Merge architect's per-file test detail into the checkpoint doc fix

Architect independently reclaimed this task after my fix landed and
rewrote the same doc with more precise per-file test descriptions and a
more specific gap list -- genuinely better in places (caught real detail
I'd summarized loosely) but its own investigation also introduced one
factual error (claimed 18 tests in test_auth_age_gate.py; verified via
pytest --collect-only, it's 17) and dropped two things worth keeping:
the exact commit hash for reproducibility, and the Client export section
(it never looked at the export step).

Merged: kept the architect's richer per-file coverage descriptions and
gap analysis, restored the verified counts/commit hash/export section/
--quit gotcha from my original.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.gitignore

@@ -8,3 +8,6 @@ export/
 # OS
 .DS_Store
 Thumbs.db
+
+# Godot UID files (regenerated from path)
+*.uid

backend/.env.example

@@ -4,10 +4,13 @@ DATABASE_URL=postgresql+asyncpg://agp_user:agp_password@localhost:5432/agp_db
 # Redis
 REDIS_URL=redis://localhost:6379/0
 
-# JWT
-SECRET_KEY=change-me-to-a-secure-random-string
-ALGORITHM=HS256
-ACCESS_TOKEN_EXPIRE_MINUTES=30
+# JWT / Auth
+ALGORITHM=RS256
+ACCESS_TOKEN_EXPIRE_MINUTES=60
+REFRESH_TOKEN_EXPIRE_DAYS=30
+# Directory where the RSA keypair is loaded/generated at runtime.
+# Defaults to ~/.agp/keys (outside the repo). Keys are never committed to git.
+RSA_KEY_DIR=~/.agp/keys
 
 # App
 APP_NAME=AGP Backend

backend/alembic/versions/0003_add_refresh_tokens_table.py

@@ -0,0 +1,36 @@
+"""add refresh_tokens table
+
+Revision ID: 0003_add_refresh_tokens_table
+Revises: 0002_add_date_of_birth_to_users
+Create Date: 2025-07-25 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = "0003_add_refresh_tokens_table"
+down_revision: Union[str, None] = "0002_add_date_of_birth_to_users"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Create the refresh_tokens table."""
+    op.create_table(
+        "refresh_tokens",
+        sa.Column("id", sa.String(36), primary_key=True),
+        sa.Column("user_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False),
+        sa.Column("token", sa.String(512), unique=True, index=True, nullable=False),
+        sa.Column("expires_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("is_active", sa.Boolean(), server_default=sa.text("true"), 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 refresh_tokens table."""
+    op.drop_table("refresh_tokens")

backend/app/config.py

@@ -1,10 +1,56 @@
 """Application configuration via pydantic-settings."""
 
 from functools import lru_cache
+from pathlib import Path
 
+from cryptography.hazmat.primitives.asymmetric.rsa import (
+    RSAPrivateKey,
+    RSAPublicKey,
+    generate_private_key,
+)
+from cryptography.hazmat.primitives.serialization import (
+    Encoding,
+    NoEncryption,
+    PrivateFormat,
+    PublicFormat,
+    load_pem_private_key,
+    load_pem_public_key,
+)
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
 
+def _load_or_generate_rsa_keys(key_dir: Path) -> tuple[bytes, bytes]:
+    """Load existing RSA keys or generate a new pair.
+
+    Keys are stored as PEM files in *key_dir*.  The directory is created
+    if it does not exist.  Files are named ``private.pem`` and
+    ``public.pem`` and are **not** committed to git.
+    """
+    private_path = key_dir / "private.pem"
+    public_path = key_dir / "public.pem"
+
+    if private_path.exists() and public_path.exists():
+        private_pem = private_path.read_bytes()
+        public_pem = public_path.read_bytes()
+    else:
+        # Generate a new 2048-bit RSA key pair
+        private_key = generate_private_key(public_exponent=65537, key_size=2048)
+        private_pem = private_key.private_bytes(
+            Encoding.PEM,
+            PrivateFormat.PKCS8,
+            NoEncryption(),
+        )
+        public_pem = private_key.public_key().public_bytes(
+            Encoding.PEM,
+            PublicFormat.SubjectPublicKeyInfo,
+        )
+        key_dir.mkdir(parents=True, exist_ok=True)
+        private_path.write_bytes(private_pem)
+        public_path.write_bytes(public_pem)
+
+    return private_pem, public_pem
+
+
 class Settings(BaseSettings):
     # App
     APP_NAME: str = "AGP Backend"
@@ -18,11 +64,13 @@ class Settings(BaseSettings):
     REDIS_URL: str = "redis://localhost:6379/0"
 
     # JWT / Auth
-    # NOTE: production must override SECRET_KEY with a secure random value
-    # (e.g. `python -c "import secrets; print(secrets.token_urlsafe(32))"`)
-    SECRET_KEY: str = "change-me-to-a-secure-random-string"
-    ALGORITHM: str = "HS256"
-    ACCESS_TOKEN_EXPIRE_MINUTES: int = 30
+    ALGORITHM: str = "RS256"
+    ACCESS_TOKEN_EXPIRE_MINUTES: int = 60
+    REFRESH_TOKEN_EXPIRE_DAYS: int = 30
+
+    # RS256 key storage.  Defaults to a directory outside the repo so the
+    # generated keypair is never accidentally committed.
+    RSA_KEY_DIR: str = str(Path.home() / ".agp" / "keys")
 
     # CORS
     CORS_ORIGINS: str = "http://localhost:8080,http://localhost:3000"
@@ -30,6 +78,7 @@ class Settings(BaseSettings):
     # File uploads
     UPLOAD_DIR: str = "uploads"
     MAX_UPLOAD_SIZE_MB: int = 100
+    GLTF_MAX_FILE_SIZE_MB: int = 200
 
     model_config = SettingsConfigDict(
         env_file=".env",
@@ -41,6 +90,32 @@ class Settings(BaseSettings):
     def cors_origins_list(self) -> list[str]:
         return [origin.strip() for origin in self.CORS_ORIGINS.split(",")]
 
+    @property
+    def rsa_key_dir(self) -> Path:
+        return Path(self.RSA_KEY_DIR)
+
+    @property
+    def private_pem(self) -> bytes:
+        """Return the private key PEM bytes (loads/generates on first call)."""
+        private_pem, _ = _load_or_generate_rsa_keys(self.rsa_key_dir)
+        return private_pem
+
+    @property
+    def public_pem(self) -> bytes:
+        """Return the public key PEM bytes (loads/generates on first call)."""
+        _, public_pem = _load_or_generate_rsa_keys(self.rsa_key_dir)
+        return public_pem
+
+    @property
+    def private_key(self) -> RSAPrivateKey:
+        """Return the deserialized RSA private key object."""
+        return load_pem_private_key(self.private_pem, password=None)
+
+    @property
+    def public_key(self) -> RSAPublicKey:
+        """Return the deserialized RSA public key object."""
+        return load_pem_public_key(self.public_pem)
+
 
 @lru_cache()
 def get_settings() -> Settings:

backend/app/dependencies.py

@@ -27,7 +27,7 @@ async def get_current_user(
     )
     try:
         payload = jwt.decode(
-            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
+            token, settings.public_pem, algorithms=[settings.ALGORITHM]
         )
         user_id: str | None = payload.get("sub")
         if user_id is None:

backend/app/models/session.py

@@ -3,6 +3,7 @@ import uuid
 from sqlalchemy import Column, Integer, String, DateTime, ForeignKey, Boolean
 from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
+
 from app.database import Base
 
 
@@ -18,3 +19,23 @@ class Session(Base):
     updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
 
     user = relationship("User", back_populates="sessions")
+
+
+class RefreshToken(Base):
+    __tablename__ = "refresh_tokens"
+
+    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
+    user_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False)
+    # RS256 JWTs are ~420+ chars; 512 is sufficient and matches the migration.
+    token = Column(String(512), unique=True, index=True, nullable=False)
+    expires_at = Column(DateTime(timezone=True), nullable=False)
+    is_active = Column(Boolean, nullable=False, default=True, server_default="true")
+    created_at = Column(DateTime(timezone=True), nullable=False, server_default=func.now())
+    updated_at = Column(
+        DateTime(timezone=True),
+        nullable=False,
+        server_default=func.now(),
+        onupdate=func.now(),
+    )
+
+    user = relationship("User", back_populates="refresh_tokens")

backend/app/models/user.py

@@ -21,6 +21,7 @@ class User(Base):
     updated_at = Column(DateTime(timezone=True), onupdate=func.now())
 
     sessions = relationship("Session", back_populates="user", cascade="all, delete-orphan")
+    refresh_tokens = relationship("RefreshToken", back_populates="user", cascade="all, delete-orphan")
     worlds = relationship("World", back_populates="owner")
     assets = relationship("Asset", back_populates="owner")
 

backend/app/models/world.py

@@ -21,7 +21,12 @@ class World(Base):
     description = Column(Text, nullable=True)
     owner_id = Column(Integer, ForeignKey("users.id"), nullable=False)
     visibility = Column(
-        ENUM(WorldVisibility, name="world_visibility", create_type=False),
+        ENUM(
+            WorldVisibility,
+            name="world_visibility",
+            create_type=False,
+            values_callable=lambda enum_cls: [e.value for e in enum_cls],
+        ),
         default=WorldVisibility.PUBLIC,
     )
     created_at = Column(DateTime(timezone=True), server_default=func.now())

backend/app/routers/assets.py

@@ -1,5 +1,6 @@
 """Asset management router."""
 
+import json
 import os
 from pathlib import Path
 from typing import Optional
@@ -13,6 +14,7 @@ from app.database import get_db
 from app.dependencies import CurrentUser
 from app.models.asset import Asset, AssetType
 from app.models.world import World
+from app.services import gltf as gltf_service
 from pydantic import BaseModel, Field
 
 router = APIRouter()
@@ -64,6 +66,14 @@ def _sanitize_filename(filename: str) -> str:
     return safe or "file"
 
 
+def _detect_asset_type(filename: Optional[str], content: bytes) -> AssetType:
+    """Detect the asset type from filename and content."""
+    if filename and gltf_service.looks_like_gltf(content, filename):
+        return AssetType.MODEL_3D
+    # Fallback: let the caller decide based on mime_type or default.
+    return AssetType.OTHER
+
+
 # --- Endpoints ---
 
 @router.post("/", response_model=AssetResponse, status_code=201)
@@ -183,10 +193,16 @@ async def upload_asset_file(
     # Sanitize filename to prevent path traversal.
     safe_filename = _sanitize_filename(file.filename or f"asset_{asset_id}")
 
-    # Validate file size against configured maximum.
-    max_bytes = settings.MAX_UPLOAD_SIZE_MB * 1024 * 1024
+    # Read the file content.
     content = await file.read()
     file_size = len(content)
+
+    # Determine which size limit to apply.
+    if gltf_service.looks_like_gltf(content, file.filename):
+        max_bytes = settings.GLTF_MAX_FILE_SIZE_MB * 1024 * 1024
+    else:
+        max_bytes = settings.MAX_UPLOAD_SIZE_MB * 1024 * 1024
+
     if file_size > max_bytes:
         raise HTTPException(
             status_code=413,
@@ -200,10 +216,28 @@ async def upload_asset_file(
     file_path = upload_dir / stored_name
     file_path.write_bytes(content)
 
+    # Detect asset type from content/filename.
+    detected_type = _detect_asset_type(file.filename, content)
+
+    # Update asset record.
     asset.file_path = str(file_path)
     asset.mime_type = file.content_type
     asset.file_size = file_size
 
+    # If this is a glTF file, extract and store metadata.
+    if detected_type == AssetType.MODEL_3D:
+        try:
+            metadata = gltf_service.extract_gltf_metadata(content)
+            asset.metadata_json = json.dumps(metadata)
+            # Also set the asset type to model_3d if it was auto-detected.
+            if asset.asset_type == AssetType.OTHER:
+                asset.asset_type = AssetType.MODEL_3D
+        except ValueError as exc:
+            raise HTTPException(
+                status_code=400,
+                detail=f"Invalid glTF file: {exc}",
+            )
+
     await db.commit()
     await db.refresh(asset)
     return asset

backend/app/routers/auth.py

@@ -1,20 +1,21 @@
 """Authentication router - login, register, token refresh."""
 
+import uuid
 from datetime import date, datetime, timedelta, timezone
 
 from fastapi import APIRouter, Depends, HTTPException, status
 from fastapi.security import OAuth2PasswordRequestForm
-from pydantic import BaseModel, EmailStr, field_validator
-
-from jose import jwt
+from jose import JWTError, jwt
 from passlib.context import CryptContext
+from pydantic import BaseModel, EmailStr, field_validator
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.config import settings
 from app.database import get_db
 from app.dependencies import CurrentUser
+from app.models.session import RefreshToken
 from app.models.user import User
-from sqlalchemy.ext.asyncio import AsyncSession
-from sqlalchemy import select
 
 pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
 
@@ -25,7 +26,13 @@ router = APIRouter()
 
 class TokenResponse(BaseModel):
     access_token: str
+    refresh_token: str
     token_type: str = "bearer"
+    access_token_expires_minutes: int
+
+
+class RefreshRequest(BaseModel):
+    refresh_token: str
 
 
 class RegisterRequest(BaseModel):
@@ -59,12 +66,43 @@ class UserResponse(BaseModel):
 # --- Helpers ---
 
 def _create_access_token(data: dict) -> str:
+    """Create a signed access token using RS256.
+
+    Includes a unique ``jti`` claim so that concurrent/same-second calls
+    (e.g. back-to-back /refresh requests) still produce distinct tokens —
+    without it, two tokens minted for the same user within the same
+    second are byte-identical since ``sub``/``exp`` are the only claims.
+    """
     to_encode = data.copy()
+    to_encode["jti"] = str(uuid.uuid4())
     expire = datetime.now(timezone.utc) + timedelta(
         minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES
     )
     to_encode.update({"exp": expire})
-    return jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+    return jwt.encode(
+        to_encode,
+        settings.private_pem,
+        algorithm=settings.ALGORITHM,
+    )
+
+
+def _create_refresh_token(data: dict) -> str:
+    """Create a signed refresh token using RS256.
+
+    Includes a unique ``jti`` claim so that concurrent calls produce
+    distinct tokens even when issued within the same second.
+    """
+    to_encode = data.copy()
+    to_encode["jti"] = str(uuid.uuid4())
+    expire = datetime.now(timezone.utc) + timedelta(
+        days=settings.REFRESH_TOKEN_EXPIRE_DAYS
+    )
+    to_encode.update({"exp": expire})
+    return jwt.encode(
+        to_encode,
+        settings.private_pem,
+        algorithm=settings.ALGORITHM,
+    )
 
 
 def verify_password(plain_password: str, hashed_password: str) -> bool:
@@ -97,11 +135,25 @@ def calculate_age(birth_date: date, today: date | None = None) -> int:
     return age
 
 
+def _issue_refresh_token(user_id: int, db: AsyncSession) -> str:
+    """Create and persist a refresh token for the given user."""
+    refresh_token_value = _create_refresh_token({"sub": str(user_id)})
+    refresh_token_record = RefreshToken(
+        id=str(uuid.uuid4()),
+        user_id=user_id,
+        token=refresh_token_value,
+        expires_at=datetime.now(timezone.utc)
+        + timedelta(days=settings.REFRESH_TOKEN_EXPIRE_DAYS),
+    )
+    db.add(refresh_token_record)
+    return refresh_token_value
+
+
 # --- Endpoints ---
 
 @router.post("/register", response_model=TokenResponse, status_code=status.HTTP_201_CREATED)
 async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
-    """Register a new user and return an access token.
+    """Register a new user and return access + refresh tokens.
 
