Code Quality

Your AI agent made the tests green. Did it fix the code, or the tests?

A quality gate for coding agents: git hooks and Stop hooks that block test tampering and hold one complexity bar on every changed function. 12 languages, one config file, no server.

The cheap way out, caught

The agent	The gate
Marked the failing test it.skip	tamper/test-skipped tests/queue.test.ts:12
Dropped two assertions	tamper/assertion-weakened tests/queue.test.ts:48
Swapped toEqual for toBeTruthy	tamper/assertion-weakened tests/queue.test.ts:52
Stubbed the module under test	note: tamper/mock-added tests/queue.test.ts:+64
Refreshed the baseline with the code	tamper/baseline-touched baseline.json:1
Shipped 50 lines, 31 covered	cov/diff: 62% (31/50 lines, minimum 80%)

Deterministic. Exit code 1, file and line in the report. No model is asked for an opinion.

How it works

flowchart LR
    A[git hooks] --> Q
    B[Stop hook: Claude, Codex, pi, omp; Grok after global hook install] --> Q
    C[OpenCode idle notice] --> Q
    Q[one script] --> D{new finding on a changed line?}
    D -->|yes| F[GATE FAIL, agent gets one round to fix]
    D -->|no| P[GATE PASS]

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• One bar. Cyclomatic complexity 10, CRAP 30, 80% coverage of added lines, no new cycles, no new dead code, no secrets.
• Old debt does not block. A baseline snapshot keeps existing findings as debt. Only new findings on changed lines fail.
• Seconds, not minutes. check runs in 3-19 s on a real repo. The full gate with tests and coverage is a manual run.
• Any language. Complexity from lizard, coverage from lcov, adapters for TypeScript, Python, Go, Rust, Java, Kotlin, C#, Swift, PHP, Ruby, C/C++, Dart.

Install

Bun is required for the gate and the shell hooks. Install for your agent:

Agent	Install
Claude Code	claude plugin marketplace add smixs/code-quality then claude plugin install code-quality@code-quality
Codex	codex plugin marketplace add smixs/code-quality then codex plugin add code-quality@code-quality; review and trust its hooks with /hooks
Grok 1.0.40	grok plugin install smixs/code-quality --trust, then from this repository or its installed plugin root run bun scripts/quality.ts install-grok-hooks
pi	pi install git:github.com/smixs/code-quality
omp	omp plugin install github:smixs/code-quality
OpenCode V1	bun add github:smixs/code-quality in a project with package.json, then add "plugin": ["file:./node_modules/code-quality"] and "skills": ["./node_modules/code-quality/skills"] to opencode.json
OpenCode V2	Add "plugins": ["github:smixs/code-quality"] to opencode.json
Skill only	npx skills add smixs/code-quality (does not install hooks)

Claude and Codex load Stop and PreToolUse hooks from the plugin. Grok 1.0.40 did not dispatch plugin hooks in a live check (total_hooks=0); install-grok-hooks writes ~/.grok/hooks/code-quality.json with both commands pointing to the current plugin root. Run it again after moving or updating that root; bun scripts/quality.ts uninstall-grok-hooks removes that file. $GROK_HOME overrides the Grok directory. pi and omp load the package extensions. OpenCode blocks the shell tool before a bypass and writes a session message on idle when the gate is red; its idle event cannot force another agent turn. OpenCode V1.18.32 reads the plugin's config.skills value but does not discover the skill from it. Add an explicit "skills": ["./node_modules/code-quality/skills"] entry to opencode.json when using a project Bun installation. In Git repositories with .quality.toml, git commit --no-verify, git commit -n, git push --no-verify, git -c core.hooksPath=... and git config core.hooksPath are blocked by default. Set [hooks] block_bypass = false in .quality.toml to disable this guard.

To enable the plugin for a team repository, commit these project settings:

// .claude/settings.json
{ "extraKnownMarketplaces": { "code-quality": { "source": { "source": "github", "repo": "smixs/code-quality" } } },
  "enabledPlugins": { "code-quality@code-quality": true } }
// .pi/settings.json
{ "packages": ["git:github.com/smixs/code-quality"] }
// opencode.json (V2)
{ "plugins": ["github:smixs/code-quality"] }

For Codex, commit .codex/config.toml:

[plugins."code-quality@code-quality"]
enabled = true

Wire each Git repository with a .quality.toml and a baseline. From the plugin checkout or installed package root:

bun scripts/quality.ts install-hooks <repo>
bun scripts/quality.ts --repo <repo> --update-baseline

install-hooks sets core.hooksPath to ~/.local/share/code-quality/git-hooks/, or $CODE_QUALITY_HOME/git-hooks/. A root pointer follows the latest invoked plugin copy. Existing repository hooks are chained. See configuration.

Jev, optional

Five calibrated yes/no questions about added test hunks (a textual test, an untested error path, a weakened assertion, a mock that hides the change, a tautological property). Notes only: Jev never changes the exit code. Two ways to connect, whichever key you have:

[review]                      # TypeSafe directly, key from console.typesafe.ai/keys
jev = true                    # TYPESAFE_API_KEY in the environment

[review]                      # or through OpenRouter
jev = true                    # OPENROUTER_API_KEY in the environment
jev_provider = "openrouter"

Details, the model pins and the curl for each: Jev reference.

Docs

• Every rule, what blocks and what only notes
• Languages and adapters
• Configure .quality.toml and hooks
• Jev: an optional classifier for test hunks
• SKILL.md, the full reference the agent reads

Credits

CRAP metric by Alberto Savoia and Brian Cunningham. Tamper taxonomy from TRACE (arXiv 2601.20103). Built on lizard, jscpd, ast-grep, gitleaks, osv-scanner, dependency-cruiser, knip, ESLint, Radon and TypeSafe Jev.

MIT. Copyright 2026 Sergey Shima.