> ## Documentation Index
> Fetch the complete documentation index at: https://docs.substrate.42.pe/llms.txt
> Use this file to discover all available pages before exploring further.

# substrate mcp — Start the MCP Server for Agent Runtimes

> substrate mcp starts the stdio MCP server that agent runtimes spawn. Exposes all 32 Substrate tools over stdin/stdout with no port or network.

`substrate mcp` speaks the Model Context Protocol over stdin/stdout, exposing all 32 Substrate tools to the agent runtime that spawns it. You rarely run this yourself — your agent runtime spawns it as a child process pointed at your project root. There is no port, no network, and no configuration required beyond placing it correctly in your runtime's config block.

## Usage

```shell theme={null}
substrate mcp
```

## Working Directory

<Warning>
  The server reads the `.substrate/` in its **working directory**. Your runtime spawns it from the project root, which is normally what you want — but a runtime spawned from a git worktree gets that worktree's empty database. Pointing the process at another checkout's working directory is the supported workaround. See [Worktrees and Clones](/agents/worktrees-and-clones).
</Warning>

## Logging

`mcp` is a long-lived process, so it records warnings and errors to `.substrate/logs/substrate.log` — including an agent's handled tool errors. Read them with `substrate logs --errors`. The process also emits the fresh-empty-database warning at startup when it opens a `.substrate/` that has boards but no task database.

## Tools

`substrate mcp` exposes 32 tools. See [MCP Overview](/mcp/overview) for the full list and descriptions.

## Configuration

See [MCP Setup](/getting-started/mcp-setup) for the config block to add to your agent runtime.