Recovered orphaned WIP before switching to a new task

.gitignore

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+# Godot editor cache / generated files
+.godot/
+
+# Godot export artifacts
+export/
+*.tmp
+
+# OS
+.DS_Store
+Thumbs.db

docs/architecture/world.md

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+# World Chunk Data Format & Persistence Architecture
+
+> **Status:** Proposed
+> **Owner:** Platform team
+> **Related:** Server authority + client prediction, avatar component system, content moderation & age verification, backend auth (JWT)
+
+## 1. Overview
+
+This document specifies the **world chunk data format** and **persistence
+schema** for **agp-game**, a Godot-based multiplayer game built by autonomous
+agents. It defines:
+
+- The **chunk data format** — both a human-readable **JSON** form (for
+  authoring, tooling, and debugging) and a compact **binary** form (for
+  runtime loading and network transfer).
+- The **SQLite schema** that persists world state on the server, including
+  chunk metadata, chunk payloads, and the world/room hierarchy.
+- The **read/write API** that the server and client use to load, save, and
+  stream chunks.
+
+The goal is a **single, versioned chunk contract** that is shared across the
+Godot client, the Python backend, and the persistence layer. A chunk is the
+atomic unit of world geometry, gameplay objects, and persistence — the server
+loads and saves whole chunks, and clients stream the chunks around them.
+
+### 1.1 Design Goals
+
+- **Versioned & forward-compatible:** Every chunk carries a format version so
+  the loader can migrate old data and reject unknown future data gracefully.
+- **Dual representation:** JSON for authoring/debugging, binary for
+  runtime/network. Both encode the *same* logical model so there is exactly one
+  source of truth for the schema.
+- **Server-authoritative persistence:** The server is the only writer to the
+  SQLite store. Clients submit *edits* (deltas) and the server applies and
+  persists them, mirroring the server-authoritative networking model.
+- **Chunk-granular persistence:** Persistence happens at chunk granularity so
+  the server can save a dirty chunk without rewriting the whole world, and can
+  stream only the chunks a client needs.
+- **Deterministic & testable:** The binary format is byte-stable for a given
+  logical payload, enabling checksums, caching, and reproducible tests.
+- **Moderation-aware:** Chunks reference content (assets, scripts) that carry
+  content flags (see `content_moderation.md`); the persistence layer stores the
+  moderation state alongside chunk data so enforcement can happen at load time.
+
+---
+
+## 2. World Model & Chunking
+
+### 2.1 World Hierarchy
+
+The world is organized as a hierarchy that matches the moderation content graph:
+
+```
+World
+ └── Room
+      └── Chunk   (the atomic persistence & streaming unit)
+           ├── Tiles / Terrain
+           ├── Static objects (props, geometry)
+           ├── Dynamic objects (spawnable entities, interactables)
+           └── Metadata (flags, version, timestamps)
+```
+
+- A **World** is the top-level container (a named, versioned space).
+- A **Room** is a bounded region within a world (a level, a building, a zone).
+- A **Chunk** is a fixed-size, axis-aligned region of a room. It is the unit of
+  load, save, and stream.
+
+### 2.2 Chunk Dimensions
+
+Chunks are **fixed-size, axis-aligned boxes** in world space. The default
+dimensions are a configuration constant so they can be tuned per world:
+
+| Constant            | Default | Description                                        |
+|---------------------|---------|----------------------------------------------------|
+| `CHUNK_SIZE_X`      | 32      | Chunk width in world units (tiles).                |
+| `CHUNK_SIZE_Y`      | 32      | Chunk height in world units (tiles).               |
+| `CHUNK_SIZE_Z`      | 1       | Chunk depth (1 = flat 2D world; >1 = volumetric).  |
+| `CHUNK_ORIGIN`      | `(0,0)` | World-space origin of chunk coordinate `(0,0)`.    |
+
+A chunk is identified by its **integer chunk coordinate** `(cx, cy, cz)`,
+computed from a world-space position `p` as:
+
+```
+cx = floor((p.x - CHUNK_ORIGIN.x) / CHUNK_SIZE_X)
+cy = floor((p.y - CHUNK_ORIGIN.y) / CHUNK_SIZE_Y)
+cz = floor((p.z - CHUNK_ORIGIN.z) / CHUNK_SIZE_Z)
+```
+
+The chunk's world-space bounding box is therefore:
+
+```
+min = (CHUNK_ORIGIN.x + cx*CHUNK_SIZE_X, ...)
