WIP checkpoint: Plan: Discovery — Browse, Search & Home

# Conflicts:
#	.gitignore
#	project.godot

.gitignore

@@ -0,0 +1,10 @@
+# Godot 4 editor cache/import directory
+.godot/
+
+# Godot export artifacts
+export/
+*.tmp
+
+# OS
+.DS_Store
+Thumbs.db

backend/.env.example

@@ -0,0 +1,20 @@
+# Database (async driver)
+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
+
+# App
+APP_NAME=AGP Backend
+APP_VERSION=0.1.0
+DEBUG=true
+CORS_ORIGINS=http://localhost:8080,http://localhost:3000
+
+# File uploads
+UPLOAD_DIR=uploads
+MAX_UPLOAD_SIZE_MB=100

backend/.gitignore

@@ -0,0 +1,4 @@
+.env
+__pycache__/
+*.pyc
+.venv/

backend/alembic.ini

@@ -0,0 +1,42 @@
+# Alembic configuration file.
+# Run: alembic upgrade head  (to apply migrations)
+# Run: alembic revision --autogenerate -m "description"  (to generate migration)
+
+[alembic]
+script_location = alembic
+prepend_sys_path = .
+sqlalchemy.url = postgresql+asyncpg://agp_user:agp_password@localhost:5432/agp_db
+
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

backend/alembic/env.py

@@ -0,0 +1,65 @@
+"""Alembic environment configuration."""
+
+import asyncio
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy.ext.asyncio import create_async_engine
+
+from app.config import settings
+from app.database import Base
+from app.models import user, session, world, asset  # noqa: F401
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+target_metadata = Base.metadata
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode."""
+    url = settings.DATABASE_URL
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def do_run_migrations(connection):
+    context.configure(connection=connection, target_metadata=target_metadata)
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+async def run_async_migrations():
+    """Run migrations in 'online' mode with async engine."""
+    connectable = create_async_engine(settings.DATABASE_URL, echo=False)
+
+    async with connectable.connect() as connection:
+        await connection.run_sync(do_run_migrations)
+
+    await connectable.dispose()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode."""
+    asyncio.run(run_async_migrations())
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

backend/alembic/script.py.mako

@@ -0,0 +1,27 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision: str = ${repr(up_revision)}
+down_revision: Union[str, None] = ${repr(down_revision)}
+branch_labels: Union[str, Sequence[str], None] = ${repr(branch_labels)}
+depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    """Upgrade database schema."""
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    """Downgrade database schema."""
+    ${downgrades if downgrades else "pass"}

backend/alembic/versions/0001_initial.py

@@ -0,0 +1,126 @@
+"""initial schema
+
+Revision ID: 0001_initial
+Revises:
+Create Date: 2024-01-01 00:00:00.000000
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0001_initial"
+down_revision: Union[str, None] = None
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade database schema."""
+    # Create ENUM types
+    world_visibility = postgresql.ENUM(
+        "public", "private", "friends_only", name="world_visibility"
+    )
+    world_visibility.create(op.get_bind(), checkfirst=True)
+
+    asset_type = postgresql.ENUM(
+        "image", "audio", "video", "document", "model_3d", "other", name="asset_type"
+    )
+    asset_type.create(op.get_bind(), checkfirst=True)
+
+    # Create users table
+    op.create_table(
+        "users",
+        sa.Column("id", sa.Integer(), primary_key=True),
+        sa.Column("username", sa.String(length=50), nullable=False),
+        sa.Column("email", sa.String(length=120), nullable=False),
+        sa.Column("hashed_password", sa.String(length=255), nullable=False),
+        sa.Column("is_active", sa.Boolean(), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=True),
+    )
+    op.create_index(op.f("ix_users_email"), "users", ["email"], unique=True)
+    op.create_index(op.f("ix_users_id"), "users", ["id"], unique=False)
+    op.create_index(op.f("ix_users_username"), "users", ["username"], unique=True)
+
+    # Create sessions table
+    op.create_table(
+        "sessions",
+        sa.Column("id", sa.String(length=36), primary_key=True),
+        sa.Column("user_id", sa.Integer(), nullable=False),
+        sa.Column("token", sa.String(), nullable=False),
+        sa.Column("expires_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("is_active", sa.Boolean(), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.ForeignKeyConstraint(["user_id"], ["users.id"], ondelete="CASCADE"),
+    )
+    op.create_index(op.f("ix_sessions_token"), "sessions", ["token"], unique=True)
+
+    # Create worlds table
+    op.create_table(
+        "worlds",
+        sa.Column("id", sa.Integer(), primary_key=True),
+        sa.Column("name", sa.String(length=255), nullable=False),
+        sa.Column("description", sa.Text(), nullable=True),
+        sa.Column("owner_id", sa.Integer(), nullable=False),
+        sa.Column(
+            "visibility",
+            postgresql.ENUM(
+                "public", "private", "friends_only", name="world_visibility"
+            ),
+            nullable=True,
+        ),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=True),
+        sa.ForeignKeyConstraint(["owner_id"], ["users.id"]),
+    )
+    op.create_index(op.f("ix_worlds_id"), "worlds", ["id"], unique=False)
+
+    # Create assets table
+    op.create_table(
+        "assets",
+        sa.Column("id", sa.Integer(), primary_key=True),
+        sa.Column("name", sa.String(length=255), nullable=False),
+        sa.Column("description", sa.Text(), nullable=True),
+        sa.Column(
+            "asset_type",
+            postgresql.ENUM(
+                "image", "audio", "video", "document", "model_3d", "other",
+                name="asset_type",
+            ),
+            nullable=False,
+        ),
+        sa.Column("file_path", sa.String(length=512), nullable=False),
+        sa.Column("file_size", sa.Integer(), nullable=True),
+        sa.Column("mime_type", sa.String(length=128), nullable=True),
+        sa.Column("metadata_json", sa.Text(), nullable=True),
+        sa.Column("world_id", sa.Integer(), nullable=True),
+        sa.Column("owner_id", sa.Integer(), nullable=False),
+        sa.Column("is_public", sa.Boolean(), nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.ForeignKeyConstraint(["owner_id"], ["users.id"]),
+        sa.ForeignKeyConstraint(["world_id"], ["worlds.id"]),
+    )
+    op.create_index(op.f("ix_assets_id"), "assets", ["id"], unique=False)
+
+
+def downgrade() -> None:
+    """Downgrade database schema."""
+    op.drop_index(op.f("ix_assets_id"), table_name="assets")
+    op.drop_table("assets")
+    op.drop_index(op.f("ix_worlds_id"), table_name="worlds")
+    op.drop_table("worlds")
+    op.drop_index(op.f("ix_sessions_token"), table_name="sessions")
+    op.drop_table("sessions")
+    op.drop_index(op.f("ix_users_username"), table_name="users")
+    op.drop_index(op.f("ix_users_id"), table_name="users")
+    op.drop_index(op.f("ix_users_email"), table_name="users")
+    op.drop_table("users")
+
+    # Drop ENUM types
+    postgresql.ENUM(name="asset_type").drop(op.get_bind(), checkfirst=True)
+    postgresql.ENUM(name="world_visibility").drop(op.get_bind(), checkfirst=True)

backend/alembic/versions/0002_add_date_of_birth_to_users.py

@@ -0,0 +1,30 @@
+"""add date_of_birth column to users table
+
+Revision ID: 0002_add_date_of_birth_to_users
+Revises: 0001_initial
+Create Date: 2025-01-01 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = "0002_add_date_of_birth_to_users"
+down_revision: Union[str, None] = "0001_initial"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Add date_of_birth column to users table."""
+    op.add_column(
+        "users",
+        sa.Column("date_of_birth", sa.Date(), nullable=True),
+    )
+
+
+def downgrade() -> None:
+    """Remove date_of_birth column from users table."""
+    op.drop_column("users", "date_of_birth")

backend/app/config.py

@@ -0,0 +1,52 @@
+"""Application configuration via pydantic-settings."""
+
+from functools import lru_cache
+
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class Settings(BaseSettings):
+    # App
+    APP_NAME: str = "AGP Backend"
+    APP_VERSION: str = "0.1.0"
+    DEBUG: bool = True
+
+    # Database (async)
+    DATABASE_URL: str = "postgresql+asyncpg://agp_user:agp_password@localhost:5432/agp_db"
+
+    # Redis
+    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
+
+    # CORS
+    CORS_ORIGINS: str = "http://localhost:8080,http://localhost:3000"
+
+    # File uploads
+    UPLOAD_DIR: str = "uploads"
+    MAX_UPLOAD_SIZE_MB: int = 100
+
+    model_config = SettingsConfigDict(
+        env_file=".env",
+        env_file_encoding="utf-8",
+        case_sensitive=True,
+    )
+
+    @property
+    def cors_origins_list(self) -> list[str]:
+        return [origin.strip() for origin in self.CORS_ORIGINS.split(",")]
+
+
+@lru_cache()
+def get_settings() -> Settings:
+    """Return cached settings instance."""
+    return Settings()
+
+
+# Convenience singleton
+settings = get_settings()

backend/app/database.py

@@ -0,0 +1,42 @@
+"""Async database engine and session factory."""
+
+from sqlalchemy.ext.asyncio import (
+    AsyncSession,
+    async_sessionmaker,
+    create_async_engine,
+)
+from sqlalchemy.orm import DeclarativeBase
+
+from app.config import settings
+
+engine = create_async_engine(
+    settings.DATABASE_URL,
+    echo=settings.DEBUG,
+    pool_size=10,
+    max_overflow=20,
+)
+
+async_session_factory = async_sessionmaker(
+    engine,
+    class_=AsyncSession,
+    expire_on_commit=False,
+)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+async def get_db() -> AsyncSession:
+    """Dependency that yields an async database session.
+
+    Handlers are responsible for committing or rolling back their own
+    transactions.  This avoids the double-commit problem where the
+    session is committed both here and in the handler.
+    """
+    async with async_session_factory() as session:
+        try:
+            yield session
+        except Exception:
+            await session.rollback()
+            raise

backend/app/dependencies.py

@@ -0,0 +1,55 @@
+"""Shared FastAPI dependencies, including JWT-based auth."""
+
+from typing import Annotated
+
+from fastapi import Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordBearer
+from jose import JWTError, jwt
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.config import settings
+from app.database import get_db
+from app.models.user import User
+
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/api/auth/login")
+
+
+async def get_current_user(
+    token: Annotated[str, Depends(oauth2_scheme)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+) -> User:
+    """Resolve the JWT bearer token to a User, or raise 401."""
+    credentials_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Could not validate credentials",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+    try:
+        payload = jwt.decode(
+            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
+        )
+        user_id: str | None = payload.get("sub")
+        if user_id is None:
+            raise credentials_exception
+    except JWTError:
+        raise credentials_exception
+
+    try:
+        user_id_int = int(user_id)
+    except (ValueError, TypeError):
+        raise credentials_exception
+
+    result = await db.execute(select(User).where(User.id == user_id_int))
+    user = result.scalar_one_or_none()
+    if user is None:
+        raise credentials_exception
+    if not user.is_active:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="User account is inactive",
+        )
+    return user
+
+
+CurrentUser = Annotated[User, Depends(get_current_user)]

backend/app/main.py

@@ -0,0 +1,46 @@
+"""FastAPI application entry point."""
+
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.config import settings
+from app.routers import auth, users, worlds, assets
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """Application lifespan: startup and shutdown events."""
+    # Startup: initialize database, connect to Redis, etc.
+    yield
+    # Shutdown: close connections, cleanup
+
+
+app = FastAPI(
+    title=settings.APP_NAME,
+    version=settings.APP_VERSION,
+    description="Agentic Game Platform - Backend API",
+    lifespan=lifespan,
+)
+
+# CORS
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=settings.cors_origins_list,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Include routers
+app.include_router(auth.router, prefix="/api/auth", tags=["auth"])
+app.include_router(users.router, prefix="/api/users", tags=["users"])
+app.include_router(worlds.router, prefix="/api/worlds", tags=["worlds"])
+app.include_router(assets.router, prefix="/api/assets", tags=["assets"])
+
+
+@app.get("/api/health")
+async def health_check():
+    """Simple health check endpoint."""
+    return {"status": "ok", "app": settings.APP_NAME}

backend/app/models/__init__.py

@@ -0,0 +1,6 @@
+from app.models.user import User
+from app.models.session import Session
+from app.models.world import World
+from app.models.asset import Asset
+
+__all__ = ["User", "Session", "World", "Asset"]

backend/app/models/asset.py

@@ -0,0 +1,40 @@
+from sqlalchemy import Column, Integer, String, ForeignKey, Text, DateTime, Boolean
+from sqlalchemy.dialects.postgresql import ENUM
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+import enum
+
+from app.database import Base
+
+
+class AssetType(str, enum.Enum):
+    IMAGE = "image"
+    AUDIO = "audio"
+    VIDEO = "video"
+    DOCUMENT = "document"
+    MODEL_3D = "model_3d"
+    OTHER = "other"
+
+
+class Asset(Base):
+    __tablename__ = "assets"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(255), nullable=False)
+    description = Column(Text, nullable=True)
+    asset_type = Column(
+        ENUM(AssetType, name="asset_type", create_type=False),
+        nullable=False,
+    )
+    file_path = Column(String(512), nullable=False)
+    file_size = Column(Integer, nullable=True)
+    mime_type = Column(String(128), nullable=True)
+    metadata_json = Column(Text, nullable=True)
+    world_id = Column(Integer, ForeignKey("worlds.id"), nullable=True)
+    owner_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    is_public = Column(Boolean, default=False, nullable=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+
+    owner = relationship("User", back_populates="assets")
+    world = relationship("World", back_populates="assets")

backend/app/models/session.py

@@ -0,0 +1,20 @@
+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
+
+
+class Session(Base):
+    __tablename__ = "sessions"
+
+    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
+    user_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False)
+    token = Column(String, unique=True, index=True, nullable=False)
+    expires_at = Column(DateTime(timezone=True), nullable=False)
+    is_active = Column(Boolean, default=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+
+    user = relationship("User", back_populates="sessions")

backend/app/models/user.py

@@ -0,0 +1,37 @@
+from datetime import date
+from typing import Optional
+
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, Date
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+
+from app.database import Base
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    id = Column(Integer, primary_key=True, index=True)
+    username = Column(String(50), unique=True, index=True, nullable=False)
+    email = Column(String(120), unique=True, index=True, nullable=False)
+    hashed_password = Column(String(255), nullable=False)
+    date_of_birth = Column(Date, nullable=True)
+    is_active = Column(Boolean, default=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    sessions = relationship("Session", back_populates="user", cascade="all, delete-orphan")
+    worlds = relationship("World", back_populates="owner")
+    assets = relationship("Asset", back_populates="owner")
+
+    @property
+    def is_adult(self) -> bool:
+        """Return True if the user is 18 or older based on date_of_birth."""
+        if self.date_of_birth is None:
+            return False
+        today = date.today()
+        age = today.year - self.date_of_birth.year
+        # Adjust if birthday hasn't occurred yet this year
+        if (today.month, today.day) < (self.date_of_birth.month, self.date_of_birth.day):
+            age -= 1
+        return age >= 18

backend/app/models/world.py

@@ -0,0 +1,31 @@
+from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey
+from sqlalchemy.dialects.postgresql import ENUM
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+import enum
+
+from app.database import Base
+
+
+class WorldVisibility(enum.Enum):
+    PUBLIC = "public"
+    PRIVATE = "private"
+    FRIENDS_ONLY = "friends_only"
+
+
+class World(Base):
+    __tablename__ = "worlds"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(255), nullable=False)
+    description = Column(Text, nullable=True)
+    owner_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    visibility = Column(
+        ENUM(WorldVisibility, name="world_visibility", create_type=False),
+        default=WorldVisibility.PUBLIC,
+    )
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    owner = relationship("User", back_populates="worlds")
+    assets = relationship("Asset", back_populates="world", cascade="all, delete-orphan")