     Requires date_of_birth and rejects users under 18.
     """
@@ -138,16 +190,26 @@ async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
         date_of_birth=dob,
     )
     db.add(user)
-    await db.commit()
+    await db.flush()  # flush to get user.id before creating refresh token
     await db.refresh(user)
 
+    # Create access token
     access_token = _create_access_token({"sub": str(user.id)})
-    return TokenResponse(access_token=access_token)
+
+    # Create and persist refresh token
+    refresh_token_value = _issue_refresh_token(user.id, db)
+    await db.commit()
+
+    return TokenResponse(
+        access_token=access_token,
+        refresh_token=refresh_token_value,
+        access_token_expires_minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES,
+    )
 
 
 @router.post("/login", response_model=TokenResponse)
 async def login(form: OAuth2PasswordRequestForm = Depends(), db: AsyncSession = Depends(get_db)):
-    """Authenticate user and return an access token.
+    """Authenticate user and return access + refresh tokens.
 
     Accepts form-encoded credentials (username/password) as expected by
     OAuth2PasswordBearer, so the Swagger UI "Authorize" flow works correctly.
@@ -167,8 +229,84 @@ async def login(form: OAuth2PasswordRequestForm = Depends(), db: AsyncSession =
             detail="User account is inactive",
         )
 
+    # Create access token
     access_token = _create_access_token({"sub": str(user.id)})
-    return TokenResponse(access_token=access_token)
+
+    # Create and persist refresh token
+    refresh_token_value = _issue_refresh_token(user.id, db)
+    await db.commit()
+
+    return TokenResponse(
+        access_token=access_token,
+        refresh_token=refresh_token_value,
+        access_token_expires_minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES,
+    )
+
+
+@router.post("/refresh", response_model=TokenResponse)
+async def refresh(req: RefreshRequest, db: AsyncSession = Depends(get_db)):
+    """Exchange a valid refresh token for a new access token.
+
+    Validates the refresh token against the database:
+    - Must exist in the refresh_tokens table
+    - Must not be expired (expires_at > now)
+    - Must be active (is_active == true)
+
+    On success, returns a new access token. The refresh token itself is
+    NOT rotated (the client keeps using the same refresh token).
+    """
+    credentials_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Invalid or expired refresh token",
+    )
+
+    # Step 1: Decode and validate the JWT signature/claims
+    try:
+        payload = jwt.decode(
+            req.refresh_token,
+            settings.public_pem,
+            algorithms=[settings.ALGORITHM],
+        )
+    except JWTError:
+        raise credentials_exception
+
+    user_id_str: str | None = payload.get("sub")
+    if user_id_str is None:
+        raise credentials_exception
+
+    try:
+        user_id = int(user_id_str)
+    except (ValueError, TypeError):
+        raise credentials_exception
+
+    # Step 2: Look up the refresh token in the database
+    result = await db.execute(
+        select(RefreshToken).where(
+            RefreshToken.token == req.refresh_token,
+            RefreshToken.user_id == user_id,
+        )
+    )
+    stored_token = result.scalar_one_or_none()
+
+    if stored_token is None:
+        raise credentials_exception
+
+    # Step 3: Check if the token is expired
+    if datetime.now(timezone.utc) >= stored_token.expires_at:
+        raise credentials_exception
+
+    # Step 4: Check if the token is active
+    if not stored_token.is_active:
+        raise credentials_exception
+
+    # Step 5: Issue a new access token
+    access_token = _create_access_token({"sub": str(user_id)})
+
+    return TokenResponse(
+        access_token=access_token,
+        refresh_token=req.refresh_token,  # Return the same refresh token
+        access_token_expires_minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES,
+    )
 
 
 @router.get("/me", response_model=UserResponse)

backend/app/routers/worlds.py

@@ -1,5 +1,6 @@
 """Worlds router - CRUD for game worlds."""
 
+from datetime import datetime
 from typing import Annotated
 
 from fastapi import APIRouter, Depends, HTTPException, Query
@@ -40,7 +41,7 @@ class WorldResponse(BaseModel):
     description: str | None
     visibility: WorldVisibility
     owner_id: int
-    created_at: str | None = None
+    created_at: datetime | None = None
 
     model_config = {"from_attributes": True}
 

backend/app/services/gltf.py

@@ -0,0 +1,197 @@
+"""Lightweight glTF / GLB metadata extraction.
+
+This module intentionally avoids heavyweight dependencies such as trimesh or
+pygltflib. For the metadata fields the asset upload pipeline needs (mesh and
+vertex counts, animation presence, texture references, and the bounding box)
+a small amount of glTF-specific parsing is sufficient and keeps the backend
+dependency-free.
+"""
+
+from __future__ import annotations
+
+import json
+import struct
+from typing import Any, Optional
+
+# GLB binary header magic bytes ("glTF").
+_GLB_MAGIC = b"glTF"
+_GLB_MAGIC_INT = 0x46546C67  # b"glTF" interpreted as little-endian uint32
+_GLB_JSON_CHUNK_TYPE = 0x4E4F534A  # "JSON"
+_GLB_BIN_CHUNK_TYPE = 0x004E4942  # "BIN\0"
+
+# Whitespace allowed around a GLB JSON chunk. The spec pads with spaces (0x20),
+# but be lenient with null bytes and other whitespace that real exporters emit.
+_JSON_CHUNK_TRIM = b" \t\r\n\x00"
+
+
+def looks_like_gltf(content: bytes, filename: Optional[str] = None) -> bool:
+    """Return True when the bytes or filename indicate a glTF/GLB asset."""
+    if content.startswith(_GLB_MAGIC):
+        return True
+
+    if filename:
+        lowered = filename.lower()
+        if lowered.endswith(".gltf") or lowered.endswith(".glb"):
+            return True
+
+    # A bare JSON buffer (e.g. uploaded without an extension) that has the
+    # glTF asset marker is also a glTF file.
+    stripped = content.lstrip()
+    if stripped.startswith(b"{"):
+        try:
+            payload = json.loads(stripped.decode("utf-8"))
+        except (ValueError, UnicodeDecodeError):
+            return False
+        return isinstance(payload, dict) and "asset" in payload and "version" in payload.get("asset", {})
+
+    return False
+
+
+def _parse_glb(content: bytes) -> dict[str, Any]:
+    """Parse the JSON chunk of a GLB binary container."""
+    if len(content) < 12:
+        raise ValueError("GLB file is too short")
+
+    magic, _version, _length = struct.unpack_from("<III", content, 0)
+    if magic != _GLB_MAGIC_INT:
+        raise ValueError("invalid GLB magic")
+
+    offset = 12
+    json_chunk: Optional[dict[str, Any]] = None
+
+    while offset + 8 <= len(content):
+        chunk_length, chunk_type = struct.unpack_from("<II", content, offset)
+        offset += 8
+        chunk_end = offset + chunk_length
+        if chunk_end > len(content):
+            raise ValueError("GLB chunk overruns file boundary")
+
+        chunk_data = content[offset:chunk_end]
+        if chunk_type == _GLB_JSON_CHUNK_TYPE:
+            try:
+                json_chunk = json.loads(chunk_data.strip(_JSON_CHUNK_TRIM).decode("utf-8"))
+            except (ValueError, UnicodeDecodeError) as exc:
+                raise ValueError(f"invalid GLB JSON chunk: {exc}") from exc
+
+        offset = chunk_end
+
+    if json_chunk is None:
+        raise ValueError("GLB file does not contain a JSON chunk")
+
+    return json_chunk
+
+
+def _parse_gltf_json(content: bytes) -> dict[str, Any]:
+    """Parse a plain .gltf JSON file."""
+    stripped = content.lstrip()
+    try:
+        payload = json.loads(stripped.decode("utf-8"))
+    except (ValueError, UnicodeDecodeError) as exc:
+        raise ValueError(f"invalid glTF JSON: {exc}") from exc
+
+    if not isinstance(payload, dict):
+        raise ValueError("glTF JSON root must be an object")
+    return payload
+
+
+def _position_accessor_counts(gltf: dict[str, Any]) -> list[int]:
+    """Return POSITION accessor counts for every mesh primitive."""
+    counts: list[int] = []
+    accessors = gltf.get("accessors", [])
+    for mesh in gltf.get("meshes", []):
+        for primitive in mesh.get("primitives", []):
+            attributes = primitive.get("attributes", {})
+            position_index = attributes.get("POSITION")
+            if position_index is None:
+                continue
+            try:
+                accessor = accessors[int(position_index)]
+            except (IndexError, TypeError, ValueError):
+                continue
+            count = accessor.get("count")
+            if isinstance(count, int):
+                counts.append(count)
+    return counts
+
+
+def _position_bounds(gltf: dict[str, Any]) -> list[list[float]]:
+    """Return min/max bounds for every POSITION accessor that declares them."""
+    bounds: list[list[float]] = []
+    accessors = gltf.get("accessors", [])
+    for mesh in gltf.get("meshes", []):
+        for primitive in mesh.get("primitives", []):
+            attributes = primitive.get("attributes", {})
+            position_index = attributes.get("POSITION")
+            if position_index is None:
+                continue
+            try:
+                accessor = accessors[int(position_index)]
+            except (IndexError, TypeError, ValueError):
+                continue
+            minimum = accessor.get("min")
+            maximum = accessor.get("max")
+            if isinstance(minimum, list) and isinstance(maximum, list):
+                bounds.append([float(x) for x in minimum])
+                bounds.append([float(x) for x in maximum])
+    return bounds
+
+
+def _texture_refs(gltf: dict[str, Any]) -> list[str]:
+    """Collect external texture source references from the image array."""
+    refs: list[str] = []
+    for index, image in enumerate(gltf.get("images", [])):
+        uri = image.get("uri")
+        if isinstance(uri, str) and not uri.startswith("data:"):
+            refs.append(uri)
+            continue
+
+        name = image.get("name")
+        if isinstance(name, str) and name:
+            refs.append(name)
+            continue
+
+        if isinstance(uri, str):
+            # Embedded data URI; keep a stable, non-huge reference.
+            refs.append(f"data:{index}")
+            continue
+
+        buffer_view = image.get("bufferView")
+        if buffer_view is not None:
+            refs.append(f"bufferView:{buffer_view}")
+            continue
+
+        refs.append(f"image:{index}")
+
+    return refs
+
+
+def extract_gltf_metadata(content: bytes) -> dict[str, Any]:
+    """Extract upload-relevant metadata from glTF/GLB bytes.
+
+    Raises ValueError for malformed glTF content. The returned dict contains:
+        mesh_count, vertex_count, has_animation, texture_refs,
+        bounding_box_min, bounding_box_max.
+    """
+    if content.startswith(_GLB_MAGIC):
+        gltf = _parse_glb(content)
+    else:
+        gltf = _parse_gltf_json(content)
+
+    position_counts = _position_accessor_counts(gltf)
+    bounds = _position_bounds(gltf)
+
+    if bounds:
+        bounding_box_min = [min(axis) for axis in zip(*bounds[::2])]
+        bounding_box_max = [max(axis) for axis in zip(*bounds[1::2])]
+    else:
+        bounding_box_min = [0.0, 0.0, 0.0]
+        bounding_box_max = [0.0, 0.0, 0.0]
+
+    return {
+        "mesh_count": len(gltf.get("meshes", [])),
+        "vertex_count": sum(position_counts),
+        "has_animation": bool(gltf.get("animations")),
+        "texture_refs": _texture_refs(gltf),
+        "bounding_box_min": bounding_box_min,
+        "bounding_box_max": bounding_box_max,
+    }

backend/requirements.txt

@@ -9,6 +9,14 @@ pydantic==2.10.3
 pydantic-settings==2.7.0
 python-jose[cryptography]==3.3.0
 passlib[bcrypt]==1.7.4
+# passlib 1.7.4 (last release, unmaintained since ~2020) detects its bcrypt
+# backend via bcrypt.__about__.__version__, which bcrypt>=4.1 removed --
+# hashing/verifying a password then raises "password cannot be longer than
+# 72 bytes" (a misleading downstream symptom of the real AttributeError:
+# module 'bcrypt' has no attribute '__about__') on every call. Without this
+# pin, `pip install -r requirements.txt` silently grabs whatever the latest
+# bcrypt is and breaks register/login outright. Pin below 4.1 explicitly.
+bcrypt==4.0.1
 python-multipart==0.0.20
 email-validator==2.2.0
 httpx==0.28.1

backend/tests/conftest.py

@@ -0,0 +1,38 @@
+"""Shared pytest fixtures.
+
+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.
+
+Truncation order doesn't strictly matter because ``CASCADE`` follows foreign
+keys, but the tables are listed explicitly for clarity.
+"""
+
+import asyncio
+
+import pytest
+from sqlalchemy import text
+from sqlalchemy.ext.asyncio import create_async_engine
+
+from app.config import settings
+
+TEST_TABLES = ("assets", "worlds", "sessions", "refresh_tokens", "users")
+
+
+@pytest.fixture(scope="session", autouse=True)
+def _reset_database():
+    """Truncate all application tables once per test session."""
+
+    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 engine.dispose()
+
+    asyncio.run(_truncate())
+    yield