+max = min + (CHUNK_SIZE_X, CHUNK_SIZE_Y, CHUNK_SIZE_Z)
+```
+
+### 2.3 Chunk Coordinate Key
+
+For storage and lookup, a chunk is addressed by a **canonical string key**:
+
+```
+"{world_id}:{room_id}:{cx}:{cy}:{cz}"
+```
+
+Example: `"w_0001:r_0001:12:-4:0"`. This key is the primary lookup key in the
+SQLite `chunks` table and is used in the read/write API.
+
+---
+
+## 3. Chunk Data Format
+
+### 3.1 Logical Model
+
+Both the JSON and binary encodings serialize the same logical chunk model. The
+logical model is defined here once; the two encodings are projections of it.
+
+```
+Chunk
+ ├── version        : uint   (format version, currently 1)
+ ├── key            : string (canonical chunk key, see §2.3)
+ ├── world_id       : string
+ ├── room_id        : string
+ ├── coord          : { cx, cy, cz }   (int)
+ ├── bounds         : { min_x, min_y, min_z, max_x, max_y, max_z } (float)
+ ├── tiles          : TileLayer[]       (terrain / tile data)
+ ├── objects        : WorldObject[]     (static + dynamic objects)
+ ├── flags          : ContentFlags      (moderation flags, see §3.5)
+ ├── meta           : { created_at, updated_at, revision, author } 
+ └── checksum       : string            (SHA-256 of canonical payload)
+```
+
+### 3.2 Tile Layer
+
+A chunk's terrain is stored as one or more **tile layers**. Each layer is a
+dense grid of tile IDs of size `CHUNK_SIZE_X × CHUNK_SIZE_Y` (× `CHUNK_SIZE_Z`
+for volumetric worlds).
+
+```
+TileLayer
+ ├── name      : string   (e.g. "ground", "walls", "decor")
+ ├── layer_id  : uint
+ ├── width     : uint     (= CHUNK_SIZE_X)
+ ├── height    : uint     (= CHUNK_SIZE_Y)
+ ├── depth     : uint     (= CHUNK_SIZE_Z)
+ ├── tiles     : uint[]   (flattened tile IDs, row-major, length = w*h*d)
+ └── palette   : TileDef[] (tile ID → tile definition, shared per layer)
+```
+
+**Tile encoding:** A tile ID is a `uint16` index into the layer's `palette`.
+`0` is reserved for "empty/air". The palette maps each tile ID to a `TileDef`:
+
+```
+TileDef
+ ├── id       : uint16
+ ├── asset_id : string   (reference to a tile/terrain asset)
+ ├── solid    : bool     (collision)
+ ├── flags    : uint32   (bitmask: walkable, climbable, liquid, ...)
+ └── variants : uint8    (number of visual variants for this tile)
+```
+
+**Rationale for palette + indices:** Storing dense `uint16` indices rather than
+full asset strings per cell keeps the binary payload small (2 bytes/cell) while
+the palette (shared across the layer) carries the rich per-tile metadata.
+
+### 3.3 World Objects
+
+Objects are the non-tile entities in a chunk: static props, interactables,
+spawn points, and dynamic-object templates.
+
+```
+WorldObject
+ ├── id          : string   (stable object id, unique within the chunk)
+ ├── type        : string   (e.g. "prop", "interactable", "spawn_point", "door")
+ ├── asset_id    : string   (reference to the object's mesh/glTF asset)
+ ├── transform   : { pos: [x,y,z], rot: [x,y,z,w], scale: [x,y,z] }
+ ├── properties  : object   (type-specific key/value map, JSON-typed)
+ ├── dynamic     : bool     (true if this is a spawnable dynamic entity)
+ └── flags       : ContentFlags (per-object moderation flags)
+```
+
+**Dynamic objects** are stored as *templates* in the chunk. Their *runtime
+state* (position, health, inventory) is **not** stored in the chunk; it lives
+in the runtime entity store and is persisted separately (see §4.4). This keeps
+chunks stable and diffable — a chunk only changes when its *static* content
+changes.
+
+### 3.4 Content Flags
+
+Each chunk (and each object) carries a **content flag set** that is the
+aggregate of the moderation flags of the assets and scripts it references. This
+mirrors the aggregation rules in `content_moderation.md`:
+
+```
+ContentFlags
+ ├── categories : { violence, sexual, language, substance, gambling, horror, hate, custom }
+ │                (each → severity: none|mild|moderate|severe)
+ ├── mature     : bool   (true if any contributing item is mature)
+ └── sources    : string[] (flag ids that contributed, for audit)
+```
+
+The server computes and persists these flags at write time so that enforcement
+(age gating, content filtering) can happen at load time without re-scanning
+assets.