backend/app/routers/assets.py

@@ -0,0 +1,209 @@
+"""Asset management router."""
+
+import os
+from pathlib import Path
+from typing import Optional
+
+from fastapi import APIRouter, Depends, HTTPException, UploadFile, File, Query
+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.asset import Asset, AssetType
+from app.models.world import World
+from pydantic import BaseModel, Field
+
+router = APIRouter()
+
+
+# --- Pydantic schemas ---
+
+class AssetCreate(BaseModel):
+    """Schema for creating an asset reference."""
+    name: str = Field(..., min_length=1, max_length=255)
+    description: Optional[str] = None
+    asset_type: AssetType
+    world_id: Optional[int] = None
+
+
+class AssetResponse(BaseModel):
+    """Schema for asset responses."""
+    id: int
+    name: str
+    description: Optional[str]
+    asset_type: AssetType
+    file_path: str
+    file_size: Optional[int]
+    mime_type: Optional[str]
+    world_id: Optional[int]
+    owner_id: int
+    is_public: bool
+    created_at: str
+    updated_at: str
+
+    model_config = {"from_attributes": True}
+
+
+class AssetUpdate(BaseModel):
+    """Schema for updating an asset."""
+    name: Optional[str] = None
+    description: Optional[str] = None
+    is_public: Optional[bool] = None
+
+
+# --- Helpers ---
+
+def _sanitize_filename(filename: str) -> str:
+    """Strip path components and unsafe characters from a filename."""
+    # Remove any directory components (path traversal protection).
+    base = os.path.basename(filename.replace("\\", "/"))
+    # Keep only safe characters.
+    safe = "".join(c for c in base if c.isalnum() or c in "._-")
+    return safe or "file"
+
+
+# --- Endpoints ---
+
+@router.post("/", response_model=AssetResponse, status_code=201)
+async def create_asset(
+    payload: AssetCreate,
+    current_user: CurrentUser,
+    db: AsyncSession = Depends(get_db),
+):
+    """Create a new asset reference."""
+    # Verify world ownership if world_id is provided
+    if payload.world_id is not None:
+        world = await db.get(World, payload.world_id)
+        if world is None:
+            raise HTTPException(status_code=404, detail="World not found")
+        if world.owner_id != current_user.id:
+            raise HTTPException(status_code=403, detail="Not owner of this world")
+
+    asset = Asset(
+        name=payload.name,
+        description=payload.description,
+        asset_type=payload.asset_type,
+        file_path="",  # Will be set after upload
+        owner_id=current_user.id,
+        world_id=payload.world_id,
+        is_public=False,
+    )
+    db.add(asset)
+    await db.commit()
+    await db.refresh(asset)
+    return asset
+
+
+@router.get("/", response_model=list[AssetResponse])
+async def list_assets(
+    current_user: CurrentUser,
+    world_id: Optional[int] = Query(None, description="Filter by world"),
+    asset_type: Optional[AssetType] = Query(None),
+    limit: int = Query(50, ge=1, le=100),
+    offset: int = Query(0, ge=0),
+    db: AsyncSession = Depends(get_db),
+):
+    """List assets with optional filters."""
+    stmt = select(Asset).where(Asset.owner_id == current_user.id)
+
+    if world_id is not None:
+        stmt = stmt.where(Asset.world_id == world_id)
+    if asset_type is not None:
+        stmt = stmt.where(Asset.asset_type == asset_type)
+
+    stmt = stmt.order_by(Asset.created_at.desc()).limit(limit).offset(offset)
+    result = await db.execute(stmt)
+    assets = result.scalars().all()
+    return assets
+
+
+@router.get("/{asset_id}", response_model=AssetResponse)
+async def get_asset(
+    asset_id: int,
+    current_user: CurrentUser,
+    db: AsyncSession = Depends(get_db),
+):
+    """Get a single asset by ID."""
+    asset = await db.get(Asset, asset_id)
+    if asset is None or asset.owner_id != current_user.id:
+        raise HTTPException(status_code=404, detail="Asset not found")
+    return asset
+
+
+@router.patch("/{asset_id}", response_model=AssetResponse)
+async def update_asset(
+    asset_id: int,
+    payload: AssetUpdate,
+    current_user: CurrentUser,
+    db: AsyncSession = Depends(get_db),
+):
+    """Update an asset."""
+    asset = await db.get(Asset, asset_id)
+    if asset is None or asset.owner_id != current_user.id:
+        raise HTTPException(status_code=404, detail="Asset not found")
+
+    update_data = payload.model_dump(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(asset, field, value)
+
+    await db.commit()
+    await db.refresh(asset)
+    return asset
+
+
+@router.delete("/{asset_id}", status_code=204)
+async def delete_asset(
+    asset_id: int,
+    current_user: CurrentUser,
+    db: AsyncSession = Depends(get_db),
+):
+    """Delete an asset."""
+    asset = await db.get(Asset, asset_id)
+    if asset is None or asset.owner_id != current_user.id:
+        raise HTTPException(status_code=404, detail="Asset not found")
+
+    await db.delete(asset)
+    await db.commit()
+
+
+@router.post("/{asset_id}/upload", response_model=AssetResponse)
+async def upload_asset_file(
+    asset_id: int,
+    current_user: CurrentUser,
+    file: UploadFile = File(...),
+    db: AsyncSession = Depends(get_db),
+):
+    """Upload a file for an existing asset."""
+    asset = await db.get(Asset, asset_id)
+    if asset is None or asset.owner_id != current_user.id:
+        raise HTTPException(status_code=404, detail="Asset not found")
+
+    # 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
+    content = await file.read()
+    file_size = len(content)
+    if file_size > max_bytes:
+        raise HTTPException(
+            status_code=413,
+            detail=f"File size {file_size} exceeds maximum allowed size {max_bytes} bytes",
+        )
+
+    # Write the file to the upload directory.
+    upload_dir = Path(settings.UPLOAD_DIR)
+    upload_dir.mkdir(parents=True, exist_ok=True)
+    stored_name = f"{asset_id}_{safe_filename}"
+    file_path = upload_dir / stored_name
+    file_path.write_bytes(content)
+
+    asset.file_path = str(file_path)
+    asset.mime_type = file.content_type
+    asset.file_size = file_size
+
+    await db.commit()
+    await db.refresh(asset)
+    return asset

backend/app/routers/auth.py

@@ -0,0 +1,177 @@
+"""Authentication router - login, register, token refresh."""
+
+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 passlib.context import CryptContext
+
+from app.config import settings
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.user import User
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+router = APIRouter()
+
+
+# --- Pydantic schemas ---
+
+class TokenResponse(BaseModel):
+    access_token: str
+    token_type: str = "bearer"
+
+
+class RegisterRequest(BaseModel):
+    username: str
+    email: EmailStr
+    password: str
+    date_of_birth: str  # ISO format date string (YYYY-MM-DD)
+
+    @field_validator("date_of_birth")
+    @classmethod
+    def validate_date_of_birth(cls, v: str) -> str:
+        """Validate that the date string is a valid date in YYYY-MM-DD format."""
+        try:
+            datetime.strptime(v, "%Y-%m-%d")
+        except ValueError:
+            raise ValueError("date_of_birth must be in YYYY-MM-DD format")
+        return v
+
+
+class UserResponse(BaseModel):
+    id: int
+    username: str
+    email: str
+    date_of_birth: str | None = None
+    is_active: bool
+    created_at: datetime | None = None
+
+    model_config = {"from_attributes": True}
+
+
+# --- Helpers ---
+
+def _create_access_token(data: dict) -> str:
+    to_encode = data.copy()
+    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)
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    """Verify a plain password against a hash."""
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def hash_password(password: str) -> str:
+    """Hash a password."""
+    return pwd_context.hash(password)
+
+
+def calculate_age(birth_date: date, today: date | None = None) -> int:
+    """Calculate age in years from a birth date.
+
+    Args:
+        birth_date: The person's date of birth.
+        today: The reference date. Defaults to today's date (UTC).
+
+    Returns:
+        Age in whole years as of the reference date.
+    """
+    if today is None:
+        today = datetime.now(timezone.utc).date()
+
+    age = today.year - birth_date.year
+    # Adjust if birthday hasn't occurred yet this year
+    if (today.month, today.day) < (birth_date.month, birth_date.day):
+        age -= 1
+    return age
+
+
+# --- 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.
+
+    Requires date_of_birth and rejects users under 18.
+    """
+    # Parse and validate date_of_birth
+    dob = datetime.strptime(req.date_of_birth, "%Y-%m-%d").date()
+    age = calculate_age(dob)
+
+    if age < 18:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=f"Must be 18 or older to register (provided date of birth: {req.date_of_birth})",
+        )
+
+    # Check if username already exists
+    result = await db.execute(select(User).where(User.username == req.username))
+    if result.scalar_one_or_none():
+        raise HTTPException(
+            status_code=status.HTTP_409_CONFLICT,
+            detail="Username already registered",
+        )
+
+    # Check if email already exists
+    result = await db.execute(select(User).where(User.email == req.email))
+    if result.scalar_one_or_none():
+        raise HTTPException(
+            status_code=status.HTTP_409_CONFLICT,
+            detail="Email already registered",
+        )
+
+    user = User(
+        username=req.username,
+        email=req.email,
+        hashed_password=hash_password(req.password),
+        date_of_birth=dob,
+    )
+    db.add(user)
+    await db.commit()
+    await db.refresh(user)
+
+    access_token = _create_access_token({"sub": str(user.id)})
+    return TokenResponse(access_token=access_token)
+
+
+@router.post("/login", response_model=TokenResponse)
+async def login(form: OAuth2PasswordRequestForm = Depends(), db: AsyncSession = Depends(get_db)):
+    """Authenticate user and return an access token.
+
+    Accepts form-encoded credentials (username/password) as expected by
+    OAuth2PasswordBearer, so the Swagger UI "Authorize" flow works correctly.
+    """
+    result = await db.execute(select(User).where(User.username == form.username))
+    user = result.scalar_one_or_none()
+
+    if not user or not verify_password(form.password, user.hashed_password):
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Incorrect username or password",
+        )
+
+    if not user.is_active:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="User account is inactive",
+        )
+
+    access_token = _create_access_token({"sub": str(user.id)})
+    return TokenResponse(access_token=access_token)
+
+
+@router.get("/me", response_model=UserResponse)
+async def get_current_user(current_user: CurrentUser):
+    """Get current user profile from the JWT token."""
+    return current_user

backend/app/routers/users.py

@@ -0,0 +1,106 @@
+"""User management router."""
+
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from pydantic import BaseModel, EmailStr
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.user import User
+
+router = APIRouter()
+
+
+# ─── Pydantic schemas ────────────────────────────────────────────────────────
+
+class UserResponse(BaseModel):
+    id: int
+    username: str
+    email: str
+    is_active: bool
+
+    model_config = {"from_attributes": True}
+
+
+class UserUpdate(BaseModel):
+    email: EmailStr | None = None
+    is_active: bool | None = None
+
+
+# ─── Endpoints ───────────────────────────────────────────────────────────────
+
+@router.get("/me", response_model=UserResponse)
+async def get_current_user_profile(
+    current_user: CurrentUser,
+):
+    """Get the currently authenticated user's profile."""
+    return current_user
+
+
+@router.get("/{user_id}", response_model=UserResponse)
+async def get_user(
+    user_id: int,
+    current_user: CurrentUser,
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    """Get a user by ID.  Only the owner can view their own profile."""
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if not user:
+        raise HTTPException(status_code=404, detail="User not found")
+
+    # Only the owner may view their own profile.
+    if user.id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not authorized to view this user")
+
+    return user
+
+
+@router.patch("/{user_id}", response_model=UserResponse)
+async def update_user(
+    user_id: int,
+    user_update: UserUpdate,
+    current_user: CurrentUser,
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    """Update a user.  Only the owner can update their own account."""
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if not user:
+        raise HTTPException(status_code=404, detail="User not found")
+
+    # Only the owner may update their own account.
+    if user.id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not authorized to update this user")
+
+    if user_update.email is not None:
+        user.email = user_update.email
+    if user_update.is_active is not None:
+        user.is_active = user_update.is_active
+
+    await db.commit()
+    await db.refresh(user)
+    return user
+
+
+@router.delete("/{user_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_user(
+    user_id: int,
+    current_user: CurrentUser,
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    """Delete a user.  Only the owner can delete their own account."""
+    result = await db.execute(select(User).where(User.id == user_id))
+    user = result.scalar_one_or_none()
+    if not user:
+        raise HTTPException(status_code=404, detail="User not found")
+
+    # Only the owner may delete their own account.
+    if user.id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not authorized to delete this user")
+
+    await db.delete(user)
+    await db.commit()

backend/app/routers/worlds.py

@@ -0,0 +1,168 @@
+"""Worlds router - CRUD for game worlds."""
+
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException, Query
+from pydantic import BaseModel, Field
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import selectinload
+
+from app.database import get_db
+from app.dependencies import CurrentUser
+from app.models.world import World, WorldVisibility
+
+router = APIRouter()
+
+DbDep = Annotated[AsyncSession, Depends(get_db)]
+
+
+# --- Pydantic schemas ---
+
+class WorldCreate(BaseModel):
+    """Schema for creating a world."""
+    name: str = Field(..., min_length=1, max_length=255)
+    description: str | None = None
+    visibility: WorldVisibility = WorldVisibility.PUBLIC
+
+
+class WorldUpdate(BaseModel):
+    """Schema for updating a world."""
+    name: str | None = Field(None, min_length=1, max_length=255)
+    description: str | None = None
+    visibility: WorldVisibility | None = None
+
+
+class WorldResponse(BaseModel):
+    """Schema for world responses."""
+    id: int
+    name: str
+    description: str | None
+    visibility: WorldVisibility
+    owner_id: int
+    created_at: str | None = None
+
+    model_config = {"from_attributes": True}
+
+
+# --- Endpoints ---
+
+@router.get("/", response_model=list[WorldResponse])
+async def list_worlds(
+    current_user: CurrentUser,
+    db: DbDep,
+    skip: int = Query(0, ge=0),
+    limit: int = Query(50, ge=1, le=100),
+    visibility: WorldVisibility | None = None,
+):
+    """List worlds visible to the current user.
+
+    PUBLIC worlds are visible to everyone.
+    PRIVATE/FRIENDS_ONLY worlds are visible to their owner.
+    """
+    query = select(World).options(selectinload(World.owner))
+
+    # Filter by visibility if specified
+    if visibility:
+        query = query.where(World.visibility == visibility)
+        if visibility != WorldVisibility.PUBLIC:
+            # Requesting a non-public visibility explicitly must not bypass
+            # ownership — otherwise any authenticated user could list every
+            # PRIVATE/FRIENDS_ONLY world in the system just by passing the
+            # filter, defeating the point of the check below.
+            query = query.where(World.owner_id == current_user.id)
+    else:
+        # Show PUBLIC worlds + owner's own worlds
+        query = query.where(
+            (World.visibility == WorldVisibility.PUBLIC)
+            | (World.owner_id == current_user.id)
+        )
+
+    query = query.offset(skip).limit(limit).order_by(World.created_at.desc())
+    result = await db.execute(query)
+    worlds = result.scalars().all()
+    return worlds
+
+
+@router.get("/{world_id}", response_model=WorldResponse)
+async def get_world(
+    world_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Get a single world by ID, respecting visibility."""
+    result = await db.execute(
+        select(World).where(World.id == world_id).options(selectinload(World.owner))
+    )
+    world = result.scalar_one_or_none()
+    if not world:
+        raise HTTPException(status_code=404, detail="World not found")
+
+    # Allow access if world is PUBLIC or owned by current user
+    if world.visibility != WorldVisibility.PUBLIC and world.owner_id != current_user.id:
+        raise HTTPException(status_code=404, detail="World not found")
+
+    return world
+
+
+@router.post("/", response_model=WorldResponse, status_code=201)
+async def create_world(
+    world_data: WorldCreate,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Create a new world."""
+    world = World(
+        name=world_data.name,
+        description=world_data.description,
+        owner_id=current_user.id,
+        visibility=world_data.visibility,
+    )
+    db.add(world)
+    await db.commit()
+    await db.refresh(world)
+    return world
+
+
+@router.put("/{world_id}", response_model=WorldResponse)
+async def update_world(
+    world_id: int,
+    world_data: WorldUpdate,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Update an existing world."""
+    result = await db.execute(select(World).where(World.id == world_id))
+    world = result.scalar_one_or_none()
+    if not world:
+        raise HTTPException(status_code=404, detail="World not found")
+
+    if world.owner_id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not owner of this world")
+
+    update_data = world_data.model_dump(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(world, field, value)
+
+    await db.commit()
+    await db.refresh(world)
+    return world
+
+
+@router.delete("/{world_id}", status_code=204)
+async def delete_world(
+    world_id: int,
+    current_user: CurrentUser,
+    db: DbDep,
+):
+    """Delete a world."""
+    result = await db.execute(select(World).where(World.id == world_id))
+    world = result.scalar_one_or_none()
+    if not world:
+        raise HTTPException(status_code=404, detail="World not found")
+
+    if world.owner_id != current_user.id:
+        raise HTTPException(status_code=403, detail="Not owner of this world")
+
+    await db.delete(world)
+    await db.commit()

backend/docker-compose.yml

@@ -0,0 +1,34 @@
+version: "3.9"
+
+services:
+  postgres:
+    image: postgres:16-alpine
+    environment:
+      POSTGRES_USER: agp_user
+      POSTGRES_PASSWORD: agp_password
+      POSTGRES_DB: agp_db
+    ports:
+      - "5432:5432"
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U agp_user -d agp_db"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+  redis:
+    image: redis:7-alpine
+    ports:
+      - "6379:6379"
+    volumes:
+      - redis_data:/data
+    healthcheck:
+      test: ["CMD", "redis-cli", "ping"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+volumes:
+  postgres_data:
+  redis_data:

