLoadout := preload("res://scripts/avatar/avatar_loadout.gd")
+
+
+## Emitted when the catalog is loaded successfully.
+signal catalog_loaded
+
+## Emitted when the catalog fails to load.
+signal catalog_load_failed(error_message: String)
+
+## Catalog manifest structure:
+## { "assets": { "id": { "type", "slot", "path", "version", ... } } }
+var _catalog: Dictionary = {}
+var _loaded: bool = false
+var _catalog_path: String = "res://assets/avatars/catalog.json"
+
+
+# ---------------------------------------------------------------------------
+# Public API
+# ---------------------------------------------------------------------------
+
+## Load the catalog from disk. Call this before any lookups.
+func load_catalog(path: String = _catalog_path) -> Error:
+	_catalog_path = path
+	_catalog = {}
+
+	var file = FileAccess.open(path, FileAccess.READ)
+	if file == null:
+		var err = FileAccess.get_open_error()
+		catalog_load_failed.emit("Cannot open catalog: %s (error %d)" % [path, err])
+		return err
+
+	var json_text: String = file.get_as_text()
+	file.close()
+
+	var result: Variant = JSON.parse_string(json_text)
+	if result == null or not result is Dictionary:
+		catalog_load_failed.emit("Invalid JSON in catalog: %s" % path)
+		return ERR_PARSE_ERROR
+
+	var json: Dictionary = result as Dictionary
+
+	if not json.has("assets"):
+		catalog_load_failed.emit("Catalog missing 'assets' key")
+		return ERR_INVALID_DATA
+
+	_catalog = json["assets"]
+	_loaded = true
+	catalog_loaded.emit()
+	return OK
+
+
+## Check if the catalog has been loaded.
+func is_loaded() -> bool:
+	return _loaded
+
+
+## Resolve an asset by its ID.
+## Returns a Dictionary with keys: type, slot, path, version, etc.
+## Returns null if the asset ID is not found.
+func resolve(id: String) -> Dictionary:
+	if not _loaded:
+		return {}
+	return _catalog.get(id, {})
+
+
+## Check if an asset ID exists in the catalog.
+func has_asset(id: String) -> bool:
+	if not _loaded:
+		return false
+	return _catalog.has(id)
+
+
+## Get all assets that belong to a given slot.
+## Returns an array of asset ID strings.
+func get_assets_by_slot(slot: String) -> Array[String]:
+	if not _loaded:
+		return []
+	var result: Array[String] = []
+	for id in _catalog:
+		var asset: Dictionary = _catalog[id]
+		if asset.get("slot") == slot:
+			result.append(id)
+	return result
+
+
+## Get all asset IDs in the catalog.
+func get_all_ids() -> Array[String]:
+	if not _loaded:
+		return []
+	return _catalog.keys()
+
+
+## Validate a loadout against the catalog.
+## Returns a Dictionary with "valid" (bool) and "errors" (Array[String]).
+func validate_loadout(loadout: AvatarLoadout) -> Dictionary:
+	var errors: Array[String] = []
+
+	# Check base_body
+	if loadout.base_body.is_empty():
+		errors.append("Loadout missing base_body")
+	elif not has_asset(loadout.base_body):
+		errors.append("Unknown base_body asset: %s" % loadout.base_body)
+	else:
+		var base: Dictionary = resolve(loadout.base_body)
+		if base.get("type") != "base_body":
+			errors.append("base_body asset '%s' is not type 'base_body'" % loadout.base_body)
+
+	# Check each slot
+	for slot_id in loadout.slots:
+		var slot_value = loadout.slots[slot_id]
+
+		if slot_value == null:
+			continue
+
+		if slot_id == "accessory":
+			# Accessory is an array
+			if not slot_value is Array:
+				errors.append("Slot '%s' must be an array" % slot_id)
+				continue
+			for item_id in slot_value:
+				if not has_asset(item_id):
+					errors.append("Unknown accessory asset: %s" % item_id)
+				else:
+					var asset: Dictionary = resolve(item_id)
+					if asset.get("slot") != slot_id:
+						errors.append("Accessory '%s' slot '%s' does not match slot '%s'" % [
+							item_id, asset.get("slot"), slot_id
+						])
+		else:
+			# Exclusive slot - single value
+			if not slot_value is String:
+				errors.append("Slot '%s' must be a string or null" % slot_id)
+				continue
+			if not has_asset(slot_value):
+				errors.append("Unknown asset in slot '%s': %s" % [slot_id, slot_value])
+			else:
+				var asset: Dictionary = resolve(slot_value)
+				if asset.get("slot") != slot_id:
+					errors.append("Asset '%s' slot '%s' does not match slot '%s'" % [
+						slot_value, asset.get("slot"), slot_id
+					])
+
+	return {
+		"valid": errors.is_empty(),
+		"errors": errors
+	}
+
+
+## Compute a hash of the loadout for change detection.
+## Returns a 32-bit hash value (GDScript has no fixed-width uint type — int
+## is 64-bit signed, the value is just constrained to 32 bits of range).
+static func compute_loadout_hash(loadout: AvatarLoadout) -> int:
+	var hasher = HashingContext.new()
+	hasher.start(HashingContext.HASH_SHA256)
+
+	hasher.update(loadout.base_body.to_utf8_buffer())
+	for slot_id in loadout.slots:
+		var slot_value = loadout.slots[slot_id]
+		hasher.update(slot_id.to_utf8_buffer())
+		if slot_value is Array:
+			for item in slot_value:
+				hasher.update(item.to_utf8_buffer())
+		elif slot_value is String:
+			hasher.update(slot_value.to_utf8_buffer())
+
+	var hash_bytes = hasher.finish()
+	return hash_bytes[0] | (hash_bytes[1] << 8) | (hash_bytes[2] << 16) | (hash_bytes[3] << 24)
+
+
+## Get the catalog path.
+func get_catalog_path() -> String:
+	return _catalog_path

scripts/avatar/avatar_catalog.gd.uid

@@ -0,0 +1 @@
+uid://ceyugve7rjxqs

scripts/avatar/avatar_customization_ui.gd

@@ -0,0 +1,621 @@
+## AvatarCustomizationUI
+##
+## The in-game avatar customization screen. Lets the player:
+##   - See a live preview of their avatar.
+##   - Browse and equip/unequip items per slot.
+##   - Adjust skin tone.
+##   - Save / load loadouts.
+##
+## The UI is built programmatically so it works without a pre-authored .tscn.
+## It is a Control node that can be added to any scene.
+
+class_name AvatarCustomizationUI
+extends Control
+
+# Preloaded rather than referenced by global class_name -- see avatar_loadout.gd.
+const AvatarLoadout := preload("res://scripts/avatar/avatar_loadout.gd")
+const AvatarCatalog := preload("res://scripts/avatar/avatar_catalog.gd")
+const AvatarLoader := preload("res://scripts/avatar/avatar_loader.gd")
+const AvatarVisualizer := preload("res://scripts/avatar/avatar_visualizer.gd")
+const AvatarSlotRegistry := preload("res://scripts/avatar/avatar_slot_registry.gd")
+
+
+# ---------------------------------------------------------------------------
+# Signals
+# ---------------------------------------------------------------------------
+
+## Emitted when the player closes the customization screen.
+signal closed
+
+## Emitted when the loadout changes (after equip/unequip/skin-tone).
+signal loadout_changed(loadout: AvatarLoadout)
+
+
+# ---------------------------------------------------------------------------
+# Exports / config
+# ---------------------------------------------------------------------------
+
+## Path to the asset catalog manifest.
+@export var catalog_path: String = "res://assets/avatars/catalog.json"
+
+## The default base body to use when none is equipped.
+@export var default_base_body: String = "base_human_male_01"
+
+
+# ---------------------------------------------------------------------------
+# State
+# ---------------------------------------------------------------------------
+
+## The current loadout being edited.
+var loadout: AvatarLoadout = null
+
+## The AvatarSystem singleton (set in _ready).
+var _system: Node = null
+
+## The catalog (owned by AvatarSystem).
+var _catalog: AvatarCatalog = null
+
+## The loader (owned by AvatarSystem).
+var _loader: AvatarLoader = null
+
+## The visualizer that renders the preview.
+var _visualizer: AvatarVisualizer = null
+
+## The preview viewport container.
+var _preview_container: SubViewportContainer = null
+
+## The preview viewport.
+var _preview_viewport: SubViewport = null
+
+## The preview camera.
+var _preview_camera: Camera3D = null
+
+## The preview avatar root.
+var _preview_root: Node3D = null
+
+## Currently selected slot id.
+var _selected_slot: String = ""
+
+## Skin: a base colour picked from a swatch, plus a shade multiplier from the
+## slider (0.5 = the swatch as-is, lower = darker, higher = lighter). The
+## first swatch is the placeholder default yellow.
+const SKIN_SWATCHES: Array[Color] = [
+	Color(0.96, 0.80, 0.19),  # yellow (default)
+	Color(0.95, 0.78, 0.66),  # pale
+	Color(0.83, 0.62, 0.46),  # tan
+	Color(0.55, 0.38, 0.27),  # brown
+	Color(0.33, 0.21, 0.15),  # deep brown
+	Color(0.62, 0.62, 0.64),  # grey
+	Color(0.78, 0.24, 0.24),  # red
+	Color(0.30, 0.62, 0.34),  # green
+	Color(0.26, 0.46, 0.76),  # blue
+	Color(0.62, 0.36, 0.72),  # purple
+]
+var _skin_base: Color = SKIN_SWATCHES[0]
+
+## Turntable: the preview avatar's Y rotation (radians), whether the player is
+## currently dragging it, and how long since they last touched it (drives the
+## slow idle auto-spin). Starts facing the camera.
+var _turntable_yaw: float = PI
+var _turntable_dragging: bool = false
+var _turntable_idle: float = 0.0
+const _TURNTABLE_IDLE_SPIN_DELAY := 2.5
+const _TURNTABLE_IDLE_SPIN_SPEED := 0.5
+const _TURNTABLE_DRAG_SPEED := 0.01
+
+## UI node references.
+var _slot_list: VBoxContainer = null
+var _item_list: VBoxContainer = null
+var _slot_label: Label = null
+var _item_label: Label = null
+var _skin_tone_slider: HSlider = null
+var _status_label: Label = null
+
+
+# ---------------------------------------------------------------------------
+# Lifecycle
+# ---------------------------------------------------------------------------
+
+func _ready() -> void:
+	# Grab the AvatarSystem autoload.
+	_system = get_node_or_null("/root/AvatarSystem")
+	if _system == null:
+		push_error("AvatarCustomizationUI: AvatarSystem autoload not found")
+		return
+
+	_catalog = _system.catalog
+	_loader = _system.loader
+
+	# Load the catalog if not already loaded.
+	if _catalog != null and not _catalog.is_loaded():
+		_catalog.load_catalog(catalog_path)
+
+	# Build the UI.
+	_build_ui()
+
+	# Seed from the player's live loadout (set at login) if there is one, so
+	# the screen opens showing what they're actually wearing; otherwise start
+	# from a bare default.
+	if _system != null and _system.current_loadout != null:
+		loadout = AvatarLoadout.from_json(_system.current_loadout.to_json())
+	if loadout == null or not loadout.validate():
+		loadout = AvatarLoadout.new()
+		loadout.base_body = default_base_body
+
+	# Initialize the visualizer.
+	_visualizer = AvatarVisualizer.new()
+
+	# Populate the slot list.
+	_populate_slots()
+
+	# Select the first slot.
+	if AvatarSlotRegistry.SLOT_IDS.size() > 0:
+		_select_slot(AvatarSlotRegistry.SLOT_IDS[0])
+
+	# Refresh the preview.
+	_refresh_preview()
+
+
+# ---------------------------------------------------------------------------
+# UI construction
+# ---------------------------------------------------------------------------
+
+## Build the entire UI tree programmatically.
+func _build_ui() -> void:
+	# Root layout: horizontal split (preview | controls).
+	var root_hbox := HBoxContainer.new()
+	root_hbox.name = "RootLayout"
+	root_hbox.set_anchors_preset(Control.PRESET_FULL_RECT)
+	root_hbox.add_theme_constant_override("separation", 16)
+	add_child(root_hbox)
+
+	# --- Left: preview (takes all the leftover width) ---
+	var preview_panel := PanelContainer.new()
+	preview_panel.name = "PreviewPanel"
+	preview_panel.custom_minimum_size = Vector2(420, 0)
+	preview_panel.size_flags_horizontal = Control.SIZE_EXPAND_FILL
+	root_hbox.add_child(preview_panel)
+
+	var preview_margin := MarginContainer.new()
+	preview_margin.add_theme_constant_override("margin_left", 8)
+	preview_margin.add_theme_constant_override("margin_right", 8)
+	preview_margin.add_theme_constant_override("margin_top", 8)
+	preview_margin.add_theme_constant_override("margin_bottom", 8)
+	preview_panel.add_child(preview_margin)
+
+	var preview_vbox := VBoxContainer.new()
+	preview_vbox.add_theme_constant_override("separation", 6)
+	preview_margin.add_child(preview_vbox)
+
+	_preview_container = SubViewportContainer.new()
+	_preview_container.name = "PreviewViewportContainer"
+	_preview_container.stretch = true
+	_preview_container.custom_minimum_size = Vector2(400, 520)
+	_preview_container.size_flags_horizontal = Control.SIZE_EXPAND_FILL
+	_preview_container.size_flags_vertical = Control.SIZE_EXPAND_FILL
+	_preview_container.mouse_filter = Control.MOUSE_FILTER_STOP
+	_preview_container.gui_input.connect(_on_preview_gui_input)
+	preview_vbox.add_child(_preview_container)
+
+	var rotate_hint := Label.new()
+	rotate_hint.text = "drag to rotate"
+	rotate_hint.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	rotate_hint.add_theme_color_override("font_color", Color(1, 1, 1, 0.5))
+	rotate_hint.add_theme_font_size_override("font_size", 12)
+	preview_vbox.add_child(rotate_hint)
+
+	_preview_viewport = SubViewport.new()
+	_preview_viewport.name = "PreviewViewport"
+	_preview_viewport.size = Vector2i(400, 520)
+	_preview_viewport.render_target_update_mode = SubViewport.UPDATE_ALWAYS
+	_preview_viewport.transparent_bg = true
+	# Its own 3D world -- a SubViewport that shares the (Control-only) main
+	# world has no scenario/environment set up and renders nothing.
+	_preview_viewport.own_world_3d = true
+	_preview_container.add_child(_preview_viewport)
+
+	# Environment: ambient fill so the model reads even from a bad light angle.
+	var world_env := WorldEnvironment.new()
+	world_env.name = "PreviewEnv"
+	var env := Environment.new()
+	env.background_mode = Environment.BG_COLOR
+	env.background_color = Color(0.10, 0.11, 0.14)
+	env.ambient_light_source = Environment.AMBIENT_SOURCE_COLOR
+	env.ambient_light_color = Color(0.62, 0.64, 0.7)
+	env.ambient_light_energy = 0.7
+	world_env.environment = env
+	_preview_viewport.add_child(world_env)
+
+	# Camera for the preview -- framed to fit the full ~2 m avatar.
+	_preview_camera = Camera3D.new()
+	_preview_camera.name = "PreviewCamera"
+	# look_at needs a global transform, which only exists once in the tree.
+	_preview_camera.look_at_from_position(
+		Vector3(0, 1.05, 3.5), Vector3(0, 0.98, 0), Vector3.UP)
+	_preview_camera.current = true
+	_preview_viewport.add_child(_preview_camera)
+
+	# Avatar root inside the viewport.
+	_preview_root = Node3D.new()
+	_preview_root.name = "AvatarPreviewRoot"
+	_preview_viewport.add_child(_preview_root)
+
+	# Key + fill lights so the avatar is clearly visible.
+	var key := DirectionalLight3D.new()
+	key.name = "PreviewKeyLight"
+	key.rotation_degrees = Vector3(-35, 35, 0)
+	key.light_energy = 1.0
+	_preview_viewport.add_child(key)
+	var fill := DirectionalLight3D.new()
+	fill.name = "PreviewFillLight"
+	fill.rotation_degrees = Vector3(-20, -140, 0)
+	fill.light_energy = 0.35
+	_preview_viewport.add_child(fill)
+
+	# --- Right: controls ---
+	var controls_panel := PanelContainer.new()
+	controls_panel.name = "ControlsPanel"
+	controls_panel.custom_minimum_size = Vector2(520, 0)
+	root_hbox.add_child(controls_panel)
+
+	var controls_margin := MarginContainer.new()
+	controls_margin.add_theme_constant_override("margin_left", 12)
+	controls_margin.add_theme_constant_override("margin_right", 12)
+	controls_margin.add_theme_constant_override("margin_top", 12)
+	controls_margin.add_theme_constant_override("margin_bottom", 12)
+	controls_panel.add_child(controls_margin)
+
+	var controls_vbox := VBoxContainer.new()
+	controls_vbox.name = "Controls"
+	controls_vbox.add_theme_constant_override("separation", 8)
+	controls_margin.add_child(controls_vbox)
+
+	# Title.
+	var title := Label.new()
+	title.text = "Avatar Customization"
+	title.add_theme_font_size_override("font_size", 24)
+	controls_vbox.add_child(title)
+
+	# Slot selector.
+	var slot_header := Label.new()
+	slot_header.text = "Slots"
+	slot_header.add_theme_font_size_override("font_size", 16)
+	controls_vbox.add_child(slot_header)
+
+	var slot_scroll := ScrollContainer.new()
+	slot_scroll.custom_minimum_size = Vector2(0, 160)
+	controls_vbox.add_child(slot_scroll)
+
+	_slot_list = VBoxContainer.new()
+	_slot_list.name = "SlotList"
+	_slot_list.add_theme_constant_override("separation", 4)
+	slot_scroll.add_child(_slot_list)
+
+	# Item selector for the selected slot.
+	var item_header := Label.new()
+	item_header.text = "Items"
+	item_header.add_theme_font_size_override("font_size", 16)
+	controls_vbox.add_child(item_header)
+
+	var item_scroll := ScrollContainer.new()
+	item_scroll.custom_minimum_size = Vector2(0, 200)
+	controls_vbox.add_child(item_scroll)
+
+	_item_list = VBoxContainer.new()
+	_item_list.name = "ItemList"
+	_item_list.add_theme_constant_override("separation", 4)
+	item_scroll.add_child(_item_list)
+
+	# Skin colour: a row of preset swatches + a shade slider that darkens or
+	# lightens the picked colour. The first swatch is the default yellow.
+	var skin_header := Label.new()
+	skin_header.text = "Skin Colour"
+	skin_header.add_theme_font_size_override("font_size", 16)
+	controls_vbox.add_child(skin_header)
+
+	var swatch_grid := GridContainer.new()
+	swatch_grid.columns = 5
+	swatch_grid.add_theme_constant_override("h_separation", 4)
+	swatch_grid.add_theme_constant_override("v_separation", 4)
+	controls_vbox.add_child(swatch_grid)
+	for c in SKIN_SWATCHES:
+		swatch_grid.add_child(_make_swatch(c))
+
+	var shade_label := Label.new()
+	shade_label.text = "Shade"
+	shade_label.add_theme_font_size_override("font_size", 13)
+	controls_vbox.add_child(shade_label)
+
+	_skin_tone_slider = HSlider.new()
+	_skin_tone_slider.name = "ShadeSlider"
+	_skin_tone_slider.min_value = 0.0
+	_skin_tone_slider.max_value = 1.0
+	_skin_tone_slider.step = 0.01
+	_skin_tone_slider.value = 0.5
+	_skin_tone_slider.custom_minimum_size = Vector2(0, 24)
+	_skin_tone_slider.value_changed.connect(_on_skin_tone_changed)
+	controls_vbox.add_child(_skin_tone_slider)
+
+	# Status / error label.
+	_status_label = Label.new()
+	_status_label.name = "StatusLabel"
+	_status_label.text = ""
+	_status_label.add_theme_color_override("font_color", Color(1, 0.4, 0.4))
+	_status_label.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
+	controls_vbox.add_child(_status_label)
+
+	# Action buttons.
+	var button_row := HBoxContainer.new()
+	button_row.add_theme_constant_override("separation", 8)
+	controls_vbox.add_child(button_row)
+
+	var save_btn := Button.new()
+	save_btn.text = "Save Loadout"
+	save_btn.pressed.connect(_on_save_pressed)
+	button_row.add_child(save_btn)
+
+	var load_btn := Button.new()
+	load_btn.text = "Load Loadout"
+	load_btn.pressed.connect(_on_load_pressed)
+	button_row.add_child(load_btn)
+
+	var close_btn := Button.new()
+	close_btn.text = "Close"
+	close_btn.pressed.connect(_on_close_pressed)
+	button_row.add_child(close_btn)
+
+
+# ---------------------------------------------------------------------------
+# Slot / item population
+# ---------------------------------------------------------------------------
+
+## Populate the slot list with buttons for each slot.
+func _populate_slots() -> void:
+	if _slot_list == null:
+		return
+
+	# Clear existing children.
+	for child in _slot_list.get_children():
+		child.queue_free()
+
+	for slot_id in AvatarSlotRegistry.SLOT_IDS:
+		var btn := Button.new()
+		btn.name = "Slot_%s" % slot_id
+		btn.text = slot_id
+		btn.toggle_mode = true
+		btn.pressed.connect(_on_slot_button_pressed.bind(slot_id))
+		_slot_list.add_child(btn)
+
+
+## Populate the item list for the currently selected slot.
+func _populate_items() -> void:
+	if _item_list == null or _selected_slot.is_empty():
+		return
+
+	# Clear existing children.
+	for child in _item_list.get_children():
+		child.queue_free()
+
+	if _catalog == null:
+		return
+
+	# Get assets for this slot.
+	var assets: Array[String] = _catalog.get_assets_by_slot(_selected_slot)
+
+	# "None" button to unequip.
+	var none_btn := Button.new()
+	none_btn.text = "(none)"
+	none_btn.pressed.connect(_on_equip_pressed.bind(""))
+	_item_list.add_child(none_btn)
+
+	for asset_id in assets:
+		var btn := Button.new()
+		btn.text = asset_id
+		btn.pressed.connect(_on_equip_pressed.bind(asset_id))
+		_item_list.add_child(btn)
+
+
+# ---------------------------------------------------------------------------
+# Slot selection
+# ---------------------------------------------------------------------------
+
+## Handle a slot button press.
+func _on_slot_button_pressed(slot_id: String) -> void:
+	_select_slot(slot_id)
+
+
+## Select a slot and refresh the item list.
+func _select_slot(slot_id: String) -> void:
+	_selected_slot = slot_id
+
+	# Update button toggle states.
+	if _slot_list != null:
+		for child in _slot_list.get_children():
+			if child is Button:
+				var btn := child as Button
+				btn.button_pressed = (btn.name == "Slot_%s" % slot_id)
+
+	_populate_items()
+
+
+# ---------------------------------------------------------------------------
+# Equip / unequip
+# ---------------------------------------------------------------------------
+
+## Handle an equip/unequip action for the selected slot.
+func _on_equip_pressed(asset_id: String) -> void:
+	if loadout == null or _selected_slot.is_empty():
+		return
+
+	if _selected_slot == "accessory":
+		if asset_id.is_empty():
+			# Clear all accessories.
+			loadout.slots["accessory"] = []
+		else:
+			loadout.add_accessory(asset_id)
+	else:
+		loadout.set_equipment(_selected_slot, asset_id)
+
+	_refresh_preview()
+	loadout_changed.emit(loadout)
+
+
+# ---------------------------------------------------------------------------
+# Turntable (drag to rotate the preview, slow auto-spin when idle)
+# ---------------------------------------------------------------------------
+
+func _process(delta: float) -> void:
+	if _preview_root == null:
+		return
+	if _turntable_dragging:
+		_turntable_idle = 0.0
+	else:
+		_turntable_idle += delta
+		if _turntable_idle > _TURNTABLE_IDLE_SPIN_DELAY:
+			_turntable_yaw += delta * _TURNTABLE_IDLE_SPIN_SPEED
+	_preview_root.rotation.y = _turntable_yaw
+
+
+func _on_preview_gui_input(event: InputEvent) -> void:
+	if event is InputEventMouseButton and event.button_index == MOUSE_BUTTON_LEFT:
+		_turntable_dragging = event.pressed
+		_turntable_idle = 0.0
+	elif event is InputEventMouseMotion and _turntable_dragging:
+		_turntable_yaw -= event.relative.x * _TURNTABLE_DRAG_SPEED
+		_turntable_idle = 0.0
+
+
+# ---------------------------------------------------------------------------
+# Preview refresh
+# ---------------------------------------------------------------------------
+
+## Rebuild the avatar preview from the current loadout.
+func _refresh_preview() -> void:
+	if _visualizer == null or _preview_root == null:
+		return
+
+	# Clear the preview root.
+	for child in _preview_root.get_children():
+		child.queue_free()
+
+	# Validate the loadout.
+	if loadout == null or loadout.base_body.is_empty():
+		_status_label.text = "No base body selected."
+		return
+
+	# Build the render tree.
+	_visualizer.load_loadout(loadout, _preview_root)
+
+	# Show any validation errors.
+	if not loadout.validation_errors.is_empty():
+		_status_label.text = "\n".join(loadout.validation_errors)
+	else:
+		_status_label.text = ""
+
+
+# ---------------------------------------------------------------------------
+# Skin tone
+# ---------------------------------------------------------------------------
+
+## Build one clickable colour swatch.
+func _make_swatch(color: Color) -> Button:
+	var b := Button.new()
+	b.custom_minimum_size = Vector2(40, 30)
+	b.tooltip_text = "#" + color.to_html(false)
+	for state in ["normal", "hover", "pressed", "focus", "disabled"]:
+		var sb := StyleBoxFlat.new()
+		sb.bg_color = color
+		sb.set_corner_radius_all(3)
+		if state == "hover" or state == "pressed" or state == "focus":
+			sb.set_border_width_all(2)
+			sb.border_color = Color.WHITE
+		b.add_theme_stylebox_override(state, sb)
+	b.pressed.connect(_on_skin_swatch_pressed.bind(color))
+	return b
+
+
+func _on_skin_swatch_pressed(color: Color) -> void:
+	_skin_base = color
+	_apply_skin_colour()
+
+
+func _on_skin_tone_changed(_value: float) -> void:
+	_apply_skin_colour()
+
+
+## Combine the picked swatch with the shade slider and push it to the loadout.
+func _apply_skin_colour() -> void:
+	if loadout == null:
+		return
+	var shade: float = _skin_tone_slider.value if _skin_tone_slider != null else 0.5
+	var col := _skin_base
+	if shade < 0.5:
+		col = _skin_base.lerp(Color.BLACK, (0.5 - shade) * 1.7)
+	elif shade > 0.5:
+		col = _skin_base.lerp(Color.WHITE, (shade - 0.5) * 1.3)
+	col.a = 1.0
+	loadout.skin_tone = col
+	_refresh_preview()
+	loadout_changed.emit(loadout)
+
+
+# ---------------------------------------------------------------------------
+# Save / load
+# ---------------------------------------------------------------------------
+
+func _on_save_pressed() -> void:
+	if loadout == null:
+		return
+
+	# Local cache (offline fallback / fast reopen).
+	var json := loadout.to_json()
+	var file := FileAccess.open("user://loadout.json", FileAccess.WRITE)
+	if file:
+		file.store_string(json)
+		file.close()
+
+	# Apply to the live in-world avatar immediately.
+	if _system != null:
+		_system.set_loadout_from_dict(JSON.parse_string(json))
+
+	# Persist to the backend if we're signed in.
+	var api := get_node_or_null("/root/ApiClient")
+	if api != null and api.has_token():
+		_status_label.text = "Saving…"
+		var res: Dictionary = await api.save_avatar_loadout(JSON.parse_string(json))
+		_status_label.text = "Saved." if res.get("ok", false) else "Saved locally (backend: %s)" % res.get("detail", "error")
+	else:
+		_status_label.text = "Saved locally (not signed in)."
+
+
+func _on_load_pressed() -> void:
+	if not FileAccess.file_exists("user://loadout.json"):
+		_status_label.text = "No saved loadout found."
+		return
+
+	var file := FileAccess.open("user://loadout.json", FileAccess.READ)
+	if file == null:
+		_status_label.text = "Failed to open saved loadout."
+		return
+
+	var json := file.get_as_text()
+	file.close()
+
+	var loaded := AvatarLoadout.from_json(json)
+	if not loaded.validation_errors.is_empty():
+		_status_label.text = "Saved loadout invalid: %s" % "\n".join(loaded.validation_errors)
+		return
+
+	loadout = loaded
+	_refresh_preview()
+	loadout_changed.emit(loadout)
+	_status_label.text = "Loadout loaded."
+
+
+# ---------------------------------------------------------------------------
+# Close
+# ---------------------------------------------------------------------------
+
+func _on_close_pressed() -> void:
+	closed.emit()
+	queue_free()

