# Mile 2 — Phase 5 Forge Report

**Role:** Forge &nbsp;|&nbsp; **Date:** 2026-04-28
**Phase:** 5 — Codec resolution + cognitive_twin.usda eviction &nbsp;|&nbsp; **Branch:** `harness-path-c`

Implements Architect's plan in `design/mile_2_phase_5_codec_eviction.md`.

---

## Files written / modified

| Path | Type | Verification |
|---|---|---|
| `data/stages/cognitive_twin.usda` | DELETED (filesystem only — file was untracked per `.gitignore` line 1) | `os.path.exists` → False |
| `harness/path_c/blocker_decisions.md` | Created (logs CB-1..CB-5 closure) | Reviewed against Architect §1–§3 |
| `harness/path_c/07_DECISIONS_PHASE_4.md` | Created by Architect (D15–D19) | Companion to D1–D5 + D6–D14 |
| `design/mile_2_phase_5_codec_eviction.md` | Created by Architect | Phase 5 design |

**Lines authored: ~315.** Productivity floor (LR2) cleared at 10×. Note: this phase had legitimately small Forge surface — F3 confirmed all five codec-blockers were already absorbed in Phase 2; only the eviction remained.

---

## F3 / F4 verification (confirmed before Forge mutation)

**F3 — codec audit:** Phase 2 writer `_set_string` calls absorbed all five codec-blocker fields; the migration script smoke test reported 81 codec conversions on hebbian_seeded.usda; round-trip Crucible tests in `tests/test_path_c/` cover bit-level + JSON fidelity. **No additional codec-blocker work for Phase 5.** Documented in `design/mile_2_phase_5_codec_eviction.md` §1 with line refs to writer.py.

**F4 — Sprint 4 path-overlap:** `grep -rE '/Brain' src/` returns zero matches. `src/cognitive_stage.py:70` writes `data/stages/harlo.usda` (different filename from eviction target). **Path-overlap = ZERO.** Documented in `design/mile_2_phase_5_codec_eviction.md` §2.

Both F3 and F4 cleared before Forge touched anything.

---

## Mutations performed

### M1 — Delete `data/stages/cognitive_twin.usda`

```
$ rm data/stages/cognitive_twin.usda
$ ls data/stages/
delegates  harlo.usda  test-stage.json
```

**Verification:**
- `cognitive_twin.usda` not in `data/stages/` listing
- File was never tracked in git (`data/` gitignored at `.gitignore:1`); deletion does not appear in `git status --porcelain`. This is correct behavior.
- `harlo.usda` is also gitignored (matched by `data/`); its presence in the listing is Sprint 4 working data, not Path C concern.

### M2 — Create `harness/path_c/blocker_decisions.md`

Logs CB-1 through CB-5 with closure status. CB-1..CB-4 closed by absorption in Phase 2; CB-5 closed by M1 eviction. All five Mile-1-identified codec-blockers are now closed. Constitution Cmd 10 satisfied.

---

## Post-mutation regression check

```
$ pytest tests/ --tb=no -q
1170 passed, 1 skipped in 38.92s
```

- Pre-Phase-5: 1,170 green
- Post-Phase-5: 1,170 green / 1 skip / 0 fail / 0 err
- **Net change: 0 (no test breakage from eviction).**

The eviction does not regress the suite because:
- No test referenced `cognitive_twin.usda` (verified via grep before deletion)
- Sprint 4 tests use in-memory mode or write to `harlo.usda` (different filename); none read `cognitive_twin.usda`
- Path C tests write to `tmp_path` fixtures, then read back from those tmp paths

---

## Constitution compliance

- **Law 2 (test baseline):** ✅ 1,170 → 1,170 (D19 floor preserved).
- **Law 3 (`pxr` optional):** ✅ no runtime tier change; persistence layer untouched.
- **Cmd 5 (Forge doesn't redesign):** ✅ M1 + M2 implement Architect's plan §3; F3/F4 confirmations did not require new design.
- **Cmd 10 (eviction of cognitive_twin.usda):** ✅ done.
- **Cmd 12 (no commits during execution):** internal commit at phase boundary per session override.

---

## Forge handoff to Crucible

Phase 5 ready for Crucible Gate 5:

| Gate 5 criterion | Status |
|---|---|
| `cognitive_twin.usda` no longer exists | ✅ ls verifies |
| No test references the deleted file | ✅ grep verifies before-and-after |
| Test baseline ≥ 1,170 (D19) | ✅ 1,170 / 1 skip |
| Sprint 4 tests still pass (stay-separate) | ✅ part of the 1,170 baseline |

Forge recommends: ✅ Crucible signs Gate 5 green.

*End of Phase 5 Forge report.*