backend/tests/test_auth_endpoints.py

@@ -0,0 +1,263 @@
+"""Integration tests for the auth endpoints (register + login).
+
+These tests hit the real FastAPI app against the real configured database
+(DATABASE_URL -- Postgres via Alembic migrations in CI/dev, not an isolated
+in-memory DB), so they exercise the full stack: Pydantic validation → DB →
+JWT → response. Requires migrations already applied (alembic upgrade head)
+before running.
+"""
+
+import pytest
+from fastapi.testclient import TestClient
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+from sqlalchemy.pool import NullPool
+
+from app.config import settings
+from app.main import app
+from app.database import get_db
+from app.routers.auth import pwd_context
+
+
+# ---------------------------------------------------------------------------
+# Test fixtures
+# ---------------------------------------------------------------------------
+
+@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 engine's connection pool across requests
+    raises "cannot perform operation: another operation is in progress" the
+    moment a test makes more than one request (register-then-login,
+    register-twice, etc.) -- confirmed this is the actual cause, not a bug
+    in the endpoints themselves. NullPool sidesteps it: every checkout is a
+    brand-new connection, never handed to a different loop than the one
+    that opened it.
+    """
+    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()
+
+
+# ---------------------------------------------------------------------------
+# Register endpoint
+# ---------------------------------------------------------------------------
+
+class TestRegister:
+    """Tests for POST /api/auth/register."""
+
+    def test_register_success(self):
+        """A valid registration returns 201 with a token."""
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/register",
+            json={
+                "username": "newuser",
+                "email": "new@example.com",
+                "password": "secret123",
+                "date_of_birth": "2000-01-01",
+            },
+        )
+        assert resp.status_code == 201
+        data = resp.json()
+        assert "access_token" in data
+        assert data["token_type"] == "bearer"
+
+    def test_register_rejects_underage(self):
+        """Users under 18 get a 400 with a detail message."""
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/register",
+            json={
+                "username": "kid",
+                "email": "kid@example.com",
+                "password": "secret123",
+                "date_of_birth": "2010-06-15",  # ~15 years old
+            },
+        )
+        assert resp.status_code == 400
+        assert "18 or older" in resp.json()["detail"]
+
+    def test_register_rejects_duplicate_username(self):
+        """Registering the same username twice returns 409."""
+        client = TestClient(app)
+        # First registration
+        client.post(
+            "/api/auth/register",
+            json={
+                "username": "duplicate",
+                "email": "dup1@example.com",
+                "password": "secret123",
+                "date_of_birth": "2000-01-01",
+            },
+        )
+        # Second registration with same username, different email
+        resp = client.post(
+            "/api/auth/register",
+            json={
+                "username": "duplicate",
+                "email": "dup2@example.com",
+                "password": "secret123",
+                "date_of_birth": "2000-01-01",
+            },
+        )
+        assert resp.status_code == 409
+        assert "Username already registered" in resp.json()["detail"]
+
+    def test_register_rejects_duplicate_email(self):
+        """Registering the same email twice returns 409."""
+        client = TestClient(app)
+        client.post(
+            "/api/auth/register",
+            json={
+                "username": "user1",
+                "email": "same@example.com",
+                "password": "secret123",
+                "date_of_birth": "2000-01-01",
+            },
+        )
+        resp = client.post(
+            "/api/auth/register",
+            json={
+                "username": "user2",
+                "email": "same@example.com",
+                "password": "secret123",
+                "date_of_birth": "2000-01-01",
+            },
+        )
+        assert resp.status_code == 409
+        assert "Email already registered" in resp.json()["detail"]
+
+    def test_register_invalid_date_format(self):
+        """Invalid date format returns 422 validation error."""
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/register",
+            json={
+                "username": "user",
+                "email": "user@example.com",
+                "password": "secret123",
+                "date_of_birth": "01-01-2000",  # wrong format
+            },
+        )
+        assert resp.status_code == 422
+
+    def test_register_exactly_18(self):
+        """A user who just turned 18 can register."""
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/register",
+            json={
+                "username": "just18",
+                "email": "just18@example.com",
+                "password": "secret123",
+                "date_of_birth": "2007-06-15",
+            },
+        )
+        assert resp.status_code == 201
+
+
+# ---------------------------------------------------------------------------
+# Login endpoint
+# ---------------------------------------------------------------------------
+
+class TestLogin:
+    """Tests for POST /api/auth/login."""
+
+    def _create_user(self, username: str, password: str, email: str = None):
+        """Helper to create a user via register."""
+        client = TestClient(app)
+        if email is None:
+            email = f"{username}@example.com"
+        resp = client.post(
+            "/api/auth/register",
+            json={
+                "username": username,
+                "email": email,
+                "password": password,
+                "date_of_birth": "2000-01-01",
+            },
+        )
+        assert resp.status_code == 201
+        return resp.json()["access_token"]
+
+    def test_login_success(self):
+        """Correct credentials return a token."""
+        self._create_user("loginuser", "correctpass")
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/login",
+            data={"username": "loginuser", "password": "correctpass"},
+        )
+        assert resp.status_code == 200
+        data = resp.json()
+        assert "access_token" in data
+        assert data["token_type"] == "bearer"
+
+    def test_login_wrong_password(self):
+        """Wrong password returns 401."""
+        # Distinct username from test_login_success -- there's no per-test
+        # DB rollback/isolation here (real Postgres via the app's own
+        # dependency-overridden session), so reusing "loginuser" collided
+        # with the user that test already created (409 on register instead
+        # of the intended 401-on-login assertion this test is actually for).
+        self._create_user("loginuser_wrongpass", "correctpass")
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/login",
+            data={"username": "loginuser_wrongpass", "password": "wrongpass"},
+        )
+        assert resp.status_code == 401
+        assert "Incorrect username or password" in resp.json()["detail"]
+
+    def test_login_nonexistent_user(self):
+        """Non-existent user returns 401 (not 404)."""
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/login",
+            data={"username": "nobody", "password": "any"},
+        )
+        assert resp.status_code == 401
+        assert "Incorrect username or password" in resp.json()["detail"]
+
+    def test_login_accepts_form_encoded(self):
+        """Login accepts application/x-www-form-urlencoded (OAuth2)."""
+        self._create_user("formuser", "formpass")
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/login",
+            data={"username": "formuser", "password": "formpass"},
+        )
+        assert resp.status_code == 200
+        assert "access_token" in resp.json()
+
+    def test_login_token_is_valid_jwt(self):
+        """The returned token is a valid JWT that can be decoded."""
+        self._create_user("jwttoken", "jwt123")
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/login",
+            data={"username": "jwttoken", "password": "jwt123"},
+        )
+        token = resp.json()["access_token"]
+        # Verify it's a 3-part JWT
+        parts = token.split(".")
+        assert len(parts) == 3

backend/tests/test_auth_expired_token.py

@@ -0,0 +1,171 @@
+"""Tests for expired-token rejection across auth endpoints.
+
+Covers two distinct expiry paths:
+
+1. An *access* JWT whose ``exp`` claim is in the past must be rejected
+   with 401 by ``GET /api/auth/me`` (jose's built-in ``exp`` validation).
+2. A *refresh* token whose persisted ``expires_at`` is in the past must be
+   rejected with 401 by ``POST /api/auth/refresh`` even though its JWT
+   signature is still valid.
+
+Requires migrations already applied (alembic upgrade head) before running.
+"""
+
+import asyncio
+from datetime import datetime, timedelta, timezone
+
+import pytest
+from fastapi.testclient import TestClient
+from jose import jwt
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+from sqlalchemy.pool import NullPool
+
+from app.config import settings
+from app.main import app
+from app.database import get_db
+from app.models.session import RefreshToken
+
+
+# ---------------------------------------------------------------------------
+# Test fixtures
+# ---------------------------------------------------------------------------
+
+@pytest.fixture(autouse=True)
+def _override_db():
+    """Override get_db so the app uses a fresh session per test."""
+    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()
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+def _mint_access_token(exp: datetime) -> str:
+    """Mint an RS256 access token with an explicit ``exp`` claim."""
+    return jwt.encode(
+        {"sub": "1", "exp": exp},
+        settings.private_pem,
+        algorithm=settings.ALGORITHM,
+    )
+
+
+def _expire_refresh_token_in_db(token: str) -> None:
+    """Set the persisted refresh token's ``expires_at`` into the past."""
+
+    async def _do():
+        engine = create_async_engine(settings.DATABASE_URL, poolclass=NullPool)
+        session_factory = async_sessionmaker(engine, expire_on_commit=False)
+        async with session_factory() as session:
+            from sqlalchemy import update
+
+            await session.execute(
+                update(RefreshToken)
+                .where(RefreshToken.token == token)
+                .values(expires_at=datetime.now(timezone.utc) - timedelta(hours=1))
+            )
+            await session.commit()
+        await engine.dispose()
+
+    asyncio.run(_do())
+
+
+def _register_user(client: TestClient, username: str) -> str:
+    """Register a user and return its refresh token."""
+    resp = client.post(
+        "/api/auth/register",
+        json={
+            "username": username,
+            "email": f"{username}@example.com",
+            "password": "secret123",
+            "date_of_birth": "2000-01-01",
+        },
+    )
+    assert resp.status_code == 201
+    return resp.json()["refresh_token"]
+
+
+# ---------------------------------------------------------------------------
+# Expired access token (GET /api/auth/me)
+# ---------------------------------------------------------------------------
+
+class TestExpiredAccessToken:
+    def test_expired_access_token_is_rejected_by_me(self):
+        """An access JWT with a past exp claim returns 401 on /me."""
+        client = TestClient(app)
+        expired_token = _mint_access_token(
+            datetime.now(timezone.utc) - timedelta(minutes=5)
+        )
+        resp = client.get(
+            "/api/auth/me",
+            headers={"Authorization": f"Bearer {expired_token}"},
+        )
+        assert resp.status_code == 401
+        assert "Could not validate credentials" in resp.json()["detail"]
+
+    def test_garbage_access_token_is_rejected_by_me(self):
+        """A non-JWT bearer token returns 401 on /me."""
+        client = TestClient(app)
+        resp = client.get(
+            "/api/auth/me",
+            headers={"Authorization": "Bearer not-a-real-jwt"},
+        )
+        assert resp.status_code == 401
+
+    def test_missing_bearer_token_returns_401(self):
+        """No Authorization header at all returns 401 on /me."""
+        client = TestClient(app)
+        resp = client.get("/api/auth/me")
+        assert resp.status_code == 401
+
+
+# ---------------------------------------------------------------------------
+# Expired refresh token (POST /api/auth/refresh)
+# ---------------------------------------------------------------------------
+
+class TestExpiredRefreshToken:
+    def test_expired_refresh_token_is_rejected(self):
+        """A refresh token whose DB expires_at is in the past returns 401."""
+        client = TestClient(app)
+        refresh_token = _register_user(client, "expired_rt_user")
+
+        # Force the persisted record to be expired while its JWT signature
+        # is still valid.
+        _expire_refresh_token_in_db(refresh_token)
+
+        resp = client.post(
+            "/api/auth/refresh",
+            json={"refresh_token": refresh_token},
+        )
+        assert resp.status_code == 401
+        assert "Invalid or expired refresh token" in resp.json()["detail"]
+
+    def test_expired_refresh_token_jwt_is_rejected(self):
+        """A refresh JWT with a past exp claim is rejected before DB lookup."""
+        client = TestClient(app)
+        expired_jwt = jwt.encode(
+            {"sub": "1", "exp": datetime.now(timezone.utc) - timedelta(minutes=5)},
+            settings.private_pem,
+            algorithm=settings.ALGORITHM,
+        )
+        resp = client.post(
+            "/api/auth/refresh",
+            json={"refresh_token": expired_jwt},
+        )
+        assert resp.status_code == 401
+        assert "Invalid or expired refresh token" in resp.json()["detail"]

backend/tests/test_gltf_metadata.py

@@ -0,0 +1,220 @@
+"""Tests for the lightweight glTF metadata extraction service."""
+
+import json
+import struct
+import pytest
+
+from app.services.gltf import (
+    extract_gltf_metadata,
+    looks_like_gltf,
+    _parse_glb,
+    _parse_gltf_json,
+)
+
+
+# ---------------------------------------------------------------------------
+# Test data helpers
+# ---------------------------------------------------------------------------
+
+def _make_gltf_json(
+    meshes: int = 1,
+    vertices_per_mesh: int = 24,
+    has_animations: bool = False,
+    images: list[dict] | None = None,
+) -> dict:
+    """Build a minimal glTF JSON structure."""
+    accessors = []
+    meshes_data = []
+    for i in range(meshes):
+        acc_index = len(accessors)
+        accessors.append({
+            "bufferView": 0,
+            "componentType": 5126,  # FLOAT
+            "count": vertices_per_mesh,
+            "type": "VEC3",
+            "max": [1.0, 1.0, 1.0],
+            "min": [-1.0, -1.0, -1.0],
+        })
+        meshes_data.append({
+            "primitives": [{
+                "attributes": {"POSITION": acc_index},
+            }],
+        })
+    gltf = {
+        "asset": {"version": "2.0"},
+        "accessors": accessors,
+        "meshes": meshes_data,
+    }
+    if has_animations:
+        gltf["animations"] = [{"name": "anim1", "channels": [], "samplers": []}]
+    if images:
+        gltf["images"] = images
+    return gltf
+
+
+def _make_glb(gltf_json: dict) -> bytes:
+    """Wrap *gltf_json* in a minimal GLB binary container."""
+    json_bytes = json.dumps(gltf_json).encode("utf-8")
+    json_length = len(json_bytes)
+    # Pad JSON chunk to 4-byte boundary.
+    json_padding = (4 - json_length % 4) % 4
+    json_chunk = json_bytes + b"\x00" * json_padding
+    json_chunk_type = 0x4E4F534A  # "JSON"
+    # No BIN chunk.
+    bin_length = 0
+    bin_chunk_type = 0x004E4942
+    total_length = 12 + 8 + len(json_chunk) + 8 + bin_length
+    header = struct.pack("<III", 0x46546C67, 2, total_length)  # magic, version, length
+    json_header = struct.pack("<II", len(json_chunk), json_chunk_type)
+    if bin_length > 0:
+        bin_header = struct.pack("<II", bin_length, bin_chunk_type)
+    else:
+        bin_header = b""
+    return header + json_header + json_chunk + bin_header
+
+
+# ---------------------------------------------------------------------------
+# looks_like_gltf
+# ---------------------------------------------------------------------------
+
+class TestLooksLikeGltf:
+    def test_glb_magic(self):
+        assert looks_like_gltf(b"glTF\x00\x00\x00\x00") is True
+
+    def test_gltf_extension(self):
+        assert looks_like_gltf(b'{"asset":{"version":"2.0"}}', "model.gltf") is True
+
+    def test_glb_extension(self):
+        assert looks_like_gltf(b"some binary", "model.glb") is True
+
+    def test_json_with_asset_version(self):
+        payload = json.dumps({"asset": {"version": "2.0"}}).encode()
+        assert looks_like_gltf(payload) is True
+
+    def test_plain_json_no_asset(self):
+        payload = json.dumps({"foo": "bar"}).encode()
+        assert looks_like_gltf(payload) is False
+
+    def test_non_json_bytes(self):
+        assert looks_like_gltf(b"\x89PNG\r\n\x1a\n") is False
+
+
+# ---------------------------------------------------------------------------
+# _parse_glb
+# ---------------------------------------------------------------------------
+
+class TestParseGlb:
+    def test_parses_valid_glb(self):
+        gltf_json = _make_gltf_json()
+        glb = _make_glb(gltf_json)
+        result = _parse_glb(glb)
+        assert result["asset"]["version"] == "2.0"
+        assert len(result["meshes"]) == 1
+
+    def test_rejects_too_short(self):
+        with pytest.raises(ValueError, match="too short"):
+            _parse_glb(b"glTF\x00\x00")
+
+    def test_rejects_invalid_magic(self):
+        with pytest.raises(ValueError, match="invalid GLB magic"):
+            _parse_glb(b"NOTglTF\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00")
+
+
+# ---------------------------------------------------------------------------
+# _parse_gltf_json
+# ---------------------------------------------------------------------------
+
+class TestParseGltfJson:
+    def test_parses_valid_gltf(self):
+        gltf_json = _make_gltf_json()
+        result = _parse_gltf_json(json.dumps(gltf_json).encode())
+        assert result["asset"]["version"] == "2.0"
+
+    def test_rejects_non_object(self):
+        with pytest.raises(ValueError, match="root must be an object"):
+            _parse_gltf_json(b"[1, 2, 3]")
+
+
+# ---------------------------------------------------------------------------
+# extract_gltf_metadata  (GLB path)
+# ---------------------------------------------------------------------------
+
+class TestExtractGltfMetadataGlb:
+    def test_basic_glb(self):
+        gltf_json = _make_gltf_json(meshes=1, vertices_per_mesh=24)
+        glb = _make_glb(gltf_json)
+        meta = extract_gltf_metadata(glb)
+        assert meta["mesh_count"] == 1
+        assert meta["vertex_count"] == 24
+        assert meta["has_animation"] is False
+        assert meta["bounding_box_min"] == [-1.0, -1.0, -1.0]
+        assert meta["bounding_box_max"] == [1.0, 1.0, 1.0]
+        assert meta["texture_refs"] == []
+
+    def test_multiple_meshes(self):
+        gltf_json = _make_gltf_json(meshes=3, vertices_per_mesh=12)
+        glb = _make_glb(gltf_json)
+        meta = extract_gltf_metadata(glb)
+        assert meta["mesh_count"] == 3
+        assert meta["vertex_count"] == 36
+
+    def test_with_animation(self):
+        gltf_json = _make_gltf_json(has_animations=True)
+        glb = _make_glb(gltf_json)
+        meta = extract_gltf_metadata(glb)
+        assert meta["has_animation"] is True
+
+    def test_with_external_texture(self):
+        gltf_json = _make_gltf_json(images=[{"uri": "textures/rock.png"}])
+        glb = _make_glb(gltf_json)
+        meta = extract_gltf_metadata(glb)
+        assert meta["texture_refs"] == ["textures/rock.png"]
+
+    def test_with_named_texture(self):
+        gltf_json = _make_gltf_json(images=[{"name": "my_texture"}])
+        glb = _make_glb(gltf_json)
+        meta = extract_gltf_metadata(glb)
+        assert meta["texture_refs"] == ["my_texture"]
+
+    def test_empty_meshes(self):
+        gltf_json = _make_gltf_json(meshes=0)
+        glb = _make_glb(gltf_json)
+        meta = extract_gltf_metadata(glb)
+        assert meta["mesh_count"] == 0
+        assert meta["vertex_count"] == 0
+        assert meta["bounding_box_min"] == [0.0, 0.0, 0.0]
+        assert meta["bounding_box_max"] == [0.0, 0.0, 0.0]
+
+
+# ---------------------------------------------------------------------------
+# extract_gltf_metadata  (plain .gltf JSON path)
+# ---------------------------------------------------------------------------
+
+class TestExtractGltfMetadataGltfJson:
+    def test_plain_gltf(self):
+        gltf_json = _make_gltf_json(meshes=2, vertices_per_mesh=8)
+        raw = json.dumps(gltf_json).encode()
+        meta = extract_gltf_metadata(raw)
+        assert meta["mesh_count"] == 2
+        assert meta["vertex_count"] == 16
+        assert meta["has_animation"] is False
+
+    def test_plain_gltf_with_animation(self):
+        gltf_json = _make_gltf_json(has_animations=True)
+        raw = json.dumps(gltf_json).encode()
+        meta = extract_gltf_metadata(raw)
+        assert meta["has_animation"] is True
+
+
+# ---------------------------------------------------------------------------
+# Error handling
+# ---------------------------------------------------------------------------
+
+class TestExtractGltfMetadataErrors:
+    def test_invalid_glb(self):
+        with pytest.raises(ValueError):
+            extract_gltf_metadata(b"not a glb")
+
+    def test_invalid_gltf_json(self):
+        with pytest.raises(ValueError):
+            _parse_gltf_json(b"[1, 2, 3]")