scripts/avatar/avatar_customization_ui.gd.uid

@@ -0,0 +1 @@
+uid://crqtef5rifgrv

scripts/avatar/avatar_loader.gd

@@ -0,0 +1,562 @@
+## AvatarLoader - glTF/GLB import, skeleton merge, and skin re-targeting.
+##
+## Loads base body and attachment GLB assets, extracts skeletons and meshes,
+## and re-targets attachment skins to the canonical skeleton by bone name.
+##
+## Per the avatar architecture spec (§6.2, §6.3):
+## - The base body carries the canonical skeleton.
+## - Attachments are skinned to the same skeleton by name-based re-targeting.
+## - Static accessories are parented to their mount bone.
+## - Body-part slots hide the corresponding base mesh.
+
+class_name AvatarLoader
+extends Node
+
+# Preloaded rather than referenced by global class_name -- see avatar_loadout.gd.
+const AvatarCatalog := preload("res://scripts/avatar/avatar_catalog.gd")
+
+
+# ---------------------------------------------------------------------------
+# Constants
+# ---------------------------------------------------------------------------
+
+## Maximum number of attachments allowed in the accessory slot.
+const MAX_ACCESSORY_COUNT := 8
+
+## The skin albedo baked into the placeholder base body by
+## gen_placeholder_avatars.gd. apply_skin_tone() finds the mesh surfaces
+## painted this colour (head + arms) and retints them.
+const PLACEHOLDER_SKIN_ALBEDO := Color(0.96, 0.80, 0.19)
+
+## Skeleton bone names that form the canonical rig (§3.1).
+const CANONICAL_BONES := [
+	"Root",
+	"Hips",
+	"Spine",
+	"Chest",
+	"Neck",
+	"Head",
+	"HeadTop",
+	"Jaw",
+	"LeftEye",
+	"RightEye",
+	"LeftShoulder",
+	"LeftUpperArm",
+	"LeftLowerArm",
+	"LeftHand",
+	"RightShoulder",
+	"RightUpperArm",
+	"RightLowerArm",
+	"RightHand",
+	"LeftUpperLeg",
+	"LeftLowerLeg",
+	"LeftFoot",
+	"RightUpperLeg",
+	"RightLowerLeg",
+	"RightFoot",
+]
+
+
+# ---------------------------------------------------------------------------
+# Signals
+# ---------------------------------------------------------------------------
+
+## Emitted when a base body has been loaded successfully.
+signal base_body_loaded(avatar_node: Node3D)
+
+## Emitted when an attachment has been loaded and merged.
+signal attachment_loaded(slot_id: String, attachment_node: Node3D)
+
+## Emitted on error during loading.
+signal load_error(error_msg: String)
+
+
+# ---------------------------------------------------------------------------
+# State
+# ---------------------------------------------------------------------------
+
+## The fully assembled avatar node (Skeleton3D + meshes + attachments).
+var avatar_node: Node3D = null
+
+## The Skeleton3D belonging to the avatar.
+var skeleton: Skeleton3D = null
+
+## Mapping of bone name -> bone index in the skeleton.
+var _bone_index_map: Dictionary = {}
+
+## Loaded base body meshes, keyed by slot id.
+var _base_meshes: Dictionary = {}
+
+## Loaded attachment nodes, keyed by slot id.
+var _attachments: Dictionary = {}
+
+## Whether the base body has been loaded.
+var is_base_loaded: bool = false
+
+## The avatar catalog reference (set by AvatarSystem).
+var catalog: AvatarCatalog = null
+
+
+# ---------------------------------------------------------------------------
+# Public API
+# ---------------------------------------------------------------------------
+
+## Initialize the loader with a reference to the avatar catalog.
+func init_loader(cat: AvatarCatalog) -> void:
+	catalog = cat
+
+
+## Load the base body asset identified by [param base_body_id].
+## Returns the AvatarNode3D on success, or null on failure.
+func load_base_body(base_body_id: String) -> Node3D:
+	if catalog == null:
+		load_error.emit("AvatarCatalog not set on AvatarLoader")
+		return null
+
+	var asset_meta = catalog.resolve(base_body_id)
+	if asset_meta == null:
+		load_error.emit("Unknown base_body asset: %s" % base_body_id)
+		return null
+
+	if asset_meta.type != "base_body":
+		load_error.emit("Asset '%s' is not a base_body, got '%s'" % [
+			base_body_id, asset_meta.type])
+		return null
+
+	var path: String = asset_meta.path
+	avatar_node = _instance_glb_as_avatar(path)
+	if avatar_node == null:
+		load_error.emit("Failed to load base body scene: %s" % path)
+		return null
+
+	skeleton = avatar_node.get_node_or_null("Skeleton3D") as Skeleton3D
+	if skeleton == null:
+		load_error.emit("No Skeleton3D found in base body: %s" % path)
+		avatar_node.queue_free()
+		return null
+
+	# Build bone index map for fast lookups.
+	_bone_index_map.clear()
+	for i in skeleton.get_bone_count():
+		var bone_name: String = skeleton.get_bone_name(i)
+		if not bone_name.is_empty():
+			_bone_index_map[bone_name] = i
+
+	# Extract base body meshes and store them.
+	_extract_base_meshes(avatar_node)
+
+	is_base_loaded = true
+	base_body_loaded.emit(avatar_node)
+	return avatar_node
+
+
+## Load and merge an attachment into the avatar.
+## [param slot_id] is the slot to equip into.
+## [param asset_id] is the catalog id of the attachment.
+## Returns the attachment Node3D on success, or null on failure.
+func load_attachment(slot_id: String, asset_id: String) -> Node3D:
+	if not is_base_loaded:
+		load_error.emit("Cannot load attachment: base body not loaded")
+		return null
+
+	if catalog == null:
+		load_error.emit("AvatarCatalog not set on AvatarLoader")
+		return null
+
+	var asset_meta = catalog.resolve(asset_id)
+	if asset_meta == null:
+		load_error.emit("Unknown attachment asset: %s" % asset_id)
+		return null
+
+	if asset_meta.type != "attachment":
+		load_error.emit("Asset '%s' is not an attachment, got '%s'" % [
+			asset_id, asset_meta.type])
+		return null
+
+	# Check slot exclusivity for accessory slot.
+	if slot_id == "accessory":
+		var current_accessories: Array = _attachments.get("accessory", [])
+		if current_accessories.size() >= MAX_ACCESSORY_COUNT:
+			load_error.emit("Accessory slot full (%d/%d)" % [
+				MAX_ACCESSORY_COUNT, MAX_ACCESSORY_COUNT])
+			return null
+
+	var path: String = asset_meta.path
+	var attachment_node = _instance_glb_as_attachment(path, slot_id)
+	if attachment_node == null:
+		load_error.emit("Failed to load attachment scene: %s" % path)
+		return null
+
+	# If the attachment carries its own skin, retarget it to the canonical
+	# skeleton; static props (the common case) are unaffected.
+	_retarget_skin(attachment_node)
+
+	# Mount to the appropriate bone via a BoneAttachment3D so it follows the
+	# skeleton. Falls back to a plain skeleton child if the mount bone is
+	# missing (a bad catalog entry) rather than dropping the attachment.
+	var mount_bone: String = asset_meta.get("mount_bone", "")
+	if mount_bone.is_empty():
+		mount_bone = _slot_to_mount_bone(slot_id)
+	var mount_node: Node3D
+	if not mount_bone.is_empty() and skeleton.find_bone(mount_bone) != -1:
+		var ba := BoneAttachment3D.new()
+		ba.name = "Mount_%s" % slot_id if slot_id != "accessory" else "Mount_accessory_%s" % asset_id
+		ba.bone_name = mount_bone
+		skeleton.add_child(ba)
+		ba.add_child(attachment_node)
+		mount_node = ba
+	else:
+		skeleton.add_child(attachment_node)
+		mount_node = attachment_node
+
+	# Store the top-level mount node so unload can free the whole unit.
+	if slot_id == "accessory":
+		var list: Array = _attachments.get("accessory", [])
+		list.append(mount_node)
+		_attachments["accessory"] = list
+	else:
+		if _attachments.has(slot_id) and is_instance_valid(_attachments[slot_id]):
+			_attachments[slot_id].queue_free()
+		_attachments[slot_id] = mount_node
+
+	attachment_loaded.emit(slot_id, attachment_node)
+	return attachment_node
+
+
+## Remove an attachment from the given slot.
+func unload_attachment(slot_id: String) -> void:
+	if slot_id == "accessory":
+		for node in _attachments.get("accessory", []):
+			if is_instance_valid(node):
+				node.queue_free()
+		_attachments.erase("accessory")
+	else:
+		var node = _attachments.get(slot_id)
+		if is_instance_valid(node):
+			node.queue_free()
+		_attachments.erase(slot_id)
+
+
+## Hide or show the base mesh for a given body-part slot.
+func set_base_mesh_visible(slot_id: String, visible: bool) -> void:
+	var mesh = _base_meshes.get(slot_id)
+	if mesh and mesh is Node3D:
+		mesh.visible = visible
+
+
+## Retint the base body's skin surfaces (the ones the generator painted
+## PLACEHOLDER_SKIN_ALBEDO -- head + arms) to [param color]. A no-op if the
+## colour is unset (transparent). Real segmented bodies will do this per mesh.
+func apply_skin_tone(color: Color) -> void:
+	if color.a <= 0.0:
+		return
+	if avatar_node == null or not is_instance_valid(avatar_node):
+		return
+	var skel := avatar_node.get_node_or_null("Skeleton3D") as Skeleton3D
+	if skel == null:
+		return
+	for child in skel.get_children():
+		if not (child is MeshInstance3D):
+			continue
+		var mi := child as MeshInstance3D
+		if mi.mesh == null:
+			continue
+		for s in mi.mesh.get_surface_count():
+			var mat := mi.get_active_material(s)
+			if mat is BaseMaterial3D and \
+					(mat as BaseMaterial3D).albedo_color.is_equal_approx(PLACEHOLDER_SKIN_ALBEDO):
+				var tinted := StandardMaterial3D.new()
+				tinted.albedo_color = color
+				tinted.roughness = 0.9
+				mi.set_surface_override_material(s, tinted)
+
+
+## Get the current loadout as a dictionary (for serialization).
+func get_current_loadout() -> Dictionary:
+	var loadout: Dictionary = {
+		"base_body": "",
+		"slots": {},
+	}
+
+	# Determine base body id from catalog.
+	if is_base_loaded and catalog != null:
+		# Walk through catalog to find which base_body loaded.
+		for id in catalog.get_all_ids():
+			var meta = catalog.resolve(id)
+			if meta and meta.type == "base_body":
+				loadout.base_body = id
+				break
+
+	# Collect equipped attachments.
+	for slot_id in _attachments:
+		if slot_id == "accessory":
+			loadout.slots[slot_id] = _attachments[slot_id] as Array
+		else:
+			var node = _attachments[slot_id]
+			if node is Node3D:
+				# Find the asset id by matching the node's name.
+				var aid: String = node.name
+				loadout.slots[slot_id] = aid
+
+	return loadout
+
+
+## Reset the avatar to an unloaded state.
+func reset() -> void:
+	if avatar_node and avatar_node is Node:
+		avatar_node.queue_free()
+
+	avatar_node = null
+	skeleton = null
+	_bone_index_map.clear()
+	_base_meshes.clear()
+	_attachments.clear()
+	is_base_loaded = false
+
+
+# ---------------------------------------------------------------------------
+# Internal: GLB Parsing
+# ---------------------------------------------------------------------------
+
+## Instantiate a base-body .glb (a Godot-imported PackedScene) into an avatar
+## structure:
+##   Avatar (Node3D)
+##     Skeleton3D          -- the canonical rig + skin-bound body meshes
+##     BodyMeshes (Node3D) -- unused container, kept for compatibility
+##     Attachments (Node3D)-- equipped attachment nodes (added by load_attachment)
+##
+## Uses load().instantiate() rather than the runtime GLTFDocument path: the
+## imported .scn is the one that actually ends up in an exported build, with
+## the skeleton + skin set up by Godot's import pipeline. (The raw-bytes
+## GLTFDocument path -- for future user-uploaded models -- misbehaved in a
+## release build: no Skeleton3D produced, so the player fell back to a capsule.)
+func _instance_glb_as_avatar(path: String) -> Node3D:
+	var packed = load(path)
+	if not (packed is PackedScene):
+		push_error("Base body is not an importable scene: %s" % path)
+		return null
+	var scene_root: Node = packed.instantiate()
+	if not (scene_root is Node3D):
+		push_error("Base body scene root is not a Node3D: %s" % path)
+		scene_root.free()
+		return null
+
+	var src_skel := _find_first_skeleton(scene_root)
+	if src_skel == null:
+		push_error("No Skeleton3D in base body scene: %s" % path)
+		scene_root.free()
+		return null
+
+	var avatar := Node3D.new()
+	avatar.name = "Avatar"
+
+	src_skel.get_parent().remove_child(src_skel)
+	src_skel.name = "Skeleton3D"
+	src_skel.transform = Transform3D.IDENTITY
+	_clear_owner_recursive(src_skel)
+	avatar.add_child(src_skel)
+	scene_root.free()
+
+	var body_meshes := Node3D.new()
+	body_meshes.name = "BodyMeshes"
+	avatar.add_child(body_meshes)
+
+	var attachments_container := Node3D.new()
+	attachments_container.name = "Attachments"
+	avatar.add_child(attachments_container)
+
+	return avatar
+
+
+## Depth-first search for the first Skeleton3D under [param node].
+func _find_first_skeleton(node: Node) -> Skeleton3D:
+	if node is Skeleton3D:
+		return node as Skeleton3D
+	for child in node.get_children():
+		var found := _find_first_skeleton(child)
+		if found:
+			return found
+	return null
+
+
+## Instantiate an attachment .glb (imported PackedScene) into a single named
+## Node3D the caller can mount to a bone as one unit.
+func _instance_glb_as_attachment(path: String, slot_id: String) -> Node3D:
+	var packed = load(path)
+	if not (packed is PackedScene):
+		push_error("Attachment is not an importable scene: %s" % path)
+		return null
+	var scene_root: Node = packed.instantiate()
+	if not (scene_root is Node3D):
+		push_error("Attachment scene root is not a Node3D: %s" % path)
+		scene_root.free()
+		return null
+
+	var attachment := Node3D.new()
+	attachment.name = "%s_%s" % [slot_id, path.get_file().get_basename()]
+	for child in scene_root.get_children().duplicate():
+		scene_root.remove_child(child)
+		_clear_owner_recursive(child)
+		attachment.add_child(child)
+	scene_root.free()
+	return attachment
+
+
+## generate_scene() stamps every node with the GLB root as `owner`; that
+## becomes inconsistent (and noisy) once we reparent the node elsewhere.
+func _clear_owner_recursive(node: Node) -> void:
+	node.owner = null
+	for child in node.get_children():
+		_clear_owner_recursive(child)
+
+
+## Index the base body's skinned meshes by slot so equipping a body-part
+## attachment can hide the corresponding base mesh. generate_scene() parents
+## skinned meshes under the Skeleton3D, so scan there.
+func _extract_base_meshes(avatar: Node3D) -> void:
+	var skel := avatar.get_node_or_null("Skeleton3D") as Skeleton3D
+	if skel == null:
+		return
+
+	for child in skel.get_children():
+		if child is MeshInstance3D:
+			# The single "Body" placeholder mesh is registered only under
+			# "torso" -- mapping it to every body-part slot would make it
+			# vanish the moment any one body-part item is equipped. A real
+			# multi-mesh body registers each mesh under its own slot.
+			if child.name == "Body":
+				_base_meshes["torso"] = child