+
+### 3.5 JSON Encoding
+
+The JSON encoding is the **authoring and debugging** representation. It is
+human-readable, diffable, and used by tools and tests. It is the canonical
+logical model serialized directly.
+
+```json
+{
+  "version": 1,
+  "key": "w_0001:r_0001:12:-4:0",
+  "world_id": "w_0001",
+  "room_id": "r_0001",
+  "coord": { "cx": 12, "cy": -4, "cz": 0 },
+  "bounds": { "min_x": 384.0, "min_y": -128.0, "min_z": 0.0,
+              "max_x": 416.0, "max_y": -96.0,  "max_z": 1.0 },
+  "tiles": [
+    {
+      "name": "ground",
+      "layer_id": 0,
+      "width": 32,
+      "height": 32,
+      "depth": 1,
+      "palette": [
+        { "id": 0, "asset_id": "", "solid": false, "flags": 0, "variants": 1 },
+        { "id": 1, "asset_id": "tiles/grass", "solid": false, "flags": 1, "variants": 4 }
+      ],
+      "tiles": [0, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 1]
+    }
+  ],
+  "objects": [
+    {
+      "id": "obj_0001",
+      "type": "interactable",
+      "asset_id": "props/chest",
+      "transform": { "pos": [400.0, -110.0, 0.0],
+                     "rot": [0.0, 0.0, 0.0, 1.0],
+                     "scale": [1.0, 1.0, 1.0] },
+      "properties": { "loot_table": "chest_basic", "locked": false },
+      "dynamic": false,
+      "flags": { "categories": { "violence": "none" }, "mature": false, "sources": [] }
+    }
+  ],
+  "flags": { "categories": { "violence": "none" }, "mature": false, "sources": [] },
+  "meta": { "created_at": "2026-08-17T00:00:00Z",
+            "updated_at": "2026-08-17T00:00:00Z",
+            "revision": 3,
+            "author": "agent-bot" },
+  "checksum": "9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08"
+}
+```
+
+> **Note on the example checksum:** The value shown above is illustrative only.
+> In practice the `checksum` field is the SHA-256 of the canonical binary
+> payload body (see §3.6.3), not of the JSON text. The value here is a
+> placeholder for documentation purposes.
+
+### 3.6 Binary Encoding
+
+The binary encoding is the **runtime and network** representation. It is compact
+and byte-stable. It uses a simple, explicitly-specified layout (no external
+serialization library) so it can be produced and consumed identically by the
+Godot client (GDScript) and the Python backend.
+
+#### 3.6.1 Header
+
+| Offset | Size | Field        | Type / Encoding                          |
+|--------|------|--------------|------------------------------------------|
+| 0      | 4    | magic        | ASCII `"AGPC"` (0x41 0x47 0x50 0x43)     |
+| 4      | 2    | version      | `uint16` LE (currently `1`)              |
+| 6      | 2    | header_len   | `uint16` LE (bytes of header after this) |
+| 8      | 4    | flags        | `uint32` LE (bitmask, reserved)          |
+| 12     | 4    | payload_len  | `uint32` LE (bytes of payload body)      |
+| 16     | 32   | checksum     | SHA-256 of payload body (hex, 32 bytes)  |
+
+Total header size: **48 bytes**.
+
+#### 3.6.2 Payload Body
+
+The payload body is a sequence of typed sections. Each section has a small
+header:
+
+| Offset | Size | Field      | Type / Encoding            |
+|--------|------|------------|----------------------------|
+| 0      | 1    | section_id | `uint8` (see table below)  |
+| 1      | 4    | section_len| `uint32` LE (bytes of section data) |
+| 5      | ...  | data       | section-specific           |
+
+Section IDs:
+
+| section_id | Section        | Data layout                                                       |
+|------------|----------------|-------------------------------------------------------------------|
+| `0x01`     | metadata       | world_id, room_id (length-prefixed strings), coord (3×int32), bounds (6×float32) |
+| `0x02`     | tile layer     | name, layer_id, dims (3×uint16), palette, dense tile indices      |
+| `0x03`     | object         | one `WorldObject` (repeated; one section per object)              |
+| `0x04`     | content flags  | category severities (8×uint8), mature (uint8), sources (string list) |
+| `0x05`     | meta           | created_at, updated_at (int64 unix), revision (uint32), author (string) |
+
+**String encoding:** length-prefixed UTF-8 — `uint16` LE byte length followed by
+the UTF-8 bytes.