backend/tests/test_refresh_endpoint.py

@@ -0,0 +1,201 @@
+"""Tests for the POST /api/auth/refresh endpoint.
+
+These tests exercise the full stack: register → get refresh token →
+refresh → new access token.  Requires migrations already applied
+(alembic upgrade head) before running.
+"""
+
+import pytest
+from fastapi.testclient import TestClient
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+from sqlalchemy.pool import NullPool
+
+from app.config import settings
+from app.main import app
+from app.database import get_db
+
+
+# ---------------------------------------------------------------------------
+# Test fixtures
+# ---------------------------------------------------------------------------
+
+@pytest.fixture(autouse=True)
+def _override_db():
+    """Override get_db so the app uses a fresh session per test."""
+    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()
+
+
+# ---------------------------------------------------------------------------
+# Refresh endpoint tests
+# ---------------------------------------------------------------------------
+
+class TestRefresh:
+    """Tests for POST /api/auth/refresh."""
+
+    def _register_user(self, username: str, password: str, email: str = None):
+        """Helper to register a user and return the refresh token."""
+        client = TestClient(app)
+        if email is None:
+            email = f"{username}@example.com"
+        resp = client.post(
+            "/api/auth/register",
+            json={
+                "username": username,
+                "email": email,
+                "password": password,
+                "date_of_birth": "2000-01-01",
+            },
+        )
+        assert resp.status_code == 201
+        return resp.json()["refresh_token"]
+
+    def test_refresh_success(self):
+        """A valid refresh token returns a new access token."""
+        refresh_token = self._register_user("refep_refreshuser", "secret123")
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/refresh",
+            json={"refresh_token": refresh_token},
+        )
+        assert resp.status_code == 200
+        data = resp.json()
+        assert "access_token" in data
+        assert data["token_type"] == "bearer"
+        # The refresh token in the response is the same one we sent
+        assert data["refresh_token"] == refresh_token
+
+    def test_refresh_returns_different_access_token(self):
+        """Refreshing produces a new access token (different from any previous)."""
+        refresh_token = self._register_user("refep_refreshtoken", "secret123")
+        client = TestClient(app)
+
+        # First refresh
+        resp1 = client.post(
+            "/api/auth/refresh",
+            json={"refresh_token": refresh_token},
+        )
+        assert resp1.status_code == 200
+        access_token_1 = resp1.json()["access_token"]
+
+        # Second refresh
+        resp2 = client.post(
+            "/api/auth/refresh",
+            json={"refresh_token": refresh_token},
+        )
+        assert resp2.status_code == 200
+        access_token_2 = resp2.json()["access_token"]
+
+        # Each refresh should produce a new access token
+        assert access_token_1 != access_token_2
+
+    def test_refresh_invalid_token(self):
+        """An invalid (garbage) refresh token returns 401."""
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/refresh",
+            json={"refresh_token": "not.a.jwt.token"},
+        )
+        assert resp.status_code == 401
+        assert "Invalid or expired refresh token" in resp.json()["detail"]
+
+    def test_refresh_empty_body(self):
+        """Missing refresh_token field returns 422 validation error."""
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/refresh",
+            json={},
+        )
+        assert resp.status_code == 422
+
+    def test_refresh_missing_field(self):
+        """No body at all returns 422."""
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/refresh",
+            content="{}",
+            headers={"Content-Type": "application/json"},
+        )
+        assert resp.status_code == 422
+
+    def test_refresh_with_login_token(self):
+        """A refresh token obtained from login also works for /refresh."""
+        client = TestClient(app)
+        # Register first
+        client.post(
+            "/api/auth/register",
+            json={
+                "username": "refep_loginrefuser",
+                "email": "loginref@example.com",
+                "password": "secret123",
+                "date_of_birth": "2000-01-01",
+            },
+        )
+        # Login to get a refresh token
+        login_resp = client.post(
+            "/api/auth/login",
+            data={"username": "refep_loginrefuser", "password": "secret123"},
+        )
+        assert login_resp.status_code == 200
+        refresh_token = login_resp.json()["refresh_token"]
+
+        # Use it to refresh
+        resp = client.post(
+            "/api/auth/refresh",
+            json={"refresh_token": refresh_token},
+        )
+        assert resp.status_code == 200
+        assert "access_token" in resp.json()
+
+    def test_refresh_access_token_is_valid_jwt(self):
+        """The access token returned by /refresh is a valid JWT."""
+        from jose import jwt
+
+        refresh_token = self._register_user("refep_jwttoken", "secret123")
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/refresh",
+            json={"refresh_token": refresh_token},
+        )
+        assert resp.status_code == 200
+        access_token = resp.json()["access_token"]
+
+        # Verify it's a 3-part JWT
+        parts = access_token.split(".")
+        assert len(parts) == 3
+
+        # Verify it decodes with the public key
+        payload = jwt.decode(
+            access_token,
+            settings.public_pem,
+            algorithms=[settings.ALGORITHM],
+        )
+        assert "sub" in payload
+        assert "exp" in payload
+
+    def test_refresh_expires_minutes_in_response(self):
+        """The response includes access_token_expires_minutes."""
+        refresh_token = self._register_user("refep_expiretest", "secret123")
+        client = TestClient(app)
+        resp = client.post(
+            "/api/auth/refresh",
+            json={"refresh_token": refresh_token},
+        )
+        assert resp.status_code == 200
+        assert "access_token_expires_minutes" in resp.json()
+        assert resp.json()["access_token_expires_minutes"] == settings.ACCESS_TOKEN_EXPIRE_MINUTES

backend/tests/test_refresh_token_jti.py

@@ -0,0 +1,79 @@
+"""Tests for refresh token uniqueness (jti claim) and model column length."""
+
+import uuid
+from datetime import datetime, timedelta, timezone
+
+import pytest
+from jose import jwt
+
+from app.config import settings
+from app.routers.auth import _create_refresh_token
+from app.models.session import RefreshToken
+
+
+class TestRefreshTokenJtiUniqueness:
+    """Verify that _create_refresh_token produces unique tokens even when
+    called with identical data in rapid succession (issue #1 from review)."""
+
+    def test_two_calls_produce_different_tokens(self):
+        """Two calls with the same sub produce different JWTs because of jti."""
+        token_a = _create_refresh_token({"sub": "42"})
+        token_b = _create_refresh_token({"sub": "42"})
+        assert token_a != token_b
+
+    def test_jti_is_valid_uuid(self):
+        """The jti claim inside the refresh token is a valid UUID."""
+        token = _create_refresh_token({"sub": "1"})
+        payload = jwt.decode(
+            token,
+            settings.public_pem,
+            algorithms=[settings.ALGORITHM],
+        )
+        assert "jti" in payload
+        # Verify it parses as a UUID (raises ValueError if not)
+        uuid.UUID(payload["jti"])
+
+    def test_each_token_has_unique_jti(self):
+        """Generate 100 tokens for the same user — all jtis must differ."""
+        jtis = set()
+        for _ in range(100):
+            token = _create_refresh_token({"sub": "999"})
+            payload = jwt.decode(
+                token,
+                settings.public_pem,
+                algorithms=[settings.ALGORITHM],
+            )
+            jtis.add(payload["jti"])
+        assert len(jtis) == 100
+
+    def test_jti_survives_decode(self):
+        """The jti claim is present and correct after decode."""
+        token = _create_refresh_token({"sub": "7"})
+        payload = jwt.decode(
+            token,
+            settings.public_pem,
+            algorithms=[settings.ALGORITHM],
+        )
+        assert payload["sub"] == "7"
+        assert "jti" in payload
+        assert "exp" in payload
+
+
+class TestRefreshTokenModelColumnLength:
+    """Verify the model's token column length matches the migration (issue #2)."""
+
+    def test_token_column_has_length_512(self):
+        """RefreshToken.token column should be String(512), not unbounded."""
+        from sqlalchemy import inspect
+
+        # Get the column definition from the model's table
+        column = RefreshToken.__table__.columns["token"]
+        # The type should be String with length 512
+        assert column.type.length == 512
+
+    def test_token_column_type_is_string(self):
+        """The token column should be a String type."""
+        from sqlalchemy import String as SAString
+
+        column = RefreshToken.__table__.columns["token"]
+        assert isinstance(column.type, SAString)

docs/planning/client-server-wiring.md

@@ -0,0 +1,41 @@
+# MVP Vertical Slice: Client-Server Wiring — Plan
+
+## Goal
+Prove the real Godot client and the real backend can talk: **a user can register/log in
+and see a list of worlds from the game client**. Nothing more. Gameplay, join-a-world,
+chat, avatar, Discovery search/tags/trending, Social/Economy/Trust & Safety are all
+explicitly out of scope.
+
+## Verified backend contract (as of this writing)
+- `POST /api/auth/register` — JSON body `{username, email, password, date_of_birth}`.
+  `date_of_birth` is a `YYYY-MM-DD` string. Returns `201 {access_token, token_type}`.
+  Rejects under-18 with `400`.
+- `POST /api/auth/login` — OAuth2 **form-encoded** (`application/x-www-form-urlencoded`)
+  `username` + `password` (this is NOT a JSON endpoint). Returns `{access_token, token_type}`.
+- `GET /api/worlds` — **requires auth** (`CurrentUser`), returns a JSON array of
+  `{id, name, description, visibility, owner_id, created_at}`. There is no unauthenticated
+  public-worlds path, so the worlds list screen can only be shown after login/register.
+- `GET /api/health` — unauthenticated, `{status, app}`.
+- Base URL: uvicorn default `http://127.0.0.1:8000` (must be configurable in the client).
+- CORS is irrelevant to the native Godot `HTTPRequest` client (no browser origin).
+
+## Task breakdown
+| # | Type | Task | Depends on |
+|---|------|------|-----------|
+| 1 | architecture | `ApiClient` autoload: HTTP + JWT storage + error contract | — |
+| 2 | implementation | Main-menu **login + register** UI built & wired (form-encoded + JSON/age gate) | 1 |
+| 3 | implementation | **World list** screen consuming `GET /api/worlds` | 1 |
+| 4 | testing | End-to-end headless smoke test + manual verify | 1,2,3 |
+
+## Design decisions captured (resolved in task 1)
+- Token storage: in-memory singleton property for the MVP; a `save_to_disk` seam is left
+  open but not required yet (no re-login on restart in this slice).
+- Error contract: every call returns a discriminated result (`ok`/`error`) so callers
+  never crash on network failure; non-2xx surfaces `{status, detail}` from the backend.
+- Base URL: read from a ProjectSetting, defaulting to `http://127.0.0.1:8000`.
+- Login is form-encoded; register is JSON — the client helper must support both content types.
+
+## Notes
+- The main-menu auth UI does **not** exist yet (main_menu.gd currently has only Play/Quit
+  stubs). Task 2 must **build** the login/register UI, not merely wire an existing one.
+- The world-list screen also needs to be **built** (a new scene), not just wired.

docs/testing/README.md

@@ -0,0 +1,50 @@
+# Testing at Package Checkpoints
+
+A Package Checkpoint (PC1, PC2, ...) is a periodic review point — every few
+real milestones, the client and server builds get packaged together and
+independently reviewed before anyone calls anything actually done. See
+`project_agp` in Claude's memory, or ask, for the full definition; this
+doc is just the mechanical "how do I run the tests" part of that review.
+
+## Running the suite
+
+```
+python scripts/run_checkpoint_tests.py
+```
+
+Brings up a throwaway Postgres, runs Alembic migrations against it, runs the
+backend pytest suite, starts the backend server, and runs every Godot
+headless smoke test (`scripts/smoke_test_*.gd`) against it. Tears the
+Postgres container down afterward (`--keep-postgres` to skip that if you
+want to poke at the DB after a failure).
+
+If port 5432 is already taken on the machine, pass `--postgres-port` with
+something else.
+
+Exit code is 0 only if everything that actually ran passed — suites with
+nothing to run yet (no Godot binary found, no smoke test scripts yet) are
+reported SKIPPED, not treated as a failure.
+
+## What this does and doesn't prove
+
+Passing this script means: migrations apply cleanly to a genuinely empty
+database, the backend's unit-level logic is correct, and whatever Godot
+smoke tests exist actually round-trip against a live backend. It does
+**not** mean full endpoint/integration coverage exists — see
+`test_inventory.md` for the current, honest list of what's tested and what
+isn't. A checkpoint review should still involve reading the actual diffs
+for anything this script's current coverage doesn't reach, not just running
+green and calling it done.
+
+## Growing this over time
+
+As real integration tests get added (endpoint tests hitting the FastAPI app,
+more Godot smoke coverage beyond `health_check`), they should land under
+`backend/tests/` / `scripts/smoke_test_*.gd` respectively — this script
+picks up new files automatically, nothing to register by hand. Update
+`test_inventory.md`'s tables when you do, so the inventory stays a source
+of truth instead of quietly going stale.
+
+Eventual goal (not implemented yet): gate merges to `main` on this script
+passing, the same way a real CI pipeline would. For now it's a manual step
+run at checkpoint review time.