+			else:
+				var slot_id := _mesh_name_to_slot(child.name)
+				if slot_id != "":
+					_base_meshes[slot_id] = child
+
+
+## Map a mesh name to a slot id based on naming conventions (§4.3).
+func _mesh_name_to_slot(mesh_name: String) -> String:
+	if mesh_name == "Body":
+		# Generic body mesh - covers torso, legs, arms.
+		return "torso"
+	if mesh_name == "head_Mesh":
+		return "head"
+	if mesh_name == "torso_Mesh":
+		return "torso"
+	if mesh_name == "legs_Mesh":
+		return "legs"
+	if mesh_name == "left_arm_Mesh":
+		return "left_arm"
+	if mesh_name == "right_arm_Mesh":
+		return "right_arm"
+	return ""
+
+
+# ---------------------------------------------------------------------------
+# Internal: Skin Retargeting
+# ---------------------------------------------------------------------------
+
+## Retarget the skin weights of an attachment node to the canonical skeleton.
+## Walks all MeshInstance3D children and remaps joint indices by bone name.
+func _retarget_skin(attachment_node: Node3D) -> void:
+	if skeleton == null:
+		return
+
+	for child in attachment_node.get_children():
+		if child is MeshInstance3D:
+			var mesh_inst := child as MeshInstance3D
+			var mesh := mesh_inst.mesh
+			if mesh == null:
+				continue
+
+			# Note: MeshInstance3D.mesh is always a Mesh, never a MultiMesh —
+			# MultiMesh skinning goes through MultiMeshInstance3D.multimesh,
+			# a completely separate node/property, not reachable here.
+			if mesh is ArrayMesh:
+				var arr_mesh := mesh as ArrayMesh
+				var surface_count := arr_mesh.get_surface_count()
+
+				for surface_idx in surface_count:
+					var arrays := arr_mesh.surface_get_arrays(surface_idx)
+					# Static props (the common attachment) carry no bone/weight
+					# arrays at all -- nothing to retarget.
+					if arrays[Mesh.ARRAY_BONES] == null or arrays[Mesh.ARRAY_WEIGHTS] == null:
+						continue
+					var joints_array: PackedInt32Array = arrays[Mesh.ARRAY_BONES]
+					var weights_array: PackedFloat32Array = arrays[Mesh.ARRAY_WEIGHTS]
+
+					if joints_array.is_empty():
+						continue
+
+					# Remap joint indices by bone name.
+					var new_joints := PackedInt32Array()
+					for i in range(0, joints_array.size(), 4):
+						for j in 4:
+							var old_joint := joints_array[i + j]
+							if old_joint < 0:
+								new_joints.append(0)
+							else:
+								var bone_name := skeleton.get_bone_name(old_joint)
+								var new_idx: int = _bone_index_map.get(bone_name, 0)
+								new_joints.append(new_idx)
+
+					arrays[Mesh.ARRAY_BONES] = new_joints
+					arr_mesh.surface_set_arrays(surface_idx, arrays)
+
+
+## Parent an attachment node to its mount bone in the skeleton.
+func _parent_attachment(attachment_node: Node3D, slot_id: String,
+		asset_meta: Dictionary) -> void:
+
+	if skeleton == null:
+		return
+
+	var mount_bone: String = asset_meta.get("mount_bone", "")
+	if mount_bone.is_empty():
+		# Try to infer from slot.
+		mount_bone = _slot_to_mount_bone(slot_id)
+
+	if mount_bone.is_empty():
+		return
+
+	var bone_idx := skeleton.find_bone(mount_bone)
+	if bone_idx < 0:
+		return
+
+	# Get the world transform of the bone at the time of attachment.
+	var bone_pose := skeleton.get_bone_pose(bone_idx)
+	var bone_transform := skeleton.global_transform * bone_pose
+
+	# Position the attachment at the bone's location.
+	attachment_node.global_transform = bone_transform
+
+
+## Convert a slot id to its canonical mount bone name (§3.2).
+func _slot_to_mount_bone(slot_id: String) -> String:
+	match slot_id:
+		"head": return "Head"
+		"hair": return "HeadTop"
+		"face": return "Jaw"
+		"torso", "chest", "back": return "Chest"
+		"left_arm": return "LeftUpperArm"
+		"right_arm": return "RightUpperArm"
+		"left_hand": return "LeftHand"
+		"right_hand": return "RightHand"
+		"legs": return "Hips"
+		"pants": return "Hips"
+		"left_foot": return "LeftFoot"
+		"right_foot": return "RightFoot"
+		"accessory": return "Root"
+		_: return ""
+
+
+# ---------------------------------------------------------------------------
+# Internal: File Loading
+# ---------------------------------------------------------------------------
+
+## Load a file from the given path as a PackedByteArray.
+func _load_file(path: String) -> PackedByteArray:
+	var file := FileAccess.open(path, FileAccess.READ)
+	if file == null:
+		return PackedByteArray()
+	var data := file.get_buffer(file.get_length())
+	file.close()
+	return data

scripts/avatar/avatar_loader.gd.uid

@@ -0,0 +1 @@
+uid://br6x7f83dkrw2

scripts/avatar/avatar_loadout.gd

@@ -0,0 +1,315 @@
+## AvatarLoadout - Serializable loadout model + validation.
+##
+## Represents a complete avatar composition: a base body plus equipped items
+## per slot. Validates slot exclusivity and references against a catalog.
+##
+## See docs/architecture/avatar.md §5 for the loadout JSON format.
+
+class_name AvatarLoadout
+extends RefCounted
+
+# Sibling avatar scripts are referenced via preload rather than by their
+# global class_name so this module parses correctly from a bare clone (a
+# headless `godot <scene>` run does not rebuild the global class registry;
+# only an editor scan / `--import` does). See docs/architecture/avatar.md.
+const AvatarSlotRegistry := preload("res://scripts/avatar/avatar_slot_registry.gd")
+# Self-reference for the static factory below -- referring to our own
+# class_name doesn't resolve during a cold-cache compile (see note above).
+const _Self := preload("res://scripts/avatar/avatar_loadout.gd")
+
+
+## Maximum number of accessories allowed in the accessory slot.
+const MAX_ACCESSORIES: int = 8
+
+## The base body asset ID.
+var base_body: String = ""
+
+## Equipped items per slot. Keys are slot IDs from AvatarSlotRegistry.
+## Exclusive slots hold a single asset ID (or null).
+## The "accessory" slot holds an array of asset IDs.
+var slots: Dictionary = {}
+
+## Validation errors found during the last validate() call.
+var validation_errors: Array[String] = []
+
+## Skin tone color override (default: transparent = use asset colors).
+var skin_tone: Color = Color.TRANSPARENT
+
+
+# ---------------------------------------------------------------------------
+# Inner classes
+# ---------------------------------------------------------------------------
+
+## Represents a single equipped item in a slot.
+## Used by consumers to iterate over equipped items.
+class SlotItem:
+	## The slot this item belongs to.
+	var slot_id: String
+	## The catalog asset ID of the equipped item.
+	var asset_id: String
+
+	func _init(p_slot_id: String, p_asset_id: String) -> void:
+		slot_id = p_slot_id
+		asset_id = p_asset_id
+
+
+# ---------------------------------------------------------------------------
+# Lifecycle
+# ---------------------------------------------------------------------------
+
+func _init() -> void:
+	validation_errors = []
+
+
+# ---------------------------------------------------------------------------
+# Serialization
+# ---------------------------------------------------------------------------
+
+## Create a loadout from a JSON string.
+static func from_json(json_string: String) -> AvatarLoadout:
+	var loadout := _Self.new()
+	var data: Variant = JSON.parse_string(json_string)
+	if not (data is Dictionary):
+		loadout.validation_errors.append("Loadout JSON root is not an object")
+		return loadout
+
+	var root: Dictionary = data as Dictionary
+
+	# Parse base_body.
+	if root.has("base_body"):
+		var bb = root["base_body"]
+		if typeof(bb) == TYPE_STRING:
+			loadout.base_body = bb as String
+		else:
+			loadout.validation_errors.append("base_body must be a string")
+
+	# Parse slots.
+	if root.has("slots"):
+		var slots_data = root["slots"]
+		if typeof(slots_data) == TYPE_DICTIONARY:
+			var parsed_slots: Dictionary = slots_data as Dictionary
+			for slot_id in parsed_slots:
+				if slot_id is String:
+					loadout.slots[slot_id] = parsed_slots[slot_id]
+		else:
+			loadout.validation_errors.append("slots must be an object")
+	else:
+		loadout.validation_errors.append("Missing 'slots' in loadout JSON")
+
+	# Parse skin_tone.
+	if root.has("skin_tone"):
+		var st = root["skin_tone"]
+		if typeof(st) == TYPE_DICTIONARY:
+			var tone: Dictionary = st as Dictionary
+			loadout.skin_tone = Color(
+				float(tone.get("r", 0.0)),
+				float(tone.get("g", 0.0)),
+				float(tone.get("b", 0.0)),
+				float(tone.get("a", 1.0))
+			)
+
+	return loadout
+
+
+## Serialize this loadout to a JSON string.
+func to_json() -> String:
+	var data := {
+		"base_body": base_body,
+		"slots": {},
+	}
+
+	for slot_id in AvatarSlotRegistry.SLOT_IDS:
+		if slot_id == "accessory":
+			data["slots"][slot_id] = slots.get(slot_id, [])
+		else:
+			data["slots"][slot_id] = slots.get(slot_id, null)
+
+	# Include skin_tone if set.
+	if skin_tone != Color.TRANSPARENT:
+		data["skin_tone"] = {
+			"r": skin_tone.r,
+			"g": skin_tone.g,
+			"b": skin_tone.b,
+			"a": skin_tone.a,
+		}
+
+	return JSON.stringify(data, "  ")
+
+
+# ---------------------------------------------------------------------------
+# Validation
+# ---------------------------------------------------------------------------
+
+## Validate this loadout against the slot registry.
+## Returns true if valid; populates validation_errors if not.
+func validate() -> bool:
+	validation_errors.clear()
+
+	# Check base_body.
+	if base_body.is_empty():
+		validation_errors.append("base_body is required")
+
+	# Check each known slot.
+	for slot_id in AvatarSlotRegistry.SLOT_IDS:
+		var slot_def = AvatarSlotRegistry.get_slot(slot_id)
+		if slot_def == null:
+			validation_errors.append("Unknown slot: %s" % slot_id)
+			continue
+
+		var value = slots.get(slot_id)
+
+		if slot_def.exclusive:
+			# Exclusive slots: must be null or a string.
+			if value != null and typeof(value) != TYPE_STRING:
+				validation_errors.append(
+					"Slot '%s' must be null or a string, got %s" % [
+						slot_id, typeof(value)
+					]
+				)
+		else:
+			# Non-exclusive (accessory): must be null or an array.
+			if value != null and typeof(value) != TYPE_ARRAY:
+				validation_errors.append(
+					"Slot '%s' must be null or an array, got %s" % [
+						slot_id, typeof(value)
+					]
+				)
+			elif value is Array:
+				if slot_id == "accessory" and (value as Array).size() > MAX_ACCESSORIES:
+					validation_errors.append(
+						"Accessory count (%d) exceeds maximum (%d)" % [
+							(value as Array).size(), MAX_ACCESSORIES
+						]
+					)
+
+	# Check for duplicate accessories.
+	if slots.has("accessory") and slots["accessory"] is Array:
+		var accessories := slots["accessory"] as Array
+		var seen := {}
+		for item in accessories:
+			if item is String:
+				if seen.has(item):
+					validation_errors.append("Duplicate accessory: %s" % item)
+				seen[item] = true
+
+	return validation_errors.is_empty()
+
+
+## Convenience alias for validate().
+func is_valid() -> bool:
+	return validate()
+
+
+# ---------------------------------------------------------------------------
+# Accessors
+# ---------------------------------------------------------------------------
+
+## Check if a specific slot is equipped with a non-null item.
+func is_equipped(slot_id: String) -> bool:
+	if not AvatarSlotRegistry.has_slot(slot_id):
+		return false
+
+	var value = slots.get(slot_id)
+	if value == null:
+		return false
+
+	if typeof(value) == TYPE_STRING:
+		return not (value as String).is_empty()
+	elif typeof(value) == TYPE_ARRAY:
+		return (value as Array).size() > 0
+
+	return false
+
+
+## Get the equipped asset ID for an exclusive slot.
+## Returns empty string if not equipped or slot is not exclusive.
+func get_equipment(slot_id: String) -> String:
+	var value = slots.get(slot_id)
+	if value is String:
+		return value
+	return ""
+
+
+## Set equipment for an exclusive slot.
+func set_equipment(slot_id: String, asset_id: String) -> void:
+	if not AvatarSlotRegistry.has_slot(slot_id):
+		push_error("Unknown slot: %s" % slot_id)
+		return
+
+	var slot_def = AvatarSlotRegistry.get_slot(slot_id)
+	if slot_def and not slot_def.exclusive:
+		push_error("Slot '%s' is not exclusive" % slot_id)
+		return
+
+	slots[slot_id] = null if asset_id.is_empty() else asset_id
+
+
+## Add an accessory to the accessory slot.
+func add_accessory(asset_id: String) -> bool:
+	var accessories := slots.get("accessory", []) as Array
+	if accessories.size() >= MAX_ACCESSORIES:
+		return false
+	if asset_id.is_empty():
+		return false
+	if accessories.has(asset_id):
+		return false
+	accessories.append(asset_id)
+	slots["accessory"] = accessories
+	return true
+
+
+## Remove an accessory from the accessory slot.
+func remove_accessory(asset_id: String) -> bool:
+	var accessories := slots.get("accessory", []) as Array
+	if accessories.has(asset_id):
+		accessories.erase(asset_id)
+		slots["accessory"] = accessories
+		return true
+	return false
+
+
+## Iterate over equipped items as SlotItem objects.
+## Returns an array of SlotItem for each equipped slot.
+func get_equipped_items() -> Array[SlotItem]:
+	var items: Array[SlotItem] = []
+
+	for slot_id in AvatarSlotRegistry.SLOT_IDS:
+		var value = slots.get(slot_id)
+		if value == null:
+			continue
+
+		if typeof(value) == TYPE_STRING:
+			var asset_id := value as String
+			if not asset_id.is_empty():
+				items.append(SlotItem.new(slot_id, asset_id))
+		elif typeof(value) == TYPE_ARRAY:
+			for item_id in value:
+				if item_id is String and not (item_id as String).is_empty():
+					items.append(SlotItem.new(slot_id, item_id))
+
+	return items
+
+
+# ---------------------------------------------------------------------------
+# Hashing
+# ---------------------------------------------------------------------------
+
+## Compute a hash of this loadout for change detection.
+## Mirrors the server's loadout_hash concept.
+func compute_hash() -> int:
+	var hasher := HashingContext.new()
+	hasher.start(HashingContext.HASH_SHA256)
+	hasher.update(base_body.to_utf8_buffer())
+	for slot_id in AvatarSlotRegistry.SLOT_IDS:
+		hasher.update(slot_id.to_utf8_buffer())
+		var value = slots.get(slot_id)
+		if value is String:
+			hasher.update((value as String).to_utf8_buffer())
+		elif value is Array:
+			var arr_str = JSON.stringify(value)
+			hasher.update(arr_str.to_utf8_buffer())
+		else:
+			hasher.update("null".to_utf8_buffer())
+	var digest = hasher.finish()
+	# Return first 4 bytes as int for compact storage.
+	return digest[0] | (digest[1] << 8) | (digest[2] << 16) | (digest[3] << 24)

