tdd-repair

Surfaces the **Test-Driven Repair** loop as a ruflo skill. Use when you have a failing test and want the source-under-test fixed automatically, with the test's pass/fail as the verification gate (no LLM-as-judge). ## When to use - Failing CI test from a recent commit — point this at the test file, get a verified fix (or a clear "couldn't repair within budget" receipt). - Local TDD workflow — write the failing test first (`tdd-workflow` skill), then run `tdd-repair` to drive the green. - Regression triage — a previously-green test went red; before opening an issue, spend ~$1 to see if the fix is trivial. ## When NOT to use - **No failing test exists.** Conformant mode (`--no-test-oracle`) is scoped for a follow-up ADR — needs MCTS over repro generation. For now, write a failing test first. - **Architectural changes.** This skill is for tactical "make red green" fixes. Cross-module refactors that incidentally break tests should be done by a human or a swarm. - **Untrusted code.** The headless `claude -p` runs with `--allowedTools Read,Edit,Bash` — no MCP, no network, no arbitrary file writes — but Bash can still touch the filesystem. Don't point this at code you wouldn't `git checkout .` after. ## Algorithm Implementation: [`scripts/tdd-repair/tdd-repair.mjs`](../../scripts/tdd-repair/tdd-repair.mjs). 1. **Pre-flight verify** — run the test command. If it already passes, exit 2 (`test-already-passes`). Repairing a green test is either a no-op or a `--test-command` typo. 2. **Spawn `claude -p`** with a focused prompt: - Failing test file path (read-only intent) - Test command (run only) - Hard constraint: do NOT modify the test - Hard constraint: do NOT add new dependencies 3. **`--allowedTools Read,Edit,Bash`** restricts capability. **`--max-budget-usd`** caps cost per attempt. **`--permission-mode acceptEdits`** auto-accepts file edits within the allowed set. 4. **Re-run the test** to verify. The test's exit code IS the fitness function — no separate sandbox / LLM-as-judge. 5. **If green:** emit `success: true` + per-attempt usage. **If red after `--max-attempts`:** emit `success: false` + receipts. Either way, the workspace is left as `claude -p` modified it (caller can `git diff` to review). ## Output shape ```json { "success": true, "data": { "repaired": true, "attemptsTaken": 1, "mode": "test-driven", "before": { "passed": false, "exitCode": 1 }, "after": { "passed": true, "exitCode": 0, "durationMs": 4321 }, "attempts": [ { "attempt": 1, "claude": { "ok": true, "durationMs": 38421, "usage": { "cost_usd": 0.0234 } }, "verify": { "passed": true } } ], "totalCostUsd": 0.0234, "budgetUsd": 5.0, "budgetExhausted": false, "shape": { "repo": "...", "test": "...", "testCommand": "...", "maxAttempts": 1, "model": "haiku" } } } ``` ## Exit codes | Code | Meaning | |---|---| | 0 | Test green after repair (success) | | 1 | Test still red after `--max-attempts` | | 2 | Config error (test file missing, test already passes, `--no-test-oracle` unsupported, etc.) | | 3 | Claude CLI exited non-zero (infrastructure failure) | | 99 | Reserved for safety tripwire (per ADR-153) | ## Safety posture | Layer | Mechanism | |---|---| | Cost cap | `--max-budget-usd` default $5, divided across `--max-attempts`. Hard ceiling — claude exits when reached. | | Capability cap | `--allowedTools Read,Edit,Bash` — no MCP, no network, no arbitrary writes. | | Scope cap | Prompt forbids modifying the test or adding dependencies. | | Confirmation gate | `--confirm` REQUIRED — without it, returns dry-run plan (mirrors `harness-evolve` / `harness-mint` convention). | | Hard timeout | 15 min total wall-clock; per-attempt budget of `timeoutMs / maxAttempts`. | | Pre-flight | Refuses to run if the test already passes (catches `--test-command` typos). | ## Inspiration Modeled on the **Test-Driven Repair** mode from [agent-harness-generator/packages/darwin-mode](https://github.com/ruvnet/agent-harness-generator/tree/main/packages/darwin-mode) ADR-175. Key design difference: instead of wrapping `metaharness-darwin evolve` (population-based search), we drive a single `claude -p` invocation. Rationale: - The test command IS the fitness function — no need for variant scoring - `claude -p` is already in our stack — no new optional dep - Bounded cost / capability are first-class flags - Resumable via `--session-id` if iteration is needed Conformant mode (no test, write own repro via MCTS) is deferred to a future ADR. ## Example ```bash # Smoke / dry-run (no --confirm yet) node plugins/ruflo-testgen/scripts/tdd-repair/tdd-repair.mjs \ --repo /path/to/myrepo \ --test tests/auth.test.ts \ --test-command "npx vitest run tests/auth.test.ts" # Actually repair (Haiku tier, $5 budget, 1 attempt) node plugins/ruflo-testgen/scripts/tdd-repair/tdd-repair.mjs \ --repo /path/to/myrepo \ --test tests/auth.test.ts \ --test-command "npx vitest run tests/auth.test.ts" \ --confirm # Bigger model + more attempts for harder bugs node plugins/ruflo-testgen/scripts/tdd-repair/tdd-repair.mjs \ --repo . --test tests/regression-2456.test.ts \ --test-command "npm test -- tests/regression-2456.test.ts" \ --model sonnet --max-attempts 3 --budget 15.00 \ --confirm ``` ## Cost ladder | Tier | Model | Per-attempt typical | Use when | |---|---|---:|---| | 1 | Haiku | $0.02 – $0.20 | First try — most "make red green" bugs are tactical | | 2 | Sonnet | $0.30 – $2.00 | Haiku failed, or the bug has multi-file scope | | 3 | Opus | $1.50 – $8.00 | Sonnet failed — architectural reasoning required (rarely worth it for a single failing test) |