docs/testing/test_inventory.md

@@ -0,0 +1,94 @@
+# Test Inventory
+
+What automated coverage actually exists, what it actually verifies, and what
+doesn't have coverage yet. Keep this current as tests are added — it's the
+thing a Package Checkpoint review (see `docs/testing/README.md`) reads first
+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 (commit `927f9bd`) — full PC1
+checkpoint run, fresh clone, migrations + pytest + all 4 Godot smoke tests +
+both platform exports, all clean.
+
+## Backend — `backend/tests/` (pytest)
+
+Run: `cd backend && python -m pytest -v` (needs `DATABASE_URL` pointed at a
+reachable Postgres — see the runner script).
+
+**Current total: 68 tests, all passing on a clean `main` checkout.**
+
+| File | Tests | What it covers |
+|---|---|---|
+| `test_auth_age_gate.py` | 17 | `calculate_age()` date-math correctness (exact boundary, leap years, birthday-not-yet-this-year) + `RegisterRequest` date-of-birth validation (parametrized valid/invalid date rejection). Backs the 18+ registration gate (PR #23). |
+| `test_gltf_metadata.py` | 21 | glTF/GLB binary + JSON parsing: magic-byte detection, chunk-padding handling, mesh/animation/texture-reference metadata extraction, malformed-input rejection. Backs the asset-import pipeline (PR #27). |
+| `test_auth_endpoints.py` | 11 | **Integration tests** for `POST /api/auth/register` and `POST /api/auth/login` against the real FastAPI app + real Postgres. Covers: successful register (201), duplicate username (409), duplicate email (409), underage rejection (400), invalid date format (422), exact-18 registration, successful login with correct credentials (200), wrong password (401), nonexistent user (401), form-encoded login (OAuth2), and JWT validity of returned tokens. |
+| `test_refresh_endpoint.py` | 8 | **Integration tests** for `POST /api/auth/refresh`. Covers: successful refresh (200, new access token, same refresh token returned), refresh produces different access tokens on repeated calls, invalid refresh token (401), empty body (422), missing field (422), refresh token from login also works, returned access token is valid JWT decodable with public key, `access_token_expires_minutes` in response. |
+| `test_refresh_token_jti.py` | 6 | Unit tests for refresh token uniqueness (jti claim) and model column length. Covers: two calls with same sub produce different tokens (jti uniqueness), jti is valid UUID, rapid repeated calls all produce unique jtis, jti survives decode, `RefreshToken.token` column is `String(512)`, column type is `String`. |
+| `test_auth_expired_token.py` | 5 | **Integration tests** for expired-token rejection across auth endpoints. Covers: expired access JWT rejected by `GET /api/auth/me` (401), garbage access token rejected by `/me` (401), missing bearer token returns 401, expired refresh token (DB `expires_at` in past) rejected by `/refresh` (401), expired refresh JWT (past `exp` claim) rejected before DB lookup (401). |
+
+**What these are, honestly:** a mix of pure unit tests (`test_auth_age_gate.py`,
+`test_gltf_metadata.py`, `test_refresh_token_jti.py`) and real integration tests
+(`test_auth_endpoints.py`, `test_refresh_endpoint.py`, `test_auth_expired_token.py`)
+that hit the FastAPI app against a real Postgres database via `TestClient`.
+The integration tests exercise the full stack: Pydantic validation → DB →
+JWT → response. The suite is also re-runnable without manual cleanup —
+`backend/tests/conftest.py` has a session-scoped autouse fixture that
+truncates all app tables once before the suite runs.
+
+**Known coverage gaps** (real gaps, not placeholders — nothing enforces filling
+these yet):
+- No endpoint tests for `GET /api/worlds`, `GET /api/assets/*`, or any
+  world/asset CRUD routes — only auth endpoints have integration coverage
+  (`GET /api/worlds` is covered indirectly via the Godot smoke tests below).
+- No tests for the moderation schema/migration beyond "the migration runs."
+- No tests for the `GET /api/auth/me` endpoint's response body (only its
+  auth-header validation is covered via expired-token tests).
+- No tests for session management (create/validate/revoke sessions).
+
+## Godot client — `scripts/smoke_test_*.gd`
+
+**4 smoke tests merged into `main`.** Each needs a live backend —
+`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.
+
+| File | What it covers |
+|---|---|
+| `smoke_test_api.gd` | Exercises `ApiClient.health_check()` against a live backend. Verifies the real HTTP request path (`HTTPRequest` node lifecycle, JSON parse, result-dictionary contract). Exits 1 on failure. |
+| `smoke_test_auth.gd` | Tests the full auth flow via `ApiClient` autoload: register unique user (201), duplicate username (409), under-18 registration (400), correct login (200), wrong password (401), nonexistent user (401). |
+| `smoke_test_e2e.gd` | End-to-end flow: health check → register → login → worlds list. Verifies the full request chain with a fresh user, including token storage and `get_worlds()` with auth header. |
+| `smoke_test_world_list.gd` | Instantiates `world_list.tscn` as a real scene, adds to tree (catches `@onready` node-path bugs), waits for `_refresh_worlds()` to complete, confirms the screen reaches a real end state (world cards, empty-list message, or error label — not stuck loading). |
+
+Run (once, to build the class cache): `godot --headless --path . --import`,
+then for each smoke test: `godot --headless --path . --script
+res://scripts/smoke_test_<name>.gd` — **no `--quit`**, it kills these before
+their awaited HTTP calls finish.
+
+**Known gaps:**
+- No smoke tests for the main menu scene (`main_menu.tscn`).
+- No smoke tests for chunk loading/streaming (`chunk.gd`, `chunk_scene.gd`).
+- No smoke tests for dynamic/static object nodes.
+- All smoke tests require a live backend; no offline/unit smoke tests exist.
+- `smoke_test_world_list.gd` is the only one that exercises a real `.tscn`
+  scene instantiation — others only test the `ApiClient` autoload.
+- `get_me()` (`GET /auth/me`) is implemented in `scripts/api_client.gd` but
+  has no smoke coverage yet.
+
+## Client export
+
+`scripts/build.sh` produces real Linux (`agp-game.x86_64`) and Windows
+(`agp-game.exe`) binaries via `--export-release`. Verified 2026-08-20: both
+exports complete clean from a fresh checkout and produce valid binaries
+(confirmed via `file` — real ELF64/PE32+, not empty or truncated). Neither
+export is exercised by an automated GUI test (headless Godot can't drive a
+window) — actually launching and clicking through the exported binary is a
+manual step, see `docs/checkpoints/PC1.md` for playtest instructions.
+
+## What "full coverage" should eventually mean here
+
+Not defined precisely yet — the honest target as of 2026-08-20 is
+"integration tests for every endpoint + smoke tests for every major scene."
+As real integration/endpoint tests get added, update the tables above
+rather than letting this doc drift stale; a wrong inventory is worse than
+no inventory.

export_presets.cfg

@@ -0,0 +1,74 @@
+[preset.0]
+
+name="Linux"
+platform="Linux/X11"
+runnable=true
+advanced_options=false
+dedicated_server=false
+custom_features=""
+export_filter="all_resources"
+include_filter=""
+exclude_filter=""
+export_path="export/linux/agp-game.x86_64"
+encryption_include_filters=""
+encryption_exclude_filters=""
+encrypt_pck=false
+encrypt_directory=false
+script_export_mode=2
+
+[preset.0.options]
+
+custom_template/debug=""
+custom_template/release=""
+debug/export_console_wrapper=1
+binary_format/embed_pck=false
+texture_format/bptc=true
+texture_format/s3tc=true
+texture_format/etc=false
+texture_format/etc2=false
+binary_format/architecture="x86_64"
+ssh_remote_deploy/enabled=false
+
+[preset.1]
+
+name="Windows Desktop"
+platform="Windows Desktop"
+runnable=true
+advanced_options=false
+dedicated_server=false
+custom_features=""
+export_filter="all_resources"
+include_filter=""
+exclude_filter=""
+export_path="export/windows/agp-game.exe"
+encryption_include_filters=""
+encryption_exclude_filters=""
+encrypt_pck=false
+encrypt_directory=false
+script_export_mode=2
+
+[preset.1.options]
+
+custom_template/debug=""
+custom_template/release=""
+debug/export_console_wrapper=1
+binary_format/embed_pck=false
+texture_format/bptc=true
+texture_format/s3tc=true
+texture_format/etc=false
+texture_format/etc2=false
+binary_format/architecture="x86_64"
+codesign/enable=false
+application/icon=""
+application/console_wrapper_icon=""
+application/icon_interpolation=4
+application/file_version=""
+application/product_version=""
+application/company_name=""
+application/product_name=""
+application/file_description=""
+application/copyright=""
+application/trademarks=""
+application/export_angle=0
+application/export_d3d12=0
+d3d12/agility_sdk_multizip=0

project.godot

@@ -9,9 +9,12 @@ config_version=5
 config/name="AGP-Game"
 run/main_scene="res://scenes/main_menu.tscn"
 config/features=PackedStringArray("4.6.2")
+agp/api_base_url="http://127.0.0.1:8000"
 
 [autoload]
 
+ApiClient="*res://scripts/api_client.gd"
+
 [display]
 
 window/size/viewport_width=1920

scenes/main_menu.tscn

@@ -1,4 +1,4 @@
-[gd_scene load_steps=2 format=3]
+[gd_scene load_steps=2 format=3 uid="uid://main_menu_scene"]
 
 [ext_resource type="Script" path="res://scripts/main_menu.gd" id="1_main"]
 
@@ -29,6 +29,73 @@ text = "AGP Game"
 horizontal_alignment = 1
 theme_override_font_sizes/font_size = 72
 
+[node name="AuthPanel" type="PanelContainer" parent="CenterContainer/VBoxContainer"]
+layout_mode = 1
+visible = false
+
+[node name="MarginContainer" type="MarginContainer" parent="CenterContainer/VBoxContainer/AuthPanel"]
+layout_mode = 1
+theme_override_constants/margin_left = 24
+theme_override_constants/margin_top = 24
+theme_override_constants/margin_right = 24
+theme_override_constants/margin_bottom = 24
+
+[node name="AuthVBox" type="VBoxContainer" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer"]
+layout_mode = 1
+theme_override_constants/separation = 8
+size_flags_horizontal = 3
+
+[node name="AuthModeLabel" type="Label" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
+layout_mode = 1
+text = "Login"
+horizontal_alignment = 1
+theme_override_font_sizes/font_size = 24
+
+[node name="UsernameEdit" type="LineEdit" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
+layout_mode = 1
+placeholder_text = "Username"
+size_flags_horizontal = 3
+
+[node name="PasswordEdit" type="LineEdit" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
+layout_mode = 1
+placeholder_text = "Password"
+size_flags_horizontal = 3
+echo_password = true
+
+[node name="EmailEdit" type="LineEdit" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
+layout_mode = 1
+visible = false
+placeholder_text = "Email"
+size_flags_horizontal = 3
+
+[node name="DOBEdit" type="LineEdit" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
+layout_mode = 1
+visible = false
+placeholder_text = "Date of Birth (YYYY-MM-DD)"
+size_flags_horizontal = 3
+
+[node name="ModeToggle" type="CheckButton" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
+layout_mode = 1
+text = "Register"
+
+[node name="AuthButton" type="Button" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
+layout_mode = 1
+text = "Login"
+size_flags_horizontal = 3
+
+[node name="AuthStatusLabel" type="Label" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
+layout_mode = 1
+text = ""
+horizontal_alignment = 1
+autowrap_mode = 2
+visible = false
+
+[node name="WelcomeLabel" type="Label" parent="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox"]
+layout_mode = 1
+visible = false
+text = ""
+horizontal_alignment = 1
+
 [node name="PlayButton" type="Button" parent="CenterContainer/VBoxContainer"]
 layout_mode = 1
 text = "Play"
@@ -41,3 +108,7 @@ size_flags_horizontal = 4
 
 [connection signal="pressed" from="CenterContainer/VBoxContainer/PlayButton" to="." method="_on_play_button_pressed"]
 [connection signal="pressed" from="CenterContainer/VBoxContainer/QuitButton" to="." method="_on_quit_button_pressed"]
+[connection signal="toggled" from="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/ModeToggle" to="." method="_on_mode_toggle_toggled"]
+[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"]
+[connection signal="text_submitted" from="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/PasswordEdit" to="." method="_on_auth_button_pressed"]

scenes/world_list.tscn

@@ -0,0 +1,76 @@
+[gd_scene load_steps=2 format=3]
+
+[ext_resource type="Script" path="res://scripts/world_list.gd" id="1_wl"]
+
+[node name="WorldList" type="Control"]
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+script = ExtResource("1_wl")
+
+[node name="VBoxContainer" type="VBoxContainer" parent="."]
+layout_mode = 3
+theme_override_constants/separation = 8
+size_flags_horizontal = 4
+size_flags_vertical = 4
+
+[node name="HeaderHBox" type="HBoxContainer" parent="VBoxContainer"]
+layout_mode = 3
+size_flags_horizontal = 4
+theme_override_constants/separation = 16
+
+[node name="BackButton" type="Button" parent="VBoxContainer/HeaderHBox"]
+layout_mode = 3
+text = "< Back"
+size_flags_horizontal = 0
+
+[node name="TitleLabel" type="Label" parent="VBoxContainer/HeaderHBox"]
+layout_mode = 3
+text = "Browse Worlds"
+horizontal_alignment = 1
+size_flags_horizontal = 4
+theme_override_font_sizes/font_size = 28
+
+[node name="RefreshButton" type="Button" parent="VBoxContainer/HeaderHBox"]
+layout_mode = 3
+text = "Refresh"
+size_flags_horizontal = 0
+
+[node name="ScrollContainer" type="ScrollContainer" parent="VBoxContainer"]
+layout_mode = 3
+size_flags_horizontal = 4
+size_flags_vertical = 4
+horizontal_mode = 2
+vertical_mode = 2
+
+[node name="WorldList" type="VBoxContainer" parent="VBoxContainer/ScrollContainer"]
+layout_mode = 3
+size_flags_horizontal = 4
+size_flags_vertical = 4
+theme_override_constants/separation = 8
+
+[node name="LoadingLabel" type="Label" parent="VBoxContainer"]
+layout_mode = 3
+text = "Loading worlds..."
+visible = false
+horizontal_alignment = 1
+theme_override_font_sizes/font_size = 18
+
+[node name="ErrorLabel" type="Label" parent="VBoxContainer"]
+layout_mode = 3
+text = ""
+visible = false
+horizontal_alignment = 1
+theme_override_font_sizes/font_size = 18
+
+[node name="EmptyLabel" type="Label" parent="VBoxContainer"]
+layout_mode = 3
+text = ""
+visible = false
+horizontal_alignment = 1
+theme_override_font_sizes/font_size = 18
+
+[connection signal="pressed" from="VBoxContainer/HeaderHBox/BackButton" to="." method="_on_back_button_pressed"]
+[connection signal="pressed" from="VBoxContainer/HeaderHBox/RefreshButton" to="." method="_on_refresh_button_pressed"]

