diff --git a/RENDER.md b/RENDER.md
index 722ac41..a3ff8c6 100644
--- a/RENDER.md
+++ b/RENDER.md
@@ -977,6 +977,19 @@ $exe = Join-Path $env:TEMP 'godot-4.6.1-openwc\Godot_v4.6.1-stable_win64.exe'
 - Cache formats, quality profiles and visual rules are unchanged. Asset-backed
   p95/p99 and visual acceptance remain required.
 
+## 2026-07-16 M2 Unique Placement Registry Extraction
+
+- `M2UniquePlacementRegistry` now owns positive ADT `MDDF.uniqueId` reservations
+  across streamed tiles using the existing `uid:<decimal>` keys.
+- Missing/zero/negative IDs remain untracked; duplicates inside one reservation
+  call are suppressed and another tile records one skipped key until owner release.
+- Owner release still lets the loader find eligible waiting tiles and enqueue the
+  existing detail retry path. First ownership remains tile-processing-order based.
+- `StreamingWorldLoader` still owns tile state, retry queues, grouping/build tasks,
+  M2 caches, MultiMesh/Node/Mesh/material/RID creation and all operation budgets.
+- M2/ADT cache formats, transforms, profiles and visible rules are unchanged.
+  Asset-backed cross-boundary p95/p99 and visual acceptance remain required.
+
 ## 2026-07-16 World Environment Snapshot Facade
 
 - `WorldEnvironmentSnapshot` carries one immutable finite time-of-day value,
diff --git a/coordination/claims/M03-RND-M2-UNIQUE-REGISTRY-001.md b/coordination/claims/M03-RND-M2-UNIQUE-REGISTRY-001.md
index f4b4637..94a8ad0 100644
--- a/coordination/claims/M03-RND-M2-UNIQUE-REGISTRY-001.md
+++ b/coordination/claims/M03-RND-M2-UNIQUE-REGISTRY-001.md
@@ -30,6 +30,7 @@ streamer into a scene-free `M2UniquePlacementRegistry`.
   `src/tools/verify_m2_unique_placement_registry.gd`,
   `docs/modules/m2-unique-placement-registry.md`, this claim
 - Shared/hotspots: `src/scenes/streaming/streaming_world_loader.gd`,
+  `src/tools/verify_m2_unique_dedupe.gd`,
   `docs/modules/world-renderer.md`, `docs/modules/README.md`, `RENDER.md`,
   `targets/03-renderer-facade.md`
 - Generated/ignored: `.godot`, native DLL, generated ADT resources, caches and
@@ -77,14 +78,23 @@ streamer into a scene-free `M2UniquePlacementRegistry`.
 
 ## Status
 
-- State: claimed
-- Done: scope, key semantics and ownership published
-- Next: implement registry, migrate loader adapters, tests and docs
+- State: handoff
+- Done: stateful registry, loader adapters, migrated smoke, regressions and docs
+- Next: milestone integrator merge and asset-backed boundary traversal later in M03
 - Blocked by:
 
