mcp-codexreview

MCP server that runs OpenAI Codex CLI (codex exec) to review git changes. Any MCP client (Claude Code, etc.) can request a Codex-powered code review of unstaged, staged, or last-commit changes.

Prerequisites

• Node.js 18+
• @openai/codex CLI installed and available on $PATH
• Codex configured with an API key (via ~/.codex/config.toml or environment)

Installation

Claude Code

claude mcp add codexreview -- npx -y mcp-codexreview

Claude Desktop

Add to your Claude Desktop configuration (claude_desktop_config.json):

{
  "mcpServers": {
    "codexreview": {
      "command": "npx",
      "args": ["-y", "mcp-codexreview"]
    }
  }
}

Install from Source

git clone https://github.com/signal-slot/mcp-codexreview.git
cd mcp-codexreview
npm install
npm run build
claude mcp add codexreview -- node /path/to/mcp-codexreview/build/index.js

MCP Tools

review_changes

Run Codex to review git changes. Codex reads the diff and provides a thorough code review.

Parameter	Type	Required	Description
type	"unstaged" | "staged" | "last_commit"	yes	Which changes to review
cwd	string	no	Git repo path (default: server working directory)
model	string	no	Override Codex model (e.g. "o3", "gpt-4.1")
instructions	string	no	Additional review focus or instructions

get_diff

Get raw git diff output without invoking Codex.

Parameter	Type	Required	Description
type	"unstaged" | "staged" | "last_commit"	yes	Which changes to diff
path	string	no	Filter to specific file or directory
cwd	string	no	Git repo path

get_changed_files

List changed files with their status (M/A/D/R).

Parameter	Type	Required	Description
type	"unstaged" | "staged" | "last_commit"	yes	Which changes to list
cwd	string	no	Git repo path

How It Works

The review_changes tool spawns codex exec with:

• -C <cwd> to target the git repo
• -s read-only sandbox (Codex can read files and run git, but cannot modify)
• -a on-failure for non-interactive execution
• --output-last-message <tmpfile> to capture the review text
• --color never for clean output

The review prompt instructs Codex to run the appropriate git diff command and provide a code review covering correctness, style, performance, security, and improvement suggestions.

License

MIT