backend/pytest.ini

@@ -0,0 +1,3 @@
+[pytest]
+asyncio_mode = auto
+testpaths = tests

backend/requirements.txt

@@ -0,0 +1,17 @@
+fastapi==0.115.6
+uvicorn[standard]==0.34.0
+sqlalchemy==2.0.36
+alembic==1.14.0
+psycopg2-binary==2.9.10
+asyncpg==0.31.0
+redis==5.2.1
+pydantic==2.10.3
+pydantic-settings==2.7.0
+python-jose[cryptography]==3.3.0
+passlib[bcrypt]==1.7.4
+python-multipart==0.0.20
+email-validator==2.2.0
+httpx==0.28.1
+pytest==8.3.4
+pytest-asyncio==0.25.0
+pytest-cov==6.0.0

backend/tests/test_auth_age_gate.py

@@ -0,0 +1,94 @@
+"""Tests for the 18+ age gate on user registration."""
+
+from datetime import date, timedelta
+
+import pytest
+
+from app.routers.auth import calculate_age
+
+
+class TestCalculateAge:
+    """Unit tests for the calculate_age helper."""
+
+    def test_exactly_18(self):
+        """A person born exactly 18 years ago today is 18."""
+        today = date(2025, 6, 15)
+        dob = today.replace(year=today.year - 18)
+        assert calculate_age(dob, today=today) == 18
+
+    def test_just_turned_18(self):
+        """A person who turned 18 yesterday is 18."""
+        today = date(2025, 6, 15)
+        dob = today.replace(year=today.year - 18) - timedelta(days=1)
+        assert calculate_age(dob, today=today) == 18
+
+    def test_one_day_short_of_18(self):
+        """A person born one day after their 18th birthday is 17."""
+        today = date(2025, 6, 15)
+        dob = today.replace(year=today.year - 18) + timedelta(days=1)
+        assert calculate_age(dob, today=today) == 17
+
+    def test_17_years_old(self):
+        """A person who is 17 years old today is 17."""
+        today = date(2025, 6, 15)
+        dob = date(2008, 6, 15)
+        assert calculate_age(dob, today=today) == 17
+
+    def test_65_years_old(self):
+        """A person who is 65 is correctly calculated."""
+        today = date(2025, 6, 15)
+        dob = today.replace(year=today.year - 65)
+        assert calculate_age(dob, today=today) == 65
+
+    def test_newborn(self):
+        """A newborn is 0."""
+        today = date(2025, 6, 15)
+        dob = today
+        assert calculate_age(dob, today=today) == 0
+
+    def test_birthday_not_yet_this_year(self):
+        """Person born Dec 31, 2000 — on Jan 1, 2025 they are still 24."""
+        dob = date(2000, 12, 31)
+        assert calculate_age(dob, today=date(2025, 1, 1)) == 24
+
+    def test_birthday_today(self):
+        """Person born Dec 31, 2000 — on Dec 31, 2024 they turn 24."""
+        dob = date(2000, 12, 31)
+        assert calculate_age(dob, today=date(2024, 12, 31)) == 24
+
+
+class TestRegisterRequestDateValidation:
+    """Tests for the RegisterRequest date_of_birth field validator."""
+
+    @pytest.mark.parametrize(
+        "dob",
+        [
+            "2000-01-01",
+            "1990-12-31",
+            "2004-02-29",  # leap day
+        ],
+    )
+    def test_valid_dates(self, dob):
+        """Valid YYYY-MM-DD dates pass validation."""
+        from app.routers.auth import RegisterRequest
+
+        req = RegisterRequest(username="u", email="u@example.com", password="p", date_of_birth=dob)
+        assert req.date_of_birth == dob
+
+    @pytest.mark.parametrize(
+        "dob",
+        [
+            "01-01-2000",
+            "2000/01/01",
+            "2000-13-01",
+            "2000-00-10",
+            "not-a-date",
+            "",
+        ],
+    )
+    def test_invalid_dates_rejected(self, dob):
+        """Invalid dates are rejected by the validator."""
+        from app.routers.auth import RegisterRequest
+
+        with pytest.raises(ValueError):
+            RegisterRequest(username="u", email="u@example.com", password="p", date_of_birth=dob)

docs/architecture/scripting_sandbox.md

@@ -0,0 +1,159 @@
+# GDScript Sandboxing for User-Written Scripts
+
+> **Status:** Proposed
+> **Owner:** Platform team
+> **Related:** Content moderation & age verification (scripts are one of the
+> three moderated content types), avatar component system
+
+## 1. Overview
+
+This document evaluates how to safely run **user-written scripts** as part of
+UGC (user-generated content) in **agp-game**, and recommends an approach.
+
+**Bottom line: Godot 4 has no built-in security sandbox for GDScript, and
+none of the three options named in the original task hold up under testing.**
+A script running anywhere inside the Godot process — however it's loaded,
+parented, or wrapped — runs with full engine privileges: arbitrary process
+execution, full filesystem read/write, and raw network access. Sandboxing
+has to happen *outside* the scripting language, not through an in-engine
+restriction mechanism, because no such mechanism exists.
+
+This was verified directly against Godot 4.6.2 (`godot --headless`, evidence
+in `sandbox_probe/` on this branch) rather than assumed from documentation,
+some of which (see §2.1) describes APIs that don't actually exist in this
+version.
+
+## 2. Options Evaluated
+
+### 2.1 Godot's built-in "ScriptServer" restrictions — does not exist
+
+There is no `ScriptServer` class in Godot 4.6.2:
+
+```
+ClassDB.class_exists("ScriptServer")  →  false
+```
+
+There's also no project setting to disable engine subsystems for scripts —
+none of `application/run/disable_os`, `disable_file_access`, or
+`disable_network` exist as settings, and `ProjectSettings.get_property_list()`
+returns nothing matching "sandbox", "restrict", or "security". Any plan that
+assumes a flag like this exists needs to be dropped; it was likely conflated
+with sandboxing features from a different engine/scripting ecosystem, or
+with **export template stripping** (which controls what ships in a build,
+not what a script can call at runtime).
+
+Directly probed capabilities of an ordinary GDScript running as a normal
+node script, no special setup:
+
+| Capability | Available to any script? |
+|---|---|
+| `OS.execute(...)` — run arbitrary processes | ✅ Yes |
+| `FileAccess.open(...)` — read/write any path the OS user can reach | ✅ Yes (read `/etc/hostname`, write `/tmp/...` both succeeded) |
+| `TCPServer` / `HTTPClient` / `HTTPRequest` / `PacketPeerUDP` / `WebSocketPeer` | ✅ All instantiate and work |
+| `ClassDB.instantiate(...)` — construct any engine class by name | ✅ Yes |
+| Loading and running a second script from source text at runtime (`GDScript.new()` + `.reload()`) | ✅ Yes |
+
+**Verdict: rejected.** There is nothing to configure here — the restriction
+surface this option assumed doesn't exist in the engine.
+
+### 2.2 Isolated SubViewport with a limited API — doesn't isolate scripts
+
+`SubViewport` is a **rendering and input isolation** primitive (it gives a
+scene subtree its own render target and can gate input propagation) — it is
+not a security or scripting boundary. A script attached to any node inside a
+`SubViewport` still runs in the same process, on the same GDScript VM, with
+the exact same access to `OS`, `FileAccess`, networking classes, and
+`ClassDB` as a script anywhere else in the tree. Nothing about being
+"inside" a SubViewport changes what API calls are reachable from a script.
+
+**Verdict: rejected.** This solves a rendering/UI-composition problem, not
+the security problem the task is asking about. Worth keeping in mind for
+other purposes (e.g. isolated preview rendering of user avatars), but it
+provides zero script sandboxing.
+
+### 2.3 Custom GDScript interpreter with an allowlist — right idea, wrong layer for "custom interpreter"
+
+Two ways to read this option, tested separately:
+
+**(a) Write/embed a separate GDScript parser+interpreter.** Not
+practical — this means re-implementing (and then indefinitely maintaining,
+in lockstep with every Godot release) a full language interpreter outside
+the engine. Far more engineering than the problem justifies.
+
+**(b) Use Godot's built-in `Expression` class as a restricted subset.**
+`Expression` *looks* like a natural allowlist mechanism — it only evaluates
+a single expression, no control flow, no arbitrary statements. But it isn't
+safe by default: it can still reach through to unsafe engine methods if you
+aren't careful about what object you hand it as a base instance:
+
+```gdscript
+var expr = Expression.new()
+expr.parse("get_environment('HOME')", ["OS"])
+expr.execute([], OS)   # → "/home/daddy"  (successfully called OS.get_environment)
+```
+
+So `Expression` is a viable building block only if the host **never passes
+a base instance (or arguments) that exposes anything sensitive** — i.e. the
+allowlisting work still has to happen at the call site, `Expression` itself
+enforces none of it.
+
+**Static text pattern-matching (blocklisting dangerous substrings like
+`"OS.execute"` before parsing) was also probed and is not a real
+defense** — it's trivially defeated by string concatenation, `call()`,
+`Callable`, or any other indirection, and produces false confidence.
+
+**Verdict: partially viable, but only as a foundation, not a solution on
+its own.** A hand-built, narrow, data-driven DSL (not full GDScript, not
+raw `Expression`) with an explicit allowlist of safe operations and *no
+ability to reference engine singletons or arbitrary objects* is the only
+version of "custom interpreter" that's actually safe. This is real
+engineering effort, not a config flag.
+
+## 3. Recommendation
+
+**Don't run untrusted GDScript in-process at all.** Given none of the three
+in-engine options provide a real boundary, the two approaches actually worth
+building are, in order of recommended priority:
+
+1. **Primary: a narrow, non-Turing-complete content DSL**, not general
+   scripting. Most UGC scripting needs in a game like this (custom
+   interactions, simple triggers, item behaviors) don't need a general
+   programming language — they need a small set of declarative
+   verbs/conditions (e.g. `on_interact: give_item("torch")`,
+   `on_enter: play_sound("chime")`). Expressed as data (JSON/Resource, not
+   code) and interpreted by trusted, hand-written GDScript on the engine
+   side. This has *zero* attack surface by construction — there's no
+   interpreter to escape because there's no general execution, just a
+   fixed, reviewed set of verbs. This is almost certainly sufficient for
+   the actual UGC use cases in this game and should be scoped against real
+   feature requirements before assuming more is needed.
+
+2. **If genuinely general scripting becomes a hard requirement**, isolate it
+   at the OS level, not the engine level: run untrusted scripts in a
+   **separate process** (a stripped-down Godot instance or a dedicated
+   interpreter) under OS sandboxing (a restricted user account, a
+   container, or `firejail`/`bwrap`/seccomp), communicating with the main
+   game over a narrow IPC/RPC boundary that only exposes intentionally-safe
+   operations. This is the only approach that provides a real security
+   boundary for arbitrary code, because it doesn't depend on the scripting
+   language cooperating — the OS enforces it. Substantially more
+   infrastructure than option 1; only worth it if option 1's DSL genuinely
+   can't express what's needed.
+
+**Do not** attempt in-process GDScript sandboxing via SubViewport,
+ScriptServer, or ad hoc blocklisting — all three were directly tested and
+none provide a real boundary (§2).
+
+## 4. Open Questions
+
+- What do actual planned UGC scripts need to *do*? (Trigger conditions,
+  simple item/state effects, dialogue branching?) This determines whether
+  the DSL in §3.1 is sufficient or whether §3.2's process isolation is
+  needed. Needs a concrete feature list before implementation starts.
+- If §3.2 is needed later, does it run per-user-session or shared/pooled?
+  Affects resource cost and isolation guarantees.
+- Interaction with the content moderation pipeline (`content_moderation.md`):
+  scripts as a moderated content type still need a moderation flag path
+  regardless of which execution model is chosen — a DSL makes static
+  analysis of *what a script can possibly do* far easier than it would be
+  for general code, which is an additional point in its favor.

docs/planning/discovery.md

@@ -0,0 +1,150 @@
+# Discovery — Browse, Search & Home — Plan
+
+> **Status:** Planned
+> **Owner:** Platform team
+> **Feature ID:** `discovery`
+> **Godot version:** 4.6.2 stable
+> **Backend:** FastAPI + SQLAlchemy (async) + PostgreSQL + Redis
+
+## 1. Overview
+
+This document breaks the **Discovery** feature into user stories and
+right-sized implementation tasks. The feature delivers:
+
+- **Home / discover page** — a default listing of experiences a player lands on.
+- **Search** — find worlds by name and by tag.
+- **Categories** — a single category per world plus free-form tags, with
+  filtering.
+- **Simple sorting** — newest, most-played, and trending. Trending starts as a
+  basic **recent-activity heuristic** (weighted recent visits); no real
+  recommendation model for MVP.
+
+Without this, nothing else built (experiences, creator content) is actually
+reachable by a real user. Discovery is the front door.
+
+## 2. Why this matters
+
+The platform's value is *reachable* content. Worlds and creator assets already
+exist in the data model (`World`, `Asset`), but there is currently:
+
+- **No public listing** of worlds (`/api/worlds` requires auth and returns only
+  PUBLIC worlds or your own worlds, ordered by `created_at` only).
+- **No search** by name or tag.
+- **No category/tag metadata** on worlds at all.
+- **No play-count or recency signal** to power "most-played" or "trending".
+- **No client UI** for browsing.
+
+Discovery closes that gap with a small, dependency-free metadata layer plus a
+read-optimized listing endpoint.
+
+## 3. Existing constraints (do not re-build)
+
+- **Auth:** JWT bearer tokens; `get_current_user` / `CurrentUser` dependency in
+  `app/dependencies.py`. Discovery **listing** must work both for anonymous
+  visitors and authenticated users, so it needs an *optional* auth dependency
+  (not `CurrentUser`, which returns 401).
+- **DB:** async SQLAlchemy + Alembic; migration head is `0002_add_date_of_birth_to_users`.
+- **Models:** `World` (id, name, description, owner_id, visibility, created_at,
+  updated_at). `User`, `Asset` (owner_id, is_public) exist. No tags/categories/
+  play-count fields yet.
+- **Routers:** `worlds.py` already owns CRUD under `/api/worlds`. Discovery adds
+  a new read-focused router rather than overloading it.
+- **Redis:** configured (`REDIS_URL`) but unused; **not required** for discovery
+  MVP (Postgres queries are sufficient at this scale).
+- **Client:** Godot 4.6.2, minimal `main_menu.gd`; no networking client, no
+  discovery UI.
+
+## 4. Key design decisions
+
+| Concern | Decision |
+|---|---|
+| Listing transport | REST (`GET /api/discovery/worlds`) — no WebSocket needed for browse |
+| Anonymous browsing | Listing/read endpoints accept **optional** auth; visibility filtering treats anonymous users as "PUBLIC only" |
+| Categories | Single `category` string column on `worlds` (indexed). Free-form for MVP; a distinct-categories list is derived with a `SELECT DISTINCT` |
+| Tags | PostgreSQL `ARRAY(String)` column on `worlds` with a GIN index for `@>` tag containment search |
+| Play count | `play_count` integer (default 0) on `worlds`, incremented atomically on visit |
+| Recency signal | `last_played_at` timestamp on `worlds` + append-only `world_visits` table for the trending heuristic |
+| Trending (MVP) | Weighted score over recent visits: `sum(decay_weight(age))` over the last N days, no ML |
+| Sorting | `newest` (created_at desc), `most_played` (play_count desc), `trending` (score desc) |
+| Pagination | `skip`/`limit` (limit capped at 100), consistent with existing routers |
+| Visibility | Discovery only surfaces `PUBLIC` worlds; never leaks private/friends_only worlds |
+
+## 5. User stories
+
+### US-1 Home / discover feed
+As a player, I can open a home/discover page and see a default list of
+experiences without searching.
+
+**Acceptance criteria**
+- Returns PUBLIC worlds only, newest-first by default.
+- Paginated with a stable total count.
+- Works anonymously and authenticated.
+- Each result includes id, name, description, category, tags, owner, play_count,
+  and created_at.
+
+### US-2 Search
+As a player, I can search experiences by name and by tag.
+
+**Acceptance criteria**
+- Case-insensitive substring search on `name`.
+- Tag search matches worlds containing *any* of the requested tags.
+- Search combines with category filter and sort.
+
+### US-3 Categories & sorting
+As a player, I can filter by category and sort by newest, most-played, or
+trending.
+
+**Acceptance criteria**
+- `category` filter matches exactly (case-insensitive).
+- Distinct category list is available for UI dropdowns.
+- `newest`, `most_played`, and `trending` sorts are supported.
+- `most_played` uses `play_count`; `trending` uses the recent-visits heuristic.
+
+### US-4 Visit tracking
+As a player, opening a world records a visit so counts and trending stay fresh.
+
+**Acceptance criteria**
+- `POST /api/worlds/{id}/visit` increments `play_count` and updates
+  `last_played_at`.
+- Appends a `world_visits` row (world_id, user_id or anonymous marker,
+  visited_at).
+- Idempotent per request; rate-limitable later.
+
+### US-5 Godot client
+As a player, I can browse, search, filter, and sort experiences from the game UI.
+
+**Acceptance criteria**
+- An HTTP API client handles the discovery endpoints (JWT + anonymous).
+- A discover/home screen lists experiences with search, category filter, and
+  sort controls.
+- Results render name, category, tags, play count, and description.
+
+## 6. Task breakdown
+
+Right-sized to 1–3 files / one coherent piece of functionality each.
+
+| # | Task | Story | Depends on |
+|---|------|-------|-----------|
+| 1 | World discovery metadata + visits model & Alembic migration | US-2, US-3, US-4 | — |
+| 2 | World visit tracking endpoint (play count + last played + visit log) | US-4 | 1 |
+| 3 | Browse + search endpoint (name/tag/category, newest + most-played) | US-1, US-2, US-3 | 1, 2 |
+| 4 | Trending sort (recent-activity heuristic over `world_visits`) | US-3 | 3 |
+| 5 | Godot discovery API client (HTTP + optional JWT) | US-5 | 3 |
+| 6 | Godot discover/home UI (feed, search, category filter, sort) | US-5 | 4, 5 |
+
+## 7. Phasing
+
+- **Phase 1 (data + core read API):** tasks 1–3 (metadata, visit tracking,
+  browse/search).
+- **Phase 2 (trending):** task 4 — the only non-trivial query; isolated so it
+  can be tuned without touching the browse surface.
+- **Phase 3 (client):** tasks 5–6, each landing after its backend dependency.
+
+## 8. Out of scope for this feature
+
+- Real recommendation models / personalization (collaborative filtering, ML).
+- Full-text search (Postgres FTS); MVP uses ILIKE substring match.
+- Faceted search with multiple simultaneous category/tag AND-semantics.
+- Featured/editorial curation and admin-curated carousels.
+- Search result relevance scoring beyond the three explicit sorts.
+- Analytics dashboards; `world_visits` is append-only signal, not a BI surface.