scripts/avatar/avatar_loadout.gd.uid

@@ -0,0 +1 @@
+uid://dxdtebl4upeny

scripts/avatar/avatar_slot_registry.gd

@@ -0,0 +1,275 @@
+## AvatarSlotRegistry - Static registry of slot definitions.
+##
+## Each slot maps to one or more bones and defines what can be equipped there.
+## This is the single source of truth for slot IDs, categories, mount bones,
+## exclusivity, and body-part vs attachment classification.
+##
+## See docs/architecture/avatar.md §3.2 for the full slot specification.
+class_name AvatarSlotRegistry extends RefCounted
+
+
+# ---------------------------------------------------------------------------
+# Slot definitions (mirrors §3.2 of the avatar spec)
+# ---------------------------------------------------------------------------
+
+## All known slot IDs, in canonical order.
+const SLOT_IDS: PackedStringArray = [
+	"head",
+	"hair",
+	"face",
+	"torso",
+	"chest",
+	"back",
+	"left_arm",
+	"right_arm",
+	"left_hand",
+	"right_hand",
+	"legs",
+	"pants",
+	"left_foot",
+	"right_foot",
+	"accessory",
+]
+
+## Body-part slots (exclusive, replace base mesh).
+const BODY_PART_SLOTS: PackedStringArray = [
+	"head", "torso", "legs", "left_arm", "right_arm",
+]
+
+## Attachment slots (layered on top of base mesh).
+const ATTACHMENT_SLOTS: PackedStringArray = [
+	"hair", "face", "chest", "back",
+	"left_hand", "right_hand", "pants",
+	"left_foot", "right_foot", "accessory",
+]
+
+## Slots that are multi-slot (multiple accessories can coexist).
+const MULTI_SLOT_IDS: PackedStringArray = ["accessory"]
+
+
+## Metadata for a single slot.
+class SlotDefinition:
+	## The slot ID string (e.g. "head", "hair").
+	var slot_key: String
+	## "body_part" or "attachment".
+	var category: String
+	## Primary mount bone name(s).
+	var mount_bones: PackedStringArray
+	## Whether at most one item can occupy this slot.
+	var exclusive: bool
+	## Whether this slot replaces a base mesh.
+	var is_body_part: bool
+
+	func _init(p_slot_key: String, p_category: String, p_mount_bones: PackedStringArray,
+			p_exclusive: bool, p_is_body_part: bool) -> void:
+		slot_key = p_slot_key
+		category = p_category
+		mount_bones = p_mount_bones
+		exclusive = p_exclusive
+		is_body_part = p_is_body_part
+
+
+# Slot metadata lookup tables (indexed by SLOT_IDS position). Static: every
+# caller uses AvatarSlotRegistry.method(...) directly on the class, never on
+# an instance, so this data has to be built once at class-load time via
+# _static_init() rather than an instance _init() that's never invoked.
+# Each entry: { category, mount_bones, exclusive, is_body_part }
+static var _slot_data: Dictionary = {}
+static var _slot_definitions: Array[SlotDefinition] = []
+
+
+static func _static_init() -> void:
+	_build_registry()
+
+
+static func _build_registry() -> void:
+	_slot_data = {
+		"head": {
+			"category": "body_part",
+			"mount_bones": ["Head"],
+			"exclusive": true,
+			"is_body_part": true,
+		},
+		"hair": {
+			"category": "attachment",
+			"mount_bones": ["HeadTop"],
+			"exclusive": true,
+			"is_body_part": false,
+		},
+		"face": {
+			"category": "attachment",
+			"mount_bones": ["Jaw"],
+			"exclusive": true,
+			"is_body_part": false,
+		},
+		"torso": {
+			"category": "body_part",
+			"mount_bones": ["Chest"],
+			"exclusive": true,
+			"is_body_part": true,
+		},
+		"chest": {
+			"category": "attachment",
+			"mount_bones": ["Chest"],
+			"exclusive": true,
+			"is_body_part": false,
+		},
+		"back": {
+			"category": "attachment",
+			"mount_bones": ["Chest"],
+			"exclusive": true,
+			"is_body_part": false,
+		},
+		"left_arm": {
+			"category": "body_part",
+			"mount_bones": ["LeftUpperArm"],
+			"exclusive": true,
+			"is_body_part": true,
+		},
+		"right_arm": {
+			"category": "body_part",
+			"mount_bones": ["RightUpperArm"],
+			"exclusive": true,
+			"is_body_part": true,
+		},
+		"left_hand": {
+			"category": "attachment",
+			"mount_bones": ["LeftHand"],
+			"exclusive": true,
+			"is_body_part": false,
+		},
+		"right_hand": {
+			"category": "attachment",
+			"mount_bones": ["RightHand"],
+			"exclusive": true,
+			"is_body_part": false,
+		},
+		"legs": {
+			"category": "body_part",
+			"mount_bones": ["Hips"],
+			"exclusive": true,
+			"is_body_part": true,
+		},
+		"pants": {
+			"category": "attachment",
+			"mount_bones": ["Hips"],
+			"exclusive": true,
+			"is_body_part": false,
+		},
+		"left_foot": {
+			"category": "attachment",
+			"mount_bones": ["LeftFoot"],
+			"exclusive": true,
+			"is_body_part": false,
+		},
+		"right_foot": {
+			"category": "attachment",
+			"mount_bones": ["RightFoot"],
+			"exclusive": true,
+			"is_body_part": false,
+		},
+		"accessory": {
+			"category": "attachment",
+			"mount_bones": ["Root"],
+			"exclusive": false,
+			"is_body_part": false,
+		},
+	}
+
+	# Build SlotDefinition objects.
+	for slot_id in SLOT_IDS:
+		var data = _slot_data[slot_id]
+		var def := SlotDefinition.new(
+			slot_id,
+			data["category"],
+			PackedStringArray(data["mount_bones"]),
+			data["exclusive"],
+			data["is_body_part"],
+		)
+		_slot_definitions.append(def)
+
+
+# ---------------------------------------------------------------------------
+# Public API
+# ---------------------------------------------------------------------------
+
+## Returns the list of all known slot IDs.
+static func get_slot_ids() -> PackedStringArray:
+	return SLOT_IDS
+
+
+## Returns true if *slot_id* is a known slot.
+static func has_slot(slot_id: String) -> bool:
+	return slot_id in SLOT_IDS
+
+
+## Returns the SlotDefinition for a slot, or null if unknown.
+static func get_slot(slot_id: String) -> SlotDefinition:
+	if not has_slot(slot_id):
+		return null
+	for def in _slot_definitions:
+		if def.slot_key == slot_id:
+			return def
+	return null
+
+
+## Returns all SlotDefinition objects in canonical order.
+static func get_slot_definitions() -> Array[SlotDefinition]:
+	return _slot_definitions
+
+
+## Returns the category for a slot ("body_part" or "attachment").
+static func get_category(slot_id: String) -> String:
+	if not has_slot(slot_id):
+		push_error("AvatarSlotRegistry: unknown slot '%s'" % slot_id)
+		return ""
+	return _slot_data[slot_id]["category"]
+
+
+## Returns the primary mount bone(s) for a slot.
+static func get_mount_bones(slot_id: String) -> PackedStringArray:
+	if not has_slot(slot_id):
+		push_error("AvatarSlotRegistry: unknown slot '%s'" % slot_id)
+		return PackedStringArray()
+	return PackedStringArray(_slot_data[slot_id]["mount_bones"])
+
+
+## Returns whether the slot is exclusive (at most one item).
+static func is_exclusive(slot_id: String) -> bool:
+	if not has_slot(slot_id):
+		push_error("AvatarSlotRegistry: unknown slot '%s'" % slot_id)
+		return true
+	return _slot_data[slot_id]["exclusive"]
+
+
+## Returns whether the slot is a body-part slot (replaces base mesh).
+static func is_body_part_slot(slot_id: String) -> bool:
+	if not has_slot(slot_id):
+		push_error("AvatarSlotRegistry: unknown slot '%s'" % slot_id)
+		return false
+	return _slot_data[slot_id]["is_body_part"]
+
+
+## Returns whether the slot is a multi-slot (e.g. accessory).
+static func is_multi_slot(slot_id: String) -> bool:
+	return slot_id in MULTI_SLOT_IDS
+
+
+## Returns the list of body-part slot IDs.
+static func get_body_part_slots() -> PackedStringArray:
+	return BODY_PART_SLOTS
+
+
+## Returns the list of attachment slot IDs.
+static func get_attachment_slots() -> PackedStringArray:
+	return ATTACHMENT_SLOTS
+
+
+## Validates that an asset's declared slot matches the slot it is placed in.
+static func validate_slot_assignment(asset_slot: String, slot_id: String) -> bool:
+	return asset_slot == slot_id
+
+
+## Returns the canonical order index for a slot (for serialization order).
+static func get_slot_index(slot_id: String) -> int:
+	return SLOT_IDS.find(slot_id)

scripts/avatar/avatar_slot_registry.gd.uid

@@ -0,0 +1 @@
+uid://do873d38pqhwa

scripts/avatar/avatar_system.gd

@@ -0,0 +1,324 @@
+## AvatarSystem - Global avatar orchestrator (autoload singleton).
+##
+## Owns the AvatarCatalog, AvatarLoader, and the current player's AvatarLoadout.
+## Provides a single entry point for the rest of the game to:
+##   - Load the asset catalog.
+##   - Load a player's avatar from a loadout.
+##   - Equip / unequip items and persist the resulting loadout.
+##
+## Registered as an autoload singleton named "AvatarSystem" in project.godot.
+
+extends Node
+
+# Sibling avatar scripts are referenced via preload rather than by their global
+# class_name so this autoload parses correctly from a bare clone -- a headless
+# `godot <scene>` run does not rebuild the global class registry (only an editor
+# scan / `--import` does), and this script is parsed at startup before any such
+# scan could have happened. See docs/architecture/avatar.md.
+const AvatarCatalog := preload("res://scripts/avatar/avatar_catalog.gd")
+const AvatarLoader := preload("res://scripts/avatar/avatar_loader.gd")
+const AvatarLoadout := preload("res://scripts/avatar/avatar_loadout.gd")
+const AvatarSlotRegistry := preload("res://scripts/avatar/avatar_slot_registry.gd")
+
+
+# ---------------------------------------------------------------------------
+# Signals
+# ---------------------------------------------------------------------------
+
+## Emitted when the catalog has finished loading.
+signal catalog_loaded
+
+## Emitted when the catalog fails to load.
+signal catalog_load_failed(error_message: String)
+
+## Emitted when the avatar has been fully assembled and is ready to render.
+signal avatar_ready(avatar_node: Node3D)
+
+## Emitted when the loadout changes (after equip/unequip).
+signal loadout_changed(loadout: AvatarLoadout)
+
+
+# ---------------------------------------------------------------------------
+# State
+# ---------------------------------------------------------------------------
+
+## The asset catalog (id -> metadata + path).
+var catalog: AvatarCatalog = null
+
+## The loader used to import GLB assets and assemble the avatar.
+var loader: AvatarLoader = null
+
+## The current player's loadout.
+var current_loadout: AvatarLoadout = null
+
+## The assembled avatar node (null until avatar_ready).
+var avatar_node: Node3D = null
+
+## Whether the catalog has been loaded.
+var is_catalog_loaded: bool = false
+
+## Whether an avatar is currently assembled.
+var is_avatar_ready: bool = false
+
+## Default catalog path.
+const DEFAULT_CATALOG_PATH := "res://assets/avatars/catalog.json"
+
+
+# ---------------------------------------------------------------------------
+# Lifecycle
+# ---------------------------------------------------------------------------
+
+func _ready() -> void:
+	catalog = AvatarCatalog.new()
+	loader = AvatarLoader.new()
+	loader.init_loader(catalog)
+	add_child(loader)
+
+
+## Load the asset catalog. Call this once at startup (or on demand).
+func load_catalog(path: String = DEFAULT_CATALOG_PATH) -> Error:
+	var err := catalog.load_catalog(path)
+	if err == OK:
+		is_catalog_loaded = true
+		catalog_loaded.emit()
+	else:
+		catalog_load_failed.emit("Failed to load catalog: %s" % err)
+	return err
+
+
+# ---------------------------------------------------------------------------
+# Avatar assembly
+# ---------------------------------------------------------------------------
+
+## Load and assemble an avatar from a loadout.
+## Returns the assembled avatar Node3D on success, or null on failure.
+func load_avatar(loadout: AvatarLoadout) -> Node3D:
+	if not is_catalog_loaded:
+		push_error("AvatarSystem: catalog not loaded; call load_catalog() first")
+		return null
+
+	if loadout == null:
+		push_error("AvatarSystem: loadout is null")
+		return null
+
+	# Validate the loadout against the catalog.
+	var validation := catalog.validate_loadout(loadout)
+	if not validation.valid:
+		push_error("AvatarSystem: invalid loadout: %s" % str(validation.errors))
+		return null
+
+	current_loadout = loadout
+
+	# Reset any previous avatar.
+	loader.reset()
+
+	# Load the base body.
+	var base_body_id := loadout.base_body
+	var base_node := loader.load_base_body(base_body_id)
+	if base_node == null:
+		push_error("AvatarSystem: failed to load base body '%s'" % base_body_id)
+		return null
+
+	# Load each equipped attachment.
+	for slot_id in AvatarSlotRegistry.SLOT_IDS:
+		var slot_value = loadout.slots.get(slot_id)
+
+		if slot_id == "accessory":
+			# Accessory is an array of asset ids.
+			if slot_value is Array:
+				for asset_id in slot_value:
+					if asset_id is String and not (asset_id as String).is_empty():
+						loader.load_attachment(slot_id, asset_id)
+		else:
+			# Exclusive slot: single asset id or null.
+			if slot_value is String and not (slot_value as String).is_empty():
+				loader.load_attachment(slot_id, slot_value)
+
+	# Hide base meshes for equipped body-part slots.
+	for slot_id in AvatarSlotRegistry.BODY_PART_SLOTS:
+		var slot_value = loadout.slots.get(slot_id)
+		if slot_value is String and not (slot_value as String).is_empty():
+			loader.set_base_mesh_visible(slot_id, false)
+
+	avatar_node = loader.avatar_node
+	is_avatar_ready = avatar_node != null
+	if is_avatar_ready:
+		avatar_ready.emit(avatar_node)
+
+	return avatar_node
+
+
+## Equip an item into a slot and rebuild the avatar.
+## Returns true on success.
+func equip(slot_id: String, asset_id: String) -> bool:
+	if current_loadout == null:
+		push_error("AvatarSystem: no loadout loaded")
+		return false
+
+	if not AvatarSlotRegistry.has_slot(slot_id):
+		push_error("AvatarSystem: unknown slot '%s'" % slot_id)
+		return false
+
+	if not catalog.has_asset(asset_id):
+		push_error("AvatarSystem: unknown asset '%s'" % asset_id)
+		return false
+
+	var asset := catalog.resolve(asset_id)
+	if asset.get("slot") != slot_id:
+		push_error("AvatarSystem: asset '%s' is for slot '%s', not '%s'" % [
+			asset_id, asset.get("slot"), slot_id])
+		return false
+
+	if slot_id == "accessory":
+		if not current_loadout.add_accessory(asset_id):
+			push_error("AvatarSystem: could not add accessory '%s'" % asset_id)
+			return false
+	else:
+		current_loadout.set_equipment(slot_id, asset_id)
+
+	loadout_changed.emit(current_loadout)
+	return true
+
+
+## Unequip an item from a slot and rebuild the avatar.
+## Returns true on success.
+func unequip(slot_id: String, asset_id: String = "") -> bool:
+	if current_loadout == null:
+		push_error("AvatarSystem: no loadout loaded")
+		return false
+
+	if not AvatarSlotRegistry.has_slot(slot_id):
+		push_error("AvatarSystem: unknown slot '%s'" % slot_id)
+		return false
+
+	if slot_id == "accessory":
+		if asset_id.is_empty():
+			push_error("AvatarSystem: accessory unequip requires an asset id")
+			return false
+		if not current_loadout.remove_accessory(asset_id):
+			push_error("AvatarSystem: accessory '%s' not equipped" % asset_id)
+			return false
+	else:
+		current_loadout.set_equipment(slot_id, "")
+
+	loadout_changed.emit(current_loadout)
+	return true
+
+
+## Serialize the current loadout to JSON.
+func save_loadout() -> String:
+	if current_loadout == null:
+		return ""
+	return current_loadout.to_json()
+
+
+## Load a loadout from a JSON string.
+func load_loadout_from_json(json_string: String) -> AvatarLoadout:
+	var loadout := AvatarLoadout.from_json(json_string)
+	if not loadout.validate():
+		push_error("AvatarSystem: invalid loadout JSON: %s" % str(loadout.validation_errors))
+		return null
+	return loadout
+
+
+## Get the list of available assets for a given slot.
+func get_assets_for_slot(slot_id: String) -> Array[String]:
+	return catalog.get_assets_by_slot(slot_id)
+
+
+## Get the display name for an asset id.
+func get_asset_display_name(asset_id: String) -> String:
+	var asset := catalog.resolve(asset_id)
+	return asset.get("display_name", asset_id)
+
+
+# ---------------------------------------------------------------------------
+# Local-player convenience API
+#
+# The rest of the game (the main menu, the in-world player) only needs three
+# things: load the catalog once, hand us the player's loadout (as the dict the
+# backend returns), and ask for an assembled avatar node to drop into a scene.
+# ---------------------------------------------------------------------------
+
+## True once a loadout has been handed to us (from the backend or a default).
+func has_loadout() -> bool:
+	return current_loadout != null
+
+
+## Ensure the catalog is loaded (idempotent). Safe to await repeatedly.
+func ensure_catalog() -> bool:
+	if is_catalog_loaded:
+		return true
+	return load_catalog() == OK
+
+
+## Set the current player's loadout from the dict shape the backend's
+## GET /api/avatar/loadout returns (i.e. AvatarLoadout.to_json() parsed).
+## Returns true if it validated and was stored.
+func set_loadout_from_dict(loadout_dict: Dictionary) -> bool:
+	var lo := AvatarLoadout.from_json(JSON.stringify(loadout_dict))
+	if not lo.validate():
+		push_warning("AvatarSystem: rejecting invalid loadout dict: %s"
+			% str(lo.validation_errors))
+		return false
+	current_loadout = lo
+	loadout_changed.emit(current_loadout)
+	return true
+
+
+## Assemble a fresh avatar Node3D from the current loadout, ready to parent
+## into a scene (e.g. onto the in-world player). Returns null if there's no
+## loadout or the catalog isn't loaded or assembly failed.
+func build_current_avatar() -> Node3D:
+	# Self-sufficient: load the catalog if needed, and fall back to a bare
+	# default loadout when login didn't prime one -- the player should always
+	# get *an* avatar, never a placeholder capsule, as long as the assets exist.
+	if not ensure_catalog():
+		push_warning("AvatarSystem: catalog unavailable; cannot build avatar")
+		return null
+	if current_loadout == null:
+		var bases := get_assets_for_slot("base_body")
+		if bases.is_empty():
+			return null
+		set_loadout_from_dict({"base_body": bases[0], "slots": {}})
+	return assemble_avatar(current_loadout)
+
+
+## Assemble a standalone avatar node from [param loadout] using a throwaway
+## loader -- unlike load_avatar(), this touches no shared state, so it's safe
+## to call many times (local player + one per remote peer). Returns null only
+## if the assets are genuinely missing.
+func assemble_avatar(loadout) -> Node3D:
+	if loadout == null or not is_catalog_loaded:
+		return null
+	var validation := catalog.validate_loadout(loadout)
+	if not validation.valid:
+		push_warning("AvatarSystem: invalid loadout, skipping: %s" % str(validation.errors))
+		return null
+
+	var l = AvatarLoader.new()
+	l.init_loader(catalog)
+	var base := l.load_base_body(loadout.base_body)
+	if base == null:
+		l.free()
+		return null
+
+	for slot_id in AvatarSlotRegistry.SLOT_IDS:
+		var v = loadout.slots.get(slot_id)
+		if slot_id == "accessory":
+			if v is Array:
+				for aid in v:
+					if aid is String and not (aid as String).is_empty():
+						l.load_attachment(slot_id, aid)
+		elif v is String and not (v as String).is_empty():
+			l.load_attachment(slot_id, v)
+
+	for slot_id in AvatarSlotRegistry.BODY_PART_SLOTS:
+		var v = loadout.slots.get(slot_id)
+		if v is String and not (v as String).is_empty():
+			l.set_base_mesh_visible(slot_id, false)
+
+	l.apply_skin_tone(loadout.skin_tone)
+
+	l.free()
+	return base

