# CODE_REVIEW: add-loop-runner

Reviewed against SPEC.md R1–R8.

## R1–R8 checklist

| Req | Status | Notes |
|-----|--------|-------|
| R1 entrypoint | ✅ | argparse `--mode` required choices; `cmd_tick` returns `summary` dict, never raises; exits 0 on unknown loop |
| R2 tick flow | ✅ | 11 steps match technical.md §7 precisely |
| R3 daemon | ✅ | `cmd_daemon` loops on `cmd_tick` + `time.sleep`; KeyboardInterrupt = DAEMON_STOPPED; `--max-iterations` honored |
| R4 harness substitution | ✅ | `_substitute` handles 7 tokens; missing tokens left literal; default command matches D8 (opencode) |
| R5 context-floor guard | ✅ | `_context_floor_ok` before any Implement call; halts `human_intervention` on `loop_mode_eligible=False`; best-effort allows tick if vram_detect itself unavailable |
| R6 idempotence | ✅ | state writes only after verdict parse + orchestrator both succeed; pre-step-10 crashes leave `.state.loop` untouched |
| R7 tests | ✅ | 18 tests, 7 classes; all subprocess stubbed |
| R8 out-of-scope | ✅ | audit/backlog/worktree-creation/prompts deferred to tasks 4–7 |

## Edge cases checked

1. **Subprocess failure in `--check-gate`** — `_run_json` returns `None`, `cmd_tick` skips with `gate_subprocess_failed`. No crash. ✅
2. **Subprocess failure in `vram_detect --loop-mode`** — best-effort allows tick (avoids a broken vram_detect tool from halting every loop on a platform where it isn't installed). ✅
3. **Empty verifier stdout** — `parse_verdict` returns `None`; `cmd_tick` halts `verifier_failed` without advancing state. ✅
4. **Fenced JSON verdict** — handled by `_FENCE_RE` regex, tries fenced body before raw text. ✅
5. **Line-commented JSON verdict** — stripped by `_strip_comments`. ✅
6. **Missing `pass` key** — `parse_verdict` requires it; returns `None`. ✅
7. **Score history shorter than window** — no capping until length > window; oldest dropped. ✅
8. **No roles configured in loop.json** — `_role_prompt` returns `None or ""`; harness gets empty prompt-path token. User's config responsibility; runtime refuses on empty cwd (Path resolve) if `_find_project_dir` fails. ✅
9. **Worktree declared but missing** — runner uses `project_root` as cwd and logs nothing (per R8 deferred to task 5). ✅
10. **`KeyboardInterrupt` mid-tick** — bubbles up; no state write happens; next tick starts fresh. ✅
11. **`KeyboardInterrupt` in daemon mode** — `_append_tick_log(DAEMON_STOPPED)` then exit 0. ✅

## Code-quality observations

1. **`_run_json` parses the last stdout line only** — correct for `--check-gate --json` (last-line contract per AGENTS.md), but assumes the harness never emits JSON mid-session. For the harness-substitution roles (Implement/Verify/Orchestrate), the runner captures full stdout (not `_run_json`), so the constraint only applies to `--check-gate` and `vram_detect --loop-mode`. Safe.
2. **Token substitution is string-only** — `{verdict}` gets `json.dumps(verdict)`. Not shell-escaped. The harness command is parsed with `shlex` by opencode's own runner; subprocess.run with list argv means no shell injection. Safe as long as `harness.command` stays list-typed (it does — the cfg loader rejects non-list commands via the `if not command: command = [...default...]` fallback). ✅
3. **No timeout on harness invocations** — explicitly per SPEC ("v1 has no timeout; harness owns its timeout policy"). Fine. Worth revisiting if a loop's harness hangs and the OS unit keeps scheduling — but the scheduler interval provides natural rate-limiting.
4. **`_invoke_harness` passes `cwd=cwd` to `subprocess.run`** — if `cwd` doesn't exist, `subprocess.run` raises `FileNotFoundError`. Caught by the outer `except (OSError, subprocess.SubprocessError)` which emits stderr and returns empty — fine. ✅
5. **`_read_state_loop` swallows `JSONDecodeError`** — returns None. Caller treats as `untracked`. A corrupt `.state.loop` becomes an untracked loop. Acceptable for v1; `--audit` flags untracked. ✅
6. **`_write_state_loop` uses `tmp.replace(f)` atomic write** — same pattern as `status.py`; crash-safe. ✅

## Verdict

APPROVE. Ready for bug_find.