 ## Handoff
 
-- Commit:
-- Results:
-- Remaining risks:
-- Documentation updated:
+- Commit: `acb3a80` (`refactor(M03): extract M2 unique placement registry`)
+- Results: dedicated contract PASS (`cases=10`, `iterations=100`, `35.688 ms`);
+  historical `uid:11785` smoke PASS; terrain/facade/internal-access/manifest/
+  shutdown/scheduler/streaming/focus/terrain-query/coordinate regressions PASS;
+  internal inventory remains `42`; editor parse and documentation/coordination/
+  diff gates PASS; checkpoint dry-run planned `7/7`
+- Remaining risks: private Azeroth corpus was absent, so the asset-backed ADT
+  placement probe could not open the map and is not counted as passed evidence;
+  first ownership remains processing-order based; M2 grouping/build/tasks/caches/
+  finalization and asset-backed p95/p99 remain pending
+- Documentation updated: `m2-unique-placement-registry.md`, module registry,
+  `world-renderer.md`, `RENDER.md`, inline API documentation and data-flow,
+  lifecycle and sequence diagrams
diff --git a/docs/modules/README.md b/docs/modules/README.md
index 8ca2f83..a6e5903 100644
--- a/docs/modules/README.md
+++ b/docs/modules/README.md
@@ -15,6 +15,7 @@
 | Terrain quality Mesh cache | Implemented extraction | [`terrain-quality-mesh-cache.md`](terrain-quality-mesh-cache.md) |
 | Terrain chunk LOD planner | Implemented extraction | [`terrain-chunk-lod-planner.md`](terrain-chunk-lod-planner.md) |
 | Terrain chunk geometry queue planner | Implemented extraction | [`terrain-chunk-geometry-queue-planner.md`](terrain-chunk-geometry-queue-planner.md) |
+| M2 unique placement registry | Implemented extraction | [`m2-unique-placement-registry.md`](m2-unique-placement-registry.md) |
 | Third-person camera | Implemented | [`third-person-camera.md`](third-person-camera.md) |
 | Character presentation | Implemented boundary / Partial fidelity | [`character-presentation.md`](character-presentation.md) |
 | Renderer | Partial | [`world-renderer.md`](world-renderer.md), [`../../RENDER.md`](../../RENDER.md) |
diff --git a/docs/modules/m2-unique-placement-registry.md b/docs/modules/m2-unique-placement-registry.md
new file mode 100644
index 0000000..f6fd9d4
--- /dev/null
+++ b/docs/modules/m2-unique-placement-registry.md
@@ -0,0 +1,220 @@
+# M2 Unique Placement Registry
+
+## Metadata
+
+| Field | Value |
+|---|---|
+| Status | Implemented extraction |
+| Target/work package | M03 / `M03-RND-M2-UNIQUE-REGISTRY-001` |
+| Owners | Cross-tile positive ADT MDDF unique-ID reservations |
+| Last verified | Worktree `work/sindo-main-codex/m03-m2-unique-registry`, 2026-07-16 |
+| Profiles/capabilities | Existing static M2 placement path; session-memory only |
+
+## Purpose
+
+Ensure a positive ADT `MDDF.uniqueId` has at most one owning streamed tile while
+allowing unkeyed placements through and returning skipped keys for loader-driven
+candidate retry after the owner unloads.
+
+## Non-goals
+
+- Own tile state, retry queues, worker/group/build jobs or detail radius rules.
+- Group placements or create MultiMesh, Mesh, Node, material or RID resources.
+- Validate M2 paths, transforms, animation, materials or build-12340 fidelity.
+- Persist reservations or define a generic identity/ownership framework.
+- Change cache formats, quality profiles or placement visibility.
+
+## Context and boundaries
+
+```mermaid
+flowchart LR
+    ADT[ADT M2 placement dictionaries] --> Loader[StreamingWorldLoader adapter]
+    Loader --> Registry[M2UniquePlacementRegistry]
+    Registry --> Accepted[Filtered placements + owned keys]
+    Registry --> Skipped[Skipped keys]
+    Accepted --> Group[Existing worker grouping/build path]
+    Skipped --> TileState[Loader-owned tile retry state]
+    Unload[Owner tile unload] --> Loader
+    Loader -->|release keys| Registry
+    Loader -->|notify released candidates| Retry[Existing detail sync queue]
+```
+
+Allowed dependencies are scalar/container values from the ADT adapter. Node,
+SceneTree, RenderingServer, ResourceLoader, WorkerThreadPool, gameplay, network,
+editor UI, files and persistent caches are forbidden.
+
+## Public API
+
+| Symbol | Kind | Purpose | Thread/lifetime | Errors |
+|---|---|---|---|---|
+| `reserve(tile_key, m2_placements)` | Command/query | Reserve available positive IDs and return fresh filtered/owned/skipped arrays | Renderer owner thread/session | Invalid non-Dictionary entries are ignored; unkeyed entries pass through |
+| `release(tile_key, unique_keys)` | Command | Release only keys owned by the supplied tile | Renderer owner thread/session | Unknown/non-owner/empty keys are ignored |
+| `clear()` | Lifecycle command | Drop every reservation on world reset/shutdown | Renderer owner thread | Idempotent |
+| `active_count()` | Query | Return current reservation count | Renderer owner thread | No failure state |
+| `diagnostic_snapshot()` | Read model | Return sorted detached key/tile ownership records | Caller-owned result | Exposes no mutable registry reference |
+
+## Inputs and outputs
+
+| Direction | Contract/data | Producer | Consumer | Ownership | Thread/lifetime |
+|---|---|---|---|---|---|
+| Input | Tile key | Streamer tile state | Registry reservation owner | Copied string | Reservation lifetime |
+| Input | Raw M2 placement dictionaries | ADT parser result | Registry | Loader-owned; read only | One reserve call |
+| Input | Claimed key array | Tile state | Registry release | Loader-owned; read only | One release call |
+| Output | Filtered placement array | Registry | M2 grouping task adapter | Fresh shallow array; placement dictionaries remain source values | One request |
+| Output | Owned `uid:<decimal>` keys | Registry | Loader tile state | Fresh strings/array | Until release |
+| Output | Skipped keys | Registry | Loader candidate retry state | Fresh strings/array | Until owner release/retry |
+| Output | Released keys | Registry | Loader candidate notifier | Fresh array in input order | One release |
+| Output | Detached diagnostics/count | Registry | Metrics/tests | Caller-owned scalars/dictionaries | One query |
+
+Only `unique_id > 0` enters the registry. Missing, zero and negative values have
+an empty key and remain untracked, matching the prior loader behavior.
+
+## Data flow
+
+```mermaid
+flowchart TD
+    Reserve[reserve tile + placements] --> Placement[Iterate placement order]
+    Placement --> Dict{Dictionary?}
+    Dict -->|no| Placement
+    Dict -->|yes| Positive{unique_id > 0?}
+    Positive -->|no| Pass[Append untracked placement]
+    Positive -->|yes| Owned{Key already owned?}
+    Owned -->|no| Claim[Set owner and append placement/key]
+    Owned -->|same tile + already in this call| Duplicate[Suppress duplicate]
+    Owned -->|same tile + first in this call| PassOwner[Append placement/key]
+    Owned -->|other tile| Skip[Append skipped key once]
+    Pass --> Placement
+    Claim --> Placement
+    Duplicate --> Placement
+    PassOwner --> Placement
+    Skip --> Placement
+    Release[release tile + keys] --> Owner{Tile is current owner?}
