Gavel

Bazel builds your monorepo. Gavel judges it. Order in the codebase!

The quality gate for Bazel monorepos — build-graph-native, local, agent-ready.

Your monorepo builds green. That's not the same as innocent. Gavel gathers the evidence as Bazel aspects, holds every change to the law you set in gavel.yaml, and returns a verdict: the regression you just introduced stands charged, while a decade of existing debt is not on trial. One verdict, handed to your CI, your terminal, and your coding agent alike.

gavel init      # open the case
gavel judge     # hear it

Install

# Homebrew — macOS & Linux
brew install gavelcode/tap/gavel

# or the install script — Linux, CI, Docker
curl -fsSL https://raw.githubusercontent.com/gavelcode/gavel/main/install.sh | sh

Prebuilt binaries for every platform are on the releases page. Gavel needs a Bazel 8.0+ (bzlmod) workspace; verify with gavel --version.

bazel build //apps/cli/cmd/gavel
# binary at bazel-bin/apps/cli/cmd/gavel/gavel_/gavel

Related MCP server: gemini-cli-mcp-slim

How it works

Every change gets its day in court.

1. The evidence comes from the build graph

Analyzers — golangci-lint, PMD, CPD, SpotBugs, Error Prone, Ruff, Bandit, ESLint, Clippy — run as Bazel aspects. They see the exact source tree, dependency graph, and toolchains Bazel already resolves; no separate scanner, no second config to drift. SonarQube re-scans the world; Gavel looks only at the targets the graph says changed (--affected), so a run stays fast as the monorepo grows. Every tool, every language, normalized to one format: SARIF.

2. You're only tried for what you changed

gavel.yaml is the quality gate — code, reviewed and versioned with the repo, not clicked into a web UI. It evaluates only what you just added against a committed baseline: new findings, coverage regressions, new architecture violations. Adopt Gavel on ten years of debt and it blocks on today's diff, never on the backlog.

projects:
  - name: payments
    pattern: "//payments/..."
    tooling:
      go: [golangci-lint, archtest]
    quality_gate:
      findings: { max_error: 0 }
      coverage: { min: 80 }
      architecture_violations: { max: 0 }

Every run saves a fingerprint snapshot; the next shows the delta — new, fixed, existing — plus the coverage trend. No server required.

  payments/api/handler.go:42  error  null check missing  golangci-lint:nilerr  NEW

  ⚖  VERDICT: FAIL — code_quality
     1 new · 8 fixed · 31 existing        coverage 73.5% (↑5.0%)        architecture PASS

3. A verdict your coding agent can request

Coding agents write code they can't see the consequences of — a lint regression, a coverage drop, a layering violation land three commits later in CI. gavel mcp starts a Model Context Protocol server that exposes judge, lint_file, findings, coverage, and arch as tools. Point Claude Code, Cursor, or Zed at it and the agent checks its own work against the same Bazel-aware gate as it writes — a quality conscience, inline.

For editors and dashboards, gavel watch re-analyzes on every save and emits a JSONL event stream. Both run fully local — no server, no network.

Gavel vs SonarQube: the case

SonarQube is a mature platform with fifteen years of rules behind it, and Gavel isn't trying to replace it. Gavel answers a question SonarQube structurally can't: which packages of my Bazel monorepo are healthy, and did this change make one of them worse — where the build graph is the unit of analysis and the inner loop is where quality is actually won.

Already running aspect's rules_lint? Keep it. Gavel reads the SARIF it drops in bazel-bin/ (gavel judge --findings-source=rules_lint) and turns those reports into a gate — baseline delta, coverage, architecture, verdict — the layer rules_lint deliberately leaves to you.

Status

Alpha — v0.1.0. Under active development; APIs and config formats may change. Gavel gates its own repository on every commit — it is its own first user.

Working today:

• gavel init — scaffold config + Bazel integration

• gavel judge — analyze, evaluate the gate, show findings and the delta

• gavel judge --project <name> · --quick · --summary · --affected — scope and shape the run

• gavel judge --absolute — evaluate all findings (release gates, nightly)

• gavel judge --json · --output-sarif report.sarif — structured output for CI, IDEs, GitHub Code Scanning

• gavel judge --server URL --token TOKEN — shared team baseline: fetch and submit

• gavel watch — re-analyze on change, emitting a JSONL event stream

• gavel mcp — Model Context Protocol server for editor / agent integration

• gavel validate — check Bazel integration health

• Baseline mode (default): fingerprint-based new/fixed/existing classification, committed to git for the team

• Analyzers: golangci-lint, PMD, CPD, SpotBugs, Error Prone, Ruff, Bandit, ESLint, Clippy

• Server (optional): web dashboard, centralized history, team baselines, API-token auth

Documentation

• Quickstart — from zero to a first verdict in five minutes

• Configuration — gavel.yaml and architecture.yml, field by field

• Baseline & delta — how new / fixed / existing is decided

• Server deployment — running gavel-server

• Full documentation index

Contributing

Issues and pull requests are welcome — see CONTRIBUTING.md and our Code of Conduct. Security reports go through SECURITY.md.

License

Apache License 2.0