docs/planning/social.md

@@ -0,0 +1,170 @@
+# Social — Friends, Chat & Groups — Plan
+
+> **Status:** Planned
+> **Owner:** Platform team
+> **Feature ID:** `social`
+> **Godot version:** 4.6.2 stable
+> **Backend:** FastAPI + SQLAlchemy (async) + PostgreSQL + Redis
+
+## 1. Overview
+
+This document breaks the **Social** feature into user stories and right-sized
+implementation tasks. The feature delivers:
+
+- **Friends & following** — a friend request/accept model plus a one-way follow
+  relationship, with block lists.
+- **Presence & status** — online/offline, custom status message, last-seen.
+- **Chat** — direct messages (DM) and in-experience (world/room) chat with
+  **first-class safety**: server-side text filtering, report-message, and rate
+  limiting.
+- **Groups** — named groups with roles (owner/admin/member) and a simple group
+  page.
+- **Public profiles** — avatar, bio, favorite experiences, and a friends list
+  that respects privacy settings.
+
+## 2. Why chat safety is the differentiator
+
+The platform is explicitly meant to pull adults away from a youth-oriented
+competitor. Chat is the highest-risk surface: it is real-time, user-generated,
+and where abuse happens fastest. Safety is therefore treated as a **blocking
+requirement**, not an add-on:
+
+- Every message passes a **server-side text filter** before it is stored or
+  delivered. The client filter is cosmetic only; the server is authoritative.
+- Every message can be **reported**; reports flow into a moderation queue with
+  actor + reason + audit trail (mirroring `content_moderation.md`).
+- Sending is **rate limited** per user (Redis token bucket) to stop flooding and
+  harassment-by-volume.
+- Report and block are always reachable from a message context in the UI.
+
+## 3. Existing constraints (do not re-build)
+
+- **Auth:** JWT bearer tokens; `get_current_user` / `CurrentUser` dependency in
+  `app/dependencies.py`. All social endpoints reuse this.
+- **DB:** async SQLAlchemy + Alembic; migration `0001_initial` is the head.
+- **Redis:** configured (`REDIS_URL`) but unused so far; adopted here for
+  presence and rate limiting.
+- **Models:** `User`, `World` (owner_id), `Asset` (owner_id, is_public). Avatars
+  and favorite-experience references point at existing rows.
+- **Client:** Godot 4.6.2, minimal `main_menu.gd`; no social UI yet.
+
+## 4. Key design decisions
+
+| Concern | Decision |
+|---|---|
+| Message transport | REST for send/history; **WebSocket** gateway for real-time delivery + presence (matches `networking.md`'s "WebSocket as secondary transport" for chat) |
+| Presence store | Redis (TTL heartbeat) + persisted `last_seen_at` on the user record |
+| Text filtering | Pluggable `TextFilter` interface with a deterministic default (profanity list + normalization) so it runs without external services; third-party hook later |
+| Rate limiting | Redis token-bucket dependency, reusable across all social endpoints |
+| Reports | `message_reports` table + moderation endpoints (list/review/resolve) with audit fields |
+| Friends vs. follow | Friends = mutual (request→accept). Follow = one-way (no approval). Block = hard deny that also hides content and prevents DMs |
+| Privacy | Per-user settings JSON (`profile_visibility`, `friends_list_visibility`, `favorites_visibility`) enforced server-side on every read |
+| Groups | `groups` + `group_members` (role: owner/admin/member) + group page aggregate endpoint |
+| Real-time | One WebSocket endpoint multiplexing presence, DM, and world-chat messages via Redis pub/sub |
+
+## 5. User stories
+
+### US-1 Friends & following
+As a player, I can send a friend request, accept/decline incoming requests,
+unfriend, follow/unfollow other players, and block users so they can't interact
+with me.
+
+**Acceptance criteria**
+- Friend requests are one-directional until accepted; accepted friendships are mutual.
+- Follow is one-way and requires no approval.
+- Block prevents DMs, hides the blocked user's profile/friends interactions, and
+  removes any existing friendship/follow between the two.
+- Duplicate/self requests are rejected idempotently.
+
+### US-2 Presence & status
+As a player, I can see whether my friends are online, their custom status, and
+when they were last seen.
+
+**Acceptance criteria**
+- Online/offline is derived from a server-side heartbeat (Redis TTL), not client claims.
+- `last_seen_at` persists and is visible (subject to privacy settings).
+- Custom status text is optional and length-limited.
+
+### US-3 Public profiles
+As a player, I can view a public profile page showing avatar, bio, favorite
+experiences, and a friends list that respects the owner's privacy settings.
+
+**Acceptance criteria**
+- Avatar and bio are editable by the owner only.
+- Favorite experiences reference existing `World` rows.
+- A viewer sees only the sections the owner's privacy settings allow; blocked
+  users see a restricted view.
+
+### US-4 Chat (DM + in-experience) with safety
+As a player, I can send direct messages and chat inside a world/room. Messages
+are filtered, rate limited, and reportable.
+
+**Acceptance criteria**
+- Server filters message text before storing/delivering; filtered content is either
+  rejected (blocking) or redacted (configurable per filter policy).
+- Send rate is limited per user (token bucket); excess sends get `429`.
+- Every message has a stable id, author, timestamp, and conversation/world scope.
+- Any message can be reported with a reason; reports are stored and reviewable.
+- Real-time delivery over WebSocket with REST fallback for history.
+
+### US-5 Groups
+As a player, I can create a group, join/leave groups, and (as owner/admin)
+manage roles and view a simple group page.
+
+**Acceptance criteria**
+- Each group has exactly one owner and any number of admins/members.
+- Role transitions are authorized (only owner can transfer ownership or promote/demote admins).
+- Group page lists name, description, member list with roles, and member count.
+
+### US-6 Godot client
+As a player, I can access friends, presence, chat, profiles, and groups from the
+game UI.
+
+**Acceptance criteria**
+- An API client handles JWT auth, HTTP, and WebSocket for all social calls.
+- Dedicated screens/panels: friends+presence, DM & world chat (with report),
+  profile page, group page.
+- Client-side filtering is cosmetic; server responses remain authoritative.
+
+## 6. Task breakdown
+
+Right-sized to 1–3 files / one coherent piece of functionality each. Task IDs
+are sequential for dependency chaining.
+
+| # | Task | Story | Depends on |
+|---|------|-------|-----------|
+| 1 | Friends/follow/block models + Alembic migration | US-1 | — |
+| 2 | Friends & follow API router | US-1 | 1 |
+| 3 | Presence & status model + endpoints (Redis heartbeat) | US-2 | — |
+| 4 | Profile model + migration + own-profile endpoints | US-3 | 1 |
+| 5 | Public profile view + favorites + privacy enforcement | US-3 | 2, 4 |
+| 6 | Chat data models + migration (conversations, messages, reports) | US-4 | — |
+| 7 | Text filtering service + profanity config | US-4 | — |
+| 8 | Redis rate-limiting dependency | US-4 | — |
+| 9 | DM chat send/list endpoints (filter + rate limit) | US-4 | 6, 7, 8 |
+| 10 | Report-message endpoint + moderation queue | US-4 | 6, 9 |
+| 11 | In-experience (world/room) chat endpoints | US-4 | 9 |
+| 12 | Real-time WebSocket gateway (presence + DM + world chat) | US-4 | 3, 9, 11 |
+| 13 | Group + membership models + migration | US-5 | — |
+| 14 | Groups API (CRUD, join/leave, roles, group page) | US-5 | 13 |
+| 15 | Godot API client (auth + HTTP + WebSocket) | US-6 | 2 |
+| 16 | Godot friends & presence UI | US-6 | 3, 15 |
+| 17 | Godot chat UI (DM + world chat + report) | US-6 | 12, 15 |
+| 18 | Godot profile page UI | US-6 | 5, 15 |
+| 19 | Godot groups UI + group page | US-6 | 14, 15 |
+
+## 7. Phasing
+
+- **Phase 1 (data + core APIs):** tasks 1–5 (friends, presence, profiles).
+- **Phase 2 (chat safety — the differentiator):** tasks 6–12 (chat + safety +
+  realtime). This is the critical path and highest priority.
+- **Phase 3 (groups):** tasks 13–14.
+- **Phase 4 (client):** tasks 15–19, each landing after its backend dependency.
+
+## 8. Out of scope for this feature
+
+- Age verification / maturity gating (covered by `content_moderation.md`).
+- Voice chat, media/image messages, message editing/deletion history.
+- Third-party profanity/toxicity vendors (the `TextFilter` interface leaves a
+  hook, but the default is deterministic and dependency-free).
+- Mobile push notifications.

project.godot

@@ -0,0 +1,24 @@
+; Engine configuration file.
+; It's best edited using the editor UI and not directly,
+; but it can also be edited by hand.
+
+config_version=5
+
+[application]
+
+config/name="AGP-Game"
+run/main_scene="res://scenes/main_menu.tscn"
+config/features=PackedStringArray("4.6.2")
+
+[autoload]
+
+[display]
+
+window/size/viewport_width=1920
+window/size/viewport_height=1080
+window/stretch/mode="canvas_items"
+
+[rendering]
+
+renderer/rendering_method="gl_compatibility"
+renderer/rendering_method.mobile="gl_compatibility"

sandbox_probe/.godot/.gdignore

@@ -0,0 +1 @@
+

sandbox_probe/probe6.gd

@@ -0,0 +1,174 @@
+extends Node
+
+func _ready():
+	print("=== SANDBOX PROBE 6: Corrected Evidence Gathering (Godot 4.6.2) ===")
+	probe_script_loading()
+	probe_os_apis()
+	probe_file_access()
+	probe_network()
+	probe_classdb()
+	probe_expression_engine()
+	probe_engine_singletons()
+	probe_worker_threads()
+	probe_project_settings()
+	probe_allowlist()
+	print("=== SANDBOX PROBE 6 END ===")
+	get_tree().quit()
+
+func probe_script_loading():
+	print("--- Script loading ---")
+	var gd = GDScript.new()
+	gd.source_code = "extends RefCounted\nfunc hello():\n\treturn 42\n"
+	var err = gd.reload()
+	print("GDScript.reload() from source_code err=", err)
+	if err == OK:
+		var inst = gd.new()
+		print("  instantiated, hello()=", inst.call("hello"))
+	var res = load("res://test_script.gd")
+	print("load('res://test_script.gd') = ", res)
+	if res:
+		print("  get_source_code() available: ", res.has_method("get_source_code"))
+	print("  GDScript instance has 'get_ast': ", gd.has_method("get_ast"))
+	print("  GDScript instance has 'get_parser': ", gd.has_method("get_parser"))
+	print("  GDScript instance has 'get_script_method_list': ", gd.has_method("get_script_method_list"))
+	print("  GDScript instance has 'get_script_property_list': ", gd.has_method("get_script_property_list"))
+
+func probe_os_apis():
+	print("--- OS APIs ---")
+	var out = []
+	var exit_code = OS.execute("echo", ["hello"], out)
+	print("OS.execute('echo') exit=", exit_code, " out=", out)
+	print("OS.get_environment('HOME') = ", OS.get_environment("HOME"))
+	print("OS has 'create_process': ", OS.has_method("create_process"))
+	print("OS.get_cmdline_args() = ", OS.get_cmdline_args())
+	print("OS.get_user_data_dir() = ", OS.get_user_data_dir())
+	print("OS.get_executable_path() = ", OS.get_executable_path())
+
+func probe_file_access():
+	print("--- File access ---")
+	var f = FileAccess.open("/etc/hostname", FileAccess.READ)
+	print("FileAccess.open('/etc/hostname') = ", f)
+	if f:
+		print("  content: ", f.get_as_text())
+		f.close()
+	var w = FileAccess.open("/tmp/godot_probe_write.txt", FileAccess.WRITE)
+	print("FileAccess.open('/tmp/...', WRITE) = ", w)
+	if w:
+		w.store_string("probe")
+		w.close()
+		print("  wrote to /tmp OK")
+	var dir = DirAccess.open("/")
+	print("DirAccess.open('/') = ", dir)
+	if dir:
+		var names = dir.get_files()
+		print("  root files count: ", names.size())
+	var res_dir = DirAccess.open("res://")
+	print("DirAccess.open('res://') = ", res_dir)
+	var user_dir = DirAccess.open("user://")
+	print("DirAccess.open('user://') = ", user_dir)
+
+func probe_network():
+	print("--- Network ---")
+	var tcp = TCPServer.new()
+	var bind_err = tcp.listen(0)
+	print("TCPServer.listen(0) err=", bind_err)
+	var http = HTTPClient.new()
+	print("HTTPClient instantiated: ", http != null)
+	var http_req = HTTPRequest.new()
+	print("HTTPRequest instantiated: ", http_req != null)
+	var udp = PacketPeerUDP.new()
+	print("PacketPeerUDP instantiated: ", udp != null)
+	var ws = WebSocketPeer.new()
+	print("WebSocketPeer instantiated: ", ws != null)
+
+func probe_classdb():
+	print("--- ClassDB ---")
+	print("ClassDB.class_exists('OS'): ", ClassDB.class_exists("OS"))
+	print("ClassDB.class_exists('FileAccess'): ", ClassDB.class_exists("FileAccess"))
+	print("ClassDB.class_exists('TCPServer'): ", ClassDB.class_exists("TCPServer"))
+	print("ClassDB.class_exists('HTTPClient'): ", ClassDB.class_exists("HTTPClient"))
+	var class_list = ClassDB.get_class_list()
+	print("ClassDB.get_class_list() count: ", class_list.size())
+	var os_methods = ClassDB.class_get_method_list("OS")
+	print("OS method count: ", os_methods.size())
+	var inst = ClassDB.instantiate("Node")
+	print("ClassDB.instantiate('Node') = ", inst)
+	print("ClassDB has 'class_get_singleton': ", ClassDB.has_method("class_get_singleton"))
+
+func probe_expression_engine():
+	print("--- Expression engine ---")
+	var expr = Expression.new()
+	var err = expr.parse("1 + 2")
+	print("Expression.parse('1 + 2') err=", err)
+	if err == OK:
+		var result = expr.execute()
+		print("  Expression.execute() = ", result)
+	var expr2 = Expression.new()
+	err = expr2.parse("OS.get_environment('HOME')")
+	print("Expression.parse('OS.get_environment') err=", err)
+	if err == OK:
+		var result2 = expr2.execute()
+		print("  Expression.execute() = ", result2)
+	var expr3 = Expression.new()
+	err = expr3.parse("get_environment('HOME')", ["OS"])
+	print("Expression.parse with base_instance err=", err)
+	if err == OK:
+		var result3 = expr3.execute([], OS)
+		print("  Expression.execute with OS base = ", result3)
+	var expr4 = Expression.new()
+	err = expr4.parse("FileAccess.open('/etc/hostname', 1)")
+	print("Expression.parse('FileAccess.open') err=", err)
+	if err == OK:
+		var result4 = expr4.execute()
+		print("  Expression.execute() = ", result4)
+	var expr5 = Expression.new()
+	err = expr5.parse("get_tree().quit()")
+	print("Expression.parse('get_tree().quit()') err=", err)
+	if err == OK:
+		var result5 = expr5.execute()
+		print("  Expression.execute() = ", result5)
+
+func probe_engine_singletons():
+	print("--- Engine singletons ---")
+	print("Engine has 'remove_singleton': ", Engine.has_method("remove_singleton"))
+	print("Engine has 'add_singleton': ", Engine.has_method("add_singleton"))
+	print("Engine.get_main_loop() = ", Engine.get_main_loop())
+
+func probe_worker_threads():
+	print("--- Worker threads ---")
+	var thread = Thread.new()
+	print("  Thread.new() = ", thread)
+	print("  WorkerThreadPool has 'add_task': ", WorkerThreadPool.has_method("add_task"))
+
+func probe_project_settings():
+	print("--- Project settings ---")
+	var settings = ProjectSettings.get_property_list()
+	var relevant = []
+	for s in settings:
+		var name = String(s.name)
+		if "sandbox" in name.to_lower() or "restrict" in name.to_lower() or "security" in name.to_lower():
+			relevant.append(name)
+	print("  Sandbox/security project settings: ", relevant)
+	print("  ProjectSettings has 'application/run/disable_os': ", ProjectSettings.has_setting("application/run/disable_os"))
+	print("  ProjectSettings has 'application/run/disable_file_access': ", ProjectSettings.has_setting("application/run/disable_file_access"))
+	print("  ProjectSettings has 'application/run/disable_network': ", ProjectSettings.has_setting("application/run/disable_network"))
+	print("  ProjectSettings has 'set_setting': ", ProjectSettings.has_method("set_setting"))
+	print("  ProjectSettings has 'save': ", ProjectSettings.has_method("save"))
+
+func probe_allowlist():
+	print("--- Allowlist / static analysis ---")
+	var dangerous_patterns = [
+		"OS.execute", "OS.create_process", "OS.get_environment",
+		"FileAccess.open", "DirAccess.open", "TCPServer", "HTTPClient",
+		"load(", "preload(", "ClassDB", "Engine.get_main_loop",
+		"get_tree().quit", "ProjectSettings"
+	]
+	var test_script = """extends Node
+func _ready():
+	var f = FileAccess.open("/etc/passwd", FileAccess.READ)
+	OS.execute("rm", ["-rf", "/"])
+"""
+	print("  Test script contains dangerous patterns:")
+	for p in dangerous_patterns:
+		if p in test_script:
+			print("    DETECTED: ", p)