+
+**Tile layer data layout (section `0x02`):**
+
+```
+name        : string
+layer_id    : uint16 LE
+width       : uint16 LE
+height      : uint16 LE
+depth       : uint16 LE
+palette_count : uint16 LE
+palette     : palette_count × TileDef
+tile_count  : uint32 LE
+tiles       : tile_count × uint16 LE   (dense, row-major)
+```
+
+```
+TileDef:
+  id        : uint16 LE
+  asset_id  : string
+  solid     : uint8
+  flags     : uint32 LE
+  variants  : uint8
+```
+
+**Object data layout (section `0x03`):**
+
+```
+id          : string
+type        : string
+asset_id    : string
+pos         : 3 × float32
+rot         : 4 × float32
+scale       : 3 × float32
+dynamic     : uint8
+properties  : JSON string (length-prefixed)
+flags       : ContentFlags (see 0x04 layout)
+```
+
+**Content flags layout (section `0x04`):**
+
+```
+violence, sexual, language, substance, gambling, horror, hate, custom
+            : 8 × uint8   (severity enum: 0=none,1=mild,2=moderate,3=severe)
+mature      : uint8
+source_count: uint16 LE
+sources     : source_count × string
+```
+
+#### 3.6.3 Byte-Stability
+
+For a given logical payload, the binary encoding is **deterministic**:
+
+- All integers are little-endian.
+- All strings are UTF-8, length-prefixed, and never null-terminated.
+- Maps (e.g. `properties`) are serialized as a **canonical JSON string** with
+  keys sorted lexicographically.
+- The `checksum` is the SHA-256 of the payload body bytes.
+
+This guarantees that two encoders produce identical bytes, enabling content
+addressing, caching, and reproducible tests.
+
+---
+
+## 4. SQLite Persistence Schema
+
+The server persists world state in a **SQLite** database. SQLite is chosen for
+its zero-configuration, single-file, transactional, and embedded nature — ideal
+for a server that owns the world store and needs ACID guarantees without a
+separate database process.
+
+### 4.1 Database Layout
+
+The database file is `world.db` (path configurable). It contains the following
+tables:
+
+```
+worlds
+rooms
+chunks
+chunk_objects
+content_flags
+revisions
+```
+
+### 4.2 `worlds`
+
+Top-level world containers.
+
+```sql
+CREATE TABLE worlds (
+    id          TEXT PRIMARY KEY,          -- e.g. 'w_0001'
+    name        TEXT NOT NULL,
+    description TEXT,
+    chunk_size_x INTEGER NOT NULL DEFAULT 32,
+    chunk_size_y INTEGER NOT NULL DEFAULT 32,
+    chunk_size_z INTEGER NOT NULL DEFAULT 1,
+    origin_x    REAL NOT NULL DEFAULT 0,
+    origin_y    REAL NOT NULL DEFAULT 0,
+    origin_z    REAL NOT NULL DEFAULT 0,
+    created_at  TEXT NOT NULL,             -- ISO-8601 UTC
+    updated_at  TEXT NOT NULL
+);
+```
+
+### 4.3 `rooms`
+
+Rooms within a world.
+
+```sql
+CREATE TABLE rooms (
+    id          TEXT PRIMARY KEY,          -- e.g. 'r_0001'
+    world_id    TEXT NOT NULL REFERENCES worlds(id) ON DELETE CASCADE,
+    name        TEXT NOT NULL,
+    bounds_min_x REAL NOT NULL,
+    bounds_min_y REAL NOT NULL,
+    bounds_min_z REAL NOT NULL DEFAULT 0,
+    bounds_max_x REAL NOT NULL,
+    bounds_max_y REAL NOT NULL,
+    bounds_max_z REAL NOT NULL DEFAULT 1,
+    created_at  TEXT NOT NULL,
+    updated_at  TEXT NOT NULL,
+    UNIQUE (world_id, name)
+);
+CREATE INDEX idx_rooms_world ON rooms(world_id);
+```
+
+### 4.4 `chunks`
+
+The core persistence table. One row per chunk. The **payload** is stored as a
+BLOB in the **binary format** (§3.6); the JSON form is derived on demand for
+authoring/debugging and is not stored (to avoid dual-write drift).