+    Owner -->|yes| Erase[Erase and return key]
+    Owner -->|no| Ignore[Leave reservation unchanged]
+```
+
+## Lifecycle/state
+
+```mermaid
+stateDiagram-v2
+    [*] --> Empty
+    Empty --> Reserved: reserve positive unowned ID
+    Reserved --> Reserved: same-owner reserve / competing skip / non-owner release
+    Reserved --> Empty: owner releases final ID
+    Reserved --> Empty: clear world/reset
+    Empty --> Empty: unkeyed reserve / unknown release / clear
+    Empty --> [*]
+    Reserved --> [*]: owner releases registry after clear
+```
+
+## Main sequence
+
+```mermaid
+sequenceDiagram
+    participant TileA as First streamed tile
+    participant Loader as StreamingWorldLoader
+    participant Registry as M2UniquePlacementRegistry
+    participant TileB as Cross-border candidate tile
+    TileA->>Loader: placements include positive unique ID
+    Loader->>Registry: reserve(tile A, placements)
+    Registry-->>Loader: accepted placement + owned key
+    TileB->>Loader: same placement ID
+    Loader->>Registry: reserve(tile B, placements)
+    Registry-->>Loader: skipped key
+    Loader->>Loader: retain skipped key in tile B state
+    TileA->>Loader: unload/remove details
+    Loader->>Registry: release(tile A, owned keys)
+    Registry-->>Loader: released key
+    Loader->>Loader: enqueue eligible tile B detail retry
+```
+
+## Ownership, threading and resources
+
+- The registry owns one private key-to-owner-string dictionary.
+- The loader owns tile-held owned/skipped arrays, retry discovery, task/build
+  lifecycle and every MultiMesh/Node/Mesh/material/RID side effect.
+- Calls currently occur on the renderer main thread. The registry has no lock and
+  must not be mutated concurrently.
+- Returned arrays and diagnostic dictionaries are fresh; source placement
+  dictionaries are passed through shallowly and must remain read-only.
+
+## Errors, cancellation and recovery
+
+| Failure | Detection | Behavior | Diagnostic | Recovery |
+|---|---|---|---|---|
+| Invalid placement variant | Type guard | Ignore entry | Contract test | Repair parser/adapter input |
+| Missing/non-positive ID | Key rule | Pass placement without ownership | Smoke/contract test | Expected legacy behavior |
+| Cross-tile duplicate | Owner lookup | Skip placement and return key once | Tile skipped-key state | Owner release triggers eligible candidate retry |
+| Non-owner release | Owner comparison | Ignore; preserve owner | Contract test | Release from recorded tile |
+| Reset/shutdown | Loader lifecycle | Clear all reservations | Shutdown regression/count | New world reserves afresh |
+
+There is no asynchronous work or cancellation inside the registry. Loader-owned
+tasks are cancelled independently before/reset around registry clearing.
+
+## Configuration and capabilities
+
+The registry introduces no settings. It applies to all positive IDs in the
+existing static M2 placement path. Detail radius, M2 enablement, build budgets
+and animation allowlists remain loader/profile configuration.
+
+## Persistence, cache and migration
+
+Reservations are runtime-only and are not serialized. M2 `.tscn/.glb`, animation,
+mesh/material refresh and ADT cache versions remain unchanged. No rebuild or
+migration is required.
+
+## Diagnostics and observability
+
+- `active_count()` continues to feed `m2_active_unique_ids` baseline metrics.
+- Detached diagnostics sort by unique key for deterministic inspection and expose
+  only strings/counts.
+- Contract timing covers repeated 256-placement reserve/release cycles. Asset-
+  backed streaming p95/p99 remains milestone acceptance work.
+
+## Verification
+
+- `verify_m2_unique_placement_registry.gd`: invalid/unkeyed handling, within-call
+  duplicate suppression, same-owner repeat, cross-tile skip, owner-checked release,
+  retry, idempotent clear, detached/sorted diagnostics, source boundary and timing.
+- `verify_m2_unique_dedupe.gd`: existing `uid:11785` cross-tile smoke now targets
+  the extracted public contract rather than loader-private methods.
+- Facade, terrain, internal-access, manifest, shutdown, scheduler, streaming and
+  coordinate regressions remain required.
+- Fidelity evidence is dedupe behavior preservation only. No new build-12340
+  visual parity claim is made.
+
+## Extension points
+
+- Expose detached ownership diagnostics through facade metrics only if needed.
+- Extract grouping/build orchestration as separate services with explicit budgets.
+
+## Capability status
+
+| Capability | Status | Evidence | Gap/next step |
+|---|---|---|---|
+| Cross-tile positive-ID ownership | Implemented extraction | Dedicated contract plus legacy smoke | Asset-backed boundary traversal timing pending |
+| Candidate retry and M2 build | Remains in loader | Existing release adapter/source boundary | Broader M2 service extraction required |
+
+## Known gaps and risks
+
+- Placement dictionaries are shallow pass-through values at the ADT boundary.
+- Same-owner reservations across separate calls intentionally pass again; the
+  caller's existing root/task guards prevent duplicate build requests.
+- First owner follows tile processing order, matching prior behavior rather than
+  a canonical geometric owner rule.
+- Group/build/load/animation caches and render finalization remain monolithic.
+
+## Source map
+
+| Path | Responsibility |
+|---|---|
+| `src/render/m2/m2_unique_placement_registry.gd` | Positive-ID keying, ownership, release and diagnostics |
+| `src/scenes/streaming/streaming_world_loader.gd` | Reservation adapters, tile state, candidate retry and M2 rendering |
+| `src/tools/verify_m2_unique_placement_registry.gd` | Contract, lifecycle, source and timing regression |
+| `src/tools/verify_m2_unique_dedupe.gd` | Historical cross-tile smoke fixture |
+
+## Related decisions and references
+
+- [`world-renderer.md`](world-renderer.md)
+- [`../../RENDER.md`](../../RENDER.md)
+- [`../../targets/roadmap/02-rendering-and-graphics.md`](../../targets/roadmap/02-rendering-and-graphics.md)
diff --git a/docs/modules/world-renderer.md b/docs/modules/world-renderer.md
index 975c27d..8f37cf5 100644
--- a/docs/modules/world-renderer.md
+++ b/docs/modules/world-renderer.md
@@ -5,9 +5,9 @@
 | Field | Value |
 |---|---|
 | Status | Partial |
-| Target/work package | M00 baseline; `M01-RND-STREAMING-FOCUS-001`; `M01-QAR-SERVER-SPAWN-RENDERER-001`; M03 facade/planner/scheduler/internal-access/ground/environment/entity packages; M03 terrain cache/LOD/geometry-queue packages |
+| Target/work package | M00 baseline; `M01-RND-STREAMING-FOCUS-001`; `M01-QAR-SERVER-SPAWN-RENDERER-001`; M03 facade/planner/scheduler/internal-access/ground/environment/entity packages; M03 terrain packages; `M03-RND-M2-UNIQUE-REGISTRY-001` |
 | Owners | Renderer workstream / milestone integrator |
-| Last verified | Worktree `work/sindo-main-codex/m03-terrain-chunk-queue`, 2026-07-16 |
+| Last verified | Worktree `work/sindo-main-codex/m03-m2-unique-registry`, 2026-07-16 |
 | Profiles/capabilities | `Performance`, `Balanced`, `High`, `Custom`; Blizzlike fidelity incomplete |
 