sandbox_probe/probe6.tscn

@@ -0,0 +1,6 @@
+[gd_scene load_steps=2 format=3]
+
+[ext_resource type="Script" path="res://probe6.gd" id="1"]
+
+[node name="Probe6" type="Node"]
+script = ExtResource("1")

sandbox_probe/project.godot

@@ -0,0 +1,8 @@
+; Engine configuration file.
+config_version=5
+
+[application]
+
+config/name="sandbox_probe"
+run/main_scene="res://probe6.tscn"
+config/features=PackedStringArray("4.6")

sandbox_probe/test_script.gd

@@ -0,0 +1,4 @@
+extends RefCounted
+
+func hello():
+	return "from test_script.gd"

scenes/main.tscn

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

scenes/main_menu.tscn

@@ -0,0 +1,43 @@
+[gd_scene load_steps=2 format=3]
+
+[ext_resource type="Script" path="res://scripts/main_menu.gd" id="1_main"]
+
+[node name="MainMenu" type="Control"]
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+script = ExtResource("1_main")
+
+[node name="CenterContainer" type="CenterContainer" parent="."]
+layout_mode = 3
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+
+[node name="VBoxContainer" type="VBoxContainer" parent="CenterContainer"]
+layout_mode = 1
+theme_override_constants/separation = 16
+size_flags_horizontal = 4
+
+[node name="TitleLabel" type="Label" parent="CenterContainer/VBoxContainer"]
+layout_mode = 1
+text = "AGP Game"
+horizontal_alignment = 1
+theme_override_font_sizes/font_size = 72
+
+[node name="PlayButton" type="Button" parent="CenterContainer/VBoxContainer"]
+layout_mode = 1
+text = "Play"
+size_flags_horizontal = 4
+
+[node name="QuitButton" type="Button" parent="CenterContainer/VBoxContainer"]
+layout_mode = 1
+text = "Quit"
+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"]

scripts/chunk.gd

@@ -0,0 +1,105 @@
+class_name Chunk
+extends Node3D
+## A single world chunk. Holds the chunk coordinate, bounds, and the
+## visual/gameplay content for that region of the world.
+##
+## Chunks are the atomic unit of world geometry, gameplay objects, and
+## persistence (see docs/architecture/world.md). The server loads and saves
+## whole chunks; clients stream the chunks around them.
+
+## Default chunk dimensions in world units (tiles). Matches the constants in
+## docs/architecture/world.md section 2.2.
+const CHUNK_SIZE_X: int = 32
+const CHUNK_SIZE_Y: int = 32
+const CHUNK_SIZE_Z: int = 1
+
+## World-space origin of chunk coordinate (0,0).
+const CHUNK_ORIGIN := Vector3(0.0, 0.0, 0.0)
+
+## Chunk coordinate (cx, cy, cz) in chunk space.
+var coord := Vector3i.ZERO
+
+## The canonical chunk key: "{world_id}:{room_id}:{cx}:{cy}:{cz}".
+var key: String = ""
+
+## World and room identifiers this chunk belongs to.
+var world_id: String = ""
+var room_id: String = ""
+
+## Format version of the chunk payload (currently 1).
+var format_version: int = 1
+
+## Revision counter, incremented on every write. Used for optimistic
+## concurrency and change detection.
+var revision: int = 0
+
+## Whether this chunk has been modified in memory but not yet flushed.
+var dirty: bool = false
+
+## Container for static objects (props, geometry) in this chunk.
+var objects: Array[Node3D] = []
+
+## Container for dynamic object templates (spawnable entities).
+var dynamic_templates: Array[Node3D] = []
+
+## The world-space bounding box of this chunk.
+var bounds: AABB
+
+
+func _init(p_coord: Vector3i = Vector3i.ZERO, p_world_id: String = "", p_room_id: String = "") -> void:
+	coord = p_coord
+	world_id = p_world_id
+	room_id = p_room_id
+	key = build_key(world_id, room_id, coord)
+	bounds = compute_bounds(coord)
+
+
+## Build the canonical chunk key from its components.
+static func build_key(p_world_id: String, p_room_id: String, p_coord: Vector3i) -> String:
+	return "%s:%s:%d:%d:%d" % [p_world_id, p_room_id, p_coord.x, p_coord.y, p_coord.z]
+
+
+## Compute the world-space bounding box for a chunk coordinate.
+static func compute_bounds(p_coord: Vector3i) -> AABB:
+	var min_pos := Vector3(
+		CHUNK_ORIGIN.x + p_coord.x * CHUNK_SIZE_X,
+		CHUNK_ORIGIN.y + p_coord.y * CHUNK_SIZE_Y,
+		CHUNK_ORIGIN.z + p_coord.z * CHUNK_SIZE_Z
+	)
+	return AABB(min_pos, Vector3(CHUNK_SIZE_X, CHUNK_SIZE_Y, CHUNK_SIZE_Z))
+
+
+## Compute the chunk coordinate that contains a world-space position.
+static func coord_for_position(p_pos: Vector3) -> Vector3i:
+	return Vector3i(
+		int(floor((p_pos.x - CHUNK_ORIGIN.x) / CHUNK_SIZE_X)),
+		int(floor((p_pos.y - CHUNK_ORIGIN.y) / CHUNK_SIZE_Y)),
+		int(floor((p_pos.z - CHUNK_ORIGIN.z) / CHUNK_SIZE_Z))
+	)
+
+
+## Add a static object to this chunk.
+func add_object(p_object: Node3D) -> void:
+	objects.append(p_object)
+	add_child(p_object)
+
+
+## Add a dynamic object template to this chunk.
+func add_dynamic_template(p_template: Node3D) -> void:
+	dynamic_templates.append(p_template)
+	add_child(p_template)
+
+
+## Remove all objects from this chunk.
+func clear_objects() -> void:
+	for obj in objects:
+		if is_instance_valid(obj):
+			obj.queue_free()
+	objects.clear()
+	dynamic_templates.clear()
+
+
+## Mark this chunk as dirty (modified but not yet persisted).
+func mark_dirty() -> void:
+	dirty = true
+	revision += 1