+
+```sql
+CREATE TABLE chunks (
+    key         TEXT PRIMARY KEY,          -- canonical key 'world:room:cx:cy:cz'
+    world_id    TEXT NOT NULL REFERENCES worlds(id) ON DELETE CASCADE,
+    room_id     TEXT NOT NULL REFERENCES rooms(id) ON DELETE CASCADE,
+    cx          INTEGER NOT NULL,
+    cy          INTEGER NOT NULL,
+    cz          INTEGER NOT NULL DEFAULT 0,
+    format_version INTEGER NOT NULL DEFAULT 1,
+    payload     BLOB NOT NULL,             -- binary chunk encoding (§3.6)
+    payload_len INTEGER NOT NULL,
+    checksum    TEXT NOT NULL,             -- SHA-256 of payload
+    revision    INTEGER NOT NULL DEFAULT 0,
+    dirty       INTEGER NOT NULL DEFAULT 0, -- 1 = needs flush to disk
+    created_at  TEXT NOT NULL,
+    updated_at  TEXT NOT NULL,
+    UNIQUE (world_id, room_id, cx, cy, cz)
+);
+CREATE INDEX idx_chunks_world_room ON chunks(world_id, room_id);
+CREATE INDEX idx_chunks_coord ON chunks(cx, cy, cz);
+```
+
+**Design notes:**
+
+- The `payload` BLOB is the single source of truth for chunk content. The
+  `checksum` guards against corruption and enables content addressing.
+- `revision` increments on every write; it is used for optimistic concurrency
+  and change detection (see §5.4).
+- `dirty` marks chunks that have been modified in memory but not yet flushed,
+  enabling a write-behind persistence strategy (see §5.5).
+
+### 4.5 `chunk_objects`
+
+A denormalized, queryable index of the objects inside each chunk. This is
+**derived** from the chunk payload and kept in sync by the write path. It exists
+so the server can answer queries like "which chunks contain a door?" without
+parsing every payload BLOB.
+
+```sql
+CREATE TABLE chunk_objects (
+    id          TEXT NOT NULL,             -- object id (unique within chunk)
+    chunk_key   TEXT NOT NULL REFERENCES chunks(key) ON DELETE CASCADE,
+    type        TEXT NOT NULL,             -- 'prop', 'interactable', ...
+    asset_id    TEXT,
+    dynamic     INTEGER NOT NULL DEFAULT 0,
+    pos_x       REAL NOT NULL,
+    pos_y       REAL NOT NULL,
+    pos_z       REAL NOT NULL DEFAULT 0,
+    PRIMARY KEY (chunk_key, id)
+);
+CREATE INDEX idx_chunk_objects_type ON chunk_objects(type);
+CREATE INDEX idx_chunk_objects_asset ON chunk_objects(asset_id);
+```
+
+**Sync mechanism:** `chunk_objects` is maintained **explicitly by the write
+path** — it is not a SQL trigger. Whenever `put_chunk` (or `delete_chunk`)
+commits a chunk, the service layer performs a **delete-and-reinsert** of that
+chunk's object rows in the same transaction: it deletes all rows for
+`chunk_key`, then inserts fresh rows parsed from the new payload. This keeps the
+index transactionally consistent with the payload and avoids the complexity and
+fragility of SQL triggers over a binary BLOB. Because the index is derived, it
+can always be rebuilt from `chunks.payload` if it ever drifts (a `rebuild_index`
+utility is provided for this).
+
+### 4.6 `content_flags`
+
+Persists the aggregated moderation flags per chunk (and optionally per object).
+This lets the server enforce age/content gates at load time without parsing
+payloads.
+
+```sql
+CREATE TABLE content_flags (
+    chunk_key   TEXT NOT NULL REFERENCES chunks(key) ON DELETE CASCADE,
+    object_id   TEXT NOT NULL DEFAULT '',  -- '' = chunk-level flag (sentinel)
+    violence    INTEGER NOT NULL DEFAULT 0,
+    sexual      INTEGER NOT NULL DEFAULT 0,
+    language    INTEGER NOT NULL DEFAULT 0,
+    substance   INTEGER NOT NULL DEFAULT 0,
+    gambling    INTEGER NOT NULL DEFAULT 0,
+    horror      INTEGER NOT NULL DEFAULT 0,
+    hate        INTEGER NOT NULL DEFAULT 0,
+    custom      INTEGER NOT NULL DEFAULT 0,
+    mature      INTEGER NOT NULL DEFAULT 0,
+    sources     TEXT NOT NULL DEFAULT '[]', -- JSON array of flag ids
+    PRIMARY KEY (chunk_key, object_id)
+);
+CREATE INDEX idx_content_flags_mature ON content_flags(mature);
+```
+
+Severity is stored as `0=none, 1=mild, 2=moderate, 3=severe`.