 ## Purpose
@@ -46,6 +46,8 @@ flowchart LR
     ChunkLod --> Loader
     Loader --> ChunkQueue[TerrainChunkGeometryQueuePlanner]
     ChunkQueue --> Loader
+    Loader --> M2Registry[M2UniquePlacementRegistry]
+    M2Registry --> Loader
     Native --> Parsed[Parsed tile/model data]
     Parsed --> Loader
     Loader --> Scene[SceneTree nodes]
@@ -112,6 +114,7 @@ from externally reading/writing loader-private queue, task, cache and tile-state
 | `TerrainQualityMeshCache.store/restore/clear` | Internal terrain service | Owns admitted full-quality revisit Mesh references and LRU | Renderer thread/map session | Rejected/missed entry leaves loader fallback unchanged |
 | `TerrainChunkLodPlanner.plan` | Internal pure terrain query | Maps populated parsed chunk indices to desired LOD 0/1/2 | Synchronous per target refresh | Invalid/disabled input returns empty for existing tile-LOD fallback |
 | `TerrainChunkGeometryQueuePlanner.plan` | Internal pure terrain query | Produces chunk create/remove requests from current and desired state | Synchronous per queue rebuild | Invalid focus returns empty arrays |
+| `M2UniquePlacementRegistry.reserve/release/clear` | Internal M2 service | Owns positive cross-tile ADT placement-ID reservations | Renderer thread/map session | Invalid/unkeyed/non-owner inputs preserve documented fallback |
 
