Aider MCP WebSocket Server

What is Aider MCP WebSocket Server?

A real MCP (Model Context Protocol) server that lets you control Aider programmatically via WebSocket, wrapping Aider’s functionality for use by editor plugins and services. It provides two server implementations: a standard MCP protocol server (recommended) and a custom WebSocket wrapper. It is for developers who want to send natural language commands to Aider from any MCP-compatible client, like Claude Desktop or custom apps.

How to use Aider MCP WebSocket Server?

Install dependencies with npm install, copy .env.example to .env and add your OpenAI API key. Start the recommended MCP server with npm run mcp, then connect via WebSocket using JSON-RPC 2.0. The server exposes tools such as aider_command, aider_add_file, and aider_run_command. Client code examples for WebSocket connection and tool calls are provided in the README.

Key features of Aider MCP WebSocket Server

• Full MCP protocol support with standard JSON-RPC 2.0 methods
• Multi-tenant isolation: one Aider child process per client
• Automatic completion detection (waits for Aider to finish)
• Isolated workspace directories per session
• Real-time bidirectional WebSocket communication
• Environment variable and CLI argument configuration

Use cases of Aider MCP WebSocket Server

• Send natural language commands to create or edit code files
• Add specific files to Aider’s context before executing commands
• Run shell commands through Aider as part of a development workflow
• Build editor plugins or services that programmatically control Aider
• Integrate Aider into CI/CD pipelines or automated code review systems

FAQ from Aider MCP WebSocket Server

What prerequisites are needed?

Node.js 18+, Aider installed and available in PATH (pip install aider-chat), and an OpenAI API key.

How does the server handle multiple clients?

Each client gets an isolated workspace directory and a separate Aider process, ensuring session separation.

Is authentication supported?

The custom WebSocket wrapper supports token-based authentication via the VALID_TOKENS environment variable (empty means no auth). The MCP server does not mention authentication.

Where are created files stored?

Files are saved in directories under workspaces/, e.g., workspaces/mcp-*/. You can check them with ls -la workspaces/.

What if the server returns too quickly or gives incomplete responses?

The MCP server includes smart completion detection that waits for Aider to finish (using a 3-second silence detection), solving the problem of premature responses.