+
+**Chunk-level vs. object-level flags:** Chunk-level flags use the **sentinel
+value `''` (empty string)** in `object_id` rather than `NULL`. This is
+deliberate: in SQLite, `NULL` values in a composite primary key are **not**
+unique-constrained, so two rows with the same `chunk_key` and `object_id = NULL`
+could be inserted accidentally. Using `''` as the sentinel means the composite
+`PRIMARY KEY (chunk_key, object_id)` enforces that there is **exactly one**
+chunk-level flag row per chunk. Object-level flags use the object's actual `id`
+(which is never empty). The application layer treats `object_id = ''` as
+"chunk-level" and any non-empty value as "object-level".
+
+### 4.7 `revisions`
+
+An append-only audit log of chunk writes. Enables rollback, auditing, and
+replication of changes.
+
+```sql
+CREATE TABLE revisions (
+    id          INTEGER PRIMARY KEY AUTOINCREMENT,
+    chunk_key   TEXT NOT NULL,             -- NOT a FK: survives chunk deletion
+    revision    INTEGER NOT NULL,
+    actor       TEXT NOT NULL,             -- user / agent id
+    action      TEXT NOT NULL,             -- 'create' | 'update' | 'delete'
+    checksum    TEXT NOT NULL,             -- SHA-256 of payload
+    payload     BLOB,                      -- full binary payload at this revision
+    created_at  TEXT NOT NULL
+);
+CREATE INDEX idx_revisions_chunk ON revisions(chunk_key);
+```
+
+**Rollback support:** The `payload` BLOB stores the **full binary chunk payload**
+at each revision. This is what makes rollback possible: to restore a chunk to a
+previous revision, the server reads the `payload` of the target revision and
+writes it back to `chunks.payload` (incrementing `revision` and appending a new
+`revisions` row). Without the payload, only the checksum would be available,
+which is insufficient to reconstruct the chunk.
+
+**Audit trail preservation:** `chunk_key` is **not** a foreign key to `chunks`.
+This means deleting a chunk does **not** cascade-delete its revision history —
+the audit trail is preserved even after a chunk is removed. (The `chunk_key`
+string is still stored so the history can be correlated to a chunk that existed
+at that time.) If a chunk is later recreated with the same key, its history is
+still intact.
+
+### 4.8 Schema Versioning & Migrations
+
+The database carries a schema version in a `meta` table:
+
+```sql
+CREATE TABLE meta (
+    key   TEXT PRIMARY KEY,
+    value TEXT NOT NULL
+);
+-- seed: INSERT INTO meta(key, value) VALUES ('schema_version', '1');
+```
+
+Migrations are applied in order at startup. Each migration is a numbered SQL
+script; the server tracks the applied version in `meta` and applies any pending
+migrations transactionally. This keeps the schema forward-compatible as the
+chunk format evolves.
+
+---
+
+## 5. Read/Write API
+
+The API is exposed as a **Python service layer** on the backend (the same
+process that owns the SQLite store) and consumed by the Godot client over the
+network transport (see `networking.md`). The service layer is the **only**
+writer to the database; clients never touch SQLite directly.
+
+### 5.1 Service Interface (Python)
+
+```python
+class WorldStore:
+    """Owns the SQLite connection and chunk read/write operations."""
+
+    def get_chunk(self, key: str) -> Chunk | None: ...
+    def get_chunk_binary(self, key: str) -> bytes | None: ...
+    def put_chunk(self, chunk: Chunk, actor: str) -> Chunk: ...
+    def delete_chunk(self, key: str, actor: str) -> None: ...
+    def list_chunks(self, world_id: str, room_id: str | None = None,
+                    bounds: Bounds | None = None) -> list[str]: ...
+    def get_chunk_flags(self, key: str) -> ContentFlags: ...
+    def flush_dirty(self) -> int: ...
+    def rollback_chunk(self, key: str, revision: int, actor: str) -> Chunk: ...