 Публичным contract не считаются `StreamingWorldLoader` methods/properties,
 внутренние dictionaries, queues, job records и generated node names. Scene-owned
@@ -136,6 +139,7 @@ loader configuration remains transitional composition data, not a caller API.
 | Internal cache | Full-quality terrain Mesh/source | Loader terrain upgrade / `TerrainQualityMeshCache` | Revisited tile state | Cache-retained Mesh reference | Map session until eviction/reset |
 | Internal plan | Parsed chunks, typed focus and immutable chunk-LOD policy | Loader / `TerrainChunkLodPlanner` | Loader desired state | Fresh dictionary; no retained resources | One target refresh |
 | Internal plan | Current/desired chunk state and typed focus | Loader / `TerrainChunkGeometryQueuePlanner` | Loader chunk queues | Fresh request arrays; no retained resources | One queue rebuild |
+| Internal registry | Tile key and M2 placement unique IDs | Loader / `M2UniquePlacementRegistry` | Filtered grouping input and tile retry state | Registry-owned strings; fresh result arrays | Map session |
 | Output | Desired tile/detail operations | Streamer plan application | Finalize queues | Loader-owned | Cross-frame |
 | Output | Terrain/M2/WMO/liquid instances | Loader/builders | Godot world/renderer | Loader/world owner | Main-thread attach |
 | Output | Detached renderer metrics | `WorldRenderFacade` | Capture/baseline tools | Caller-owned deep copy | On demand |
@@ -179,6 +183,8 @@ flowchart TD
     ChunkLod --> DesiredChunkLod[Desired chunk LOD state]
     DesiredChunkLod --> ChunkQueue[TerrainChunkGeometryQueuePlanner]
     ChunkQueue --> B
+    R --> M2Registry[M2UniquePlacementRegistry reserve]
+    M2Registry --> M2
     R --> B[RenderBudgetScheduler permits]
     B --> Terrain[Terrain attach/upgrade]
     B --> M2[M2 group/MultiMesh attach]
@@ -290,6 +296,9 @@ sequenceDiagram
 - `TerrainChunkGeometryQueuePlanner` is stateless and owns only call-local
   create/remove request calculation and sorting. The loader adopts the fresh
   arrays and retains removal-first drains, budgets and render side effects.
+- `M2UniquePlacementRegistry` owns only positive unique-key to tile-key strings.
+  The loader retains owned/skipped tile arrays, candidate retry, grouping/build
+  tasks, caches and all MultiMesh/Node/Mesh/material/RID side effects.
 - Rendered-ground query results and diagnostic snapshots are caller-owned values;
   the facade never returns Mesh, Node, tile-state or queue references.
 - Loaded-mesh ground sampling is renderer diagnostics, not authoritative gameplay
@@ -372,6 +381,9 @@ Exact exported settings and cache versions remain documented in [`../../RENDER.m
 - Terrain chunk geometry queue contract: current/desired comparison, tile-LOD
   takeover, sparse origin fallback, stable removals, nearest creates, loader
   drain boundary and bounded multi-tile timing without a world scene.
+- M2 unique placement contract: unkeyed pass-through, within-call/cross-tile
+  dedupe, owner release/retry, clear, detached diagnostics, loader boundary and
+  bounded reserve/release timing without a world scene.
 - Budget scheduler contract: exact lane exhaustion, shared chunk removal/create
   priority, independent lanes, frame reset, invalid limits, terminal cancellation,
   dependency boundaries and bounded permit timing without loading a world scene.
@@ -401,6 +413,7 @@ Exact exported settings and cache versions remain documented in [`../../RENDER.m
 |---|---|---|---|
 | ADT streaming/terrain | Partial | M00 checkpoints and current scenes | Fidelity/performance gaps remain |
 | Static M2 placement | Partial | MultiMesh/dedupe probes | Full materials/animation/effects |
+| M2 unique placement registry | Implemented extraction | Scene-free ownership/lifecycle/timing contract and historical `uid:11785` smoke | Group/build/tasks/finalization and asset-backed p95/p99 remain pending |
 | WMO rendering | Partial | Cached group rendering | Portals/rooms/material parity |
 | Liquids | Partial | MH2O/MLIQ paths | LiquidType/depth/shore fidelity |
 | Sky/light | Partial | DBC controller/logs | Zone transition paired validation |
diff --git a/src/render/m2/m2_unique_placement_registry.gd b/src/render/m2/m2_unique_placement_registry.gd
new file mode 100644
index 0000000..9b81d47
--- /dev/null
+++ b/src/render/m2/m2_unique_placement_registry.gd
@@ -0,0 +1,88 @@
+class_name M2UniquePlacementRegistry
+extends RefCounted
+
+## Session-memory ownership registry for positive ADT MDDF unique IDs.
+
+var _owner_tile_by_unique_key: Dictionary = {}
+
+
+## Reserves unowned positive unique IDs for one tile and returns fresh arrays.
+## Unkeyed placements pass through without entering registry ownership.
+func reserve(tile_key: String, m2_placements: Array) -> Dictionary:
+	var filtered_placements: Array = []
+	var unique_keys: Array = []
+	var skipped_unique_keys: Array = []
+	for placement_variant in m2_placements:
+		if not (placement_variant is Dictionary):
+			continue
+		var placement: Dictionary = placement_variant
+		var unique_key := _unique_key_for_placement(placement)
+		if unique_key.is_empty():
+			filtered_placements.append(placement)
+			continue
+		if _owner_tile_by_unique_key.has(unique_key):
+			var owner_tile := String(_owner_tile_by_unique_key[unique_key])
+			if owner_tile == tile_key and unique_keys.has(unique_key):
+				continue
+			if owner_tile != tile_key:
+				if not skipped_unique_keys.has(unique_key):
+					skipped_unique_keys.append(unique_key)
+				continue
+		_owner_tile_by_unique_key[unique_key] = tile_key
+		if not unique_keys.has(unique_key):
+			unique_keys.append(unique_key)
+		filtered_placements.append(placement)
+	return {
+		"placements": filtered_placements,
+		"unique_keys": unique_keys,
+		"skipped_unique_keys": skipped_unique_keys,
+	}
+
+
+## Releases only keys currently owned by the supplied tile and returns them in
+## input order so the loader can notify waiting candidate tiles.
+func release(tile_key: String, unique_keys: Array) -> Array:
+	var released_unique_keys: Array = []
+	for unique_key_variant in unique_keys:
+		var unique_key := String(unique_key_variant)
+		if unique_key.is_empty() or not _owner_tile_by_unique_key.has(unique_key):
+			continue
+		if String(_owner_tile_by_unique_key[unique_key]) != tile_key:
+			continue
+		_owner_tile_by_unique_key.erase(unique_key)
+		released_unique_keys.append(unique_key)
+	return released_unique_keys
+
+
+## Removes all reservations during world reset or renderer shutdown.
+func clear() -> void:
+	_owner_tile_by_unique_key.clear()
+
+
+## Returns the number of currently owned positive unique IDs.
+func active_count() -> int:
+	return _owner_tile_by_unique_key.size()
+
+
+## Returns detached, key-sorted scalar diagnostics without registry references.
+func diagnostic_snapshot() -> Dictionary:
+	var sorted_unique_keys: Array = _owner_tile_by_unique_key.keys()
+	sorted_unique_keys.sort()
+	var owners: Array = []
+	for unique_key_variant in sorted_unique_keys:
+		var unique_key := String(unique_key_variant)
+		owners.append({
+			"unique_key": unique_key,
+			"tile_key": String(_owner_tile_by_unique_key[unique_key]),
+		})
+	return {
+		"active_count": owners.size(),
+		"owners": owners,
+	}
+
+
+func _unique_key_for_placement(placement: Dictionary) -> String:
+	var unique_id := int(placement.get("unique_id", -1))
+	if unique_id <= 0:
+		return ""
+	return "uid:%d" % unique_id
diff --git a/src/render/m2/m2_unique_placement_registry.gd.uid b/src/render/m2/m2_unique_placement_registry.gd.uid
new file mode 100644
index 0000000..b05280e
--- /dev/null
+++ b/src/render/m2/m2_unique_placement_registry.gd.uid
@@ -0,0 +1 @@
+uid://cqdvx0qnpcte1
diff --git a/src/scenes/streaming/streaming_world_loader.gd b/src/scenes/streaming/streaming_world_loader.gd
index 856d2aa..7e4478f 100644
--- a/src/scenes/streaming/streaming_world_loader.gd
+++ b/src/scenes/streaming/streaming_world_loader.gd
@@ -24,6 +24,9 @@ const TERRAIN_CHUNK_LOD_PLANNER_SCRIPT := preload("res://src/render/terrain/terr
 const TERRAIN_CHUNK_GEOMETRY_QUEUE_PLANNER_SCRIPT := preload(
 	"res://src/render/terrain/terrain_chunk_geometry_queue_planner.gd"
 )
+const M2_UNIQUE_PLACEMENT_REGISTRY_SCRIPT := preload(
+	"res://src/render/m2/m2_unique_placement_registry.gd"
+)
 const STREAMING_TARGET_PLANNER_SCRIPT := preload("res://src/render/streaming/streaming_target_planner.gd")
 const STREAMING_TARGET_POLICY_SCRIPT := preload("res://src/render/streaming/streaming_target_policy.gd")
 const RENDER_BUDGET_SCHEDULER_SCRIPT := preload("res://src/render/streaming/render_budget_scheduler.gd")
@@ -207,7 +210,9 @@ var _m2_group_result_mutex := Mutex.new()
 var _m2_group_result_queue: Array = []
 var _m2_build_jobs: Dictionary = {}
 var _m2_build_queue: Array = []
-var _m2_unique_registry: Dictionary = {}
+var _m2_unique_placement_registry := (
+	M2_UNIQUE_PLACEMENT_REGISTRY_SCRIPT.new()
+)
 var _m2_mesh_cache: Dictionary = {}
 var _m2_mesh_load_requests: Dictionary = {}
 var _m2_mesh_finalize_queue: Array = []
@@ -1011,7 +1016,7 @@ func render_baseline_snapshot() -> Dictionary:
 			"chunk_remove": _chunk_remove_queue.size(),
 		},
 		"cache_entries": _tile_mesh_cache.size(),
-		"m2_active_unique_ids": _m2_unique_registry.size(),
+		"m2_active_unique_ids": _m2_unique_placement_registry.active_count(),
 		"wmo_instances": _wmo_registry.size(),
 	}
 