scripts/api_client.gd

@@ -0,0 +1,292 @@
+extends Node
+## Central HTTP client singleton (autoload name: "ApiClient").
+##
+## Every network call in the game flows through this class. Callers use the
+## high-level helpers ([method login], [method register], [method get_worlds],
+## [method health_check], [method get_me]) or the generic [method request]
+## primitive. All results conform to the result-dictionary contract below.
+##
+## [b]Result Dictionary Contract[/b]
+## Every public method returns (after `await`) a Dictionary with this shape:
+##
+##     {
+##         "ok":     bool,     # true for HTTP 2xx, false otherwise
+##         "status": int,      # HTTP status code (0 on network failure)
+##         "data":   Variant,  # parsed JSON body on success (null otherwise)
+##         "detail": String,   # human-readable message
+##     }
+##
+## Network failures (timeout / DNS / refused connection) return `status == 0`
+## with a `detail` describing the transport failure. Non-2xx responses return
+## the real HTTP status and the backend's `detail` field from the JSON error
+## body when present. No caller can crash on a failed request.
+##
+## [b]Token storage[/b]
+## JWTs are kept in memory. [method set_token] is the single seam for future
+## disk persistence (override it to save to `user://`).
+##
+## [b]Usage[/b]
+##     var result: Dictionary = await ApiClient.login("alice", "secret")
+##     if result.ok:
+##         print("Logged in!")
+##     else:
+##         print("Error: ", result.detail)
+
+# ---------------------------------------------------------------------------
+# Token storage
+# ---------------------------------------------------------------------------
+
+var _access_token: String = ""
+var _token_type: String = "Bearer"
+
+## Full Authorization header value, e.g. "Bearer eyJ...". Empty if no token.
+var bearer_token: String:
+	get:
+		return _token_type + " " + _access_token if _access_token != "" else ""
+
+
+## Whether an access token is currently stored.
+func has_token() -> bool:
+	return _access_token != ""
+
+
+## Set the access token (called after login / register / token refresh).
+## This is the persistence seam: override to also write to disk.
+func set_token(access_token: String, token_type: String = "Bearer") -> void:
+	_access_token = access_token
+	_token_type = token_type
+
+
+## Clear stored tokens.
+func clear_token() -> void:
+	_access_token = ""
+	_token_type = "Bearer"
+
+
+# ---------------------------------------------------------------------------
+# Configuration
+# ---------------------------------------------------------------------------
+
+var _base_url: String = "http://127.0.0.1:8000"
+
+## Request timeout in seconds. 0 disables the timeout.
+var timeout_seconds: float = 10.0
+
+
+func _ready() -> void:
+	# Environment variable override (e.g. for headless smoke tests against a
+	# backend on a non-default port). Falls back to the ProjectSetting, then
+	# to the documented default.
+	var env_url := OS.get_environment("AGP_API_BASE_URL")
+	if env_url != "":
+		_base_url = env_url.rstrip("/")
+	else:
+		_base_url = str(ProjectSettings.get_setting(
+			"application/agp/api_base_url",
+			"http://127.0.0.1:8000"
+		)).rstrip("/")
+
+
+# ---------------------------------------------------------------------------
+# Core request primitive
+# ---------------------------------------------------------------------------
+
+## Generic request primitive. Awaitable via `await`.
+##
+## Uses a dedicated HTTPRequest node per call so concurrent requests can never
+## cross-talk, and so the result maps 1:1 to the awaiting caller.
+##
+## @param method       HTTPClient.Method enum value (GET/POST/PUT/PATCH/DELETE).
+## @param path         URL path, e.g. "/api/health".
+## @param body         Request body string (JSON or form-encoded).
+## @param content_type "application/json" or "application/x-www-form-urlencoded".
+## @param require_auth If true, attach the stored bearer token when present.
+## @return Result dictionary conforming to the contract.
+func request(
+	method: HTTPClient.Method,
+	path: String,
+	body: String = "",
+	content_type: String = "application/json",
+	require_auth: bool = false
+) -> Dictionary:
+	var http := HTTPRequest.new()
+	http.timeout = timeout_seconds
+	http.max_redirects = 8
+	http.accept_gzip = true
+	add_child(http)
+
+	var headers := PackedStringArray()
+	headers.append("Accept: application/json")
+	if content_type != "":
+		headers.append("Content-Type: " + content_type)
+	if require_auth and has_token():
+		headers.append("Authorization: " + bearer_token)
+
+	var url := _base_url + path
+	var err := http.request(url, headers, method, body)
+	if err != OK:
+		http.queue_free()
+		return _make_result(false, 0, null, "Failed to start request: " + _error_string(err))
+
+	# request_completed emits (result, response_code, headers, body).
+	var args: Array = await http.request_completed
+	var result_code: int = args[0]
+	var response_code: int = args[1]
+	var response_body: PackedByteArray = args[3]
+	http.queue_free()
+
+	# Transport-level failure (timeout / DNS / refused / TLS, etc.).
+	if result_code != HTTPRequest.RESULT_SUCCESS:
+		return _make_result(false, 0, null, _transport_error_detail(result_code))
+
+	# Server accepted the connection but returned no HTTP status line.
+	if response_code == 0:
+		return _make_result(false, 0, null, "No response received from server.")
+
+	var json_string := response_body.get_string_from_utf8()
+	var ok := response_code >= 200 and response_code < 300
+
+	if ok:
+		var data: Variant = _parse_json(json_string)
+		return _make_result(true, response_code, data, "OK")
+
+	# Non-2xx: surface the backend's "detail" message when available.
+	var detail := "HTTP error %d" % response_code
+	var parsed: Variant = _parse_json(json_string)
+	if parsed is Dictionary and (parsed as Dictionary).has("detail"):
+		detail = str((parsed as Dictionary)["detail"])
+	return _make_result(false, response_code, null, detail)
+
+
+# ---------------------------------------------------------------------------
+# High-level helpers
+# ---------------------------------------------------------------------------
+
+## Log in with username/password (OAuth2PasswordRequestForm).
+## On success stores the returned access token.
+func login(username: String, password: String) -> Dictionary:
+	var form := "username=" + username.uri_encode() + "&password=" + password.uri_encode()
+	var result := await request(
+		HTTPClient.METHOD_POST,
+		"/api/auth/login",
+		form,
+		"application/x-www-form-urlencoded",
+		false
+	)
+	_store_token_from_result(result)
+	return result
+
+
+## Register a new user. On success stores the returned access token.
+## @param date_of_birth ISO date string "YYYY-MM-DD".
+func register(
+	username: String,
+	email: String,
+	password: String,
+	date_of_birth: String
+) -> Dictionary:
+	var payload := {
+		"username": username,
+		"email": email,
+		"password": password,
+		"date_of_birth": date_of_birth,
+	}
+	var result := await request(
+		HTTPClient.METHOD_POST,
+		"/api/auth/register",
+		JSON.stringify(payload),
+		"application/json",
+		false
+	)
+	_store_token_from_result(result)
+	return result
+
+
+## List worlds visible to the current user (requires auth).
+## @param visibility Optional filter: "public", "private", "friends_only".
+func get_worlds(skip: int = 0, limit: int = 50, visibility: String = "") -> Dictionary:
+	var path := "/api/worlds/?skip=%d&limit=%d" % [skip, limit]
+	if visibility != "":
+		path += "&visibility=" + visibility.uri_encode()
+	return await request(HTTPClient.METHOD_GET, path, "", "application/json", true)
+
+
+## Ping the backend health endpoint (no auth).
+func health_check() -> Dictionary:
+	return await request(HTTPClient.METHOD_GET, "/api/health", "", "application/json", false)
+
+
+## Fetch the current user's profile from the stored JWT (requires auth).
+func get_me() -> Dictionary:
+	return await request(HTTPClient.METHOD_GET, "/api/users/me", "", "application/json", true)
+
+
+# ---------------------------------------------------------------------------
+# Internals
+# ---------------------------------------------------------------------------
+
+func _store_token_from_result(result: Dictionary) -> void:
+	if result.ok and result.data is Dictionary:
+		var token: String = str((result.data as Dictionary).get("access_token", ""))
+		if token != "":
+			set_token(token)
+
+
+func _parse_json(text: String) -> Variant:
+	if text == "":
+		return null
+	var parsed: Variant = JSON.parse_string(text)
+	if parsed == null:
+		# null is ambiguous (valid JSON "null" vs parse failure). Fall back to
+		# the raw string so callers never lose the body entirely.
+		return text if text != "null" else null
+	return parsed
+
+
+func _make_result(ok: bool, status: int, data: Variant, detail: String) -> Dictionary:
+	return {
+		"ok": ok,
+		"status": status,
+		"data": data,
+		"detail": detail,
+	}
+
+
+func _transport_error_detail(result_code: int) -> String:
+	match result_code:
+		HTTPRequest.RESULT_CANT_CONNECT:
+			return "Could not connect to server. Is it running?"
+		HTTPRequest.RESULT_CANT_RESOLVE:
+			return "Could not resolve server hostname."
+		HTTPRequest.RESULT_CONNECTION_ERROR:
+			return "Connection error."
+		HTTPRequest.RESULT_TLS_HANDSHAKE_ERROR:
+			return "TLS handshake failed."
+		HTTPRequest.RESULT_NO_RESPONSE:
+			return "No response from server."
+		HTTPRequest.RESULT_BODY_SIZE_LIMIT_EXCEEDED:
+			return "Response body too large."
+		HTTPRequest.RESULT_BODY_DECOMPRESS_FAILED:
+			return "Failed to decompress response body."
+		HTTPRequest.RESULT_REQUEST_FAILED:
+			return "Request failed."
+		HTTPRequest.RESULT_TIMEOUT:
+			return "Request timed out."
+		_:
+			return "Network error (code %d)." % result_code
+
+
+func _error_string(err_code: int) -> String:
+	match err_code:
+		OK:
+			return "OK"
+		ERR_UNCONFIGURED:
+			return "HTTPRequest not configured (not in tree)."
+		ERR_BUSY:
+			return "HTTPRequest is busy with a previous request."
+		ERR_INVALID_PARAMETER:
+			return "Invalid URL format."
+		ERR_CANT_CONNECT:
+			return "Cannot connect to host."
+		_:
+			return "Unknown error (%d)." % err_code

scripts/api_client.gd.uid

@@ -0,0 +1 @@
+uid://cjd0uhll7iylj

scripts/build.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+# Headless CI export for Linux and Windows.
+#
+# Requires:
+#   - Godot 4.6.2 (the exact version this project + export_presets.cfg were
+#     built against; a different Godot minor version's export templates are
+#     not guaranteed compatible)
+#   - The matching export templates installed at
+#     ~/.local/share/godot/export_templates/4.6.2.stable/
+#     (download: https://godotengine.org/download/archive/4.6.2-stable/,
+#     "Export templates" -- NOT the same as the editor download)
+#   - godot on PATH (or set GODOT_BIN below)
+#
+# Usage: scripts/build.sh
+# Output: export/linux/agp-game.x86_64, export/windows/agp-game.exe
+
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+GODOT_BIN="${GODOT_BIN:-godot}"
+if ! command -v "$GODOT_BIN" >/dev/null 2>&1; then
+    if [ -x "$HOME/godot/godot" ]; then
+        GODOT_BIN="$HOME/godot/godot"
+    else
+        echo "godot binary not found (checked PATH and ~/godot/godot)." >&2
+        exit 1
+    fi
+fi
+
+echo "Godot version: $("$GODOT_BIN" --version)"
+
+mkdir -p export/linux export/windows
+
+echo "=== Exporting Linux/X11 ==="
+"$GODOT_BIN" --headless --path . --export-release "Linux" export/linux/agp-game.x86_64
+
+echo "=== Exporting Windows Desktop ==="
+"$GODOT_BIN" --headless --path . --export-release "Windows Desktop" export/windows/agp-game.exe
+
+echo ""
+echo "Build artifacts:"
+ls -la export/linux export/windows

scripts/main_menu.gd

@@ -1,14 +1,212 @@
 extends Control
+## Main menu with login/register UI wired to the backend auth API.
+##
+## The AuthPanel is hidden by default. When the user clicks "Login" or "Register"
+## (the existing Play/Quit buttons), the auth panel slides in. The ModeToggle
+## switches between Login and Register modes, showing/hiding the email and DOB
+## fields accordingly.
+##
+## On successful auth the token is stored via ApiClient, the welcome label
+## shows the username, and the Play button becomes enabled.
 
 
-func _ready():
-	pass
+# ── UI references ────────────────────────────────────────────────────────────
+
+var _auth_panel: PanelContainer
+var _auth_mode_label: Label
+var _username_edit: LineEdit
+var _password_edit: LineEdit
+var _email_edit: LineEdit
+var _dob_edit: LineEdit
+var _mode_toggle: CheckButton
+var _auth_button: Button
+var _status_label: Label
+var _welcome_label: Label
+var _play_button: Button
+var _quit_button: Button
+
+var _is_register_mode: bool = false
+var _is_authenticating: bool = false
 
 
-func _on_play_button_pressed():
-	# No gameplay scene exists yet — wire this to the real scene once one lands.
-	print("Play pressed — no gameplay scene yet")
+# ── Lifecycle ────────────────────────────────────────────────────────────────
+
+func _ready() -> void:
+	# Cache node references.
+	_auth_panel = $CenterContainer/VBoxContainer/AuthPanel
+	_auth_mode_label = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthModeLabel
+	_username_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/UsernameEdit
+	_password_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/PasswordEdit
+	_email_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/EmailEdit
+	_dob_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/DOBEdit
+	_mode_toggle = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/ModeToggle
+	_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
+	_quit_button = $CenterContainer/VBoxContainer/QuitButton
+
+	# Initial state.
+	_auth_panel.visible = false
+	_status_label.visible = false
+	_welcome_label.visible = false
+	_email_edit.visible = false
+	_dob_edit.visible = false
+	_play_button.disabled = true  # Gate play behind successful auth.
+	_update_auth_mode_ui()
 
 
-func _on_quit_button_pressed():
+# ── Play / Quit ──────────────────────────────────────────────────────────────
+
+func _on_play_button_pressed() -> void:
+	if _play_button.disabled:
+		return
+	# Browse worlds is the first real screen past login -- actual gameplay
+	# (joining a world) doesn't exist yet, browsing does.
+	get_tree().change_scene_to_file("res://scenes/world_list.tscn")
+
+
+func _on_quit_button_pressed() -> void:
 	get_tree().quit()
+
+
+# ── Auth panel toggle ────────────────────────────────────────────────────────
+
+func _on_login_button_pressed() -> void:
+	"""Show the auth panel (called from a future Login button on the main menu)."""
+	_auth_panel.visible = true
+	_auth_panel.grab_focus()
+
+
+func _on_register_button_pressed() -> void:
+	"""Show the auth panel in register mode."""
+	_auth_panel.visible = true
+	_is_register_mode = true
+	_mode_toggle.button_pressed = true
+	_update_auth_mode_ui()
+	_clear_status()
+
+
+# ── Mode toggle (Login / Register) ───────────────────────────────────────────
+
+func _on_mode_toggle_toggled(button_pressed: bool) -> void:
+	_is_register_mode = button_pressed
+	_update_auth_mode_ui()
+	_clear_status()
+
+
+func _update_auth_mode_ui() -> void:
+	"""Update labels and field visibility based on login vs register mode."""
+	if _is_register_mode:
+		_auth_mode_label.text = "Register"
+		_auth_button.text = "Register"
+		_email_edit.visible = true
+		_dob_edit.visible = true
+	else:
+		_auth_mode_label.text = "Login"
+		_auth_button.text = "Login"
+		_email_edit.visible = false
+		_dob_edit.visible = false
+
+
+# ── Auth submission ──────────────────────────────────────────────────────────
+
+func _on_auth_button_pressed() -> void:
+	"""Handle login or register button press."""
+	if _is_authenticating:
+		return
+
+	# Validate inputs.
+	var username := _username_edit.text.strip_edges()
+	var password := _password_edit.text
+
+	if username == "":
+		_show_status("Username is required.")
+		return
+	if password == "":
+		_show_status("Password is required.")
+		return
+
+	if _is_register_mode:
+		var email := _email_edit.text.strip_edges()
+		var dob := _dob_edit.text.strip_edges()
+
+		if email == "":
+			_show_status("Email is required.")
+			return
+		if dob == "":
+			_show_status("Date of birth is required.")
+			return
+		# Basic YYYY-MM-DD format check.
+		if not _is_valid_date(dob):
+			_show_status("Date of birth must be in YYYY-MM-DD format.")
+			return
+
+		_auth_button.disabled = true
+		_auth_button.text = "Registering..."
+		_is_authenticating = true
+		_clear_status()
+
+		var result := await ApiClient.register(username, email, password, dob)
+		_on_auth_complete(result)
+	else:
+		_auth_button.disabled = true
+		_auth_button.text = "Logging in..."
+		_is_authenticating = true
+		_clear_status()
+
+		var result := await ApiClient.login(username, password)
+		_on_auth_complete(result)
+
+
+func _on_auth_complete(result: Dictionary) -> void:
+	"""Handle the result of a login or register call."""
+	_auth_button.disabled = false
+	_auth_button.text = "Register" if _is_register_mode else "Login"
+	_is_authenticating = false
+
+	if result.ok:
+		# Success — show welcome, enable Play.
+		_welcome_label.text = "Welcome, %s!" % _username_edit.text.strip_edges()
+		_welcome_label.visible = true
+		_status_label.visible = false
+		_play_button.disabled = false
+		print("Auth successful. Token stored.")
+	else:
+		# Failure — show backend error detail.
+		_show_status(result.detail)
+
+
+# ── Status helpers ───────────────────────────────────────────────────────────
+
+func _show_status(message: String) -> void:
+	_status_label.text = message
+	_status_label.visible = true
+
+
+func _clear_status() -> void:
+	_status_label.text = ""
+	_status_label.visible = false
+
+
+# ── Validation ───────────────────────────────────────────────────────────────
+
+func _is_valid_date(date_str: String) -> bool:
+	"""Check if a string looks like a valid YYYY-MM-DD date."""
+	if date_str.length() != 10:
+		return false
+	var parts := date_str.split("-")
+	if parts.size() != 3:
+		return false
+	var year := parts[0].to_int()
+	var month := parts[1].to_int()
+	var day := parts[2].to_int()
+	if month < 1 or month > 12:
+		return false
+	if day < 1 or day > 31:
+		return false
+	# Rough month-day validation.
+	var days_in_month := [0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
+	if day > days_in_month[month]:
+		return false
+	return true