+    def rebuild_index(self, chunk_key: str | None = None) -> int: ...
+    def migrate(self) -> None: ...
+```
+
+### 5.2 Encoding Helpers
+
+The service layer provides symmetric encode/decode functions shared by the
+client and server:
+
+```python
+def encode_binary(chunk: Chunk) -> bytes: ...
+def decode_binary(data: bytes) -> Chunk: ...
+def encode_json(chunk: Chunk) -> str: ...
+def decode_json(text: str) -> Chunk: ...
+def checksum(payload: bytes) -> str: ...
+```
+
+These are the single implementation of the format spec (§3), so the Godot
+client and Python backend never drift.
+
+### 5.3 Network RPCs
+
+The chunk API is exposed to the client via RPCs (matching the networking
+architecture). All chunk traffic is **reliable** (chunks are discrete,
+must-arrive data).
+
+| RPC                        | Direction | Payload                                   | Notes |
+|----------------------------|-----------|-------------------------------------------|-------|
+| `request_chunk`            | C → S     | `{ key }`                                 | Client asks for a chunk |
+| `chunk_data`               | S → C     | `{ key, binary_payload, checksum }`       | Server streams a chunk |
+| `request_chunk_edit`       | C → S     | `{ key, base_revision, delta }`           | Client submits an edit |
+| `chunk_edit_result`        | S → C     | `{ key, success, new_revision, error? }`  | Acknowledges an edit |
+| `chunk_invalidated`        | S → C     | `{ key, new_revision }`                   | Server pushes a change |
+| `request_chunk_flags`      | C → S     | `{ key }`                                 | Age/content gate check |
+
+### 5.4 Edit & Concurrency Model
+
+- **Read:** Client requests a chunk; server returns the binary payload and its
+  `revision`.
+- **Edit:** Client submits a **delta** against a known `base_revision`. The
+  server applies the delta, increments `revision`, persists, and returns the new
+  revision.
+- **Optimistic concurrency:** If the chunk's current revision differs from the
+  client's `base_revision`, the server rejects the edit with a conflict error
+  and the client re-fetches and re-applies. This prevents lost updates when two
+  clients edit the same chunk.
+- **Deltas:** A delta is a JSON patch (RFC 6902 style) applied to the chunk's
+  logical model. The server validates the patched chunk (schema, bounds,
+  moderation) before persisting.
+
+### 5.5 Write-Behind Persistence
+
+To amortize disk I/O, the server keeps a **dirty set** of chunks modified in
+memory and flushes them to SQLite in batches:
+
+1. `put_chunk` updates the in-memory chunk and marks it `dirty`.
+2. A background flusher periodically calls `flush_dirty()`, which writes all
+   dirty chunks in a single transaction and clears the `dirty` flag.
+3. On graceful shutdown, `flush_dirty()` is called to ensure durability.
+
+This keeps the hot path (in-memory chunk access) fast while guaranteeing
+durability at shutdown and on a configurable interval.
+
+**Recovery after unclean shutdown:** The `dirty` column in the `chunks` table
+exists specifically to support recovery if the process crashes before a flush
+completes. On startup, the server scans for rows where `dirty = 1` and treats
+them as **unflushed in-memory state that was lost** — it re-reads the last
+persisted payload from `chunks.payload` (the last durable state) and clears the
+`dirty` flag. In other words, `dirty = 1` at startup means "the last write was
+not durable; discard the in-memory delta and fall back to the persisted
+payload." This guarantees that the on-disk state is always a consistent,
+previously-committed snapshot, never a partially-written chunk. (The in-memory
+dirty set is authoritative during normal operation; the `dirty` column is only a
+recovery marker.)
+
+### 5.6 Streaming & Caching
+
+- The server streams only the chunks a client needs (those within the client's
+  view radius), using `list_chunks` with a bounds query.
+- Chunks are cached in memory (LRU) keyed by `key`; the cache is invalidated on
+  write.
+- The binary payload is content-addressed by `checksum`, so unchanged chunks can
+  be served from cache without re-reading SQLite.
+
+---
+
+## 6. Format Versioning & Migration
+
+- The chunk format `version` field (currently `1`) is checked on decode. A
+  decoder that encounters a higher version than it supports **rejects** the
+  chunk with a clear error rather than misreading it.
+- The SQLite `schema_version` in `meta` drives database migrations (§4.8).
