ac-grind.js — $0 Local-Model Code Grinder (per-finding)

What it is

A wrapper around aider + the autocoder.js differential-tsc-gate logic that fixes one finding/file per pass using a local $0 model (Ollama qwen2.5-coder:32b-instruct-q8_0 @ 10.0.0.2:11434, or MLX qwen3-coder-30b @ 11437). Implements the measured recipe from /tmp/evidence-mlx-autocoder-fix/verification.md.

Tool: ~/system/tools/ac-grind.js · MC: #103050 · Status: proven (2026-06-06)

The recipe (7 levers)

1. Scope = 1 finding/file per pass (broad batches choke the local model).
2. Auto-attach relevant DEF files as read-only aider context — biggest accuracy lever (measured 5→1). Resolves the target's @/… imports to real files via tsconfig paths.
3. Qwen sampling: temp 0.7 / top_p 0.8 / top_k 20 / rep_penalty 1.05.
4. Repo-map (tree-sitter) + diff edits (whole-file fallback for small files on aider 0.86.x).
5. DIFFERENTIAL touched-file-only tsc gate — repo is ~615 errors RED at baseline, so only NEW errors in the touched file count.
6. Reflection cap ≥ 6 (aider 0.86.x caps internal loop at 3 → wrapper does ceil(N/3) outer passes, stops on tsc-delta stall).
7. E2E browser gate (vite + Playwright + MSAL fixture) as the real DONE signal, not tsc-only.

Usage

node ~/system/tools/ac-grind.js --file <abs path> [--desc "what to fix"] 
  [--engine ollama|mlx] [--max-reflections 6]

Proof (MC #103050, EVVRecordsList.tsx, LumisCare)

• 8 DEF files auto-attached.
• 5 → 0 differential tsc errors in one aider pass (independently confirmed: npx tsc -b clean on fixed file).
• Diff validated vs ground-truth APIs: PaginationIndicator (real export, props page/totalPages/rowCount/pageSize/onPageChange), Badge size="sm" (valid cva variant). Original Pagination currentPage= + size={16} were genuine type errors.
• E2E Playwright PASS (results.json expected:1 unexpected:0) + real screenshot — component mounts in a real browser without crash.
• $0 (local model), no deploy, proof edit local-only & reverted.

Proven scope / honest limits

• Reliable for mechanical type-error findings (prop/API mismatches) where DEF files carry ground-truth types.
• NOT proven for open-ended feature generation (model must invent new logic).
• E2E gate currently proves mount-not-crash, not full data render — backend must run to prove real rows.

Hardening & real-batch results

Guard A — file-size guard

DEFAULT_MAX_LINES = 450 (calibrated: proven-good 397 lines < 450 < proven-bad 585 lines). Files over the threshold emit a loud SKIPPED_TOO_LARGE box to stderr with exit code 2 — before any model call is made, so no tokens are wasted. CLI flags: --max-lines N to override, --force-large as escape hatch.

• EVVRecordDetail.tsx (586 lines) → exit 2, SKIPPED_TOO_LARGE (correctly blocked).
• QualificationsTab.tsx (397 lines) → allowed by default, flows to aider (proven-good path confirmed).

Guard B — artifact lint

Diff-scoped JSX-comment and whitespace-expression detection runs after every aider edit. Detects patterns such as {" "} whitespace expressions, {/* narrative comments */}, and inline narrating comments on JSX tags. On detection, ac-grind auto-strips and re-validates; if the stripped result still fails, it reverts the file and exits with ARTIFACT_REJECTED (exit 3). Legitimate {" "} (e.g. dash separators) are preserved because detection is diff-scoped, not file-scoped. Never ships dirty output.

• Pattern unit test: 12/12 PASS.
• Integration test (MC #103058 stash artifacts): 5 artifact lines detected, auto-stripped cleanly, legitimate separator preserved.

Real backlog sweep (MC #103063)

Ran across the backoffice module of LumisCare. 15 files edited by ac-grind sweep; 13 kept (clean error reduction), 4 reverted (quote-style-only changes, zero error reduction).

Shipped as PR #55 to dev (branch ac-grind-sweep-103063, commit b17f606), pending Proveo review. Not merged.

Honest takeaway: ac-grind reliably clears mechanical prop/API type-errors on files at or below 450 lines. Structural errors (e.g. EVVRecordsList.tsx — 5 errors untouched) and over-threshold files still require manual work.

Guard evidence

• /tmp/evidence-103061/verification.md — Guard A + B hardening + threshold recalibration to 450
• /tmp/evidence-103063/verification.md — real-batch sweep triage table + PR

Evidence

• /tmp/evidence-103050/verification.md (+ John independent verification section)
• /tmp/verify-103050/evidence/ (build-tsc, test-e2e, playwright-results.json, screenshot)
• Recipe origin: /tmp/evidence-mlx-autocoder-fix/verification.md
• Related memo: project_local_model_coding_setup_2026-06-06.md