Nacgarg Bazel MCP Server

🚀 Bazel MCP Server

A local MCP server that exposes the capabilities of the Bazel build system to MCP-enabled AI agents.

This is particularly useful when there's a lack of existing command-line tools in the MCP environment or when the shell environment is misconfigured, preventing the use of Bazel.

✨ Features

The Bazel MCP server provides the following tools:

• bazel_build_target: Build a specified Bazel target.
• bazel_query_target: Query the dependency graph of targets matching a specific pattern.
• bazel_test_target: Run tests for a specified target.
• bazel_list_targets: List all available targets in the workspace (requires a path parameter, use "//" to represent all targets).
• bazel_fetch_dependencies: Fetch external dependencies.
• bazel_set_workspace_path: Change the Bazel workspace path at runtime.

Except for bazel_set_workspace_path, each command supports an optional additionalArgs parameter, allowing you to pass extra arguments to the underlying Bazel command. This is useful for specifying flags like --verbose_failures or --test_output=all.

🚀 Quick Start

📦 Installation

Using Cursor

Add the following content to .cursor/mcp.json:

You don't need to provide the workspace path because the LLM can change the workspace path at runtime using set_workspace_path.

If you encounter issues, you can use the --bazel_path flag to specify the path to the Bazel binary.

⚠️ Important Note

This method does not work in a remote SSH session in Cursor because the MCP server runs locally.

{
  "mcpServers": {
    "bazel": {
      "command": "npx",
      "args": [
        "-y",
        "github:nacgarg/bazel-mcp-server",

        // If you need to specify the path to the Bazel binary
        "--bazel_path", 
        "/absolute/path/to/your/bazel/binary",

        // If you need to specify the workspace path
        "--workspace_path",
        "/absolute/path/to/your/bazel/workspace"

        // See the configuration table below for more options
      ]
    }
  }
}

Using Claude Desktop

You can use the same configuration as for Cursor.

Running Independently

# Run directly from GitHub (no installation required)
npx -y github:nacgarg/bazel-mcp-server

# Run from source code
git clone https://github.com/nacgarg/bazel-mcp-server.git
cd bazel-mcp-server
npm install
npm run build
dist/index.js

Configuration

This MCP server supports the following configuration methods, used in order of priority:

1. Command-line arguments
2. Environment variables
3. Configuration files

Configuration Table

🔧 Debugging

Set the DEBUG=true environment variable to enable verbose logging in the console.

Setting the log path is also very useful for debugging, especially when the client does not print logs to the console (e.g., Cursor).

📄 License

This project is released under the MIT License. For more details, see the LICENSE file.