@@ -2965,7 +2970,7 @@ func _clear_streamed_world() -> void:
 	for key in _m2_build_jobs.keys():
 		_cancel_m2_build_job(String(key))
 	_m2_build_queue.clear()
-	_m2_unique_registry.clear()
+	_m2_unique_placement_registry.clear()
 	_m2_mesh_load_requests.clear()
 	_m2_mesh_finalize_queue.clear()
 	_m2_runtime_rebuild_required_cache.clear()
@@ -4129,7 +4134,10 @@ func _request_tile_m2_assets(
 	if _m2_group_tasks.has(key) or _m2_build_jobs.has(key):
 		return result
 
-	var filtered := _reserve_tile_m2_placements(key, m2_placements)
+	var filtered: Dictionary = _m2_unique_placement_registry.reserve(
+		key,
+		m2_placements
+	)
 	var filtered_placements: Array = filtered.get("placements", [])
 	result["unique_keys"] = filtered.get("unique_keys", [])
 	result["skipped_unique_keys"] = filtered.get("skipped_unique_keys", [])
@@ -4143,46 +4151,6 @@ func _request_tile_m2_assets(
 	return result
 
 
-func _reserve_tile_m2_placements(tile_key: String, m2_placements: Array) -> Dictionary:
-	var filtered_placements: Array = []
-	var unique_keys: Array = []
-	var skipped_unique_keys: Array = []
-	for index in m2_placements.size():
-		var placement_variant = m2_placements[index]
-		if not (placement_variant is Dictionary):
-			continue
-		var placement: Dictionary = placement_variant
-		var unique_key := _m2_unique_key(placement)
-		if unique_key.is_empty():
-			filtered_placements.append(placement)
-			continue
-		if _m2_unique_registry.has(unique_key):
-			var entry: Dictionary = _m2_unique_registry[unique_key]
-			var owner_tile := String(entry.get("tile", ""))
-			if owner_tile == tile_key and unique_keys.has(unique_key):
-				continue
-			if owner_tile != tile_key:
-				if not skipped_unique_keys.has(unique_key):
-					skipped_unique_keys.append(unique_key)
-				continue
-		_m2_unique_registry[unique_key] = {"tile": tile_key}
-		if not unique_keys.has(unique_key):
-			unique_keys.append(unique_key)
-		filtered_placements.append(placement)
-	return {
-		"placements": filtered_placements,
-		"unique_keys": unique_keys,
-		"skipped_unique_keys": skipped_unique_keys,
-	}
-
-
-func _m2_unique_key(placement: Dictionary) -> String:
-	var uid: int = int(placement.get("unique_id", -1))
-	if uid <= 0:
-		return ""
-	return "uid:%d" % uid
-
-
 func _release_tile_m2_unique_keys(state: Dictionary, notify_candidates: bool = true) -> void:
 	var tile_key := String(state.get("key", ""))
 	var unique_keys: Array = state.get("m2_unique_keys", [])
@@ -4191,16 +4159,7 @@ func _release_tile_m2_unique_keys(state: Dictionary, notify_candidates: bool = t
 		state["m2_skipped_unique_keys"] = []
 		return
 
-	var released_keys: Array = []
-	for unique_key_variant in unique_keys:
-		var unique_key := String(unique_key_variant)
-		if unique_key.is_empty() or not _m2_unique_registry.has(unique_key):
-			continue
-		var entry: Dictionary = _m2_unique_registry[unique_key]
-		if String(entry.get("tile", "")) != tile_key:
-			continue
-		_m2_unique_registry.erase(unique_key)
-		released_keys.append(unique_key)
+	var released_keys: Array = _m2_unique_placement_registry.release(tile_key, unique_keys)
 
 	state["m2_unique_keys"] = []
 	state["m2_skipped_unique_keys"] = []
diff --git a/src/tools/verify_m2_unique_dedupe.gd b/src/tools/verify_m2_unique_dedupe.gd
index 4aeb07f..39aa28d 100644
--- a/src/tools/verify_m2_unique_dedupe.gd
+++ b/src/tools/verify_m2_unique_dedupe.gd
@@ -1,12 +1,14 @@
 extends SceneTree
 