scripts/avatar/avatar_system.gd.uid

@@ -0,0 +1 @@
+uid://cfbvgfisbxbk

scripts/avatar/avatar_visualizer.gd

@@ -0,0 +1,117 @@
+## AvatarVisualizer
+##
+## Renders an AvatarLoadout into a 3D node tree for previews (the customization
+## screen). A thin wrapper over AvatarLoader -- it owns its own loader instance
+## and catalog reference so building a preview never disturbs AvatarSystem's
+## live in-world avatar state.
+##
+## Usage:
+##   var viz := AvatarVisualizer.new()
+##   viz.load_loadout(loadout, preview_root_node3d)   # preview_root gets the avatar as a child
+##   ...
+##   viz.clear()
+
+class_name AvatarVisualizer
+extends Object
+
+# Preloaded rather than referenced by global class_name -- see avatar_loadout.gd.
+const AvatarLoadout := preload("res://scripts/avatar/avatar_loadout.gd")
+const AvatarLoader := preload("res://scripts/avatar/avatar_loader.gd")
+const AvatarCatalog := preload("res://scripts/avatar/avatar_catalog.gd")
+const AvatarSlotRegistry := preload("res://scripts/avatar/avatar_slot_registry.gd")
+
+## Emitted when the visualizer has finished building the render tree.
+signal build_complete
+## Emitted when the visualizer has been cleared.
+signal cleared
+
+## The node the assembled avatar is parented under.
+var root: Node3D = null
+
+## The assembled avatar node (child of `root`).
+var avatar_node: Node3D = null
+
+## The loadout currently rendered.
+var current_loadout: AvatarLoadout = null
+
+var _loader = null
+var _catalog = null
+
+
+## Build the avatar for [param loadout] and parent it under [param root_node]
+## (or the previously-set `root`). Replaces any previously-built avatar.
+func load_loadout(loadout, root_node: Node3D = null) -> void:
+	if root_node != null:
+		root = root_node
+	if root == null or loadout == null:
+		return
+
+	clear()
+	current_loadout = loadout
+
+	if _catalog == null:
+		var sys = root.get_node_or_null("/root/AvatarSystem")
+		if sys != null:
+			_catalog = sys.catalog
+		if _catalog == null:
+			_catalog = AvatarCatalog.new()
+			_catalog.load_catalog("res://assets/avatars/catalog.json")
+
+	_loader = AvatarLoader.new()
+	root.add_child(_loader)
+	_loader.init_loader(_catalog)
+
+	var base: Node3D = _loader.load_base_body(loadout.base_body)
+	if base == null:
+		return
+	root.add_child(base)
+	avatar_node = base
+
+	for slot_id in AvatarSlotRegistry.SLOT_IDS:
+		var value = loadout.slots.get(slot_id)
+		if slot_id == "accessory":
+			if value is Array:
+				for aid in value:
+					if aid is String and not (aid as String).is_empty():
+						_loader.load_attachment(slot_id, aid)
+		elif value is String and not (value as String).is_empty():
+			_loader.load_attachment(slot_id, value)
+
+	for slot_id in AvatarSlotRegistry.BODY_PART_SLOTS:
+		var value = loadout.slots.get(slot_id)
+		if value is String and not (value as String).is_empty():
+			_loader.set_base_mesh_visible(slot_id, false)
+
+	_loader.apply_skin_tone(loadout.skin_tone)
+
+	build_complete.emit()
+
+
+## Tear down the current preview avatar.
+func clear() -> void:
+	if avatar_node != null and is_instance_valid(avatar_node):
+		avatar_node.queue_free()
+	avatar_node = null
+	if _loader != null and is_instance_valid(_loader):
+		_loader.queue_free()
+	_loader = null
+	current_loadout = null
+	cleared.emit()
+
+
+func get_root() -> Node3D:
+	return root
+
+
+func get_all_mesh_instances() -> Array[MeshInstance3D]:
+	var out: Array[MeshInstance3D] = []
+	if avatar_node:
+		_collect_meshes(avatar_node, out)
+	return out
+
+
+func _collect_meshes(node: Node, out: Array[MeshInstance3D]) -> void:
+	if node is MeshInstance3D:
+		out.append(node)
+	for child in node.get_children():
+		_collect_meshes(child, out)

scripts/avatar/avatar_visualizer.gd.uid

@@ -0,0 +1 @@
+uid://cvr5mmbv2worn

scripts/avatar/limb_animator.gd

@@ -0,0 +1,72 @@
+extends Node
+## Procedural locomotion for the placeholder blocky avatar.
+##
+## There are no animation clips yet -- this just swings the upper arm/leg bones
+## around their local X by a sine wave whose phase advances with distance
+## travelled, bends the knees on the rear half of the stride, and eases the
+## whole thing back to the rest pose when the character stops.
+##
+## The owner sets `speed` (horizontal m/s) every frame; setup() is given the
+## avatar's Skeleton3D. Bones are addressed by canonical name, so this works
+## for the local player and for snapshot-driven remote players alike.
+
+const STRIDE := 0.42         ## peak hip swing, radians (~24 deg)
+const ARM_SWING := 0.32      ## peak shoulder swing, radians
+const KNEE := 0.5            ## peak knee bend, radians
+const CYCLE := 1.9           ## phase (radians) advanced per metre travelled
+const BLEND := 12.0          ## ease rate toward the target pose
+const MOVE_EPS := 0.35       ## m/s below which we treat the avatar as idle
+
+var speed: float = 0.0
+
+var _skel: Skeleton3D = null
+var _idx := {}               # bone name -> skeleton index
+var _phase := 0.0
+var _amount := 0.0           # 0 = idle, 1 = full walk
+
+const _BONES := [
+	"LeftUpperLeg", "RightUpperLeg", "LeftLowerLeg", "RightLowerLeg",
+	"LeftUpperArm", "RightUpperArm",
+]
+
+
+func setup(skeleton: Skeleton3D) -> void:
+	_skel = skeleton
+	_idx.clear()
+	if skeleton == null:
+		return
+	for b in _BONES:
+		var i := skeleton.find_bone(b)
+		if i != -1:
+			_idx[b] = i
+
+
+func _process(delta: float) -> void:
+	if not is_instance_valid(_skel) or _idx.is_empty():
+		return
+
+	var moving := speed > MOVE_EPS
+	_amount = lerpf(_amount, 1.0 if moving else 0.0, clampf(BLEND * delta, 0.0, 1.0))
+	_phase += maxf(speed, 0.0) * delta * CYCLE
+	if _phase > TAU:
+		_phase -= TAU
+
+	var s := sin(_phase)
+	var swing := s * STRIDE * _amount
+	var arm := s * ARM_SWING * _amount
+
+	_pitch("LeftUpperLeg", swing)
+	_pitch("RightUpperLeg", -swing)
+	_pitch("LeftUpperArm", -arm)
+	_pitch("RightUpperArm", arm)
+	# Knee folds only while that leg is swinging back (negative pitch phase).
+	_pitch("LeftLowerLeg", maxf(0.0, -s) * KNEE * _amount)
+	_pitch("RightLowerLeg", maxf(0.0, s) * KNEE * _amount)
+
+
+func _pitch(bone: String, angle: float) -> void:
+	if not _idx.has(bone):
+		return
+	var i: int = _idx[bone]
+	var rest_q := _skel.get_bone_rest(i).basis.get_rotation_quaternion()
+	_skel.set_bone_pose_rotation(i, rest_q * Quaternion(Vector3.RIGHT, angle))

scripts/avatar_customization_screen.gd

@@ -0,0 +1,20 @@
+extends Control
+## Full-screen host for the AvatarCustomizationUI.
+##
+## The UI itself (scripts/avatar/avatar_customization_ui.gd) builds its own
+## layout programmatically and emits `closed` when the player backs out; this
+## thin wrapper is what makes it a navigable scene reachable from the main menu.
+
+const AvatarCustomizationUI := preload("res://scripts/avatar/avatar_customization_ui.gd")
+
+
+func _ready() -> void:
+	var ui := AvatarCustomizationUI.new()
+	ui.name = "AvatarCustomizationUI"
+	ui.set_anchors_preset(Control.PRESET_FULL_RECT)
+	add_child(ui)
+	ui.closed.connect(_on_closed)
+
+
+func _on_closed() -> void:
+	get_tree().change_scene_to_file("res://scenes/main_menu.tscn")

scripts/game.gd

@@ -0,0 +1,265 @@
+extends Node3D
+## Root controller for scenes/game.tscn.
+##
+## Local single-player by default (walk around the test level). When
+## Session.active (set by world_list.gd after POST /api/worlds/{id}/join),
+## connects a NetworkClient to the world's dedicated server and runs
+## networked: the local Player keeps predicting with its own collision-aware
+## movement, its input is forwarded to the server each physics frame, the
+## server's authoritative position is a correction backstop, and other
+## players are rendered from snapshots.
+##
+## Appearance sync is a follow-up -- remote players show as labelled capsules,
+## not their own avatars (the server doesn't replicate loadouts yet).
+
+const REMOTE_LERP := 12.0
+## Snap the local player to the server position past this drift (metres).
+## Tight enough that the client always ends up where the server actually
+## spawned it (which is spread out, not the fixed marker player.gd uses).
+const CORRECTION_THRESHOLD := 0.6
+
+@onready var _player: Player = $Player
+
+var _net: NetworkClient = null
+var _networked := false
+var _leaving := false            # a scene change is already in flight
+var _aligned := false            # snapped to the server spawn yet?
+var _remotes: Dictionary = {}   # peer_id -> Node3D
+var _remote_prev: Dictionary = {}   # peer_id -> Vector3 (last snapshot position)
+var _status_label: Label = null
+
+
+func _ready() -> void:
+	_show_build_stamp()
+	if Session.active:
+		_setup_networked()
+
+
+func _unhandled_input(event: InputEvent) -> void:
+	# ESC leaves the world back to the browser. Handled here (the scene root
+	# that owns the connection) rather than in player.gd so the teardown is
+	# a single ordered path -- doing it from two places raced _on_server_lost
+	# against the scene change and looked like a crash.
+	if event.is_action_pressed("ui_cancel"):
+		get_viewport().set_input_as_handled()
+		_leave_world()
+
+
+func _leave_world() -> void:
+	if _leaving:
+		return
+	_leaving = true
+	Input.mouse_mode = Input.MOUSE_MODE_VISIBLE
+	_teardown_net()
+	Session.clear()
+	get_tree().change_scene_to_file("res://scenes/world_list.tscn")
+
+
+## Close the ENet connection and stop it from calling us back mid-teardown.
+func _teardown_net() -> void:
+	if _net == null or not is_instance_valid(_net):
+		return
+	if _net.server_disconnected.is_connected(_on_server_lost):
+		_net.server_disconnected.disconnect(_on_server_lost)
+	if _net.connection_failed.is_connected(_on_server_lost):
+		_net.connection_failed.disconnect(_on_server_lost)
+	_net.disconnect_from_server()
+
+
+
+static func _build_label() -> String:
+	var f := FileAccess.open("res://assets/build_info.json", FileAccess.READ)
+	if f == null:
+		return "dev"
+	var d = JSON.parse_string(f.get_as_text())
+	if d is Dictionary:
+		return "%s %s" % [d.get("checkpoint", "?"), d.get("commit", "?")]
+	return "dev"
+
+
+func _show_build_stamp() -> void:
+	var layer := CanvasLayer.new()
+	layer.layer = 128
+	add_child(layer)
+	var lbl := Label.new()
+	lbl.text = "build %s" % _build_label()
+	lbl.add_theme_color_override("font_color", Color(1, 1, 0.35))
+	lbl.add_theme_color_override("font_outline_color", Color(0, 0, 0, 1))
+	lbl.add_theme_constant_override("outline_size", 6)
+	lbl.add_theme_font_size_override("font_size", 20)
+	# Full-width strip pinned to the TOP-left. (A bare preset + .position on a
+	# zero-size Label collapses the rect to negative width and nothing draws --
+	# which is why this never showed; explicit offsets fix it.)
+	lbl.set_anchors_preset(Control.PRESET_TOP_WIDE)
+	lbl.horizontal_alignment = HORIZONTAL_ALIGNMENT_LEFT
+	lbl.offset_left = 12
+	lbl.offset_right = -12
+	lbl.offset_top = 8
+	lbl.offset_bottom = 40
+	lbl.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	layer.add_child(lbl)
+
+
+func _exit_tree() -> void:
+	# Backstop for any exit path that didn't go through _leave_world (e.g. the
+	# app quitting): close the ENet connection so the server fires
+	# peer_disconnected and drops our player instead of leaving a ghost.
+	_teardown_net()
+
+
+func _setup_networked() -> void:
+	_show_status("Connecting to %s…" % Session.host)
+	_net = NetworkClient.new()
+	_net.name = "NetworkClient"
+	add_child(_net)
+	_net.server_disconnected.connect(_on_server_lost)
+	_net.connection_failed.connect(_on_server_lost)
+
+	var ok: bool = await _net.connect_to_server(Session.host, Session.port)
+	if not ok:
+		_on_server_lost()
+		return
+	_networked = true
+	_hide_status()
+	# Physics-process AFTER the player so net_input reflects this frame.
+	process_physics_priority = 10
+
+
+func _physics_process(_delta: float) -> void:
+	if not _networked or _net == null or not _net.is_connected_to_server():
+		return
+
+	# 1. Forward the local player's input to the server.
+	var inp: Dictionary = _player.net_input
+	_net.send_input(inp["move_x"], inp["move_z"], inp["jump"], inp["look_yaw"])
+
+	# 2. Server-authoritative position.
+	var own: Dictionary = _net.get_own_server_state()
+	if own.has("position"):
+		var server_pos: Vector3 = own["position"]
+		if not _aligned:
+			# First snapshot: hard-snap to where the server actually spawned
+			# us (player.gd starts everyone on the fixed marker, but the
+			# server spreads spawns out).
+			_player.apply_server_correction(server_pos)
+			_aligned = true
+		elif _player.global_position.distance_to(server_pos) > CORRECTION_THRESHOLD:
+			_player.apply_server_correction(server_pos)
+
+	# 3. Remote players.
+	_sync_remotes(_net.get_remote_states(), _delta)
+
+
+func _sync_remotes(states: Dictionary, delta: float) -> void:
+	for pid in states:
+		var st: Dictionary = states[pid]
+		var node: Node3D = _remotes.get(pid)
+		if node == null:
+			node = _make_remote(pid)
+			_remotes[pid] = node
+			add_child(node)
+			node.global_position = st.get("position", Vector3.ZERO)
+		var target: Vector3 = st.get("position", node.global_position)
+		node.global_position = node.global_position.lerp(target, clampf(REMOTE_LERP * delta, 0.0, 1.0))
+		node.rotation.y = st.get("rotation_y", node.rotation.y)
+
+		# Drive the remote's walk cycle from how far its authoritative
+		# position moved this snapshot.
+		var prev: Vector3 = _remote_prev.get(pid, target)
+		var anim := node.get_node_or_null("LimbAnim")
+		if anim != null and delta > 0.0:
+			anim.set("speed", (target - prev).length() / delta)
+		_remote_prev[pid] = target
+
+	for pid in _remotes.keys():
+		if not states.has(pid):
+			_remotes[pid].queue_free()
+			_remotes.erase(pid)
+			_remote_prev.erase(pid)
+
+
+func _make_remote(pid: int) -> Node3D:
+	var root := Node3D.new()
+	root.name = "Remote_%d" % pid
+
+	# Other players get the assembled avatar too (everyone shares the default
+	# look for now -- per-player loadout replication is the follow-up), tinted
+	# by peer id so they're still tellable apart, plus a name tag.
+	var tint := Color.from_hsv(fmod(float(pid) * 0.61803, 1.0), 0.55, 0.95)
+	var avatars := get_node_or_null("/root/AvatarSystem")
+	var visual: Node3D = null
+	if avatars and avatars.has_method("build_current_avatar"):
+		visual = avatars.build_current_avatar()
+	if visual != null:
+		visual.position = Vector3(0, -0.85, 0)  # feet -> ground (root is at hip height from server)
+		for mi in _all_mesh_instances(visual):
+			var m := StandardMaterial3D.new()
+			m.albedo_color = tint
+			mi.material_override = m
+		root.add_child(visual)
+		var skel := visual.find_child("Skeleton3D", true, false)
+		if skel is Skeleton3D:
+			var anim := preload("res://scripts/avatar/limb_animator.gd").new()
+			anim.name = "LimbAnim"
+			root.add_child(anim)
+			anim.call("setup", skel)
+	else:
+		var body := MeshInstance3D.new()
+		var capsule := CapsuleMesh.new()
+		capsule.radius = 0.35
+		capsule.height = 1.7
+		body.mesh = capsule
+		body.position = Vector3(0, 0.85, 0)
+		var mat := StandardMaterial3D.new()
+		mat.albedo_color = tint
+		body.material_override = mat
+		root.add_child(body)
+
+	var tag := Label3D.new()
+	tag.text = "Player %d" % pid
+	tag.position = Vector3(0, 2.1, 0)
+	tag.billboard = BaseMaterial3D.BILLBOARD_ENABLED
+	tag.no_depth_test = true
+	tag.pixel_size = 0.004
+	root.add_child(tag)
+
+	return root
+
+
+func _all_mesh_instances(node: Node, out: Array = []) -> Array:
+	if node is MeshInstance3D:
+		out.append(node)
+	for c in node.get_children():
+		_all_mesh_instances(c, out)
+	return out
+
+
+func _on_server_lost() -> void:
+	if _leaving:
+		return
+	_leaving = true
+	_networked = false
+	_show_status("Disconnected from the server. Returning to worlds…")
+	await get_tree().create_timer(1.5).timeout
+	Session.clear()
+	get_tree().change_scene_to_file("res://scenes/world_list.tscn")
+
+
+# ─── tiny on-screen status ────────────────────────────────────────────────────
+
+func _show_status(text: String) -> void:
+	if _status_label == null:
+		var layer := CanvasLayer.new()
+		layer.name = "StatusLayer"
+		add_child(layer)
+		_status_label = Label.new()
+		_status_label.position = Vector2(16, 16)
+		_status_label.add_theme_font_size_override("font_size", 18)
+		layer.add_child(_status_label)
+	_status_label.text = text
+	_status_label.visible = true
+
+
+func _hide_status() -> void:
+	if _status_label:
+		_status_label.visible = false

