Build check

The machine's verdict, not an opinion. Everything here either passes or fails, and a failure is never a judgment call. Run this before the reasoning-based reviews — reviewing code that does not compile wastes effort on a file that is about to change.

Fast, deterministic, and the highest-value-per-token check in the set.

Read .claude/review/CONVENTIONS.md first — §1 for stack detection, §3 for scope (you need it to tell a pre-existing failure from one this change introduced), and §6 for where the report goes. Your report format differs from the other skills' by design: this one reports gates and failures, not severity-ranked findings.

1. Discover the gates — never assume them

Do not run commands from memory or from a template. A guessed command that does not exist wastes a minute and produces a scary error that is not a finding.

Read the project's own definition of its gates, in this order:

1. CLAUDE.md / AGENTS.md — if the commands are written down, use exactly those and skip the rest of this discovery.
2. The manifest's script block — package.json scripts, Makefile targets, pyproject.toml [tool.*] sections, Cargo.toml, composer.json scripts, Taskfile.yml, justfile.
3. CI config — .github/workflows/*.yml, .gitlab-ci.yml, Jenkinsfile. This is the most reliable source there is: it is the exact set of gates the project already enforces on every push, in the order it enforces them.
4. Config files as evidence a tool is configured — a tsconfig.json, an eslint config, .ruff.toml, .golangci.yml, pytest.ini.

Use the project's package manager, detected from its lockfile — pnpm-lock.yaml → pnpm, yarn.lock → yarn, bun.lockb → bun, otherwise npm. Running npm in a pnpm workspace produces failures that belong to you, not the code.

Typical shapes, as a reference for what to look for — not a list to run:

Ecosystem	Types	Lint	Test	Build
Node/TS	tsc --noEmit	eslint . / biome check	vitest run, jest	framework build script
Python	mypy, pyright	ruff check	pytest	python -m build
Go	go vet	golangci-lint run	go test ./...	go build ./...
Rust	—	cargo clippy	cargo test	cargo build --release
JVM	compiler	spotbugs, checkstyle	mvn test	mvn package

2. Run them

From the project root, in order: types → lint → tests → build. Cheapest and most localizing first.

Do not stop at the first failure. Run every gate that can still run and report the complete picture — one root cause often lights up several gates, and the user wants the whole list, not the first symptom.

Rules that keep the result honest:

• A gate the project does not have is not a failure. Report it as not configured and move on. Never invent one, and never run a tool the project has not set up — a first-ever mypy run on an untyped codebase emits hundreds of errors that are noise, not findings.
• If dependencies are not installed, install them with the detected package manager's clean-install command first, and say that you did.
• Allow real time for the build gate. It is usually the slowest and the most valuable, because it catches whole-program errors — bad exports, boundary violations, missing assets — that a typechecker alone will not.
• Run from the project root; do not cd elsewhere mid-command. In a monorepo, run from the affected package's root and say which package.

3. Diagnose, don't paste

A wall of compiler output is not a report. For each distinct failure:

1. Read the file at the reported line. The error message names a symptom; the cause is often a few lines up, or in an imported type.
2. Group by root cause. Twenty errors from one bad type export are one finding, not twenty. Say which errors collapse into it.
3. Distinguish an error introduced by the current change from a pre-existing one — check git diff to see if the line is new. Pre-existing failures on an untouched file are still reported, but flagged as pre-existing so the user knows the change did not cause them.
4. Give the fix, specifically. Not "fix the type error" — name the change.

For any failure that mentions a framework or library API, apply the installed-version rule from .claude/review/CONVENTIONS.md before diagnosing. The fix for an error in the installed version is frequently not the fix you remember from an older one, and a confidently wrong fix here costs more than no fix at all.

4. Report

Short and factual. Write to .claude/reviews/build-check-<stamp>.md and print the path.

# Build check

**Verdict:** PASS | FAIL
**Stack:** <language, framework + version, package manager>

| Gate | Command | Result | Detail |
|------|---------|--------|--------|
| types | `<cmd>` | ✅ PASS | 0 errors |
| lint | `<cmd>` | ❌ FAIL | 3 errors, 1 warning |
| tests | — | — | not configured |
| build | `<cmd>` | ⏭️ NOT RUN | blocked by lint failure |

## Failures

### `<lint cmd>` — 3 errors, all from one cause
- **Where:** `src/components/Gallery.tsx:12`
- **Cause:** <the actual root cause; the rule fires once per usage at lines 12, 19, 24>
- **Fix:** <the specific change>
- **Introduced by:** this change | pre-existing

Rules: any gate failing → FAIL. If you skip a gate because an earlier one blocked it, mark it NOT RUN with the reason — never leave it implied. A gate the project does not have is not configured, which is neither a pass nor a fail.

Record the exact commands you ran. It is what makes the result reproducible, and it lets the user correct your discovery if you picked the wrong ones.

If everything passes, say so in two lines and stop. A green build does not need commentary, and this skill does not offer code opinions — that is code-audit.

5. Fixing

This skill diagnoses. Apply fixes only if the user asks — then re-run the full gate sequence afterward and report the new state, since fixes routinely surface the next error behind the one they cleared.