-const STREAMING_WORLD_LOADER := preload("res://src/scenes/streaming/streaming_world_loader.gd")
+const M2_UNIQUE_PLACEMENT_REGISTRY := preload(
+	"res://src/render/m2/m2_unique_placement_registry.gd"
+)
 
 var _failures := 0
 
 
 func _initialize() -> void:
-	var loader = STREAMING_WORLD_LOADER.new()
+	var registry: RefCounted = M2_UNIQUE_PLACEMENT_REGISTRY.new()
 	var placement := {
 		"name_id": 0,
 		"unique_id": 11785,
@@ -15,30 +17,24 @@ func _initialize() -> void:
 		"scale": 1.0,
 	}
 
-	var first: Dictionary = loader.call("_reserve_tile_m2_placements", "30_49", [placement])
+	var first: Dictionary = registry.call("reserve", "30_49", [placement])
 	_expect((first.get("placements", []) as Array).size() == 1, "first tile should reserve unique M2 placement")
 	_expect((first.get("unique_keys", []) as Array).has("uid:11785"), "first tile should own uid:11785")
 	_expect((first.get("skipped_unique_keys", []) as Array).is_empty(), "first tile should not skip uid:11785")
 
-	var duplicate: Dictionary = loader.call("_reserve_tile_m2_placements", "31_49", [placement])
+	var duplicate: Dictionary = registry.call("reserve", "31_49", [placement])
 	_expect((duplicate.get("placements", []) as Array).is_empty(), "second tile should skip duplicate uid:11785")
 	_expect((duplicate.get("skipped_unique_keys", []) as Array).has("uid:11785"), "second tile should remember skipped uid:11785")
 
-	loader.call("_release_tile_m2_unique_keys", {
-		"key": "30_49",
-		"m2_unique_keys": ["uid:11785"],
-		"m2_skipped_unique_keys": [],
-	}, false)
-	var after_release: Dictionary = loader.call("_reserve_tile_m2_placements", "31_49", [placement])
+	registry.call("release", "30_49", ["uid:11785"])
+	var after_release: Dictionary = registry.call("reserve", "31_49", [placement])
 	_expect((after_release.get("placements", []) as Array).size() == 1, "second tile should reserve uid:11785 after owner release")
 	_expect((after_release.get("unique_keys", []) as Array).has("uid:11785"), "second tile should own uid:11785 after release")
 
-	var same_tile_loader = STREAMING_WORLD_LOADER.new()
-	var same_tile_duplicate: Dictionary = same_tile_loader.call("_reserve_tile_m2_placements", "31_49", [placement, placement])
+	var same_tile_registry: RefCounted = M2_UNIQUE_PLACEMENT_REGISTRY.new()
+	var same_tile_duplicate: Dictionary = same_tile_registry.call("reserve", "31_49", [placement, placement])
 	_expect((same_tile_duplicate.get("placements", []) as Array).size() == 1, "same tile should keep only one copy of duplicate uid:11785")
 
