# Plan: metadata_generational_handle_20260624

3 tasks, 3 atomic commits. Same pattern as child 1.

## Phase 1: Behavioral Test (1 task)

- [ ] Task 1.1: Write `tests/test_metadata_generational_handle.py`.
  - WHERE: New file `tests/test_metadata_generational_handle.py`
  - WHAT: 4 tests (per spec FR3)
  - HOW: Use 1-space indentation
  - SAFETY: Test imports `MetadataHandle` and `MetadataHandleRegistry` from their production location
  - COMMIT: `test(metadata): behavioral test for generational handle (MetadataHandle + Registry)`
  - GIT NOTE: 4 tests; will be RED until Phase 2 ships
  - VERIFY: `uv run pytest tests/test_metadata_generational_handle.py -v` shows 4/4 FAIL (expected)

## Phase 2: Implementation (1 task)

- [ ] Task 2.1: Add `MetadataHandle` + `MetadataHandleRegistry` + migrate lifetime-check code.
  - WHERE: `src/aggregate.py` (or another existing module; no new `src/<thing>.py` files)
  - WHAT:
    - Add `@dataclass(frozen=True) class MetadataHandle` with `index: int` and `generation: int`
    - Add `class MetadataHandleRegistry` with `register`, `lookup`, `bump_generation` methods
    - Migrate lifetime-check sites in `src/aggregate.py`, `src/ai_client.py`, and any other production files
  - HOW: Use `manual-slop_py_add_def` for the new types; `manual-slop_edit_file` for the migration sites
  - SAFETY: Verify with `ast.parse`; run the 4 tests + the child-1 tests + the 14 previously-failing tests
  - COMMIT: `feat(metadata): MetadataHandle + Registry + lifetime-check migrations`
  - GIT NOTE: Lifetime checks now go through registry.lookup; generation mismatch returns NIL_METADATA from child 1
  - VERIFY: `uv run pytest tests/test_metadata_generational_handle.py tests/test_metadata_nil_sentinel.py -v` shows all PASS

## Phase 3: Verification + Budget Gate (1 task)

- [ ] Task 3.1: Run all 6 VCs; capture the budget gate measurement.
  - WHERE: All audit gates + test suite + SSDL measurement
  - WHAT:
    - Run VC1-VC6
    - Compute the new effective-codepaths number
    - Compare to post-child-1 measurement; require drop ≥ 20%
    - Write TRACK_COMPLETION report
    - Update state.toml to `status = "completed"`, all 3 phases completed
    - Append to campaign_measurements_20260624.md
    - Update conductor/tracks.md
  - HOW: Same as child 1 phase 3
  - SAFETY: Same as child 1
  - COMMIT: 3 commits (state, TRACK_COMPLETION, tracks.md)
  - GIT NOTE: Per workflow.md
  - VERIFY: All 6 VCs pass; budget gate met; campaign unblocked for child 3

## Commit Log (Expected)

1. `test(metadata): behavioral test for generational handle` (Task 1.1)
2. `feat(metadata): MetadataHandle + Registry + lifetime-check migrations` (Task 2.1)
3. `conductor(state): metadata_generational_handle_20260624 SHIPPED` (Task 3.1)
4. `docs(reports): TRACK_COMPLETION for metadata_generational_handle_20260624` (Task 3.1)
5. `conductor(tracks): add metadata_generational_handle_20260624 row` (Task 3.1)

## Verification Commands

```bash
# VC1: types exist
grep -rn "class MetadataHandle\|class MetadataHandleRegistry" src/

# VC2: production uses handle
grep -rn "registry.lookup\|registry.register" src/

# VC3: tests pass
uv run pytest tests/test_metadata_generational_handle.py -v

# VC4: budget gate
uv run python -c "from src.code_path_audit_ssdl import compute_effective_codepaths; ...; print(compute_effective_codepaths(metadata_profile, 'src'))"

# VC5: full test suite
uv run python scripts/run_tests_batched.py

# VC6: 4 audit gates
uv run python scripts/audit_weak_types.py --strict
uv run python scripts/generate_type_registry.py --check
uv run python scripts/audit_main_thread_imports.py
uv run python scripts/audit_no_models_config_io.py
```