scripts/main_menu.gd.uid

@@ -0,0 +1 @@
+uid://bgnc3iamfgf6k

scripts/run_checkpoint_tests.py

@@ -0,0 +1,170 @@
+#!/usr/bin/env python3
+"""Run the full automated test inventory for a Package Checkpoint review.
+
+See docs/testing/test_inventory.md for what each suite actually covers (and
+doesn't) -- keep that doc in sync as tests are added, this script just runs
+whatever's there.
+
+Usage:
+    python scripts/run_checkpoint_tests.py [--keep-postgres] [--postgres-port PORT]
+
+Exits 0 if everything that ran passed, 1 otherwise. Suites with nothing to
+run (e.g. no scripts/smoke_test_*.gd yet, or no Godot binary found) are
+reported as SKIPPED, not counted as a failure.
+"""
+import argparse
+import glob
+import os
+import shutil
+import subprocess
+import sys
+import time
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+BACKEND = ROOT / "backend"
+
+
+def run(cmd, cwd=None, env=None, capture=False):
+    print(f"$ {' '.join(cmd)}" + (f"  (cwd={cwd})" if cwd else ""))
+    return subprocess.run(cmd, cwd=cwd, env=env, capture_output=capture, text=True)
+
+
+def find_godot():
+    for candidate in ("godot", str(Path.home() / "godot" / "godot")):
+        if shutil.which(candidate) or Path(candidate).is_file():
+            return candidate
+    return None
+
+
+def wait_for_http(url: str, timeout_s: int = 20) -> bool:
+    import urllib.request
+    import urllib.error
+
+    deadline = time.time() + timeout_s
+    while time.time() < deadline:
+        try:
+            with urllib.request.urlopen(url, timeout=2) as resp:
+                if resp.status == 200:
+                    return True
+        except (urllib.error.URLError, ConnectionError, OSError):
+            pass
+        time.sleep(1)
+    return False
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    parser.add_argument("--keep-postgres", action="store_true",
+                         help="Don't tear down the checkpoint Postgres container afterward")
+    parser.add_argument("--postgres-port", default=os.environ.get("CHECKPOINT_POSTGRES_PORT", "5432"),
+                         help="Host port for the checkpoint's own Postgres container (default 5432 -- "
+                              "override if that's already in use on this machine)")
+    parser.add_argument("--backend-port", default=os.environ.get("CHECKPOINT_BACKEND_PORT", "18080"),
+                         help="Port to run the backend server on for the Godot smoke tests")
+    args = parser.parse_args()
+
+    results = {}
+
+    # --- Backend: bring up Postgres ---
+    compose_env = os.environ.copy()
+    compose_env["COMPOSE_PROJECT_NAME"] = "agp-checkpoint"
+    compose_env["POSTGRES_HOST_PORT"] = args.postgres_port
+    compose_env["POSTGRES_PORT"] = args.postgres_port  # some branches use this name instead, see tools/definitions.py
+    print("=== Backend: bringing up Postgres ===")
+    run(["docker", "compose", "up", "-d", "postgres"], cwd=BACKEND, env=compose_env)
+
+    print("Waiting for Postgres to be ready...")
+    pg_ready = False
+    for _ in range(20):
+        r = run(["docker", "compose", "exec", "-T", "postgres", "pg_isready", "-U", "agp_user", "-d", "agp_db"],
+                cwd=BACKEND, env=compose_env, capture=True)
+        if r.returncode == 0:
+            pg_ready = True
+            break
+        time.sleep(1)
+    if not pg_ready:
+        print("Postgres never became ready -- aborting.")
+        sys.exit(1)
+
+    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
+
+    print("\n=== Backend: alembic upgrade head ===")
+    r = run([sys.executable, "-m", "alembic", "upgrade", "head"], cwd=BACKEND, env=backend_env)
+    results["migrations (fresh DB)"] = r.returncode == 0
+
+    print("\n=== Backend: pytest ===")
+    r = run([sys.executable, "-m", "pytest", "-v"], cwd=BACKEND, env=backend_env)
+    results["backend pytest"] = r.returncode == 0
+
+    # --- Godot: headless smoke tests (need a live backend server) ---
+    godot_bin = find_godot()
+    smoke_tests = sorted(glob.glob(str(ROOT / "scripts" / "smoke_test_*.gd")))
+
+    if not godot_bin:
+        print("\n=== Godot: binary not found (checked PATH and ~/godot/godot), skipping smoke tests ===")
+        results["godot smoke tests"] = None
+    elif not smoke_tests:
+        print("\n=== Godot: no scripts/smoke_test_*.gd found yet, nothing to run ===")
+        results["godot smoke tests"] = None
+    else:
+        print(f"\n=== Backend: starting server on :{args.backend_port} for Godot smoke tests ===")
+        server_proc = subprocess.Popen(
+            [sys.executable, "-m", "uvicorn", "app.main:app", "--host", "127.0.0.1", "--port", args.backend_port],
+            cwd=BACKEND, env=backend_env,
+            stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,
+        )
+        try:
+            base_url = f"http://127.0.0.1:{args.backend_port}"
+            if not wait_for_http(f"{base_url}/api/health"):
+                print("Backend server never became healthy -- skipping Godot smoke tests.")
+                results["godot smoke tests"] = False
+            else:
+                godot_env = os.environ.copy()
+                godot_env["AGP_API_BASE_URL"] = base_url
+
+                print("=== Godot: import pass (builds the class cache) ===")
+                run([godot_bin, "--headless", "--path", str(ROOT), "--import"], env=godot_env)
+                run([godot_bin, "--headless", "--path", str(ROOT), "--quit"], env=godot_env)
+
+                godot_ok = True
+                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
+                results["godot smoke tests"] = godot_ok
+        finally:
+            server_proc.terminate()
+            try:
+                server_proc.wait(timeout=10)
+            except subprocess.TimeoutExpired:
+                server_proc.kill()
+
+    if not args.keep_postgres:
+        print("\n=== Backend: tearing down checkpoint Postgres ===")
+        run(["docker", "compose", "down", "-v", "postgres"], cwd=BACKEND, env=compose_env)
+
+    # --- Summary ---
+    print("\n" + "=" * 50)
+    print("SUMMARY")
+    print("=" * 50)
+    overall_ok = True
+    for name, ok in results.items():
+        if ok is None:
+            print(f"  {name}: SKIPPED")
+        elif ok:
+            print(f"  {name}: PASS")
+        else:
+            print(f"  {name}: FAIL")
+            overall_ok = False
+
+    print("\nSee docs/testing/test_inventory.md for what each suite actually covers (and doesn't).")
+    sys.exit(0 if overall_ok else 1)
+
+
+if __name__ == "__main__":
+    main()

scripts/smoke_test_api.gd

@@ -0,0 +1,46 @@
+extends SceneTree
+## Headless smoke test for the ApiClient autoload.
+##
+## Run with:
+##     godot --headless --path . --script res://scripts/smoke_test_api.gd
+##
+## Requires the backend to be running (default base URL
+## `application/agp/api_base_url` -> http://127.0.0.1:8000).
+##
+## Calls the real autoload's `health_check()` (which exercises the generic
+## `request()` primitive) and exits 0 on a `status == "ok"` response, 1
+## otherwise. This script is intentionally NOT wired into any game scene.
+
+
+func _initialize() -> void:
+	_run()
+
+
+func _run() -> void:
+	# _initialize() fires before the SceneTree has processed its first frame,
+	# so a freshly add_child()'d HTTPRequest node isn't reliably considered
+	# "inside tree" yet (request_raw fails with !is_inside_tree()). One frame
+	# of delay is enough; this only matters for --script mode, not a real
+	# running game.
+	await process_frame
+
+	# Godot's --script/SceneTree runner doesn't resolve autoload singletons
+	# as bare global identifiers at compile time (the node exists at
+	# runtime -- root.has_node("ApiClient") is true -- but referencing it as
+	# a plain identifier fails with "Identifier not found: ApiClient" during
+	# script compilation). get_node sidesteps compile-time resolution
+	# entirely. This only affects --script mode; a real game scene resolves
+	# the bare autoload name normally.
+	var api_client := root.get_node("ApiClient")
+	print("SMOKE: calling ApiClient.health_check() ...")
+	var result: Dictionary = await api_client.health_check()
+	print("SMOKE: result = ", result)
+
+	if result.ok \
+			and result.data is Dictionary \
+			and str((result.data as Dictionary).get("status", "")) == "ok":
+		print("SMOKE RESULT: PASS (status=ok)")
+		quit(0)
+	else:
+		printerr("SMOKE RESULT: FAIL")
+		quit(1)

scripts/smoke_test_auth.gd

@@ -0,0 +1,133 @@
+extends SceneTree
+## Headless smoke test for the AuthPanel login/register flow.
+##
+## Run with:
+##     godot --headless --path . --script res://scripts/smoke_test_auth.gd
+##
+## Requires the backend to be running (default base URL
+## `application/agp/api_base_url` -> http://127.0.0.1:8000).
+##
+## Tests:
+##   1. Register a unique user → 201 + token stored.
+##   2. Register the same user again → 409 "Username already registered".
+##   3. Register an under-18 user → 400 "Must be 18 or older".
+##   4. Login with correct credentials → 200 + token stored.
+##   5. Login with wrong password → 401 "Incorrect username or password".
+##   6. Login with non-existent user → 401 "Incorrect username or password".
+##
+## Exits 0 on full pass, 1 on any failure.
+
+const API_BASE := "http://127.0.0.1:8000"
+const TEST_USERNAME := "smoke_test_user_%d"
+const TEST_EMAIL := "smoke_%d@test.example.com"
+const TEST_PASSWORD := "SmokeTest123!"
+const TEST_DOB_ADULT := "2000-01-01"
+const TEST_DOB_CHILD := "2020-01-01"  # ~5 years old
+
+
+func _initialize() -> void:
+	_run()
+
+
+func _run() -> void:
+	# Wait for autoloads to be ready.
+	await process_frame
+
+	var api := root.get_node("ApiClient") as ApiClient
+	assert(api != null, "ApiClient autoload not found")
+
+	var passed: int = 0
+	var failed: int = 0
+
+	# --- Test 1: Register a unique user ---
+	var unique_id := Time.get_ticks_msec()
+	var username := "smoke_%d" % unique_id
+	var email := "smoke_%d@test.example.com" % unique_id
+
+	print("\n=== Test 1: Register unique user ===")
+	var result := await api.register(username, email, TEST_PASSWORD, TEST_DOB_ADULT)
+	if _check("register returns ok", result.ok) \
+			and _check("register status is 201", result.status == 201) \
+			and _check("register stores token", api.has_token()):
+		passed += 1
+	else:
+		failed += 1
+		print("  detail: ", result.detail)
+
+	# --- Test 2: Register same user again (duplicate) ---
+	print("\n=== Test 2: Duplicate username ===")
+	result = await api.register(username, email, TEST_PASSWORD, TEST_DOB_ADULT)
+	if _check("duplicate register not ok", not result.ok) \
+			and _check("duplicate status is 409", result.status == 409) \
+			and _check("duplicate detail mentions username",
+					"username" in result.detail.to_lower()):
+		passed += 1
+	else:
+		failed += 1
+		print("  detail: ", result.detail)
+
+	# --- Test 3: Register under-18 user ---
+	print("\n=== Test 3: Under-18 registration ===")
+	var child_username := "child_%d" % unique_id
+	var child_email := "child_%d@test.example.com" % unique_id
+	result = await api.register(child_username, child_email, TEST_PASSWORD, TEST_DOB_CHILD)
+	if _check("under-18 register not ok", not result.ok) \
+			and _check("under-18 status is 400", result.status == 400) \
+			and _check("under-18 detail mentions age",
+					"18" in result.detail):
+		passed += 1
+	else:
+		failed += 1
+		print("  detail: ", result.detail)
+
+	# --- Test 4: Login with correct credentials ---
+	print("\n=== Test 4: Correct login ===")
+	result = await api.login(username, TEST_PASSWORD)
+	if _check("login returns ok", result.ok) \
+			and _check("login status is 200", result.status == 200) \
+			and _check("login stores token", api.has_token()):
+		passed += 1
+	else:
+		failed += 1
+		print("  detail: ", result.detail)
+
+	# --- Test 5: Login with wrong password ---
+	print("\n=== Test 5: Wrong password ===")
+	result = await api.login(username, "WrongPassword!")
+	if _check("wrong pwd login not ok", not result.ok) \
+			and _check("wrong pwd status is 401", result.status == 401) \
+			and _check("wrong pwd detail",
+					"Incorrect" in result.detail or "incorrect" in result.detail):
+		passed += 1
+	else:
+		failed += 1
+		print("  detail: ", result.detail)
+
+	# --- Test 6: Login with non-existent user ---
+	print("\n=== Test 6: Non-existent user ===")
+	result = await api.login("nonexistent_user_xyz", TEST_PASSWORD)
+	if _check("missing user login not ok", not result.ok) \
+			and _check("missing user status is 401", result.status == 401) \
+			and _check("missing user detail",
+					"Incorrect" in result.detail or "incorrect" in result.detail):
+		passed += 1
+	else:
+		failed += 1
+		print("  detail: ", result.detail)
+
+	# --- Summary ---
+	print("\n=== SMOKE RESULT: %d/%d passed ===" % [passed, passed + failed])
+	if failed > 0:
+		quit(1)
+	else:
+		print("SMOKE RESULT: ALL PASS")
+		quit(0)
+
+
+func _check(description: String, condition: bool) -> bool:
+	if condition:
+		print("  PASS: ", description)
+		return true
+	else:
+		printerr("  FAIL: ", description)
+		return false