scripts/chunk.gd.uid

@@ -0,0 +1 @@
+uid://dc6j7kqjitc6g

scripts/chunk_data_decoder.gd

@@ -0,0 +1,667 @@
+class_name ChunkDataDecoder
+extends RefCounted
+## Decodes chunk binary payloads (and JSON) into logical chunk data.
+##
+## Implements the binary format spec from docs/architecture/world.md §3.6.
+## Both the Godot client and Python backend use this class to ensure
+## identical encoding/decoding behavior.
+##
+## ## Binary Format Overview
+##
+## ```
+## Header (48 bytes):
+##   [0:4]   magic "AGPC"
+##   [4:6]   version (uint16 LE)
+##   [6:8]   header_len (uint16 LE)
+##   [8:12]  flags (uint32 LE)
+##   [12:16] payload_len (uint32 LE)
+##   [16:48] checksum (SHA-256 hex, 32 bytes)
+##
+## Payload Body (sections):
+##   [section_id:1][section_len:4][data:section_len]
+## ```
+
+
+## Content flags parsed from a chunk.
+class ContentFlags:
+	## Severity levels: 0=none, 1=mild, 2=moderate, 3=severe
+	var violence: int = 0
+	var sexual: int = 0
+	var language: int = 0
+	var substance: int = 0
+	var gambling: int = 0
+	var horror: int = 0
+	var hate: int = 0
+	var custom: int = 0
+	var mature: bool = false
+	var sources: Array[String] = []
+
+	func is_mature() -> bool:
+		return mature
+
+	func has_severe_content() -> bool:
+		return (violence >= 3 or sexual >= 3 or language >= 3 or
+		        substance >= 3 or gambling >= 3 or horror >= 3 or
+		        hate >= 3 or custom >= 3)
+
+	func get_max_severity() -> int:
+		return maxi(
+			violence, maxi(sexual, maxi(language, maxi(substance,
+			maxi(gambling, maxi(horror, maxi(hate, custom)))))))
+
+	func to_dict() -> Dictionary:
+		return {
+			"categories": {
+				"violence": violence,
+				"sexual": sexual,
+				"language": language,
+				"substance": substance,
+				"gambling": gambling,
+				"horror": horror,
+				"hate": hate,
+				"custom": custom,
+			},
+			"mature": mature,
+			"sources": sources,
+		}
+
+	func from_dict(d: Dictionary) -> void:
+		if d.has("categories"):
+			violence = d["categories"].get("violence", 0)
+			sexual = d["categories"].get("sexual", 0)
+			language = d["categories"].get("language", 0)
+			substance = d["categories"].get("substance", 0)
+			gambling = d["categories"].get("gambling", 0)
+			horror = d["categories"].get("horror", 0)
+			hate = d["categories"].get("hate", 0)
+			custom = d["categories"].get("custom", 0)
+		mature = d.get("mature", false)
+		sources = d.get("sources", [])
+
+
+## A tile layer definition (palette + dense tile indices).
+class TileLayerData:
+	var name: String = ""
+	var layer_id: int = 0
+	var width: int = 0
+	var height: int = 0
+	var depth: int = 1
+	var palette: Array[TileDef] = []
+	var tiles: PackedInt32Array = PackedInt32Array()
+
+	func tile_count() -> int:
+		return width * height * depth
+
+	func get_tile(x: int, y: int, z: int = 0) -> int:
+		if x < 0 or x >= width or y < 0 or y >= height or z < 0 or z >= depth:
+			return 0  # Out of bounds returns empty tile
+		var idx := (z * height + y) * width + x
+		if idx < tiles.size():
+			return tiles[idx]
+		return 0
+
+	func get_tile_def(tile_id: int) -> TileDef:
+		for def in palette:
+			if def.id == tile_id:
+				return def
+		return null
+
+
+## A world object parsed from chunk data.
+class WorldObjectData:
+	var id: String = ""
+	var type: String = ""
+	var asset_id: String = ""
+	var position: Vector3 = Vector3.ZERO
+	var rotation: Vector4 = Vector4(0, 0, 0, 1)
+	var scale: Vector3 = Vector3.ONE
+	var properties: Dictionary = {}
+	var dynamic: bool = false
+	var flags: ContentFlags = ContentFlags.new()
+
+
+## The complete decoded chunk payload.
+class ChunkPayload:
+	var version: int = 1
+	var key: String = ""
+	var world_id: String = ""
+	var room_id: String = ""
+	var coord: Vector3i = Vector3i.ZERO
+	var bounds: AABB = AABB()
+	var tile_layers: Array[TileLayerData] = []
+	var objects: Array[WorldObjectData] = []
+	var flags: ContentFlags = ContentFlags.new()
+	var created_at: int = 0  # Unix timestamp
+	var updated_at: int = 0  # Unix timestamp
+	var revision: int = 0
+	var author: String = ""
+	var checksum: String = ""
+
+
+# ───────────────── Binary Decoding ─────────────────
+
+static var MAGIC := PackedByteArray([0x41, 0x47, 0x50, 0x43])  # "AGPC"
+const HEADER_SIZE: int = 48
+const SECTION_META: int = 0x01
+const SECTION_TILE: int = 0x02
+const SECTION_OBJECT: int = 0x03
+const SECTION_FLAGS: int = 0x04
+const SECTION_REVISION_META: int = 0x05
+
+
+## Decode a binary chunk payload into a ChunkPayload.
+## Returns null if the data is invalid or version is unsupported.
+static func decode_binary(data: PackedByteArray) -> ChunkPayload:
+	if data.size() < HEADER_SIZE:
+		push_error("ChunkDataDecoder: Data too short for header (%d bytes)" % data.size())
+		return null
+
+	# Verify magic
+	var magic := PackedByteArray(data.slice(0, 4))
+	if magic != MAGIC:
+		push_error("ChunkDataDecoder: Invalid magic bytes")
+		return null
+
+	# Read header fields
+	var version := _read_uint16(data, 4)
+	if version != 1:
+		push_error("ChunkDataDecoder: Unsupported chunk version %d" % version)
+		return null
+
+	var header_len := _read_uint16(data, 6)
+	var flags := _read_uint32(data, 8)
+	var payload_len := _read_uint32(data, 12)
+	var checksum := _read_hex_string(data, 16, 32)
+
+	# Verify payload length
+	if data.size() < HEADER_SIZE + payload_len:
+		push_error("ChunkDataDecoder: Payload too short")
+		return null
+
+	var payload := data.slice(HEADER_SIZE, HEADER_SIZE + payload_len)
+
+	# Verify checksum
+	var computed_checksum := _sha256_hex(payload)
+	if computed_checksum != checksum:
+		push_error("ChunkDataDecoder: Checksum mismatch")
+		# Continue anyway for resilience
+
+	var result := ChunkPayload.new()
+	result.version = version
+	result.checksum = checksum
+
+	# Parse sections
+	var offset := 0
+	while offset < payload.size():
+		if offset + 5 > payload.size():
+			break
+
+		var section_id := payload[offset]
+		var section_len := _read_uint32(payload, offset + 1)
+
+		if offset + 5 + section_len > payload.size():
+			break
+
+		var section_data := payload.slice(offset + 5, offset + 5 + section_len)
+
+		match section_id:
+			SECTION_META:
+				_parse_metadata_section(section_data, result)
+			SECTION_TILE:
+				_parse_tile_section(section_data, result)
+			SECTION_OBJECT:
+				_parse_object_section(section_data, result)
+			SECTION_FLAGS:
+				_parse_flags_section(section_data, result.flags)
+			SECTION_REVISION_META:
+				_parse_revision_meta_section(section_data, result)
+
+		offset += 5 + section_len
+
+	return result
+
+
+## Encode a ChunkPayload into binary format.
+static func encode_binary(payload: ChunkPayload) -> PackedByteArray:
+	var sections := PackedByteArray()
+
+	# Build metadata section
+	sections.append_array(_build_metadata_section(payload))
+	# Build tile sections
+	for layer in payload.tile_layers:
+		sections.append_array(_build_tile_section(layer))
+	# Build object sections
+	for obj in payload.objects:
+		sections.append_array(_build_object_section(obj))
+	# Build flags section
+	sections.append_array(_build_flags_section(payload.flags))
+	# Build revision meta section
+	sections.append_array(_build_revision_meta_section(payload))
+
+	var payload_bytes := PackedByteArray(sections)
+	var checksum := _sha256_hex(payload_bytes)
+
+	# Build header
+	var header := PackedByteArray()
+	header.append_array(MAGIC)
+	header.append_array(_write_uint16(1))  # version
+	header.append_array(_write_uint16(0))  # header_len (after this field)
+	header.append_array(_write_uint32(0))  # flags
+	header.append_array(_write_uint32(payload_bytes.size()))
+	header.append_array(_hex_to_bytes(checksum))
+
+	return header + payload_bytes
+
+
+# ───────────────── Section Parsers ─────────────────
+
+static func _parse_metadata_section(data: PackedByteArray, result: ChunkPayload) -> void:
+	var offset := 0
+
+	# world_id (length-prefixed string)
+	var world_id_len := _read_uint16(data, offset)
+	offset += 2
+	result.world_id = data.slice(offset, offset + world_id_len).get_string_from_utf8()
+	offset += world_id_len
+
+	# room_id (length-prefixed string)
+	var room_id_len := _read_uint16(data, offset)
+	offset += 2
+	result.room_id = data.slice(offset, offset + room_id_len).get_string_from_utf8()
+	offset += room_id_len
+
+	# coord (3 × int32)
+	result.coord = Vector3i(
+		_read_int32(data, offset),
+		_read_int32(data, offset + 4),
+		_read_int32(data, offset + 8)
+	)
+	offset += 12
+
+	# bounds (6 × float32)
+	var min_pos := Vector3(
+		_read_float32(data, offset),
+		_read_float32(data, offset + 4),
+		_read_float32(data, offset + 8)
+	)
+	var max_pos := Vector3(
+		_read_float32(data, offset + 12),
+		_read_float32(data, offset + 16),
+		_read_float32(data, offset + 20)
+	)
+	result.bounds = AABB(min_pos, max_pos - min_pos)
+
+
+static func _parse_tile_section(data: PackedByteArray, result: ChunkPayload) -> void:
+	var layer := TileLayerData.new()
+	var offset := 0
+
+	# name (length-prefixed string)
+	var name_len := _read_uint16(data, offset)
+	offset += 2
+	layer.name = data.slice(offset, offset + name_len).get_string_from_utf8()
+	offset += name_len
+
+	# layer_id (uint16)
+	layer.layer_id = _read_uint16(data, offset)
+	offset += 2
+
+	# dimensions (3 × uint16)
+	layer.width = _read_uint16(data, offset)
+	offset += 2
+	layer.height = _read_uint16(data, offset)
+	offset += 2
+	layer.depth = _read_uint16(data, offset)
+	offset += 2
+
+	# palette
+	var palette_count := _read_uint16(data, offset)
+	offset += 2
+	for _i in range(palette_count):
+		var tile_def := TileDef.new()
+		tile_def.id = _read_uint16(data, offset)
+		offset += 2
+
+		var asset_id_len := _read_uint16(data, offset)
+		offset += 2
+		tile_def.asset_id = data.slice(offset, offset + asset_id_len).get_string_from_utf8()
+		offset += asset_id_len
+
+		tile_def.solid = data[offset] != 0
+		offset += 1
+
+		tile_def.flags = _read_uint32(data, offset)
+		offset += 4
+
+		tile_def.variants = data[offset]
+		offset += 1
+
+		layer.palette.append(tile_def)
+
+	# tiles
+	var tile_count := _read_uint32(data, offset)
+	offset += 4
+	for i in range(tile_count):
+		layer.tiles.append(_read_uint16(data, offset))
+		offset += 2
+
+	result.tile_layers.append(layer)
+
+
+static func _parse_object_section(data: PackedByteArray, result: ChunkPayload) -> void:
+	var obj := WorldObjectData.new()
+	var offset := 0
+
+	# id (length-prefixed string)
+	var id_len := _read_uint16(data, offset)
+	offset += 2
+	obj.id = data.slice(offset, offset + id_len).get_string_from_utf8()
+	offset += id_len
+
+	# type (length-prefixed string)
+	var type_len := _read_uint16(data, offset)
+	offset += 2
+	obj.type = data.slice(offset, offset + type_len).get_string_from_utf8()
+	offset += type_len
+
+	# asset_id (length-prefixed string)
+	var asset_id_len := _read_uint16(data, offset)
+	offset += 2
+	obj.asset_id = data.slice(offset, offset + asset_id_len).get_string_from_utf8()
+	offset += asset_id_len
+
+	# position (3 × float32)
+	obj.position = Vector3(
+		_read_float32(data, offset),
+		_read_float32(data, offset + 4),
+		_read_float32(data, offset + 8)
+	)
+	offset += 12
+
+	# rotation (4 × float32)
+	obj.rotation = Vector4(
+		_read_float32(data, offset),
+		_read_float32(data, offset + 4),
+		_read_float32(data, offset + 8),
+		_read_float32(data, offset + 12)
+	)
+	offset += 16
+
+	# scale (3 × float32)
+	obj.scale = Vector3(
+		_read_float32(data, offset),
+		_read_float32(data, offset + 4),
+		_read_float32(data, offset + 8)
+	)
+	offset += 12
+
+	# dynamic (uint8)
+	obj.dynamic = data[offset] != 0
+	offset += 1
+
+	# properties (length-prefixed JSON string)
+	var props_len := _read_uint16(data, offset)
+	offset += 2
+	var props_str := data.slice(offset, offset + props_len).get_string_from_utf8()
+	offset += props_len
+	obj.properties = JSON.parse_string(props_str) or {}
+
+	# flags (ContentFlags)
+	obj.flags.violence = data[offset]
+	offset += 1
+	obj.flags.sexual = data[offset]
+	offset += 1
+	obj.flags.language = data[offset]
+	offset += 1
+	obj.flags.substance = data[offset]
+	offset += 1
+	obj.flags.gambling = data[offset]
+	offset += 1
+	obj.flags.horror = data[offset]
+	offset += 1
+	obj.flags.hate = data[offset]
+	offset += 1
+	obj.flags.custom = data[offset]
+	offset += 1
+	obj.flags.mature = data[offset] != 0
+	offset += 1
+
+	var source_count := _read_uint16(data, offset)
+	offset += 2
+	for _i in range(source_count):
+		var src_len := _read_uint16(data, offset)
+		offset += 2
+		obj.flags.sources.append(data.slice(offset, offset + src_len).get_string_from_utf8())
+		offset += src_len
+
+	result.objects.append(obj)
+
+
+static func _parse_flags_section(data: PackedByteArray, flags: ContentFlags) -> void:
+	flags.violence = data[0]
+	flags.sexual = data[1]
+	flags.language = data[2]
+	flags.substance = data[3]
+	flags.gambling = data[4]
+	flags.horror = data[5]
+	flags.hate = data[6]
+	flags.custom = data[7]
+	flags.mature = data[8] != 0
+
+	var offset := 9
+	var source_count := _read_uint16(data, offset)
+	offset += 2
+	for _i in range(source_count):
+		var src_len := _read_uint16(data, offset)
+		offset += 2
+		flags.sources.append(data.slice(offset, offset + src_len).get_string_from_utf8())
+		offset += src_len
+
+
+static func _parse_revision_meta_section(data: PackedByteArray, result: ChunkPayload) -> void:
+	var offset := 0
+	# created_at (int64 unix)
+	result.created_at = _read_int64(data, offset)
+	offset += 8
+	# updated_at (int64 unix)
+	result.updated_at = _read_int64(data, offset)
+	offset += 8
+	# revision (uint32)
+	result.revision = _read_uint32(data, offset)
+	offset += 4
+	# author (length-prefixed string)
+	var author_len := _read_uint16(data, offset)
+	offset += 2
+	result.author = data.slice(offset, offset + author_len).get_string_from_utf8()
+
+
+# ───────────────── Section Builders ─────────────────
+
+static func _build_metadata_section(payload: ChunkPayload) -> PackedByteArray:
+	var data := PackedByteArray()
+	data.append_array(_write_string(payload.world_id))
+	data.append_array(_write_string(payload.room_id))
+	data.append_array(_write_int32(payload.coord.x))
+	data.append_array(_write_int32(payload.coord.y))
+	data.append_array(_write_int32(payload.coord.z))
+	data.append_array(_write_float32(payload.bounds.position.x))
+	data.append_array(_write_float32(payload.bounds.position.y))
+	data.append_array(_write_float32(payload.bounds.position.z))
+	data.append_array(_write_float32(payload.bounds.size.x))
+	data.append_array(_write_float32(payload.bounds.size.y))
+	data.append_array(_write_float32(payload.bounds.size.z))
+	return data
+
+
+static func _build_tile_section(layer: TileLayerData) -> PackedByteArray:
+	var data := PackedByteArray()
+	data.append_array(_write_string(layer.name))
+	data.append_array(_write_uint16(layer.layer_id))
+	data.append_array(_write_uint16(layer.width))
+	data.append_array(_write_uint16(layer.height))
+	data.append_array(_write_uint16(layer.depth))
+	data.append_array(_write_uint16(layer.palette.size()))
+
+	for tile_def in layer.palette:
+		data.append_array(_write_uint16(tile_def.id))
+		data.append_array(_write_string(tile_def.asset_id))
+		data.append(tile_def.solid as int)
+		data.append_array(_write_uint32(tile_def.flags))
+		data.append(tile_def.variants)
+
+	data.append_array(_write_uint32(layer.tiles.size()))
+	for tile_id in layer.tiles:
+		data.append_array(_write_uint16(tile_id))
+
+	return _wrap_section(data, SECTION_TILE)
+
+
+static func _build_object_section(obj: WorldObjectData) -> PackedByteArray:
+	var data := PackedByteArray()
+	data.append_array(_write_string(obj.id))
+	data.append_array(_write_string(obj.type))
+	data.append_array(_write_string(obj.asset_id))
+	data.append_array(_write_float32(obj.position.x))
+	data.append_array(_write_float32(obj.position.y))
+	data.append_array(_write_float32(obj.position.z))
+	data.append_array(_write_float32(obj.rotation.x))
+	data.append_array(_write_float32(obj.rotation.y))
+	data.append_array(_write_float32(obj.rotation.z))
+	data.append_array(_write_float32(obj.rotation.w))
+	data.append_array(_write_float32(obj.scale.x))
+	data.append_array(_write_float32(obj.scale.y))
+	data.append_array(_write_float32(obj.scale.z))
+	data.append(obj.dynamic as int)
+
+	var props_json := JSON.stringify(obj.properties, "  ")
+	data.append_array(_write_string(props_json))
+
+	data.append(obj.flags.violence)
+	data.append(obj.flags.sexual)
+	data.append(obj.flags.language)
+	data.append(obj.flags.substance)
+	data.append(obj.flags.gambling)
+	data.append(obj.flags.horror)
+	data.append(obj.flags.hate)
+	data.append(obj.flags.custom)
+	data.append(obj.flags.mature as int)
+	data.append_array(_write_uint16(obj.flags.sources.size()))
+	for src in obj.flags.sources:
+		data.append_array(_write_string(src))
+
+	return _wrap_section(data, SECTION_OBJECT)
+
+
+static func _build_flags_section(flags: ContentFlags) -> PackedByteArray:
+	var data := PackedByteArray()
+	data.append(flags.violence)
+	data.append(flags.sexual)
+	data.append(flags.language)
+	data.append(flags.substance)
+	data.append(flags.gambling)
+	data.append(flags.horror)
+	data.append(flags.hate)
+	data.append(flags.custom)
+	data.append(flags.mature as int)
+	data.append_array(_write_uint16(flags.sources.size()))
+	for src in flags.sources:
+		data.append_array(_write_string(src))
+	return _wrap_section(data, SECTION_FLAGS)
+
+
+static func _build_revision_meta_section(payload: ChunkPayload) -> PackedByteArray:
+	var data := PackedByteArray()
+	data.append_array(_write_int64(payload.created_at))
+	data.append_array(_write_int64(payload.updated_at))
+	data.append_array(_write_uint32(payload.revision))
+	data.append_array(_write_string(payload.author))
+	return _wrap_section(data, SECTION_REVISION_META)
+
+
+static func _wrap_section(data: PackedByteArray, section_id: int) -> PackedByteArray:
+	var wrapped := PackedByteArray()
+	wrapped.append(section_id)
+	wrapped.append_array(_write_uint32(data.size()))
+	wrapped.append_array(data)
+	return wrapped
+
+
+# ───────────────── Binary Helpers ─────────────────
+
+static func _read_uint16(data: PackedByteArray, offset: int) -> int:
+	return data[offset] | (data[offset + 1] << 8)
+
+static func _read_uint32(data: PackedByteArray, offset: int) -> int:
+	return (data[offset] | (data[offset + 1] << 8) |
+	        (data[offset + 2] << 16) | (data[offset + 3] << 24))
+
+static func _read_int32(data: PackedByteArray, offset: int) -> int:
+	var val := _read_uint32(data, offset)
+	if val >= 0x80000000:
+		return val - 0x100000000
+	return val
+
+static func _read_int64(data: PackedByteArray, offset: int) -> int:
+	var lo := _read_uint32(data, offset)
+	var hi := _read_uint32(data, offset + 4)
+	return hi * 0x100000000 + lo
+
+static func _read_float32(data: PackedByteArray, offset: int) -> float:
+	var bits := _read_uint32(data, offset)
+	return bits as float  # GDScript float is 64-bit; bits repr works for IEEE 754
+
+static func _read_hex_string(data: PackedByteArray, offset: int, length: int) -> String:
+	var hex_chars := "0123456789abcdef"
+	var result := ""
+	for i in range(length):
+		var byte_val := data[offset + i]
+		result += hex_chars[byte_val >> 4]
+		result += hex_chars[byte_val & 0x0F]
+	return result
+
+
+static func _write_uint16(val: int) -> PackedByteArray:
+	return PackedByteArray([(val & 0xFF), (val >> 8) & 0xFF])
+
+static func _write_uint32(val: int) -> PackedByteArray:
+	return PackedByteArray([
+		val & 0xFF, (val >> 8) & 0xFF, (val >> 16) & 0xFF, (val >> 24) & 0xFF
+	])
+
+static func _write_int32(val: int) -> PackedByteArray:
+	return _write_uint32(val)
+
+static func _write_int64(val: int) -> PackedByteArray:
+	var lo := val & 0xFFFFFFFF
+	var hi := (val >> 32) & 0xFFFFFFFF
+	return _write_uint32(lo) + _write_uint32(hi)
+
+static func _write_float32(val: float) -> PackedByteArray:
+	var bits := val as int
+	return _write_uint32(bits)
+
+static func _write_string(s: String) -> PackedByteArray:
+	var bytes := s.to_utf8_buffer()
+	return _write_uint16(bytes.size()) + bytes
+
+static func _hex_to_bytes(hex_str: String) -> PackedByteArray:
+	var result := PackedByteArray()
+	for i in range(0, hex_str.length(), 2):
+		var byte_val := ("0x" + hex_str.substr(i, 2)).hex_to_int()
+		result.append(byte_val)
+	return result
+
+
+# ───────────────── SHA-256 ─────────────────
+
+static func _sha256_hex(data: PackedByteArray) -> String:
+	var ctx := HashingContext.new()
+	ctx.start(HashingContext.HASH_SHA256)
+	ctx.update(data)
+	var hash := ctx.finish()
+	var hex_chars := "0123456789abcdef"
+	var result := ""
+	for byte_val in hash:
+		result += hex_chars[(byte_val >> 4) & 0x0F]
+		result += hex_chars[byte_val & 0x0F]
+	return result

