Check

---
name: check
description: Validate code quality — auto-fix formatting/lint, verify types, run tests. Use when asked to "validate code", "check code", or validate before committing; also lint-only asks ("run linter", "fix lint errors"). Don't use for committing, pushing, or writing new tests.
argument-hint: '[--check]'
---

# Check

Run the project's own quality gates — format/lint fix, type check, tests — whatever this project defines. Detect the toolchain; never assume npm. Lint-only ask → steps 1–3, skip tests. `--check` or check-only wording ("check lint", "run the linter" without "fix") → skip step 2, so no file is written.

## Workflow

1. **Detect the project's commands.** Prefer a task the project already defines over a raw tool call:
   - Node → `package.json` scripts (`lint:fix`/`lint-fix`, `lint`, `typecheck`/`tsc`, `test`)
   - Python → `pyproject.toml` / `tox.ini` / `Makefile` (`ruff --fix`/`black`, `ruff`/`flake8`, `mypy`, `pytest`)
   - Go → `gofmt -w`, `golangci-lint run` / `go vet`, `go build ./...`, `go test ./...`
   - Rust → `cargo fmt`, `cargo clippy`, `cargo check`, `cargo test`
   - else → read the `Makefile` / CI config for the equivalent targets
2. **Format + lint fix** (the fix variant). These rewrite files in place and exit 0 silently — capture what changed right after (`git status --short` / `git diff --stat`) and remember it for the report. The user is about to commit; they need to know their tree was modified.
3. **Lint + types** (check variants).
4. **Tests.**
5. Report: an **Auto-fixed** section listing files the fix step changed (or "nothing auto-fixed"), then overall **PASS** or **FAIL** with `file:line` error references.

## Rules

- Detect the project's commands — never hardcode a package manager
- Auto-fix before reporting errors, unless `--check` — but never modify files silently; always report which files auto-fix changed
- Run fix → check → test sequentially
- If the fix step fails, still run check + tests; report all failures at the end
- Report errors as `file:line` references
- Never commit, stage, or push anything

## Error Handling

- If no recognizable manifest/tasks → ask the user for the validate command, or report and stop
- If a step's command doesn't exist → skip it, note it was skipped
- If all steps missing → report nothing to run, stop
- If tests time out → report and suggest raising the runner's timeout
- If a runner crashes (exit code other than 0 or 1) → report crash output and stop