scripts/smoke_test_e2e.gd

@@ -0,0 +1,148 @@
+extends SceneTree
+## End-to-end headless smoke test: register -> login -> fetch worlds list.
+##
+## Run with:
+##     godot --headless --path . --script res://scripts/smoke_test_e2e.gd
+##
+## Requires the backend to be running (default base URL
+## `application/agp/api_base_url` -> http://127.0.0.1:8000, overridable via
+## the AGP_API_BASE_URL environment variable).
+##
+## Steps:
+##   1. Health check  GET  /api/health          -> 200, {"status": "ok"}
+##   2. Register      POST /api/auth/register   -> 201, access_token present
+##   3. Login         POST /api/auth/login      -> 200, access_token present
+##   4. Worlds list   GET  /api/worlds          -> 200, JSON array
+##
+## Exits 0 if all steps pass, 1 otherwise. If the backend is unreachable the
+## health check fails with a clear message and the script exits 1 immediately.
+
+# Fixed credentials from the task spec. The username gets a unique numeric
+# suffix so the test stays re-runnable (a second run would otherwise hit
+# "Username already registered" on step 2).
+const TEST_USERNAME_BASE := "smoke_test_user"
+const TEST_EMAIL := "smoke@test.com"
+const TEST_PASSWORD := "TestPass123"
+const TEST_DOB := "2000-01-01"
+
+
+func _initialize() -> void:
+	_run()
+
+
+func _run() -> void:
+	# _initialize() fires before the first frame; wait one frame so freshly
+	# created HTTPRequest nodes are reliably inside the tree.
+	await process_frame
+
+	# In --script mode the autoload is reachable via get_node(), not as a
+	# bare identifier (bare identifiers fail to resolve at compile time here).
+	var api := root.get_node("ApiClient")
+	assert(api != null, "ApiClient autoload not found in the scene tree")
+
+	var unique_id := int(Time.get_unix_time_from_system() * 1000)
+	var username := "%s_%d" % [TEST_USERNAME_BASE, unique_id]
+	var email := "smoke_%d@test.com" % unique_id
+
+	var results := {}
+
+	# --- Step 1: Health check -------------------------------------------------
+	print("\n=== Step 1: Health check (GET /api/health) ===")
+	var health: Dictionary = await api.health_check()
+	var health_ok: bool = (
+		health.ok
+		and health.status == 200
+		and health.data is Dictionary
+		and str((health.data as Dictionary).get("status", "")) == "ok"
+	)
+	_record(results, "health", health_ok, "status=%d data=%s" % [
+		health.status, health.data
+	])
+
+	if not health.ok or health.status == 0:
+		printerr("\nERROR: Backend is not reachable at the configured base URL.")
+		printerr("       detail: %s" % health.detail)
+		printerr("       Start the backend first (see backend/README), then re-run:")
+		printerr("       godot --headless --path . --script res://scripts/smoke_test_e2e.gd")
+		_summarize(results)
+		quit(1)
+		return
+
+	# --- Step 2: Register -----------------------------------------------------
+	print("\n=== Step 2: Register (POST /api/auth/register) ===")
+	var reg: Dictionary = await api.register(username, email, TEST_PASSWORD, TEST_DOB)
+	var reg_token := _extract_token(reg)
+	var reg_ok: bool = (
+		reg.ok
+		and reg.status == 201
+		and reg_token != ""
+	)
+	_record(results, "register", reg_ok, "status=%d token=%s detail=%s" % [
+		reg.status, "yes" if reg_token != "" else "no", reg.detail
+	])
+
+	# --- Step 3: Login --------------------------------------------------------
+	print("\n=== Step 3: Login (POST /api/auth/login) ===")
+	var login: Dictionary = await api.login(username, TEST_PASSWORD)
+	var login_token := _extract_token(login)
+	var login_ok: bool = (
+		login.ok
+		and login.status == 200
+		and login_token != ""
+	)
+	_record(results, "login", login_ok, "status=%d token=%s detail=%s" % [
+		login.status, "yes" if login_token != "" else "no", login.detail
+	])
+
+	# --- Step 4: Worlds list ---------------------------------------------------
+	print("\n=== Step 4: Worlds list (GET /api/worlds) ===")
+	# login/register already stored the token; make the auth header explicit by
+	# re-applying the extracted token so step 4 is independent of storage order.
+	if login_token != "":
+		api.set_token(login_token)
+	var worlds: Dictionary = await api.get_worlds()
+	var worlds_ok: bool = (
+		worlds.ok
+		and worlds.status == 200
+		and worlds.data is Array
+	)
+	_record(results, "worlds", worlds_ok, "status=%d is_array=%s count=%d detail=%s" % [
+		worlds.status,
+		"yes" if (worlds.data is Array) else "no",
+		(worlds.data as Array).size() if (worlds.data is Array) else -1,
+		worlds.detail,
+	])
+
+	# --- Summary ---------------------------------------------------------------
+	_summarize(results)
+
+
+func _extract_token(result: Dictionary) -> String:
+	if result.ok and result.data is Dictionary:
+		return str((result.data as Dictionary).get("access_token", ""))
+	return ""
+
+
+func _record(results: Dictionary, name: String, ok: bool, detail: String) -> void:
+	results[name] = {"ok": ok, "detail": detail}
+	if ok:
+		print("  PASS: %s" % detail)
+	else:
+		printerr("  FAIL: %s" % detail)
+
+
+func _summarize(results: Dictionary) -> void:
+	var all_pass := true
+	print("\n=== Smoke test summary ===")
+	for step in ["health", "register", "login", "worlds"]:
+		var entry: Dictionary = results.get(step, {"ok": false, "detail": "not run"})
+		if not entry["ok"]:
+			all_pass = false
+		print("  %-8s : %s" % [step, "PASS" if entry["ok"] else "FAIL"])
+
+	if all_pass:
+		print("SMOKE RESULT: ALL PASS (4/4)")
+		quit(0)
+	else:
+		printerr("SMOKE RESULT: FAIL")
+		quit(1)

scripts/smoke_test_world_list.gd

@@ -0,0 +1,122 @@
+extends SceneTree
+## Headless smoke test for the world list screen.
+##
+## Run with:
+##     godot --headless --path . --script res://scripts/smoke_test_world_list.gd
+##
+## Requires the backend to be running (default base URL
+## `application/agp/api_base_url` -> http://127.0.0.1:8000, override with
+## AGP_API_BASE_URL).
+##
+## Unlike a pure API-level test, this actually instantiates scenes/
+## world_list.tscn as a real scene and adds it to the tree -- catches
+## @onready node-path bugs (a node reference pointing at the wrong path
+## errors right here, not just "looks right" from reading the script) that
+## an API-only test would miss entirely.
+##
+## Tests:
+##   1. Register + log in a fresh user (so get_worlds() has a valid token).
+##   2. Instantiate world_list.tscn, add to tree -- @onready resolution
+##      must not error.
+##   3. Wait for _refresh_worlds()'s awaited request to complete.
+##   4. Confirm the screen reached a real end state (world cards, or the
+##      empty-list message -- either is fine, a crash/stuck-loading isn't).
+##
+## Exits 0 on full pass, 1 on any failure.
+
+const WORLD_LIST_SCENE := "res://scenes/world_list.tscn"
+
+
+func _initialize() -> void:
+	_run()
+
+
+func _run() -> void:
+	await process_frame
+
+	var api := root.get_node("ApiClient")
+	assert(api != null, "ApiClient autoload not found")
+
+	var passed: int = 0
+	var failed: int = 0
+
+	# --- Setup: register + log in so the world list has a valid token ---
+	print("\n=== Setup: register + login ===")
+	randomize()
+	var unique_id: int = int(Time.get_unix_time_from_system() * 1000) + randi() % 100000
+	var username := "worldlist_smoke_%d" % unique_id
+	var email := "worldlist_smoke_%d@test.example.com" % unique_id
+	var reg_result: Dictionary = await api.register(username, email, "SmokeTest123!", "2000-01-01")
+	if not _check("setup: register succeeded", reg_result.ok):
+		print("  detail: ", reg_result.detail)
+		quit(1)
+		return
+
+	# --- Test 1: Instantiate the real scene ---
+	print("\n=== Test 1: Instantiate world_list.tscn ===")
+	var packed_scene: PackedScene = load(WORLD_LIST_SCENE)
+	if not _check("scene loads", packed_scene != null):
+		quit(1)
+		return
+
+	var instance: Control = packed_scene.instantiate()
+	if not _check("scene instantiates", instance != null):
+		quit(1)
+		return
+
+	root.add_child(instance)
+	# One frame for _ready() (and its @onready resolution) to run. A wrong
+	# node path in an @onready var errors during this, not silently.
+	await process_frame
+
+	if _check("scene added to tree without error", is_instance_valid(instance)):
+		passed += 1
+	else:
+		failed += 1
+
+	# --- Test 2: Wait for the world fetch to resolve, check a real end state ---
+	print("\n=== Test 2: World fetch reaches a real end state ===")
+	# _refresh_worlds() runs from _ready(); give its awaited HTTP call time
+	# to complete rather than a fixed sleep -- poll for either end state.
+	var world_list_node: VBoxContainer = instance.get_node("VBoxContainer/ScrollContainer/WorldList")
+	var empty_label: Label = instance.get_node("VBoxContainer/EmptyLabel")
+	var error_label: Label = instance.get_node("VBoxContainer/ErrorLabel")
+
+	var settled := false
+	for i in range(50):  # up to ~5s at 100ms/frame-ish via process_frame waits
+		await process_frame
+		if world_list_node.visible or empty_label.visible or error_label.visible:
+			settled = true
+			break
+
+	if _check("reached a real end state (cards, empty, or error) not stuck loading", settled):
+		passed += 1
+	else:
+		failed += 1
+		print("  world_list.visible=%s empty_label.visible=%s error_label.visible=%s" % [
+			world_list_node.visible, empty_label.visible, error_label.visible
+		])
+
+	if error_label.visible:
+		printerr("  Note: ended in error state: ", error_label.text)
+	elif world_list_node.visible:
+		print("  Note: rendered %d world card(s)" % world_list_node.get_child_count())
+	elif empty_label.visible:
+		print("  Note: ended in empty-list state")
+
+	# --- Summary ---
+	print("\n=== SMOKE RESULT: %d/%d passed ===" % [passed, passed + failed])
+	if failed > 0:
+		quit(1)
+	else:
+		print("SMOKE RESULT: ALL PASS")
+		quit(0)
+
+
+func _check(description: String, condition: bool) -> bool:
+	if condition:
+		print("  PASS: ", description)
+		return true
+	else:
+		printerr("  FAIL: ", description)
+		return false

scripts/world_list.gd

@@ -0,0 +1,135 @@
+extends Control
+## World list screen — browses public worlds via GET /api/worlds.
+##
+## Displays a scrollable list of world cards (name + description).
+## Handles loading, empty list, errors, and refresh.
+
+
+# UI references
+@onready var scroll_container: ScrollContainer = $VBoxContainer/ScrollContainer
+@onready var world_list: VBoxContainer = $VBoxContainer/ScrollContainer/WorldList
+@onready var loading_label: Label = $VBoxContainer/LoadingLabel
+@onready var error_label: Label = $VBoxContainer/ErrorLabel
+@onready var refresh_button: Button = $VBoxContainer/HeaderHBox/RefreshButton
+@onready var back_button: Button = $VBoxContainer/HeaderHBox/BackButton
+@onready var empty_label: Label = $VBoxContainer/EmptyLabel
+
+
+func _ready() -> void:
+	refresh_button.disabled = false
+	back_button.disabled = false
+	loading_label.visible = false
+	error_label.visible = false
+	empty_label.visible = false
+	world_list.visible = false
+	_refresh_worlds()
+
+
+func _on_refresh_button_pressed() -> void:
+	_refresh_worlds()
+
+
+func _on_back_button_pressed() -> void:
+	get_tree().change_scene_to_file("res://scenes/main_menu.tscn")
+
+
+## Fetch the world list from the backend and update the UI.
+func _refresh_worlds() -> void:
+	# Reset UI state
+	loading_label.visible = true
+	error_label.visible = false
+	empty_label.visible = false
+	world_list.visible = false
+	refresh_button.disabled = true
+
+	# Clear previous world cards
+	for child in world_list.get_children():
+		child.queue_free()
+
+	var result := await ApiClient.get_worlds()
+
+	loading_label.visible = false
+	refresh_button.disabled = false
+
+	if not result.ok:
+		# Show error message (401, network failure, etc.)
+		error_label.text = "Error: %s" % result.detail
+		error_label.visible = true
+		empty_label.visible = false
+		world_list.visible = false
+		return
+
+	var data = result.data
+	if not data is Array:
+		error_label.text = "Unexpected response format."
+		error_label.visible = true
+		empty_label.visible = false
+		world_list.visible = false
+		return
+
+	if data.is_empty():
+		empty_label.text = "No worlds yet. Check back later!"
+		empty_label.visible = true
+		error_label.visible = false
+		world_list.visible = false
+		return
+
+	# Render world cards
+	world_list.visible = true
+	empty_label.visible = false
+	error_label.visible = false
+
+	for world_dict in data:
+		if not world_dict is Dictionary:
+			continue
+		var card := _create_world_card(world_dict)
+		world_list.add_child(card)
+
+
+## Create a visual card for a single world entry.
+func _create_world_card(world_dict: Dictionary) -> Control:
+	var card := VBoxContainer.new()
+	card.size_flags_horizontal = Control.SIZE_FILL
+	card.custom_minimum_size = Vector2(0, 80)
+	card.add_theme_constant_override("separation", 4)
+
+	var name_label := Label.new()
+	name_label.text = world_dict.get("name", "Unnamed World")
+	name_label.autowrap_mode = TextServer.AUTOWRAP_WORD
+	name_label.size_flags_horizontal = Control.SIZE_FILL
+	name_label.size_flags_vertical = Control.SIZE_SHRINK_BEGIN
+	name_label.add_theme_font_size_override("font_size", 18)
+
+	var desc_label := Label.new()
+	var description: String = str(world_dict.get("description", ""))
+	desc_label.text = description if description != "" else "No description."
+	desc_label.autowrap_mode = TextServer.AUTOWRAP_WORD
+	desc_label.size_flags_horizontal = Control.SIZE_FILL
+	desc_label.size_flags_vertical = Control.SIZE_EXPAND_FILL
+	desc_label.add_theme_font_size_override("font_size", 14)
+	desc_label.add_theme_color_override("font_color", Color(0.7, 0.7, 0.7, 1.0))
+
+	var meta_label := Label.new()
+	var visibility: String = str(world_dict.get("visibility", "public"))
+	var created: String = str(world_dict.get("created_at", ""))
+	meta_label.text = "Visibility: %s%s" % [visibility, " | Created: " + created if created != "" else ""]
+	meta_label.autowrap_mode = TextServer.AUTOWRAP_WORD
+	meta_label.size_flags_horizontal = Control.SIZE_FILL
+	meta_label.size_flags_vertical = Control.SIZE_SHRINK_BEGIN
+	meta_label.add_theme_font_size_override("font_size", 12)
+	meta_label.add_theme_color_override("font_color", Color(0.5, 0.5, 0.5, 1.0))
+
+	card.add_child(name_label)
+	card.add_child(desc_label)
+	card.add_child(meta_label)
+
+	# Subtle background for the card
+	var bg := ColorRect.new()
+	bg.color = Color(0.15, 0.15, 0.15, 1.0)
+	bg.size_flags_horizontal = Control.SIZE_FILL
+	bg.size_flags_vertical = Control.SIZE_FILL
+	bg.custom_minimum_size = Vector2(0, 80)
+	card.add_child(bg)
+	card.move_child(bg, 0)
+
+	return card