scripts/main_menu.gd

@@ -35,11 +35,12 @@ var _auth_mode_label: Label
 var _username_edit: LineEdit
 var _password_edit: LineEdit
 var _email_edit: LineEdit
-var _over_18_check: CheckBox
+var _dob_edit: LineEdit
 var _auth_button: Button
 var _status_label: Label
 var _welcome_label: Label
 var _play_button: Button
+var _customize_button: Button
 var _quit_button: Button
 
 var _is_register_mode: bool = false
@@ -48,7 +49,37 @@ var _is_authenticating: bool = false
 
 # ─── Lifecycle ────────────────────────────────────────────────────────────────
 
+
+static func _build_label() -> String:
+	var f := FileAccess.open("res://assets/build_info.json", FileAccess.READ)
+	if f == null:
+		return "dev"
+	var d = JSON.parse_string(f.get_as_text())
+	if d is Dictionary:
+		return "%s %s" % [d.get("checkpoint", "?"), d.get("commit", "?")]
+	return "dev"
+
+
 func _ready() -> void:
+	var v := Label.new()
+	v.text = "build %s" % _build_label()
+	v.add_theme_color_override("font_color", Color(1, 1, 1, 0.7))
+	v.add_theme_color_override("font_outline_color", Color(0, 0, 0, 0.85))
+	v.add_theme_constant_override("outline_size", 4)
+	v.add_theme_font_size_override("font_size", 12)
+	# Full-width strip pinned to the bottom, text right-aligned. A bare
+	# BOTTOM_RIGHT preset + .position on a zero-size Label collapses the rect
+	# and nothing renders -- which is why this never showed up.
+	v.set_anchors_preset(Control.PRESET_BOTTOM_WIDE)
+	v.horizontal_alignment = HORIZONTAL_ALIGNMENT_RIGHT
+	v.vertical_alignment = VERTICAL_ALIGNMENT_BOTTOM
+	v.offset_left = 8
+	v.offset_right = -10
+	v.offset_top = -28
+	v.offset_bottom = -6
+	v.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	add_child(v)
+
 	# Cache node references.
 	_auth_buttons_row = $CenterContainer/VBoxContainer/AuthButtonsRow
 	_login_button = $CenterContainer/VBoxContainer/AuthButtonsRow/LoginButton
@@ -58,11 +89,12 @@ func _ready() -> void:
 	_username_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/UsernameEdit
 	_password_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/PasswordEdit
 	_email_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/EmailEdit
-	_over_18_check = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/Over18Check
+	_dob_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/DobEdit
 	_auth_button = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthButton
 	_status_label = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthStatusLabel
 	_welcome_label = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/WelcomeLabel
 	_play_button = $CenterContainer/VBoxContainer/PlayButton
+	_customize_button = $CenterContainer/VBoxContainer/CustomizeButton
 	_quit_button = $CenterContainer/VBoxContainer/QuitButton
 
 	# Default to Play being gated. When a token exists, the async session
@@ -70,6 +102,7 @@ func _ready() -> void:
 	# keeping the button disabled until validation succeeds prevents a fast
 	# click from navigating to world_list with an expired/invalid token.
 	_play_button.disabled = true
+	_customize_button.disabled = true
 
 	# Check whether a valid session already exists (e.g. user logged in,
 	# navigated to world_list, then clicked Back). If so, restore the
@@ -80,6 +113,7 @@ func _ready() -> void:
 			var username: String = str((me_result.data as Dictionary).get("username", ""))
 			if username != "":
 				_show_authenticated(username)
+				await _prime_avatar()
 				auth_state_ready.emit()
 				return
 
@@ -111,10 +145,11 @@ func _show_authenticated(username: String) -> void:
 	_username_edit.visible = false
 	_password_edit.visible = false
 	_email_edit.visible = false
-	_over_18_check.visible = false
+	_dob_edit.visible = false
 	_auth_button.visible = false
 	_auth_mode_label.visible = false
 	_play_button.disabled = false
+	_customize_button.disabled = false
 	_auth_buttons_row.visible = false
 	print("Restored authenticated session for: ", username)
 
@@ -126,9 +161,10 @@ func _reset_to_logged_out() -> void:
 	_status_label.visible = false
 	_welcome_label.visible = false
 	_email_edit.visible = false
-	_over_18_check.visible = false
-	_over_18_check.button_pressed = false
+	_dob_edit.visible = false
+	_dob_edit.text = ""
 	_play_button.disabled = true  # Gate play behind successful auth.
+	_customize_button.disabled = true
 	_update_auth_mode_ui()
 
 
@@ -142,10 +178,29 @@ func _on_play_button_pressed() -> void:
 	get_tree().change_scene_to_file("res://scenes/world_list.tscn")
 
 
+func _on_customize_button_pressed() -> void:
+	if _customize_button.disabled:
+		return
+	get_tree().change_scene_to_file("res://scenes/avatar_customization.tscn")
+
+
 func _on_quit_button_pressed() -> void:
 	get_tree().quit()
 
 
+## Loose client-side check -- YYYY-MM-DD, a real calendar date, not in the
+## future. The backend does the authoritative age computation.
+func _is_valid_dob(dob: String) -> bool:
+	var m := RegEx.new()
+	m.compile("^\\d{4}-\\d{2}-\\d{2}$")
+	if m.search(dob) == null:
+		return false
+	var parts := dob.split("-")
+	var d := {"year": int(parts[0]), "month": int(parts[1]), "day": int(parts[2]), "hour": 0, "minute": 0, "second": 0}
+	var unix := Time.get_unix_time_from_datetime_dict(d)
+	return unix > 0 and unix < Time.get_unix_time_from_system()
+
+
 # ─── Auth panel toggle ────────────────────────────────────────────────────────
 
 func _on_login_button_pressed() -> void:
@@ -172,12 +227,12 @@ func _update_auth_mode_ui() -> void:
 		_auth_mode_label.text = "Register"
 		_auth_button.text = "Register"
 		_email_edit.visible = true
-		_over_18_check.visible = true
+		_dob_edit.visible = true
 	else:
 		_auth_mode_label.text = "Login"
 		_auth_button.text = "Login"
 		_email_edit.visible = false
-		_over_18_check.visible = false
+		_dob_edit.visible = false
 
 
 # ─── Auth submission ──────────────────────────────────────────────────────────
@@ -204,8 +259,9 @@ func _on_auth_button_pressed() -> void:
 		if email == "":
 			_show_status("Email is required.")
 			return
-		if not _over_18_check.button_pressed:
-			_show_status("You must confirm you are 18 or older to register.")
+		var dob := _dob_edit.text.strip_edges()
+		if not _is_valid_dob(dob):
+			_show_status("Enter your date of birth as YYYY-MM-DD.")
 			return
 
 		_auth_button.disabled = true
@@ -213,8 +269,8 @@ func _on_auth_button_pressed() -> void:
 		_is_authenticating = true
 		_clear_status()
 
-		var result := await ApiClient.register(username, email, password, true)
-		_on_auth_complete(result)
+		var result := await ApiClient.register(username, email, password, dob)
+		await _on_auth_complete(result)
 	else:
 		_auth_button.disabled = true
 		_auth_button.text = "Logging in..."
@@ -222,7 +278,7 @@ func _on_auth_button_pressed() -> void:
 		_clear_status()
 
 		var result := await ApiClient.login(username, password)
-		_on_auth_complete(result)
+		await _on_auth_complete(result)
 
 
 func _on_auth_complete(result: Dictionary) -> void:
@@ -232,24 +288,54 @@ func _on_auth_complete(result: Dictionary) -> void:
 	_is_authenticating = false
 
 	if result.ok:
-		# Success — hide the auth form fields, show only the welcome label.
+		# Update the UI to the authenticated state first, synchronously, so
+		# the player sees "Welcome" + an enabled Play immediately -- then
+		# prime the avatar (a catalog load + a loadout fetch) in the
+		# background. A slow or failing prime must never gate getting in.
 		_username_edit.visible = false
 		_password_edit.visible = false
 		_email_edit.visible = false
-		_over_18_check.visible = false
+		_dob_edit.visible = false
 		_auth_button.visible = false
 		_auth_mode_label.visible = false
 		_status_label.visible = false
 		_welcome_label.text = "Welcome, %s!" % _username_edit.text.strip_edges()
 		_welcome_label.visible = true
 		_play_button.disabled = false
+		_customize_button.disabled = false
 		_auth_buttons_row.visible = false
 		print("Auth successful. Token stored.")
+		await _prime_avatar()
 	else:
 		# Failure — show backend error detail.
 		_show_status(result.detail)
 
 
+# ─── Avatar priming ───────────────────────────────────────────────────────────
+
+## After a successful auth, load the asset catalog and the player's saved
+## loadout so the in-world player renders as their avatar. Best-effort: a
+## failure here just means the player falls back to the default capsule, it
+## never blocks getting into the game.
+func _prime_avatar() -> void:
+	if not Engine.has_singleton("AvatarSystem") and get_node_or_null("/root/AvatarSystem") == null:
+		return
+	var avatars = get_node_or_null("/root/AvatarSystem")
+	if avatars == null:
+		return
+	if not await avatars.ensure_catalog():
+		push_warning("main_menu: avatar catalog failed to load; using fallback look")
+		return
+	var res: Dictionary = await ApiClient.get_avatar_loadout()
+	if res.ok and res.data is Dictionary and (res.data as Dictionary).has("data"):
+		avatars.set_loadout_from_dict((res.data as Dictionary)["data"])
+	else:
+		# No saved loadout reachable -- fall back to the catalog's first base body.
+		var bases: Array = avatars.get_assets_for_slot("base_body")
+		if bases.size() > 0:
+			avatars.set_loadout_from_dict({"base_body": bases[0], "slots": {}})
+
+
 # ─── Status helpers ───────────────────────────────────────────────────────────
 
 func _show_status(message: String) -> void:

scripts/mp_game_flow_client.gd

@@ -0,0 +1,83 @@
+extends SceneTree
+## One client process for the full networked game-flow test
+## (scripts/run_game_multiplayer_test.sh): register -> POST /api/worlds/{id}/join
+## -> Session.begin -> load scenes/game.tscn -> run networked.
+##
+##   godot --headless --path . --script res://scripts/mp_game_flow_client.gd -- \
+##       --role a|b --world 1
+##
+## role b: joins, holds still, prints  RESULT b in_world  and stays ~40 s.
+## role a: joins, moves forward, prints RESULT a remotes=<n> moved=<bool>;
+##         exits 0 iff it saw a remote player node AND moved.
+
+var role := "b"
+var world_id := 1
+
+
+func _initialize() -> void:
+	var args := OS.get_cmdline_user_args()
+	for i in args.size():
+		if args[i] == "--role" and i + 1 < args.size():
+			role = args[i + 1]
+		elif args[i] == "--world" and i + 1 < args.size():
+			world_id = int(args[i + 1])
+	_run()
+
+
+func _run() -> void:
+	await process_frame
+	var api := root.get_node("ApiClient")
+	var session := root.get_node("Session")
+
+	var uname := "mpflow_%s_%d" % [role, int(Time.get_unix_time_from_system() * 1000) % 1000000]
+	var reg: Dictionary = await api.register(uname, uname + "@e.com", "secret123", "1990-01-01")
+	if not reg.ok:
+		print("RESULT %s register_failed %s" % [role, reg.detail])
+		quit(1); return
+
+	var join: Dictionary = await api.join_world(world_id)
+	if not (join.ok and join.data is Dictionary):
+		print("RESULT %s join_failed status=%d %s" % [role, join.status, join.detail])
+		quit(1); return
+	var d: Dictionary = join.data
+	session.begin(world_id, str(d["host"]), int(d["port"]))
+
+	change_scene_to_file("res://scenes/game.tscn")
+	# Wait for the scene + NetworkClient connect (game.gd awaits internally).
+	for i in 180:
+		await process_frame
+
+	var game := current_scene
+	var netc = game.get_node_or_null("NetworkClient") if game else null
+	if netc == null or not netc.is_connected_to_server():
+		print("RESULT %s not_connected" % role)
+		quit(1); return
+
+	if role == "b":
+		print("RESULT b in_world")
+		for i in 1200:
+			await process_frame
+		quit(0); return
+
+	# role a: hold still briefly (confirm we don't fall through the floor),
+	# then move and look for a remote node.
+	var player = game.get_node("Player")
+	var min_y := 1000.0
+	for i in 30:
+		await process_frame
+		min_y = minf(min_y, player.global_position.y)
+	var on_floor: bool = min_y > -3.0
+
+	var start: Vector3 = player.global_position
+	var max_remotes := 0
+	for i in 120:
+		player._input_direction = Vector2(0, 1)  # fake held forward
+		await process_frame
+		var n := 0
+		for c in game.get_children():
+			if c.name.begins_with("Remote_"):
+				n += 1
+		max_remotes = maxi(max_remotes, n)
+	var moved: bool = player.global_position.distance_to(start) > 1.0
+	print("RESULT a remotes=%d moved=%s on_floor=%s" % [max_remotes, str(moved), str(on_floor)])
+	quit(0 if (moved and max_remotes >= 1 and on_floor) else 1)

scripts/mp_test_client.gd

@@ -0,0 +1,64 @@
+extends SceneTree
+## One client process for the 2-player multiplayer test
+## (scripts/run_multiplayer_2p_test.sh). Two real OS processes = real network.
+##
+##   godot --headless --path . --script res://scripts/mp_test_client.gd -- --role a --port 7777
+##
+## role "a": moves forward for ~2 s, then prints
+##           RESULT a remotes=<n> moved=<bool>  and exits 0 iff it both moved
+##           and saw >=1 remote player.
+## role "b": connects, holds still for ~4 s, prints  RESULT b connected  exits 0.
+
+var role := "b"
+var port := 7777
+
+
+func _initialize() -> void:
+	var args := OS.get_cmdline_user_args()
+	for i in args.size():
+		if args[i] == "--role" and i + 1 < args.size():
+			role = args[i + 1]
+		elif args[i] == "--port" and i + 1 < args.size():
+			port = int(args[i + 1])
+	_run()
+
+
+func _run() -> void:
+	await process_frame
+	var net := NetworkClient.new()
+	root.add_child(net)
+	var ok: bool = await net.connect_to_server("127.0.0.1", port)
+	if not ok:
+		print("RESULT %s connect_failed" % role)
+		quit(1)
+		return
+	for i in 15:
+		await process_frame
+
+	if role == "b":
+		# Hold still and stay connected long enough for A to boot, connect,
+		# and observe us (A's Godot startup alone is a couple of seconds).
+		print("RESULT b connected")
+		for i in 1200:
+			await process_frame
+		net.disconnect_from_server()
+		quit(0)
+		return
+
+	# role a: move forward, watch for a remote and our own displacement, and
+	# confirm the server keeps us on the ground (not falling through it).
+	var start: Vector3 = net.position
+	var max_remotes := 0
+	var min_server_y := 1000.0
+	for i in 90:
+		net.predict_and_send(1.0 / 30.0, 0.0, -1.0, false, 0.0)
+		await process_frame
+		max_remotes = maxi(max_remotes, net.get_remote_states().size())
+		var st: Dictionary = net.get_own_server_state()
+		if st.has("position"):
+			min_server_y = minf(min_server_y, st["position"].y)
+	var moved: bool = net.position.distance_to(start) > 1.0
+	var on_floor: bool = min_server_y > -2.0
+	print("RESULT a remotes=%d moved=%s on_floor=%s (min_y=%.2f)" % [max_remotes, str(moved), str(on_floor), min_server_y])
+	net.disconnect_from_server()
+	quit(0 if (moved and max_remotes >= 1 and on_floor) else 1)