-	loader.free()
-	same_tile_loader.free()
 	if _failures > 0:
 		push_error("M2 unique dedupe verification failed: %d issue(s)" % _failures)
 		quit(1)
diff --git a/src/tools/verify_m2_unique_placement_registry.gd b/src/tools/verify_m2_unique_placement_registry.gd
new file mode 100644
index 0000000..738f66f
--- /dev/null
+++ b/src/tools/verify_m2_unique_placement_registry.gd
@@ -0,0 +1,156 @@
+extends SceneTree
+
+## Asset-free ownership, lifecycle, dependency and timing regression for M2 IDs.
+
+const REGISTRY_SCRIPT := preload("res://src/render/m2/m2_unique_placement_registry.gd")
+const LOADER_PATH := "res://src/scenes/streaming/streaming_world_loader.gd"
+
+
+func _initialize() -> void:
+	var failures: Array[String] = []
+	_verify_unkeyed_and_invalid_placements(failures)
+	_verify_same_tile_and_cross_tile_deduplication(failures)
+	_verify_owner_checked_release_and_retry(failures)
+	_verify_clear_and_detached_diagnostics(failures)
+	_verify_loader_boundary(failures)
+	var elapsed_milliseconds := _verify_bounded_timing(failures)
+	if not failures.is_empty():
+		for failure in failures:
+			push_error("M2_UNIQUE_PLACEMENT_REGISTRY: %s" % failure)
+		quit(1)
+		return
+	print(
+		"M2_UNIQUE_PLACEMENT_REGISTRY PASS cases=10 iterations=100 elapsed_ms=%.3f"
+		% elapsed_milliseconds
+	)
+	quit(0)
+
+
+func _verify_unkeyed_and_invalid_placements(failures: Array[String]) -> void:
+	var registry: RefCounted = REGISTRY_SCRIPT.new()
+	var result: Dictionary = registry.call("reserve", "tile-a", [
+		{"unique_id": -1},
+		{"unique_id": 0},
+		{"name_id": 7},
+		"invalid",
+	])
+	_expect_equal((result["placements"] as Array).size(), 3, "unkeyed placements pass", failures)
+	_expect_true((result["unique_keys"] as Array).is_empty(), "unkeyed placements not owned", failures)
+	_expect_equal(int(registry.call("active_count")), 0, "unkeyed active count", failures)
+
+
+func _verify_same_tile_and_cross_tile_deduplication(failures: Array[String]) -> void:
+	var registry: RefCounted = REGISTRY_SCRIPT.new()
+	var placement := {"unique_id": 11785, "name_id": 0}
+	var first: Dictionary = registry.call("reserve", "30_49", [placement, placement])
+	_expect_equal((first["placements"] as Array).size(), 1, "same call duplicate filtered", failures)
+	_expect_string_array((first["unique_keys"] as Array), ["uid:11785"], "first owner key", failures)
+	var same_owner_retry: Dictionary = registry.call("reserve", "30_49", [placement])
+	_expect_equal((same_owner_retry["placements"] as Array).size(), 1, "same owner later call passes", failures)
+	var competing: Dictionary = registry.call("reserve", "31_49", [placement, placement])
+	_expect_true((competing["placements"] as Array).is_empty(), "competing tile filtered", failures)
+	_expect_string_array(
+		competing["skipped_unique_keys"] as Array,
+		["uid:11785"],
+		"competing skip recorded once",
+		failures
+	)
+
+
+func _verify_owner_checked_release_and_retry(failures: Array[String]) -> void:
+	var registry: RefCounted = REGISTRY_SCRIPT.new()
+	var placement := {"unique_id": 44}
+	registry.call("reserve", "owner", [placement])
+	_expect_true(
+		(registry.call("release", "other", ["uid:44"]) as Array).is_empty(),
+		"non-owner release ignored",
+		failures
+	)
+	_expect_equal(int(registry.call("active_count")), 1, "non-owner keeps reservation", failures)
+	var released: Array = registry.call("release", "owner", ["", "uid:44", "uid:44"])
+	_expect_string_array(released, ["uid:44"], "owner release order and dedupe", failures)
+	var retried: Dictionary = registry.call("reserve", "other", [placement])
+	_expect_equal((retried["placements"] as Array).size(), 1, "waiting tile reserves after release", failures)
+
+
+func _verify_clear_and_detached_diagnostics(failures: Array[String]) -> void:
+	var registry: RefCounted = REGISTRY_SCRIPT.new()
+	registry.call("reserve", "tile-b", [{"unique_id": 20}])
+	registry.call("reserve", "tile-a", [{"unique_id": 10}])
+	var snapshot: Dictionary = registry.call("diagnostic_snapshot")
+	var owners: Array = snapshot["owners"]
+	_expect_equal(int(snapshot["active_count"]), 2, "diagnostic count", failures)
+	_expect_string_equal(String(owners[0]["unique_key"]), "uid:10", "diagnostic sorted", failures)
+	owners[0]["tile_key"] = "mutated"
+	var fresh_snapshot: Dictionary = registry.call("diagnostic_snapshot")
+	_expect_string_equal(
+		String((fresh_snapshot["owners"] as Array)[0]["tile_key"]),
+		"tile-a",
+		"diagnostics detached",
+		failures
+	)
+	registry.call("clear")
+	registry.call("clear")
+	_expect_equal(int(registry.call("active_count")), 0, "clear idempotent", failures)
+
+
+func _verify_loader_boundary(failures: Array[String]) -> void:
+	var source := _read_text(LOADER_PATH, failures)
+	_expect_true(source.contains("M2_UNIQUE_PLACEMENT_REGISTRY_SCRIPT.new()"), "loader composes registry", failures)
+	_expect_true(source.contains("_m2_unique_placement_registry.reserve("), "loader delegates reserve", failures)
+	_expect_true(source.contains("_m2_unique_placement_registry.release("), "loader delegates release", failures)
+	_expect_true(source.contains("_m2_unique_placement_registry.clear()"), "loader delegates clear", failures)
+	_expect_true(not source.contains("var _m2_unique_registry"), "loader omits registry dictionary", failures)
+	_expect_true(not source.contains("func _m2_unique_key("), "loader omits key formula", failures)
+
+
+func _verify_bounded_timing(failures: Array[String]) -> float:
+	var placements: Array = []
+	for placement_index in range(256):
+		placements.append({"unique_id": placement_index + 1})
+	var registry: RefCounted = REGISTRY_SCRIPT.new()
+	var started_microseconds := Time.get_ticks_usec()
+	for _iteration in range(100):
+		var reservation: Dictionary = registry.call("reserve", "owner", placements)
+		registry.call("release", "owner", reservation["unique_keys"])
+	var elapsed_milliseconds := float(Time.get_ticks_usec() - started_microseconds) / 1000.0
+	_expect_true(elapsed_milliseconds < 1000.0, "100 reserve/release cycles remain bounded", failures)
+	return elapsed_milliseconds
+
+
+func _read_text(path: String, failures: Array[String]) -> String:
+	var file := FileAccess.open(path, FileAccess.READ)
+	if file == null:
+		failures.append("cannot open %s" % path)
+		return ""
+	return file.get_as_text()
+
+
+func _expect_equal(actual_value: int, expected_value: int, label: String, failures: Array[String]) -> void:
+	if actual_value != expected_value:
+		failures.append("%s expected %d, got %d" % [label, expected_value, actual_value])
+
+
+func _expect_string_equal(
+		actual_value: String,
+		expected_value: String,
+		label: String,
+		failures: Array[String]
+) -> void:
+	if actual_value != expected_value:
+		failures.append("%s expected %s, got %s" % [label, expected_value, actual_value])
+
+
+func _expect_string_array(
+		actual_values: Array,
+		expected_values: Array,
+		label: String,
+		failures: Array[String]
+) -> void:
+	if actual_values != expected_values:
+		failures.append("%s expected %s, got %s" % [label, expected_values, actual_values])
+
+
+func _expect_true(actual_value: bool, label: String, failures: Array[String]) -> void:
+	if not actual_value:
+		failures.append("%s expected true" % label)
diff --git a/src/tools/verify_m2_unique_placement_registry.gd.uid b/src/tools/verify_m2_unique_placement_registry.gd.uid
new file mode 100644
index 0000000..79abead
--- /dev/null
+++ b/src/tools/verify_m2_unique_placement_registry.gd.uid
@@ -0,0 +1 @@
+uid://inw4fft20be0