scripts/chunk_data_decoder.gd.uid

@@ -0,0 +1 @@
+uid://bv445xrd6f5tk

scripts/chunk_scene.gd

@@ -0,0 +1,170 @@
+class_name ChunkScene
+extends Node3D
+## A visual representation of a single loaded world chunk.
+##
+## This node is instantiated by [ChunkStreamManager] when a chunk is loaded.
+## It holds the tile layers, world objects, and metadata for one chunk of the
+## world. The scene is responsible for rendering the chunk's visual content
+## and exposing its gameplay objects to the rest of the game.
+##
+## ## Structure
+##
+## ```
+## ChunkScene (Node3D)
+##  ├── TileLayer (Node3D)  # one per tile layer (ground, walls, decor, ...)
+##  ├── StaticObject (Node3D)  # props, geometry, interactables
+##  └── DynamicObject (Node3D)  # spawnable entities (templates)
+## ```
+##
+## ## Lifecycle
+##
+## 1. [ChunkStreamManager] requests chunk data from the server.
+## 2. Server responds with binary payload.
+## 3. [ChunkStreamManager] decodes the payload and creates a [ChunkScene].
+## 4. [ChunkScene] populates itself with tile layers and objects.
+## 5. When the player moves out of range, [ChunkStreamManager] calls
+##    [method ChunkScene.queue_free] to unload it.
+
+## The chunk coordinate this scene represents.
+var coord: Vector3i = Vector3i.ZERO
+
+## The canonical chunk key.
+var key: String = ""
+
+## World-space bounding box of this chunk.
+var bounds: AABB = AABB()
+
+## Format version of the chunk data.
+var format_version: int = 1
+
+## Revision counter from the server.
+var revision: int = 0
+
+## List of tile layers in this chunk.
+var tile_layers: Array[TileLayer] = []
+
+## List of world objects (static + dynamic) in this chunk.
+var world_objects: Array[WorldObject] = []
+
+## Content moderation flags for this chunk.
+var content_flags: ChunkDataDecoder.ContentFlags = ChunkDataDecoder.ContentFlags.new()
+
+## Whether this chunk has been modified locally (not yet synced to server).
+var is_dirty: bool = false
+
+
+func _ready() -> void:
+	# Position this chunk scene at its world-space origin
+	global_position = bounds.position
+	# Set up collision shape for the chunk bounds
+	_setup_collision()
+
+
+func _setup_collision() -> void:
+	# Add a collision shape for the chunk's bounding box
+	var collision := CollisionShape3D.new()
+	var shape := BoxShape3D.new()
+	shape.size = bounds.size
+	collision.shape = shape
+	collision.name = "ChunkBounds"
+	add_child(collision)
+
+
+## Add a tile layer to this chunk scene.
+func add_tile_layer(layer: TileLayer) -> void:
+	tile_layers.append(layer)
+	var layer_node := TileLayerNode.new()
+	layer_node.tile_layer = layer
+	layer_node.chunk_coord = coord
+	add_child(layer_node)
+
+
+## Add a world object to this chunk scene.
+func add_object(obj: WorldObject) -> void:
+	world_objects.append(obj)
+	if obj.is_dynamic:
+		_add_dynamic_object(obj)
+	else:
+		_add_static_object(obj)
+
+
+func _add_static_object(obj: WorldObject) -> void:
+	var static_obj := StaticObjectNode.new()
+	static_obj.world_object = obj
+	static_obj.position = obj.position
+	static_obj.quaternion = Quaternion(obj.rotation.x, obj.rotation.y, obj.rotation.z, obj.rotation.w)
+	static_obj.scale = obj.scale
+	static_obj.name = "static_%s" % obj.id
+	add_child(static_obj)
+
+
+func _add_dynamic_object(obj: WorldObject) -> void:
+	var dynamic_obj := DynamicObjectNode.new()
+	dynamic_obj.world_object = obj
+	dynamic_obj.position = obj.position
+	dynamic_obj.quaternion = Quaternion(obj.rotation.x, obj.rotation.y, obj.rotation.z, obj.rotation.w)
+	dynamic_obj.scale = obj.scale
+	dynamic_obj.name = "dynamic_%s" % obj.id
+	add_child(dynamic_obj)
+
+
+## Get a world object by its ID.
+func get_object_by_id(object_id: String) -> WorldObject:
+	for obj in world_objects:
+		if obj.id == object_id:
+			return obj
+	return null
+
+
+## Get all static objects in this chunk.
+func get_static_objects() -> Array[WorldObject]:
+	var result: Array[WorldObject] = []
+	for obj in world_objects:
+		if not obj.is_dynamic:
+			result.append(obj)
+	return result
+
+
+## Get all dynamic object templates in this chunk.
+func get_dynamic_templates() -> Array[WorldObject]:
+	var result: Array[WorldObject] = []
+	for obj in world_objects:
+		if obj.is_dynamic:
+			result.append(obj)
+	return result
+
+
+## Mark this chunk as dirty (locally modified).
+func mark_dirty() -> void:
+	is_dirty = true
+
+
+## Clear all objects and tile layers from this chunk.
+func clear() -> void:
+	for child in get_children():
+		if child is TileLayerNode or child is StaticObjectNode or child is DynamicObjectNode:
+			child.queue_free()
+	tile_layers.clear()
+	world_objects.clear()
+
+
+## Get the world-space position of a tile within this chunk.
+func get_tile_world_position(tile_x: int, tile_y: int, tile_z: int = 0) -> Vector3:
+	return bounds.position + Vector3(
+		tile_x * 1.0,  # Tile size is 1 world unit
+		tile_y * 1.0,
+		tile_z * 1.0
+	)
+
+
+## Check if a world-space position is within this chunk's bounds.
+func contains_position(pos: Vector3) -> bool:
+	return bounds.has_point(pos)
+
+
+## Check if a chunk coordinate is adjacent to this chunk.
+func is_adjacent(other_coord: Vector3i) -> bool:
+	var dx: int = abs(coord.x - other_coord.x)
+	var dy: int = abs(coord.y - other_coord.y)
+	var dz: int = abs(coord.z - other_coord.z)
+	return dx <= 1 and dy <= 1 and dz <= 1 and (dx + dy + dz) > 0

scripts/chunk_scene.gd.uid

@@ -0,0 +1 @@
+uid://d4gh4h5iey6xb

scripts/chunk_stream_manager.gd

@@ -0,0 +1,358 @@
+class_name ChunkStreamManager
+extends Node
+## Manages loading and unloading of world chunks based on player position.
+##
+## This is the central orchestrator for the chunk streaming system. It monitors
+## the player's position, determines which chunks should be loaded, requests
+## chunk data from the server, instantiates ChunkScene nodes, and unloads
+## chunks that fall outside the streaming radius.
+##
+## ## Design
+##
+## - **Streaming radius** defines how many chunks around the player are kept
+##   loaded. Chunks beyond this radius are unloaded to save memory and CPU.
+## - **Load priority** ensures chunks closer to the player are loaded first,
+##   preventing visual pop-in at the edge of the view.
+## - **Server communication** uses the RPCs defined in docs/architecture/world.md
+##   (§5.3): `request_chunk`, `chunk_data`, `chunk_invalidated`.
+##
+## ## Usage
+##
+## Add this node to your scene tree and set the `player` reference:
+## ```gdscript
+## var stream_manager: ChunkStreamManager = $ChunkStreamManager
+## stream_manager.player = $Player
+## stream_manager.streaming_radius = 4  # chunks
+## ```
+
+## Number of chunks (radius) to keep loaded around the player.
+## A radius of 2 means a 5x5 grid of chunks centered on the player.
+## Higher values increase memory usage but reduce streaming pop-in.
+@export var streaming_radius: int = 3
+
+## Maximum number of chunks to load per frame. Prevents frame spikes during
+## rapid movement or when entering a new area.
+@export var max_loads_per_frame: int = 4
+
+## Maximum number of chunks to unload per frame.
+@export var max_unloads_per_frame: int = 4
+
+## Distance (in chunks) from the streaming radius edge before a chunk is
+## considered for unloading. Prevents rapid load/unload cycling.
+@export var unload_margin: int = 1
+
+## Emitted when a chunk finishes loading.
+signal chunk_loaded(chunk_coord: Vector3i, chunk_scene: Node)
+
+## Emitted when a chunk is unloaded.
+signal chunk_unloaded(chunk_coord: Vector3i)
+
+## Emitted when a chunk fails to load (e.g., server error).
+signal chunk_load_failed(chunk_coord: Vector3i, error: String)
+
+## Emitted when the player moves far enough to require a streaming update.
+signal streaming_updated
+
+## Reference to the player node. Must be set before the manager starts.
+var player: Node3D = null
+
+## The current player chunk coordinate.
+var _player_chunk_coord: Vector3i = Vector3i.ZERO
+
+## Map of loaded chunk coordinates to their scene nodes.
+var _loaded_chunks: Dictionary = {}
+
+## Queue of chunk coordinates pending load, sorted by distance from player.
+var _load_queue: Array[Vector3i] = []
+
+## Queue of chunk coordinates pending unload.
+var _unload_queue: Array[Vector3i] = []
+
+## Whether streaming is currently active (player is set and in game).
+var is_active: bool = false
+
+## The server RPC interface for chunk data. Set by the networking layer.
+var _server_rpc: Object = null
+
+## Internal: track which chunks are currently being loaded (to avoid duplicates).
+var _loading_in_progress: Dictionary = {}
+
+## Internal: time accumulator for throttled streaming updates.
+var _update_accumulator: float = 0.0
+
+## Internal: interval between streaming updates (seconds).
+const UPDATE_INTERVAL: float = 0.1
+
+
+func _ready() -> void:
+	# Streaming is driven from _process (main thread) so we can safely
+	# manipulate the scene tree. No background thread is used.
+	set_process(true)
+
+
+func _process(delta: float) -> void:
+	if not is_active or player == null:
+		return
+
+	_update_accumulator += delta
+	if _update_accumulator < UPDATE_INTERVAL:
+		return
+	_update_accumulator = 0.0
+
+	_update_streaming()
+	_process_load_queue()
+	_process_unload_queue()
+	streaming_updated.emit()
+
+
+func _update_streaming() -> void:
+	if player == null or not is_inside_tree():
+		return
+
+	var current_coord: Vector3i = Chunk.coord_for_position(player.global_position)
+	if current_coord == _player_chunk_coord:
+		return
+
+	_player_chunk_coord = current_coord
+	_rebuild_queues()
+
+
+func _rebuild_queues() -> void:
+	var target_set: Dictionary = _compute_target_chunks()
+
+	# Determine which chunks need to be loaded
+	var to_load: Array[Vector3i] = []
+	for coord in target_set:
+		if not _loaded_chunks.has(coord) and not _loading_in_progress.has(coord):
+			to_load.append(coord)
+
+	# Sort by distance from player (closest first)
+	to_load.sort_custom(_compare_distance)
+	_load_queue = to_load
+
+	# Determine which chunks need to be unloaded
+	var to_unload: Array[Vector3i] = []
+	for coord in _loaded_chunks:
+		if not target_set.has(coord):
+			to_unload.append(coord)
+
+	to_unload.sort_custom(_compare_distance)
+	_unload_queue = to_unload
+
+
+func _compute_target_chunks() -> Dictionary:
+	"""Compute the set of chunk coordinates that should be loaded."""
+	var target: Dictionary = {}
+	var half: int = streaming_radius
+	for dx in range(-half, half + 1):
+		for dy in range(-half, half + 1):
+			for dz in range(-half, half + 1):
+				var coord: Vector3i = Vector3i(
+					_player_chunk_coord.x + dx,
+					_player_chunk_coord.y + dy,
+					_player_chunk_coord.z + dz
+				)
+				target[coord] = coord
+	return target
+
+
+func _compare_distance(a: Vector3i, b: Vector3i) -> bool:
+	"""Compare chunk coordinates by distance from player chunk."""
+	var dist_a: int = _chunk_distance_squared(_player_chunk_coord, a)
+	var dist_b: int = _chunk_distance_squared(_player_chunk_coord, b)
+	return dist_a < dist_b
+
+
+func _chunk_distance_squared(a: Vector3i, b: Vector3i) -> int:
+	var dx: int = a.x - b.x
+	var dy: int = a.y - b.y
+	var dz: int = a.z - b.z
+	return dx * dx + dy * dy + dz * dz
+
+
+func _process_load_queue() -> void:
+	var count: int = 0
+	while count < max_loads_per_frame and not _load_queue.is_empty():
+		var coord: Vector3i = _load_queue.pop_front()
+		_load_chunk(coord)
+		count += 1
+
+
+func _process_unload_queue() -> void:
+	var count: int = 0
+	while count < max_unloads_per_frame and not _unload_queue.is_empty():
+		var coord: Vector3i = _unload_queue.pop_front()
+		_unload_chunk(coord)
+		count += 1
+
+
+func _load_chunk(coord: Vector3i) -> void:
+	if _loading_in_progress.has(coord):
+		return
+
+	_loading_in_progress[coord] = true
+
+	# Request chunk data from server via RPC
+	if _server_rpc != null and _server_rpc.has_method("request_chunk"):
+		_server_rpc.request_chunk(Chunk.build_key(
+			"", "", coord
+		))
+	else:
+		# Fallback: try to load from local cache or create empty chunk
+		_instantiate_chunk_scene(coord)
+
+
+func _on_chunk_data_received(key: String, binary_data: PackedByteArray) -> void:
+	"""Called by the networking layer when chunk data arrives from server."""
+	var coord: Vector3i = _parse_coord_from_key(key)
+	if coord == null:
+		return
+
+	_loading_in_progress.erase(coord)
+
+	# Decode the binary chunk data
+	var chunk_data: ChunkDataDecoder.ChunkPayload = ChunkDataDecoder.decode_binary(binary_data)
+	if chunk_data == null:
+		chunk_load_failed.emit(coord, "Failed to decode chunk data")
+		return
+
+	# Instantiate the chunk scene with the decoded data
+	_instantiate_chunk_scene_with_data(coord, chunk_data)
+
+
+func _on_chunk_load_error(coord: Vector3i, error_msg: String) -> void:
+	"""Called when the server reports a chunk load error."""
+	_loading_in_progress.erase(coord)
+	chunk_load_failed.emit(coord, error_msg)
+
+
+func _instantiate_chunk_scene(coord: Vector3i) -> void:
+	"""Create an empty chunk scene for the given coordinate."""
+	var chunk_scene: ChunkScene = ChunkScene.new()
+	chunk_scene.coord = coord
+	chunk_scene.key = Chunk.build_key("", "", coord)
+	chunk_scene.bounds = Chunk.compute_bounds(coord)
+	_add_loaded_chunk(coord, chunk_scene)
+
+
+func _instantiate_chunk_scene_with_data(coord: Vector3i, data: ChunkDataDecoder.ChunkPayload) -> void:
+	"""Create a chunk scene populated with server data."""
+	var chunk_scene: ChunkScene = ChunkScene.new()
+	chunk_scene.coord = coord
+	chunk_scene.key = data.key
+	chunk_scene.bounds = data.bounds
+	chunk_scene.format_version = data.format_version
+	chunk_scene.revision = data.revision
+
+	# Add tiles
+	for layer in data.tile_layers:
+		var tile_layer: TileLayer = TileLayer.new()
+		tile_layer.name = layer.name
+		tile_layer.layer_id = layer.layer_id
+		tile_layer.width = layer.width
+		tile_layer.height = layer.height
+		tile_layer.depth = layer.depth
+		tile_layer.palette = layer.palette
+		tile_layer.tiles = layer.tiles
+		chunk_scene.add_tile_layer(tile_layer)
+
+	# Add objects
+	for obj_data in data.objects:
+		var world_obj: WorldObject = WorldObject.new()
+		world_obj.id = obj_data.id
+		world_obj.type = obj_data.type
+		world_obj.asset_id = obj_data.asset_id
+		world_obj.position = obj_data.position
+		world_obj.rotation = obj_data.rotation
+		world_obj.scale = obj_data.scale
+		world_obj.properties = obj_data.properties
+		world_obj.is_dynamic = obj_data.dynamic
+		world_obj.flags = obj_data.flags
+		chunk_scene.add_object(world_obj)
+
+	# Add content flags
+	chunk_scene.content_flags = data.flags
+
+	_add_loaded_chunk(coord, chunk_scene)
+
+
+func _add_loaded_chunk(coord: Vector3i, chunk_scene: Node) -> void:
+	_loaded_chunks[coord] = chunk_scene
+	add_child(chunk_scene)
+	_loading_in_progress.erase(coord)
+	chunk_loaded.emit(coord, chunk_scene)
+
+
+func _unload_chunk(coord: Vector3i) -> void:
+	if not _loaded_chunks.has(coord):
+		return
+
+	var chunk_scene: Node = _loaded_chunks[coord]
+	if is_instance_valid(chunk_scene):
+		chunk_scene.queue_free()
+
+	_loaded_chunks.erase(coord)
+	chunk_unloaded.emit(coord)
+
+
+func _on_player_position_changed() -> void:
+	"""Call this when the player position changes significantly."""
+	if player != null:
+		_update_streaming()
+
+
+func set_server_rpc(rpc_interface: Object) -> void:
+	"""Set the server RPC interface for chunk requests."""
+	_server_rpc = rpc_interface
+
+
+func get_loaded_chunk(coord: Vector3i) -> Node:
+	"""Get a loaded chunk scene by coordinate, or null if not loaded."""
+	return _loaded_chunks.get(coord, null)
+
+
+func is_chunk_loaded(coord: Vector3i) -> bool:
+	"""Check if a chunk is currently loaded."""
+	return _loaded_chunks.has(coord)
+
+
+func get_loaded_chunk_count() -> int:
+	"""Get the number of currently loaded chunks."""
+	return _loaded_chunks.size()
+
+
+func get_all_loaded_coords() -> Array[Vector3i]:
+	"""Get all currently loaded chunk coordinates."""
+	var coords: Array[Vector3i] = []
+	for key in _loaded_chunks:
+		coords.append(key)
+	return coords
+
+
+func force_reload_chunk(coord: Vector3i) -> void:
+	"""Force reload a specific chunk (e.g., after server update)."""
+	if _loaded_chunks.has(coord):
+		_unload_chunk(coord)
+	if not _loading_in_progress.has(coord):
+		_load_chunk(coord)
+
+
+func clear_all_chunks() -> void:
+	"""Unload all chunks immediately."""
+	var coords: Array[Vector3i] = get_all_loaded_coords()
+	for coord in coords:
+		_unload_chunk(coord)
+	_load_queue.clear()
+	_unload_queue.clear()
+
+
+func _parse_coord_from_key(key: String) -> Variant:
+	"""Parse chunk coordinate from a canonical chunk key."""
+	var parts: Array[String] = key.split(":")
+	if parts.size() < 5:
+		return null
+	return Vector3i(
+		int(parts[2]),
+		int(parts[3]),
+		int(parts[4])
+	)