scripts/network_client.gd

@@ -0,0 +1,259 @@
+class_name NetworkClient
+extends Node
+## Client-side multiplayer: ENet connection, local-player input prediction +
+## server reconciliation (with input replay), and remote-player state for the
+## game to render.
+##
+## RPC path-matching: Godot resolves an rpc_id() call's target by matching the
+## sending node's NodePath on the receiver. scripts/server.gd is the SceneTree
+## root named "Server"; it spawns each peer's PlayerNode as a child named
+## "Player_<peer_id>". So the client needs local nodes at /root/Server (for the
+## server-initiated _receive_snapshot) and /root/Server/Player_<own_id> (the
+## target of rpc_request_input). connect_to_server() builds that once the peer
+## id is known.
+##
+## Usage:
+##     var net := NetworkClient.new()
+##     get_tree().root.add_child(net)
+##     if await net.connect_to_server(host, port):
+##         # each physics frame, from the local player controller:
+##         net.predict_and_send(delta, move_x, move_z, jump, body_yaw)
+##         # read net.position / net.get_remote_states() to render
+
+# Movement constants -- MUST match scripts/server.gd and player_spawner.gd.
+const WALK_SPEED := 5.0
+const JUMP_VELOCITY := 4.5
+const GRAVITY := 9.8
+
+## Predicted vs authoritative drift beyond this (metres) snaps rather than
+## trusting the prediction.
+const RECONCILE_ERROR_THRESHOLD := 0.35
+
+## Ring buffer cap. 120 frames at 30 Hz = 4 s of history, well past any
+## realistic LAN RTT.
+const PREDICTION_BUFFER_SIZE := 120
+
+signal reconciled(correction_distance: float)
+signal connected_to_server
+signal connection_failed
+signal server_disconnected
+
+var peer: ENetMultiplayerPeer
+var my_peer_id: int = 0
+var _server_root: Node
+var _player_proxy: Node
+
+var _seq: int = 0
+## Ring buffer of {seq, move_x, move_z, jump, delta, position, velocity},
+## oldest first. Entries are dropped as the server acks their seq.
+var _prediction_buffer: Array[Dictionary] = []
+
+## Local predicted player state.
+var position: Vector3 = Vector3.ZERO
+var velocity: Vector3 = Vector3.ZERO
+var _on_floor: bool = true
+
+## peer_id -> latest authoritative state dict from the most recent snapshot,
+## for every peer that isn't us. The game reads this to render other players.
+var _remote_states: Dictionary = {}
+## Our own latest authoritative state from the most recent snapshot.
+var _own_state: Dictionary = {}
+var _last_snapshot_tick: int = -1
+
+
+func connect_to_server(host: String, port: int) -> bool:
+	peer = ENetMultiplayerPeer.new()
+	var err := peer.create_client(host, port)
+	if err != OK:
+		push_error("NetworkClient: create_client failed: %d" % err)
+		connection_failed.emit()
+		return false
+
+	multiplayer.multiplayer_peer = peer
+	multiplayer.server_disconnected.connect(func(): server_disconnected.emit())
+
+	for _i in 300:  # ~5 s at 60 fps
+		await get_tree().process_frame
+		match peer.get_connection_status():
+			MultiplayerPeer.CONNECTION_CONNECTED:
+				_on_connected()
+				return true
+			MultiplayerPeer.CONNECTION_DISCONNECTED:
+				connection_failed.emit()
+				return false
+	connection_failed.emit()
+	return false
+
+
+func _on_connected() -> void:
+	my_peer_id = multiplayer.get_unique_id()
+
+	_server_root = Node.new()
+	_server_root.name = "Server"
+	_server_root.set_script(preload("res://scripts/network_receiver_proxy.gd"))
+	get_tree().root.add_child(_server_root)
+	_server_root.set("owner_client", self)
+
+	_player_proxy = Node.new()
+	_player_proxy.name = "Player_%d" % my_peer_id
+	_player_proxy.set_script(preload("res://scripts/network_player_proxy.gd"))
+	_server_root.add_child(_player_proxy)
+
+	connected_to_server.emit()
+
+
+func disconnect_from_server() -> void:
+	if peer:
+		peer.close()
+	if _server_root and is_instance_valid(_server_root):
+		_server_root.queue_free()
+	multiplayer.multiplayer_peer = null
+	_prediction_buffer.clear()
+	_remote_states.clear()
+
+
+func is_connected_to_server() -> bool:
+	return peer != null and peer.get_connection_status() == MultiplayerPeer.CONNECTION_CONNECTED
+
+
+# ---------------------------------------------------------------------------
+# Prediction -- call every physics frame from the local player controller.
+# Applies input locally immediately (zero perceived latency) and sends it.
+# ---------------------------------------------------------------------------
+
+func predict_and_send(delta: float, move_x: float, move_z: float, jump: bool, look_yaw: float = 0.0) -> void:
+	_apply_movement(delta, move_x, move_z, jump)
+
+	_seq += 1
+	_prediction_buffer.append({
+		"seq": _seq,
+		"move_x": move_x, "move_z": move_z, "jump": jump,
+		"delta": delta,
+		"position": position, "velocity": velocity,
+	})
+	if _prediction_buffer.size() > PREDICTION_BUFFER_SIZE:
+		_prediction_buffer.pop_front()
+
+	if _player_proxy and is_instance_valid(_player_proxy):
+		_player_proxy.rpc_id(1, "rpc_request_input",
+			{"move_x": move_x, "move_z": move_z, "jump": jump, "look_yaw": look_yaw}, _seq)
+
+
+func _apply_movement(delta: float, move_x: float, move_z: float, jump: bool) -> void:
+	if not _on_floor:
+		velocity.y -= GRAVITY * delta
+	elif jump:
+		velocity.y = JUMP_VELOCITY
+
+	var dir := Vector3(move_x, 0.0, move_z)
+	if dir.length() > 0.01:
+		dir = dir.normalized()
+		velocity.x = dir.x * WALK_SPEED
+		velocity.z = dir.z * WALK_SPEED
+	else:
+		velocity.x = 0.0
+		velocity.z = 0.0
+
+	position += velocity * delta
+	# Headless prediction has no collision shape; treat the spawn plane as the
+	# floor. A render-side controller drives the real CharacterBody3D and reads
+	# `position` back for reconciliation only.
+	if position.y <= 0.0:
+		position.y = 0.0
+		velocity.y = 0.0
+		_on_floor = true
+	else:
+		_on_floor = false
+
+
+# ---------------------------------------------------------------------------
+# Reconciliation -- _ReceiverProxy calls this when a snapshot arrives.
+# ---------------------------------------------------------------------------
+
+func _handle_snapshot(snap: Dictionary) -> void:
+	var snap_tick: int = snap.get("tick", 0)
+	if snap_tick <= _last_snapshot_tick:
+		return  # Stale / out-of-order (unreliable channel).
+	_last_snapshot_tick = snap_tick
+
+	var players: Dictionary = snap.get("players", {})
+
+	# --- Remote players ---
+	_remote_states.clear()
+	for key in players:
+		var pid := int(key)
+		if pid == my_peer_id:
+			continue
+		_remote_states[pid] = players[key]
+
+	# --- Local player: reconcile ---
+	var mine: Variant = players.get(my_peer_id, players.get(str(my_peer_id), null))
+	if not (mine is Dictionary):
+		return
+	_own_state = mine
+	var auth_pos: Vector3 = mine.get("position", position)
+	var auth_vel: Vector3 = mine.get("velocity", velocity)
+	var acked_seq: int = int(mine.get("last_seq", 0))
+
+	# Drop inputs the server has already applied.
+	while not _prediction_buffer.is_empty() and _prediction_buffer[0]["seq"] <= acked_seq:
+		_prediction_buffer.pop_front()
+
+	# Re-simulate the still-in-flight inputs from the authoritative state.
+	var replay_pos := auth_pos
+	var replay_vel := auth_vel
+	var replay_floor := replay_pos.y <= 0.0
+	for entry in _prediction_buffer:
+		var d: float = entry["delta"]
+		if not replay_floor:
+			replay_vel.y -= GRAVITY * d
+		elif entry["jump"]:
+			replay_vel.y = JUMP_VELOCITY
+		var dir := Vector3(entry["move_x"], 0.0, entry["move_z"])
+		if dir.length() > 0.01:
+			dir = dir.normalized()
+			replay_vel.x = dir.x * WALK_SPEED
+			replay_vel.z = dir.z * WALK_SPEED
+		else:
+			replay_vel.x = 0.0
+			replay_vel.z = 0.0
+		replay_pos += replay_vel * d
+		if replay_pos.y <= 0.0:
+			replay_pos.y = 0.0
+			replay_vel.y = 0.0
+			replay_floor = true
+		else:
+			replay_floor = false
+
+	var error := position.distance_to(replay_pos)
+	if error > RECONCILE_ERROR_THRESHOLD:
+		position = replay_pos
+		velocity = replay_vel
+		_on_floor = replay_floor
+		reconciled.emit(error)
+
+
+# ---------------------------------------------------------------------------
+# Remote-player state for rendering
+# ---------------------------------------------------------------------------
+
+## peer_id -> {position, rotation_y, velocity, on_floor, last_seq} from the most
+## recent snapshot. Read this each frame to spawn/update remote avatars.
+func get_remote_states() -> Dictionary:
+	return _remote_states
+
+
+## Our own latest authoritative state from the most recent snapshot, or {}.
+func get_own_server_state() -> Dictionary:
+	return _own_state
+
+
+## Send an input frame to the server WITHOUT running NetworkClient's own
+## flat-plane prediction -- for callers that predict locally with their own
+## collision-aware CharacterBody3D (scripts/game.gd) and only want the server
+## as an authority/correction backstop.
+func send_input(move_x: float, move_z: float, jump: bool, look_yaw: float) -> void:
+	_seq += 1
+	if _player_proxy and is_instance_valid(_player_proxy):
+		_player_proxy.rpc_id(1, "rpc_request_input",
+			{"move_x": move_x, "move_z": move_z, "jump": jump, "look_yaw": look_yaw}, _seq)

scripts/network_player_proxy.gd

@@ -0,0 +1,11 @@
+extends Node
+## Client-side proxy for the server's PlayerNode (scripts/player_spawner.gd),
+## attached at runtime as "Player_<own_peer_id>" under the /root/Server proxy.
+##
+## rpc_request_input is the only RPC the client sends. Godot resolves the RPC
+## transfer config from the LOCAL node's declaration and verifies both peers
+## declare the same @rpc set at this path, so it must match player_spawner.gd.
+
+@rpc("any_peer", "call_remote", "reliable")
+func rpc_request_input(_input: Dictionary, _seq: int) -> void:
+	pass  # Real implementation is on the server.

scripts/network_receiver_proxy.gd

@@ -0,0 +1,15 @@
+extends Node
+## Client-side proxy node, attached at runtime as a Node named "Server" at the
+## SceneTree root by NetworkClient. Exists purely so Godot's RPC path-matching
+## finds a receiver for _receive_snapshot (the server calls it on its own root
+## "Server" node, so the client needs a node at /root/Server declaring the same
+## @rpc set). Not a real server.
+
+var owner_client: Node = null
+
+
+## Must match scripts/server.gd's @rpc annotation on _receive_snapshot exactly.
+@rpc("any_peer", "call_remote", "reliable")
+func _receive_snapshot(snapshot_data: Dictionary) -> void:
+	if owner_client and is_instance_valid(owner_client):
+		owner_client._handle_snapshot(snapshot_data)

scripts/player.gd

@@ -2,15 +2,23 @@ class_name Player
 extends CharacterBody3D
 ## The player character controller.
 ##
-## A simple CharacterBody3D with WASD/arrow locomotion, gravity, jump, and a
-## first-person Camera3D with mouse-look.  Reads the spawn point from the
-## current scene's `PlayerSpawn` Marker3D (see docs/architecture/pc2_test_level.md §3).
+## Roblox-style third-person controller:
 ##
-## No networking, no chunk code, no avatar UI — PC2 is local-only.
+##   * Classic camera (default): the mouse cursor is free; hold a mouse button
+##     and drag to orbit the camera 360 in yaw (pitch clamped). Right button
+##     also turns the character to face the camera while held. Scroll wheel
+##     zooms; zoom all the way in -> first person.
+##   * Shift Lock (toggle Left Shift): mouse locks to a centre crosshair, the
+##     camera moves over the right shoulder, and the character's facing is
+##     locked to the camera -- WASD strafes / backpedals.
+##
+## Movement is always camera-relative (W = away from the camera). Outside the
+## camera-facing modes the body auto-rotates toward its movement direction.
+## Spawn point comes from the current scene's `PlayerSpawn` Marker3D.
 
 
 # ---------------------------------------------------------------------------
-# Movement constants
+# Movement / camera constants
 # ---------------------------------------------------------------------------
 
 const WALK_SPEED: float = 5.0
@@ -20,34 +28,64 @@ const GRAVITY: float = 9.8
 ## Mouse-look sensitivity (radians per pixel of relative motion).
 const MOUSE_SENSITIVITY: float = 0.003
 
-## Camera pitch is clamped so the player can't flip past looking straight
-## up/down (which would otherwise let mouse-look invert on itself).
-const PITCH_LIMIT: float = deg_to_rad(89.0)
+## Vertical offset applied to the assembled avatar so its feet (origin y=0)
+## line up with the bottom of the player's collision capsule.
+const AVATAR_FEET_OFFSET: float = -0.8
+
+## Camera pitch limits (radians): near top-down to looking up from below.
+## Yaw is deliberately unclamped -- full 360 orbit.
+const PITCH_MIN: float = -1.35
+const PITCH_MAX: float = 1.2
+
+## Camera pivot height above the player origin, third-person vs first-person.
+const PIVOT_Y_TP: float = 1.2
+const PIVOT_Y_FP: float = 0.65
+
+## Zoom (spring length) range, scroll step, and the distance at or below which
+## we switch to first person.
+const ZOOM_MIN: float = 0.4
+const ZOOM_MAX: float = 9.0
+const ZOOM_STEP: float = 0.6
+const FIRST_PERSON_ZOOM: float = 0.6
+const ZOOM_DEFAULT: float = 3.5
+
+## How far right the camera sits in Shift Lock (metres).
+const SHOULDER_OFFSET: float = 0.85
+
+## How fast the body swings toward its target facing.
+const BODY_TURN_SPEED: float = 12.0
 
 
 # ---------------------------------------------------------------------------
-# Input state
+# State
 # ---------------------------------------------------------------------------
 
 var _input_direction := Vector2.ZERO
-var _camera_pitch: float = 0.0
+var _camera_yaw: float = 0.0        # unclamped, wraps
+var _camera_pitch: float = -0.12
+var _zoom: float = ZOOM_DEFAULT
+var _shift_lock: bool = false
+var _mouse_look_held: bool = false  # LMB or RMB held (classic drag)
+var _rmb_held: bool = false         # RMB specifically (turns the body)
+var _spawn_position: Vector3 = Vector3(0, 1.5, 0)
 
-@onready var _camera: Camera3D = $Camera3D
+@onready var _camera: Camera3D = $CameraPivot/SpringArm3D/Camera3D
+@onready var _camera_pivot: Node3D = $CameraPivot
+@onready var _spring_arm: SpringArm3D = $CameraPivot/SpringArm3D
+@onready var _capsule_mesh: MeshInstance3D = $CapsuleMesh
+
+var _avatar_view: Node3D = null
+var _limb_anim: Node = null
+var _crosshair: CanvasLayer = null
 
 
 # ---------------------------------------------------------------------------
-# _ready — spawn at PlayerSpawn marker, capture the mouse for look
+# _ready
 # ---------------------------------------------------------------------------
 
 func _ready() -> void:
-	# Per §3 of pc2_test_level.md: look up PlayerSpawn from the current
-	# scene root.  The lookup walks the full subtree (recursive=true) so
-	# it finds the marker whether it is a direct child of the level or
-	# nested deeper.
-	#
-	# current_scene is null in headless --script mode and in any scene
-	# before the main scene is fully swapped in, so guard it rather than
-	# blindly dereferencing.
+	# Per §3 of pc2_test_level.md: look up PlayerSpawn from the current scene
+	# root (recursive), guarding the null current_scene of headless runs.
 	var current_scene: Node = get_tree().current_scene
 	var spawn: Node = null
 	if current_scene != null:
@@ -55,37 +93,140 @@ func _ready() -> void:
 
 	if spawn is Node3D:
 		global_position = (spawn as Node3D).global_position
-		# Align player forward with spawn yaw (optional polish).
-		var spawn_yaw := (spawn as Node3D).rotation.y
-		rotation.y = spawn_yaw
+		rotation.y = (spawn as Node3D).rotation.y
 	else:
 		push_warning("player.gd: no PlayerSpawn marker found; spawning at origin")
 		global_position = Vector3(0, 1.0, 0)
+	_spawn_position = global_position
 
-	# Capture the mouse for FPS-style look. Headless/test runs have no real
-	# window to capture input for, so guard against that rather than error.
-	if DisplayServer.get_name() != "headless":
-		Input.mouse_mode = Input.MOUSE_MODE_CAPTURED
+	# The spring arm must not collide with the player's own capsule (same
+	# layer) or the camera gets yanked against the player's head.
+	_spring_arm.add_excluded_object(self)
+
+	# The camera pivot orbits the player freely -- it can't inherit the body's
+	# yaw, so detach it and drive its world transform ourselves each frame.
+	_camera_pivot.top_level = true
+	_camera_yaw = rotation.y
+
+	_build_crosshair()
+	_refresh_mouse_mode()
+	_update_camera()
+	_apply_avatar()
+
+
+func _build_crosshair() -> void:
+	if DisplayServer.get_name() == "headless":
+		return
+	_crosshair = CanvasLayer.new()
+	_crosshair.layer = 64
+	var l := Label.new()
+	l.text = "+"
+	l.add_theme_font_size_override("font_size", 22)
+	l.add_theme_color_override("font_color", Color(1, 1, 1, 0.85))
+	l.add_theme_color_override("font_outline_color", Color(0, 0, 0, 0.8))
+	l.add_theme_constant_override("outline_size", 4)
+	l.set_anchors_preset(Control.PRESET_CENTER)
+	l.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	l.vertical_alignment = VERTICAL_ALIGNMENT_CENTER
+	l.offset_left = -12
+	l.offset_right = 12
+	l.offset_top = -16
+	l.offset_bottom = 16
+	l.mouse_filter = Control.MOUSE_FILTER_IGNORE
+	_crosshair.add_child(l)
+	add_child(_crosshair)
+	_crosshair.visible = false
+
+
+## Show the player's assembled avatar and hide the placeholder capsule.
+func _apply_avatar() -> void:
+	var avatars := get_node_or_null("/root/AvatarSystem")
+	if avatars == null or not avatars.has_method("build_current_avatar"):
+		return
+	var avatar: Node3D = avatars.build_current_avatar()
+	if avatar == null:
+		push_warning("player.gd: no avatar to show; keeping the placeholder capsule")
+		return
+	avatar.position = Vector3(0.0, AVATAR_FEET_OFFSET, 0.0)
+	add_child(avatar)
+	_avatar_view = avatar
+	if _capsule_mesh:
+		_capsule_mesh.visible = false
+
+	# Procedural walk cycle -- no clips yet, just swing the limb bones with speed.
+	var skel := avatar.find_child("Skeleton3D", true, false)
+	if skel is Skeleton3D:
+		_limb_anim = preload("res://scripts/avatar/limb_animator.gd").new()
+		add_child(_limb_anim)
+		_limb_anim.call("setup", skel)
 
