# M00-QAR-TILE-OWNERSHIP-001 — Waterfall terrain tile ownership

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<!-- OPENWC_INTEGRATION:ACCEPTED:M00-QAR-TILE-OWNERSHIP-001:2306200 -->

## Ownership

- Target: M00
- Program: QAR
- Owner/Agent ID: sindo-main-codex
- Branch: `work/sindo-main-codex/m00-waterfall-tile-ownership`
- Lease expires UTC: 2026-07-13
- Integrator: milestone integrator

## Outcome

Identify the runtime transition that prevents waterfall tile `30_49` from exposing a terrain mesh to the height probe.

## Non-goals

- Changing streaming budgets or terrain behavior.
- Rebuilding caches or modifying extracted assets.
- Adding a production terrain query service.

## Paths

- Exclusive: terrain probe runtime ownership diagnostics
- Shared/hotspots: renderer baseline documentation
- Generated/ignored: local probe reports and caches

## Contracts and data

- Public API/events: additive diagnostic JSON fields
- Schema/format version: terrain report remains schema 1
- Migration/compatibility: additive fields only
- Consumers: M00 fidelity diagnosis

## Dependencies

- Requires: merged terrain-height probe and local cache inventory
- Blocks: waterfall terrain ownership classification
- External state: local extracted/cache data

## Verification

- Commands: isolated waterfall probe, coordination and documentation gates
- Fixtures: checkpoint tile `30_49`
- Fidelity evidence: runtime state correlated with build 12340 waterfall viewpoint
- Performance budget: offline diagnostic

## Documentation deliverables

- Inline public API docs: diagnostic output fields
- Module specification: verification/source map if behavior changes
- Data-flow diagram: update ownership transition if needed
- Sequence/state/dependency diagrams: document observed tile transition
- Source map/status updates: baseline findings

## Simplicity and naming

- Important names introduced: `available`, `queued_index`, `loading`, `state_present`, `mesh_source`
- Simplest considered solution: inspect existing loader registries read-only
- Rejected complexity/abstractions: new tracing framework
- Unavoidable complexity and justification: none
- Measured optimization evidence: not applicable

## Status

- State: ready
- Done: raw/cache inventory, isolated runtime state, mesh AABB/local probe and nearby sampling diagnosis
- Next: integrator review; placement/composition remains the actual paired-camera gap
- Blocked by:

## Handoff

- Commit: branch HEAD
- Results: tile 30_49 ownership and meshes are healthy; exact ray misses a triangle seam/edge, while a 2-unit offset samples terrain at 113.872
- Remaining risks: nearby estimate is diagnostic and must not become a gameplay terrain-query contract
- Documentation updated: `docs/RENDER_BASELINE.md`, `docs/modules/world-renderer.md`