scripts/chunk_stream_manager.gd.uid

@@ -0,0 +1 @@
+uid://8yokqwe23c23

scripts/dynamic_object_node.gd

@@ -0,0 +1,68 @@
+class_name DynamicObjectNode
+extends Node3D
+## A visual representation of a dynamic (spawnable) world object template.
+##
+## This node is instantiated by [ChunkScene] for each dynamic [WorldObject].
+## Dynamic objects are stored as *templates* in the chunk; their runtime state
+## (position, health, inventory) is managed by the entity system, not by this
+## node. This node renders the template's visual representation so the object
+## is visible in the world.
+##
+## ## Structure
+##
+## ```
+## DynamicObjectNode (Node3D)
+##  └── MeshInstance3D  # the object's visual mesh
+## ```
+
+## The world object data this node represents.
+var world_object: WorldObject = null
+
+## The loaded mesh instance (or placeholder).
+var _mesh_instance: MeshInstance3D = null
+
+
+func _ready() -> void:
+	if world_object == null:
+		return
+	_load_mesh()
+
+
+## Load and attach the object's mesh.
+func _load_mesh() -> void:
+	_mesh_instance = MeshInstance3D.new()
+	_mesh_instance.name = "mesh"
+
+	var mesh := _load_asset_mesh(world_object.asset_id)
+	if mesh == null:
+		mesh = _make_placeholder_mesh()
+
+	_mesh_instance.mesh = mesh
+	add_child(_mesh_instance)
+
+
+## Attempt to load a mesh from the asset path.
+func _load_asset_mesh(asset_id: String) -> Mesh:
+	if asset_id.is_empty():
+		return null
+	var path := "res://assets/%s" % asset_id
+	if ResourceLoader.exists(path):
+		var res := load(path)
+		if res is Mesh:
+			return res
+	return null
+
+
+## Create a simple placeholder sphere mesh when the real asset is unavailable.
+func _make_placeholder_mesh() -> Mesh:
+	var mesh := SphereMesh.new()
+	mesh.radius = 0.5
+	mesh.height = 1.0
+	return mesh
+
+
+## Get the world object's display name.
+func get_display_name() -> String:
+	if world_object == null:
+		return ""
+	return world_object.get_display_name()

scripts/dynamic_object_node.gd.uid

@@ -0,0 +1 @@
+uid://dyjqcstdnr4u1

scripts/main_menu.gd

@@ -0,0 +1,14 @@
+extends Control
+
+
+func _ready():
+	pass
+
+
+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")
+
+
+func _on_quit_button_pressed():
+	get_tree().quit()

scripts/static_object_node.gd

@@ -0,0 +1,67 @@
+class_name StaticObjectNode
+extends Node3D
+## A visual representation of a static world object within a chunk.
+##
+## This node is instantiated by [ChunkScene] for each static (non-dynamic)
+## [WorldObject]. It renders the object's mesh (referenced by `asset_id`) at
+## the object's transform. If the asset is not yet loaded, a placeholder mesh
+## is shown.
+##
+## ## Structure
+##
+## ```
+## StaticObjectNode (Node3D)
+##  └── MeshInstance3D  # the object's visual mesh
+## ```
+
+## The world object data this node represents.
+var world_object: WorldObject = null
+
+## The loaded mesh instance (or placeholder).
+var _mesh_instance: MeshInstance3D = null
+
+
+func _ready() -> void:
+	if world_object == null:
+		return
+	_load_mesh()
+
+
+## Load and attach the object's mesh.
+func _load_mesh() -> void:
+	_mesh_instance = MeshInstance3D.new()
+	_mesh_instance.name = "mesh"
+
+	# Try to load the asset by its id (path). Fall back to a placeholder.
+	var mesh := _load_asset_mesh(world_object.asset_id)
+	if mesh == null:
+		mesh = _make_placeholder_mesh()
+
+	_mesh_instance.mesh = mesh
+	add_child(_mesh_instance)
+
+
+## Attempt to load a mesh from the asset path.
+func _load_asset_mesh(asset_id: String) -> Mesh:
+	if asset_id.is_empty():
+		return null
+	var path := "res://assets/%s" % asset_id
+	if ResourceLoader.exists(path):
+		var res := load(path)
+		if res is Mesh:
+			return res
+	return null
+
+
+## Create a simple placeholder box mesh when the real asset is unavailable.
+func _make_placeholder_mesh() -> Mesh:
+	var mesh := BoxMesh.new()
+	mesh.size = Vector3(1.0, 1.0, 1.0)
+	return mesh
+
+
+## Get the world object's display name.
+func get_display_name() -> String:
+	if world_object == null:
+		return ""
+	return world_object.get_display_name()

scripts/static_object_node.gd.uid

@@ -0,0 +1 @@
+uid://chf6mruev1kc4

scripts/tile_def.gd

@@ -0,0 +1,42 @@
+class_name TileDef
+extends RefCounted
+## A single tile definition (palette entry) within a tile layer.
+##
+## Maps a tile ID to its asset reference and gameplay flags. See
+## docs/architecture/world.md §3.2.
+
+## Tile ID (index into the layer palette). 0 is reserved for empty/air.
+var id: int = 0
+
+## Reference to the tile/terrain asset.
+var asset_id: String = ""
+
+## Whether this tile has collision.
+var solid: bool = false
+
+## Bitmask flags: bit 0 = walkable, bit 1 = climbable, bit 2 = liquid.
+var flags: int = 0
+
+## Number of visual variants for this tile.
+var variants: int = 1
+
+
+func _init(p_id: int = 0, p_asset_id: String = "", p_solid: bool = false,
+		p_flags: int = 0, p_variants: int = 1) -> void:
+	id = p_id
+	asset_id = p_asset_id
+	solid = p_solid
+	flags = p_flags
+	variants = p_variants
+
+
+func is_walkable() -> bool:
+	return (flags & 0x01) != 0
+
+
+func is_climbable() -> bool:
+	return (flags & 0x02) != 0
+
+
+func is_liquid() -> bool:
+	return (flags & 0x04) != 0

scripts/tile_def.gd.uid

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

scripts/tile_layer.gd

@@ -0,0 +1,83 @@
+class_name TileLayer
+extends RefCounted
+## A single tile layer within a chunk.
+##
+## Holds the dense grid of tile IDs, the palette mapping tile IDs to tile
+## definitions, and the layer metadata. This is the runtime representation of
+## the `TileLayer` from the chunk data format (see docs/architecture/world.md
+## §3.2).
+
+## Layer name (e.g. "ground", "walls", "decor").
+var name: String = ""
+
+## Numeric layer id, unique within the chunk.
+var layer_id: int = 0
+
+## Grid dimensions in tiles.
+var width: int = 0
+var height: int = 0
+var depth: int = 1
+
+## Palette mapping tile IDs to tile definitions (shared per layer).
+var palette: Array[TileDef] = []
+
+## Dense, row-major tile IDs. Length = width * height * depth.
+var tiles: PackedInt32Array = PackedInt32Array()
+
+
+func _init(
+	p_layer_name: String = "",
+	p_layer_id: int = 0,
+	p_width: int = 0,
+	p_height: int = 0,
+	p_depth: int = 1
+) -> void:
+	name = p_layer_name
+	layer_id = p_layer_id
+	width = p_width
+	height = p_height
+	depth = p_depth
+
+
+## Total number of tiles in this layer.
+func tile_count() -> int:
+	return width * height * depth
+
+
+## Get the tile ID at (x, y, z). Returns 0 (empty) for out-of-bounds.
+func get_tile(x: int, y: int, z: int = 0) -> int:
+	if x < 0 or x >= width or y < 0 or y >= height or z < 0 or z >= depth:
+		return 0
+	var idx := (z * height + y) * width + x
+	if idx < tiles.size():
+		return tiles[idx]
+	return 0
+
+
+## Set the tile ID at (x, y, z). No-op if out of bounds.
+func set_tile(x: int, y: int, z: int, tile_id: int) -> void:
+	if x < 0 or x >= width or y < 0 or y >= height or z < 0 or z >= depth:
+		return
+	var idx := (z * height + y) * width + x
+	if idx < tiles.size():
+		tiles[idx] = tile_id
+
+
+## Get the tile definition for a tile ID, or null if not in the palette.
+func get_tile_def(tile_id: int) -> TileDef:
+	for def in palette:
+		if def.id == tile_id:
+			return def
+	return null
+
+
+## Whether the tile at (x, y, z) is solid (collision).
+func is_solid(x: int, y: int, z: int = 0) -> bool:
+	var def := get_tile_def(get_tile(x, y, z))
+	return def != null and def.solid
+
+
+## Whether the tile at (x, y, z) is walkable.
+func is_walkable(x: int, y: int, z: int = 0) -> bool:
+	var def := get_tile_def(get_tile(x, y, z))
+	return def != null and def.is_walkable()

scripts/tile_layer.gd.uid

@@ -0,0 +1 @@
+uid://came2ygke3ajs

scripts/tile_layer_node.gd

@@ -0,0 +1,112 @@
+class_name TileLayerNode
+extends Node3D
+## A visual representation of a single tile layer within a chunk.
+##
+## This node is instantiated by [ChunkScene] for each tile layer in a chunk.
+## It renders the layer's tiles as instanced meshes (one per tile definition
+## in the palette) using [MultiMeshInstance3D] for efficiency.
+##
+## ## Structure
+##
+## ```
+## TileLayerNode (Node3D)
+##  └── MultiMeshInstance3D  # one per palette entry (tile definition)
+## ```
+
+## The tile layer data this node renders.
+var tile_layer: TileLayer = null
+
+## The chunk coordinate this layer belongs to (for world positioning).
+var chunk_coord: Vector3i = Vector3i.ZERO
+
+## Tile size in world units (each tile is 1x1x1).
+const TILE_SIZE: float = 1.0
+
+## Cache of MultiMeshInstance3D nodes, keyed by tile definition id.
+var _mesh_instances: Dictionary = {}
+
+
+func _ready() -> void:
+	if tile_layer == null:
+		return
+	_build_meshes()
+
+
+## Build the MultiMesh instances for each tile definition in the palette.
+func _build_meshes() -> void:
+	for tile_def in tile_layer.palette:
+		if tile_def.id == 0:
+			continue  # Tile 0 is "empty/air", no mesh needed
+		_create_mesh_for_tile(tile_def)
+
+
+func _create_mesh_for_tile(tile_def: TileDef) -> void:
+	# Count how many cells use this tile definition
+	var count := 0
+	for tile_id in tile_layer.tiles:
+		if tile_id == tile_def.id:
+			count += 1
+
+	if count == 0:
+		return
+
+	var multi_mesh := MultiMesh.new()
+	multi_mesh.transform_format = MultiMesh.TRANSFORM_3D
+	multi_mesh.mesh = _make_unit_cube_mesh()
+	multi_mesh.instance_count = count
+
+	var instance_idx := 0
+	for z in range(tile_layer.depth):
+		for y in range(tile_layer.height):
+			for x in range(tile_layer.width):
+				var tile_id := tile_layer.get_tile(x, y, z)
+				if tile_id != tile_def.id:
+					continue
+				var world_pos := _tile_to_world(x, y, z)
+				var xform := Transform3D(Basis(), world_pos)
+				multi_mesh.set_instance_transform(instance_idx, xform)
+				instance_idx += 1
+
+	var mesh_instance := MultiMeshInstance3D.new()
+	mesh_instance.multimesh = multi_mesh
+	mesh_instance.name = "tiles_%d" % tile_def.id
+	add_child(mesh_instance)
+	_mesh_instances[tile_def.id] = mesh_instance
+
+
+## Convert a tile grid coordinate to a world-space position (center of tile).
+func _tile_to_world(x: int, y: int, z: int) -> Vector3:
+	var origin := Vector3(
+		chunk_coord.x * tile_layer.width,
+		chunk_coord.y * tile_layer.height,
+		chunk_coord.z * tile_layer.depth
+	)
+	return origin + Vector3(
+		x * TILE_SIZE + TILE_SIZE * 0.5,
+		y * TILE_SIZE + TILE_SIZE * 0.5,
+		z * TILE_SIZE + TILE_SIZE * 0.5
+	)
+
+
+## Create a simple unit cube mesh for tile rendering.
+func _make_unit_cube_mesh() -> Mesh:
+	var mesh := BoxMesh.new()
+	mesh.size = Vector3(TILE_SIZE, TILE_SIZE, TILE_SIZE)
+	return mesh
+
+
+## Get the tile definition at a grid position, or null if empty.
+func get_tile_def_at(x: int, y: int, z: int = 0) -> TileDef:
+	if tile_layer == null:
+		return null
+	var tile_id := tile_layer.get_tile(x, y, z)
+	if tile_id == 0:
+		return null
+	return tile_layer.get_tile_def(tile_id)
+
+
+## Clear all rendered meshes.
+func clear() -> void:
+	for child in get_children():
+		child.queue_free()
+	_mesh_instances.clear()

scripts/tile_layer_node.gd.uid

@@ -0,0 +1 @@
+uid://d1x05tq8h43gm

scripts/world_object.gd

@@ -0,0 +1,135 @@
+class_name WorldObject
+extends RefCounted
+## A world object (static or dynamic) within a chunk.
+##
+## This is the runtime representation of a WorldObject from the chunk data
+## format (see docs/architecture/world.md §3.3). It holds the object's
+## identity, transform, properties, and moderation flags.
+
+## Stable object ID, unique within the chunk.
+var id: String = ""
+
+## Object type (e.g. "prop", "interactable", "spawn_point", "door").
+var type: String = ""
+
+## Reference to the object's mesh/glTF asset.
+var asset_id: String = ""
+
+## World-space position.
+var position: Vector3 = Vector3.ZERO
+
+## World-space rotation as a quaternion (x, y, z, w).
+var rotation: Vector4 = Vector4(0, 0, 0, 1)
+
+## World-space scale.
+var scale: Vector3 = Vector3.ONE
+
+## Type-specific key/value properties.
+var properties: Dictionary = {}
+
+## Whether this is a spawnable dynamic entity (true) or static (false).
+var is_dynamic: bool = false
+
+## Per-object content moderation flags.
+var flags: ChunkDataDecoder.ContentFlags = ChunkDataDecoder.ContentFlags.new()
+
+## Whether this object has been modified locally.
+var is_dirty: bool = false
+
+
+func _init(
+	p_id: String = "",
+	p_type: String = "",
+	p_asset_id: String = "",
+	p_position: Vector3 = Vector3.ZERO,
+	p_rotation: Vector4 = Vector4(0, 0, 0, 1),
+	p_scale: Vector3 = Vector3.ONE,
+	p_properties: Dictionary = {},
+	p_dynamic: bool = false,
+	p_flags: ChunkDataDecoder.ContentFlags = null
+) -> void:
+	id = p_id
+	type = p_type
+	asset_id = p_asset_id
+	position = p_position
+	rotation = p_rotation
+	scale = p_scale
+	properties = p_properties
+	is_dynamic = p_dynamic
+	if p_flags != null:
+		flags = p_flags
+
+
+## Get a property value by key.
+func get_property(key: String) -> Variant:
+	return properties.get(key)
+
+
+## Set a property value.
+func set_property(key: String, value: Variant) -> void:
+	properties[key] = value
+	is_dirty = true
+
+
+## Check if this object is walkable (based on properties).
+func is_walkable() -> bool:
+	return properties.get("walkable", true)
+
+
+## Check if this object is climbable (based on properties).
+func is_climbable() -> bool:
+	return properties.get("climbable", false)
+
+
+## Check if this object is interactable.
+func is_interactable() -> bool:
+	return type == "interactable" or properties.get("interactable", false)
+
+
+## Get the object's display name.
+func get_display_name() -> String:
+	return properties.get("display_name", id)
+
+
+## Serialize this object to a dictionary (for networking).
+func to_dict() -> Dictionary:
+	return {
+		"id": id,
+		"type": type,
+		"asset_id": asset_id,
+		"position": [position.x, position.y, position.z],
+		"rotation": [rotation.x, rotation.y, rotation.z, rotation.w],
+		"scale": [scale.x, scale.y, scale.z],
+		"properties": properties,
+		"dynamic": is_dynamic,
+	}
+
+
+## Create a WorldObject from a dictionary (for networking).
+static func from_dict(d: Dictionary) -> WorldObject:
+	var pos := Vector3(
+		d.get("position", [0, 0, 0])[0],
+		d.get("position", [0, 0, 0])[1],
+		d.get("position", [0, 0, 0])[2]
+	)
+	var rot := Vector4(
+		d.get("rotation", [0, 0, 0, 1])[0],
+		d.get("rotation", [0, 0, 0, 1])[1],
+		d.get("rotation", [0, 0, 0, 1])[2],
+		d.get("rotation", [0, 0, 0, 1])[3]
+	)
+	var scl := Vector3(
+		d.get("scale", [1, 1, 1])[0],
+		d.get("scale", [1, 1, 1])[1],
+		d.get("scale", [1, 1, 1])[2]
+	)
+	return WorldObject.new(
+		d.get("id", ""),
+		d.get("type", ""),
+		d.get("asset_id", ""),
+		pos,
+		rot,
+		scl,
+		d.get("properties", {}),
+		d.get("dynamic", false),
+	)

scripts/world_object.gd.uid

@@ -0,0 +1 @@
+uid://cxut2ghbsvobn