Mesa Code Review is a local rules engine that checks code changes against your team’s rules during development. You define rules as markdown files in your repo. Mesa runs them against git diffs and your codebase context and reports violations. If nothing is violated, it says nothing.
It works standalone from the CLI, or integrates with Claude Code for automatic reviews during development.
Installing
brew install mesa-dot-dev/homebrew-tap/code-review
Quickstart
Initialize Mesa in your repo
This walks you through setup:
- Creates
.mesa/config.yaml and .mesa/rules/
- Offers to generate rules from your codebase, use our starter rules, or start from scratch
- Sets up Claude Code integration (MCP server & Claude Code slash commands and hooks)
- Stores your API key in
.env.local if provided
Generate rules or write your own
Mesa scans your codebase, detects conventions and patterns, and proposes rules. You review each one interactively and choose which to keep.You can also create individual rules: Run a review
Mesa diffs your current branch against the base, matches changed files to rules, and reports any violations. Use the —help flag for more options Rules
Rules live in .mesa/rules/ as markdown files. Each rule defines what to check, which files it applies to, and how severe a violation is.
---
id: no-console-log
title: No console.log in production code
severity: warning
globs:
- "**/*.ts"
- "**/*.tsx"
- "!**/*.test.ts"
---
console.log, console.warn, and console.debug should not appear in
production code. Use a structured logging library instead.
### Violations
```
console.log("Processing order", orderId, customerEmail);
```
### Compliant
```
logger.info("Processing order", { orderId });
```
### Violations and ### Compliant sections provide code examples.
Globs use repo-root-relative paths, so rules work correctly in monorepos. Scope rules to specific directories like src/api/**/*.ts rather than broad wildcards.
Claude Code integration
mesa init sets up three things for Claude Code automatically.
Stop hook
Every time Claude Code finishes writing code, Mesa reviews the uncommitted changes. If violations are found, Claude is blocked and asked to fix them before completing.
MCP server
Mesa registers as an MCP server via .mcp.json. Claude Code discovers it on startup and gains access to Mesa’s tools for reviewing code, creating rules, and generating rules.
Slash commands
Available inside Claude Code after mesa init:
| Command | Description |
|---|
/mesa-review | Run a code review manually |
/mesa-createrule | Create a new rule with AI assistance |
/mesa-generaterules | Auto-generate rules from your codebase |
Configuration
.mesa/config.yaml is created by mesa init:
# AI model for reviews
model:
provider: anthropic # anthropic | openai | google
name: claude-opus-4-6
# Output settings
output:
cursor_deeplink: true # Print Cursor IDE links for violations
# Review tuning
review:
max_steps: 50 # Max tool-calling steps per review batch
files_per_batch: 2 # Files reviewed together per batch
# Claude Code stop hook
hook:
enabled: true # Auto-review when Claude Code finishes writing
ANTHROPIC_API_KEY, OPENAI_API_KEY, GOOGLE_API_KEY) or from .env.local / .env files.
CLI reference
Core commands
| Command | Description |
|---|
mesa init | Set up Mesa in your repo (config, rules, hooks, Claude Code integration) |
mesa review | Review code changes against your rules |
mesa stats | Show review history and cost analytics |
mesa index | Build the import graph for richer review context |
Rule management
| Command | Description |
|---|
mesa rules generate | Auto-generate rules by analyzing your codebase |
mesa rules create [dir] | Create a new rule with AI assistance, scoped to a directory |
mesa rules list | List all rules with IDs, titles, and severity |
mesa rules explain <id> | Show full details for a rule |
mesa rules validate | Check all rule files for correct structure |
mesa rules for <paths> | Show which rules match given files or directories |
mesa rules delete <id> | Delete a rule |
mesa review options
-b, --base Base branch to diff against [default: "main"]
--head Head ref to review [default: "HEAD"]
-o, --output Output format: console, json [default: "console"]
-v, --verbose Show detailed progress [default: false]
--debug Write debug logs to .mesa/.tmp/ [default: false]
-c, --config Path to config file [default: ".mesa/config.yaml"]
--rules Path to rules directory [default: ".mesa/rules/"]
Use mesa stats to see aggregated analytics from your local review history, including cost, token usage, and violation trends.