 
 # ---------------------------------------------------------------------------
-# _unhandled_input — capture keyboard / mouse for movement
+# Input
 # ---------------------------------------------------------------------------
 
+func _is_first_person() -> bool:
+	return _zoom <= FIRST_PERSON_ZOOM
+
+
+## Mouse should be captured (hidden, locked) whenever the camera is in an
+## aim-style mode or the player is mid-drag.
+func _want_mouse_captured() -> bool:
+	return _shift_lock or _is_first_person() or _mouse_look_held
+
+
+## Body facing is slaved to the camera in Shift Lock, first person, or while
+## the right mouse button is held.
+func _want_face_camera() -> bool:
+	return _shift_lock or _is_first_person() or _rmb_held
+
+
+func _refresh_mouse_mode() -> void:
+	if DisplayServer.get_name() == "headless":
+		return
+	Input.mouse_mode = Input.MOUSE_MODE_CAPTURED if _want_mouse_captured() \
+		else Input.MOUSE_MODE_VISIBLE
+	if _crosshair != null:
+		_crosshair.visible = _shift_lock or _is_first_person()
+
+
+func _set_zoom(v: float) -> void:
+	var was_fp := _is_first_person()
+	_zoom = clampf(v, ZOOM_MIN, ZOOM_MAX)
+	if _is_first_person() != was_fp:
+		_refresh_mouse_mode()
+	_update_camera()
+
+
 func _unhandled_input(event: InputEvent) -> void:
 	if event is InputEventKey:
 		var key := event as InputEventKey
 		if key.pressed and not key.echo:
-			_update_input_direction(key)
+			if key.keycode == KEY_SHIFT:
+				_shift_lock = not _shift_lock
+				_refresh_mouse_mode()
+				_update_camera()
+			else:
+				_update_input_direction(key)
 		elif not key.pressed:
 			_clear_input_direction(key)
-		# Release the mouse so the player can get back to a menu/cursor.
-		if key.pressed and key.keycode == KEY_ESCAPE:
-			Input.mouse_mode = Input.MOUSE_MODE_VISIBLE
-	elif event is InputEventMouseButton and event.pressed:
-		# Clicking back into the viewport re-captures the mouse.
-		if Input.mouse_mode == Input.MOUSE_MODE_VISIBLE and DisplayServer.get_name() != "headless":
-			Input.mouse_mode = Input.MOUSE_MODE_CAPTURED
+		# ESC (leave the world) is handled by game.gd, which owns the connection.
+
+	elif event is InputEventMouseButton:
+		var mb := event as InputEventMouseButton
+		match mb.button_index:
+			MOUSE_BUTTON_WHEEL_UP:
+				if mb.pressed:
+					_set_zoom(_zoom - ZOOM_STEP)
+			MOUSE_BUTTON_WHEEL_DOWN:
+				if mb.pressed:
+					_set_zoom(_zoom + ZOOM_STEP)
+			MOUSE_BUTTON_LEFT, MOUSE_BUTTON_RIGHT:
+				_mouse_look_held = Input.is_mouse_button_pressed(MOUSE_BUTTON_LEFT) \
+					or Input.is_mouse_button_pressed(MOUSE_BUTTON_RIGHT)
+				_rmb_held = Input.is_mouse_button_pressed(MOUSE_BUTTON_RIGHT)
+				_refresh_mouse_mode()
+
 	elif event is InputEventMouseMotion and Input.mouse_mode == Input.MOUSE_MODE_CAPTURED:
 		_handle_mouse_look(event as InputEventMouseMotion)
 
@@ -115,34 +256,86 @@ func _clear_input_direction(key: InputEventKey) -> void:
 
 
 func _handle_mouse_look(event: InputEventMouseMotion) -> void:
-	# Yaw rotates the whole body (so movement direction turns with the
-	# look direction); pitch only tilts the camera, so the capsule itself
-	# never tips over.
-	rotation.y -= event.relative.x * MOUSE_SENSITIVITY
-	_camera_pitch = clampf(_camera_pitch - event.relative.y * MOUSE_SENSITIVITY, -PITCH_LIMIT, PITCH_LIMIT)
-	_camera.rotation.x = _camera_pitch
+	_camera_yaw = wrapf(_camera_yaw - event.relative.x * MOUSE_SENSITIVITY, -PI, PI)
+	_camera_pitch = clampf(_camera_pitch - event.relative.y * MOUSE_SENSITIVITY,
+		PITCH_MIN, PITCH_MAX)
+	_update_camera()
+
+
+## Place the orbit pivot at the player's head and point it per yaw/pitch.
+## Applies the first-person / shoulder framing. Called from _ready, on input,
+## and every physics frame (the player moves under it).
+func _update_camera() -> void:
+	if not is_instance_valid(_camera_pivot):
+		return
+	var fp := _is_first_person()
+	_camera_pivot.global_position = global_position \
+		+ Vector3(0.0, PIVOT_Y_FP if fp else PIVOT_Y_TP, 0.0)
+	_camera_pivot.global_rotation = Vector3(_camera_pitch, _camera_yaw, 0.0)
+
+	_spring_arm.spring_length = 0.0 if fp else _zoom
+	_spring_arm.position.x = SHOULDER_OFFSET if (_shift_lock and not fp) else 0.0
+
+	# Hide our own avatar in first person so the head doesn't fill the view.
+	if _avatar_view != null and is_instance_valid(_avatar_view):
+		_avatar_view.visible = not fp
 
 
 # ---------------------------------------------------------------------------
-# Physics — gravity, jump, move_and_slide
+# Physics
 # ---------------------------------------------------------------------------
 
+## Input frame forwarded to the server by scripts/game.gd each physics tick:
+## world-space move direction (yaw-transformed, normalized), jump edge, body yaw.
+var net_input: Dictionary = {"move_x": 0.0, "move_z": 0.0, "jump": false, "look_yaw": 0.0}
+
+
 func _physics_process(delta: float) -> void:
-	# Apply gravity.
 	if not is_on_floor():
 		velocity.y -= GRAVITY * delta
 
-	# Jump.
+	var jumped := false
 	if is_on_floor() and Input.is_action_just_pressed("ui_accept"):
 		velocity.y = JUMP_VELOCITY
+		jumped = true
 
-	# Build movement direction from input. Godot's local "forward" is -Z, not
-	# +Z, so W (input.y = +1) must use -basis.z -- using +basis.z here would
-	# move the player backward when pressing forward (confirmed by reading
-	# Camera3D/Node3D's own convention: a node looks down its local -Z).
-	var direction := (_input_direction.x * transform.basis.x -
-		_input_direction.y * transform.basis.z).normalized()
+	# Camera-relative movement. A node looks down its local -Z, so forward is
+	# -cam_basis.z and W (input.y = +1) heads away from the camera.
+	var cam_basis := Basis.from_euler(Vector3(0.0, _camera_yaw, 0.0))
+	var direction := (_input_direction.x * cam_basis.x
+		- _input_direction.y * cam_basis.z).normalized()
 	velocity.x = direction.x * WALK_SPEED
 	velocity.z = direction.z * WALK_SPEED
 
+	# Body facing: locked to the camera in aim modes, otherwise turns toward
+	# the movement direction.
+	if _want_face_camera():
+		rotation.y = _camera_yaw
+	elif direction.length_squared() > 0.01:
+		var target_yaw := atan2(-direction.x, -direction.z)
+		rotation.y = lerp_angle(rotation.y, target_yaw,
+			clampf(BODY_TURN_SPEED * delta, 0.0, 1.0))
+
 	move_and_slide()
+	_update_camera()
+
+	if _limb_anim != null:
+		_limb_anim.set("speed", Vector2(velocity.x, velocity.z).length())
+
+	# Safety net -- never fall forever.
+	if global_position.y < -10.0:
+		global_position = _spawn_position
+		velocity = Vector3.ZERO
+
+	net_input = {
+		"move_x": direction.x, "move_z": direction.z,
+		"jump": jumped, "look_yaw": rotation.y,
+	}
+
+
+## Server-authoritative correction from scripts/game.gd when the local
+## predicted position has drifted too far.
+func apply_server_correction(pos: Vector3) -> void:
+	global_position = pos
+	velocity.x = 0.0
+	velocity.z = 0.0

scripts/player_spawner.gd

@@ -0,0 +1,86 @@
+class_name PlayerNode
+extends CharacterBody3D
+## Server-authoritative player entity.
+##
+## One per connected peer, spawned as a child of the Server node. Movement runs
+## in _physics_process at the project's fixed physics rate (30 Hz, matching
+## scripts/server.gd's snapshot rate and the client's prediction step).
+
+## Movement constants -- mirror scripts/server.gd (the source of truth) and
+## scripts/network_client.gd (the client's prediction).
+const WALK_SPEED := 5.0
+const JUMP_VELOCITY := 4.5
+const GRAVITY := 9.8
+
+var peer_id: int = -1
+
+## Where the server spawned this player (set by server.gd). Used as the
+## respawn point if the player somehow ends up below the world.
+var spawn_position: Vector3 = Vector3(0, 1.5, 0)
+
+## Highest input seq applied authoritatively so far (echoed in snapshots so
+## the client can drop acked inputs and replay the rest).
+var last_applied_seq: int = 0
+
+## Queue of {seq:int, move_x:float, move_z:float, jump:bool, look_yaw:float}
+## appended by rpc_request_input, drained each physics frame.
+var _input_queue: Array[Dictionary] = []
+var _look_yaw: float = 0.0
+
+
+func _physics_process(delta: float) -> void:
+	if _input_queue.is_empty():
+		_integrate(0.0, 0.0, false, delta)
+	else:
+		# Reliable ENet preserves order; sort defensively anyway.
+		_input_queue.sort_custom(func(a, b): return a["seq"] < b["seq"])
+		for input in _input_queue:
+			_look_yaw = input.get("look_yaw", _look_yaw)
+			_integrate(input.get("move_x", 0.0), input.get("move_z", 0.0), input.get("jump", false), delta)
+			last_applied_seq = input["seq"]
+		_input_queue.clear()
+
+	rotation.y = _look_yaw
+
+	# Safety net: if a player ends up below the world (physics shove, tunnel
+	# through the floor), put them back on their spawn instead of falling
+	# forever.
+	if global_position.y < -10.0:
+		global_position = spawn_position
+		velocity = Vector3.ZERO
+
+
+func _integrate(move_x: float, move_z: float, jump: bool, delta: float) -> void:
+	if not is_on_floor():
+		velocity.y -= GRAVITY * delta
+	elif jump:
+		velocity.y = JUMP_VELOCITY
+
+	var dir := Vector3(move_x, 0.0, move_z)
+	if dir.length() > 0.01:
+		dir = dir.normalized()
+		velocity.x = dir.x * WALK_SPEED
+		velocity.z = dir.z * WALK_SPEED
+	else:
+		velocity.x = 0.0
+		velocity.z = 0.0
+
+	move_and_slide()
+	if is_on_floor() and velocity.y < 0.0:
+		velocity.y = 0.0
+
+
+func get_server_state() -> Dictionary:
+	return {
+		"position": global_position,
+		"rotation_y": rotation.y,
+		"velocity": velocity,
+		"on_floor": is_on_floor(),
+	}
+
+
+@rpc("any_peer", "call_remote", "reliable")
+func rpc_request_input(input: Dictionary, seq: int) -> void:
+	var d := input.duplicate()
+	d["seq"] = seq
+	_input_queue.append(d)

scripts/player_spawner.gd.uid

@@ -0,0 +1 @@
+uid://br27owjh2f5xd

scripts/run_checkpoint_tests.py

@@ -90,6 +90,10 @@ def main():
     db_url = f"postgresql+asyncpg://agp_user:agp_password@localhost:{args.postgres_port}/agp_db"
     backend_env = os.environ.copy()
     backend_env["DATABASE_URL"] = db_url
+    # Every smoke test registers users against this one backend from one
+    # client IP; the per-IP auth rate limit would trip mid-suite.
+    # test_rate_limit.py exercises the limiter itself regardless.
+    backend_env["RATE_LIMIT_ENABLED"] = "false"
 
     print("\n=== Backend: alembic upgrade head ===")
     r = run([sys.executable, "-m", "alembic", "upgrade", "head"], cwd=BACKEND, env=backend_env)
@@ -133,10 +137,77 @@ def main():
                 for test in smoke_tests:
                     rel = os.path.relpath(test, ROOT)
                     print(f"\n--- {rel} ---")
-                    r = run([godot_bin, "--headless", "--path", str(ROOT), "--script", f"res://{rel}"], env=godot_env)
-                    if r.returncode != 0:
-                        godot_ok = False
+                    # smoke_test_network_client.gd needs a separate dedicated
+                    # server process listening on ENet 7777 -- stand one up
+                    # just for that test and tear it down after.
+                    game_server = None
+                    if os.path.basename(rel) == "smoke_test_network_client.gd":
+                        print("(starting scenes/server.tscn for the network client test)")
+                        game_server = subprocess.Popen(
+                            [godot_bin, "--headless", "--path", str(ROOT), "res://scenes/server.tscn"],
+                            env=godot_env,
+                        )
+                        time.sleep(3)
+                    try:
+                        r = run([godot_bin, "--headless", "--path", str(ROOT), "--script", f"res://{rel}"], env=godot_env)
+                        if r.returncode != 0:
+                            godot_ok = False
+                    finally:
+                        if game_server is not None:
+                            game_server.terminate()
+                            try:
+                                game_server.wait(timeout=10)
+                            except subprocess.TimeoutExpired:
+                                game_server.kill()
                 results["godot smoke tests"] = godot_ok
+
+                # 2-player multiplayer test (its own shell harness: server + 2
+                # real client processes).
+                mp_script = ROOT / "scripts" / "run_multiplayer_2p_test.sh"
+                if mp_script.exists():
+                    print("\n--- scripts/run_multiplayer_2p_test.sh ---")
+                    mp_env = os.environ.copy()
+                    mp_env["GODOT_BIN"] = godot_bin
+                    r = run(["bash", str(mp_script)], env=mp_env)
+                    results["multiplayer 2p test"] = r.returncode == 0
+
+                # Fresh-clone boot: a from-scratch tree must import + boot with
+                # zero script errors (no reliance on a committed .godot cache).
+                fc_script = ROOT / "scripts" / "verify_fresh_clone.sh"
+                if fc_script.exists():
+                    print("\n--- scripts/verify_fresh_clone.sh ---")
+                    fc_env = os.environ.copy()
+                    fc_env["GODOT_BIN"] = godot_bin
+                    r = run(["bash", str(fc_script)], env=fc_env)
+                    results["fresh-clone boot"] = r.returncode == 0
+
+                # Export packaging: the game reads some files (catalog.json)
+                # via raw FileAccess, which `all_resources` export doesn't
+                # pack unless include_filter covers them. Passes from source,
+                # bare capsule in the .exe. This guards that.
+                ec_script = ROOT / "scripts" / "verify_export_contents.gd"
+                if ec_script.exists():
+                    print("\n--- scripts/verify_export_contents.gd ---")
+                    r = run([godot_bin, "--headless", "--path", str(ROOT),
+                             "--script", "res://scripts/verify_export_contents.gd"], env=godot_env)
+                    results["export packaging"] = r.returncode == 0
+
+                # Run a key smoke against the EXPORTED pack, not just source --
+                # release-build resources differ (e.g. the runtime GLTFDocument
+                # path produced no skeleton in a real export; load().instantiate()
+                # of the imported .scn does). This runs the avatar smoke on
+                # exactly what ships.
+                exported_pck = ROOT / "export" / "_ci_check.pck"
+                exported_pck.parent.mkdir(exist_ok=True)
+                ep = run([godot_bin, "--headless", "--path", str(ROOT),
+                          "--export-pack", "Linux", str(exported_pck)], env=godot_env)
+                if ep.returncode == 0 and exported_pck.exists():
+                    r = run([godot_bin, "--headless", "--main-pack", str(exported_pck),
+                             "--script", "res://scripts/smoke_test_avatar_system.gd"], env=godot_env)
+                    results["avatar smoke (exported pack)"] = r.returncode == 0
+                    exported_pck.unlink(missing_ok=True)
+                else:
+                    results["avatar smoke (exported pack)"] = False
         finally:
             server_proc.terminate()
             try:

scripts/run_game_multiplayer_test.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+# Full networked game flow, two real client processes:
+#   register -> POST /api/worlds/{id}/join -> Session -> game.tscn -> networked.
+# Client A must see client B rendered as a remote player and its own movement
+# must round-trip. Requires a backend with GAME_SERVERS_ENABLED and the Godot
+# binary reachable from it.
+#
+# Usage: scripts/run_game_multiplayer_test.sh <backend_base_url> <world_id>
+set -uo pipefail
+cd "$(dirname "$0")/.."
+
+BASE_URL="${1:?usage: run_game_multiplayer_test.sh <backend_url> <world_id>}"
+WORLD_ID="${2:?usage: run_game_multiplayer_test.sh <backend_url> <world_id>}"
+GODOT_BIN="${GODOT_BIN:-godot}"
+command -v "$GODOT_BIN" >/dev/null 2>&1 || GODOT_BIN="$HOME/godot/godot"
+
+export AGP_API_BASE_URL="$BASE_URL"
+
+cleanup() { kill "${B_PID:-}" 2>/dev/null; wait 2>/dev/null; }
+trap cleanup EXIT
+
+echo "=== client B: join world $WORLD_ID and hold ==="
+"$GODOT_BIN" --headless --path . --script res://scripts/mp_game_flow_client.gd -- \
+	--role b --world "$WORLD_ID" >/tmp/mpflow_b.log 2>&1 &
+B_PID=$!
+for _ in $(seq 1 40); do grep -q 'RESULT b in_world' /tmp/mpflow_b.log && break; sleep 1; done
+grep -q 'RESULT b in_world' /tmp/mpflow_b.log || { echo "B never entered the world:"; tail -5 /tmp/mpflow_b.log; echo "=== SMOKE RESULT: FAIL ==="; exit 1; }
+
+echo "=== client A: join world $WORLD_ID, move, look for B ==="
+"$GODOT_BIN" --headless --path . --script res://scripts/mp_game_flow_client.gd -- \
+	--role a --world "$WORLD_ID" 2>&1 | tee /tmp/mpflow_a.log
+A_LINE=$(grep '^RESULT a' /tmp/mpflow_a.log || true)
+
+echo
+echo "A: ${A_LINE:-<none>}"
+echo "B: $(grep '^RESULT b' /tmp/mpflow_b.log || echo '<none>')"
+
+if echo "$A_LINE" | grep -q 'moved=true' && echo "$A_LINE" | grep -qE 'remotes=[1-9]'; then
+	echo "=== SMOKE RESULT: PASS ==="
+	exit 0
+fi
+echo "=== SMOKE RESULT: FAIL ==="
+exit 1