MCP Tools

Reeboot supports the Model Context Protocol (MCP) for connecting external tool servers. Any MCP-compatible server can be wired in via configuration — no code changes required.

MCP is enabled by default (extensions.core.mcp: true) but requires at least one server in mcp.servers to be useful.

How It Works — The Proxy Pattern

Rather than registering each MCP server’s tools directly (which costs 150–300 tokens per tool in the system prompt), reeboot exposes a single mcp proxy tool (~200 tokens total).

The agent uses it in two steps:

Step 1 — Discover tools:

mcp({ action: "list", server: "filesystem" })
→ [{ name: "read_file", description: "...", schema: {...} }, ...]

Step 2 — Call a tool:

mcp({ action: "call", server: "filesystem", tool: "read_file", input: { path: "/tmp/data.csv" } })
→ { content: "..." }

This keeps token cost fixed regardless of how many tools each server exposes.

Configuration

Add servers to mcp.servers[] in ~/.reeboot/config.json:

{
  "mcp": {
    "servers": [
      {
        "name": "filesystem",
        "command": "npx",
        "args": ["-y", "@modelcontextprotocol/server-filesystem", "/home/user/documents"],
        "env": {},
        "permissions": {
          "network": false,
          "filesystem": true
        }
      },
      {
        "name": "github",
        "command": "npx",
        "args": ["-y", "@modelcontextprotocol/server-github"],
        "env": { "GITHUB_TOKEN": "ghp_..." },
        "permissions": {
          "network": true,
          "filesystem": false
        }
      }
    ]
  }
}

Server Fields

Field	Type	Required	Description
`name`	string	✅	Unique identifier used in `mcp({ server: "name" })` calls.
`command`	string	✅	Executable to spawn (e.g. `"npx"`, `"python"`, `"/usr/local/bin/my-server"`).
`args`	string[]		Arguments passed to the command.
`env`	object		Environment variables set for the server process. Useful for API keys.
`permissions.network`	boolean		Allow the server process to make outbound network requests. Default: `false`.
`permissions.filesystem`	boolean		Allow the server process filesystem access. Default: `false`.

Lifecycle

Servers are lazy-started — spawned as child processes on the first mcp tool call, not at agent startup. They are killed on session_shutdown.

Limitations (v1)

stdio only — HTTP and SSE transports are not supported in v1.
Manual config — no wizard setup step; servers must be added to config.json manually.
No hot-reload — restart reeboot after adding or changing MCP servers.

Configuration Reference

Field	Type	Default	Description
`mcp.servers`	array	`[]`	List of MCP server definitions.
`extensions.core.mcp`	boolean	`true`	Enable/disable the `mcp` proxy tool entirely.