+- Chunk payloads are migrated **lazily**: when a chunk is read and its
+  `format_version` is older than the current one, the server migrates it to the
+  current version in memory and marks it dirty so it is rewritten on the next
+  flush. This avoids a costly full-world migration at startup.
+
+---
+
+## 7. Security & Integrity
+
+- **Server-authoritative writes:** Only the `WorldStore` writes to SQLite;
+  clients submit deltas that are validated before application.
+- **Checksum verification:** Every chunk payload is checksummed (SHA-256) on
+  write and verified on read. Corruption is detected and the chunk is re-fetched
+  or flagged.
+- **Bounds validation:** Chunk coordinates and object positions are validated
+  against the world's chunk dimensions and room bounds before persistence.
+- **Moderation enforcement:** `content_flags` are checked at load time; mature
+  chunks are gated behind the age-verification flow (see `content_moderation.md`).
+- **Input validation:** All string fields are length-limited and validated
+  against allowed character sets to prevent injection and oversized payloads.
+
+---
+
+## 8. Open Questions / Future Work
+
+- **Volumetric worlds:** The schema and format already support `CHUNK_SIZE_Z >
+  1`, but the tooling and streaming for 3D chunks are not yet specified.
+- **Chunk compression:** For very large worlds, the binary payload could be
+  compressed (e.g. zstd) before storage/transfer. The header reserves a `flags`
+  bitmask for a compression flag.
+- **Multi-server sharding:** If a single SQLite file becomes a bottleneck, the
+  `chunks` table could be sharded by `world_id` across multiple databases. The
+  key design already supports this (world_id is a leading key component).
+- **Delta compression for streaming:** Instead of sending full chunks, the
+  server could send only the delta between revisions to reduce bandwidth for
+  frequently-updated chunks.

identity_check.txt

@@ -1 +0,0 @@
-testing coder-bot identity

project.godot

@@ -0,0 +1,16 @@
+; 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.tscn"
+config/features=PackedStringArray("4.6.2")
+
+[display]
+
+window/size/viewport_width=1280
+window/size/viewport_height=720

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")

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/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

test_out.txt

@@ -0,0 +1,15 @@
+Godot Engine v4.6.2.stable.official.71f334935 - https://godotengine.org
+
+roundtrip bounds.position = (0.0, 0.0, 0.0)  (expected (0.5, 1.5, 2.5))
+roundtrip coord = (0, 0, 0)  (expected (1, 2, 3))
+format_version present? -> <null>
+version field -> 1
+SCRIPT ERROR: Invalid assignment of property or key 'properties' with value of type 'bool' on a base object of type 'RefCounted (WorldObjectData)'.
+          at: _parse_object_section (res://scripts/chunk_data_decoder.gd:407)
+          GDScript backtrace (most recent call first):
+              [0] _parse_object_section (res://scripts/chunk_data_decoder.gd:407)
+              [1] _init (res://test_review.gd:25)
+SCRIPT ERROR: Out of bounds get index '0' (on base: 'Array[WorldObjectData]')
+          at: _init (res://test_review.gd:26)
+          GDScript backtrace (most recent call first):
+              [0] _init (res://test_review.gd:26)

test_review.gd

@@ -0,0 +1,22 @@
+extends SceneTree
+
+func _init() -> void:
+	# 1. float32 encode/decode
+	var b: PackedByteArray = ChunkDataDecoder._write_float32(0.5)
+	print("float32(0.5) bytes = ", b, " (expected 00 00 00 3f)")
+	var decoded_f: float = ChunkDataDecoder._read_float32(PackedByteArray([0x00, 0x00, 0x00, 0x3f]), 0)
+	print("read_float32 of 0x3f000000 = ", decoded_f, " (expected 0.5)")
+
+	# 2. metadata section wrapping: inspect first bytes of encoded payload
+	var payload: ChunkDataDecoder.ChunkPayload = ChunkDataDecoder.ChunkPayload.new()
+	payload.world_id = "w"
+	payload.room_id = "r"
+	payload.coord = Vector3i(1, 2, 3)
+	var meta: PackedByteArray = ChunkDataDecoder._build_metadata_section(payload)
+	print("metadata section first 12 bytes = ", meta.slice(0, 12))
+
+	# 3. properties parse with empty-ish string
+	var props_str := "{}"
+	var val = JSON.parse_string(props_str) or {}
+	print("'JSON.parse_string(props_str) or {{}}' type = ", typeof(val), " value = ", val)
+	quit()