MCP Servers

SideCar supports the Model Context Protocol (MCP) for connecting to external tools and data sources.

What is MCP?

MCP is an open protocol that lets AI assistants call external tools — databases, APIs, file systems, and custom scripts. MCP tools appear alongside SideCar’s built-in tools and go through the same approval flow.

Configuration

Add MCP servers via the sidecar.mcpServers setting:

"sidecar.mcpServers": {
  "server-name": {
    "command": "executable",
    "args": ["arg1", "arg2"]
  }
}

SideCar uses stdio transport to communicate with MCP servers.

Examples

Filesystem server

Give SideCar access to files outside your workspace:

"sidecar.mcpServers": {
  "filesystem": {
    "command": "npx",
    "args": ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/directory"]
  }
}

SQLite database

Query a local database:

"sidecar.mcpServers": {
  "sqlite": {
    "command": "npx",
    "args": ["-y", "@modelcontextprotocol/server-sqlite", "/path/to/database.db"]
  }
}

GitHub

Access GitHub repos, issues, and PRs:

"sidecar.mcpServers": {
  "github": {
    "command": "npx",
    "args": ["-y", "@modelcontextprotocol/server-github"],
    "env": {
      "GITHUB_TOKEN": "your-token"
    }
  }
}

How MCP tools work

MCP tools are discovered automatically when the server starts
They appear in the agent’s tool list alongside built-in tools
Tool calls go through the same approval flow (cautious/autonomous/manual)
Tool permissions (sidecar.toolPermissions) apply to MCP tools by name
Settings changes trigger automatic reconnection

Troubleshooting

Verify the MCP server is installed: run the command manually in your terminal
Check the “SideCar Agent” output channel for connection errors
Ensure npx is in your PATH if using npx-based servers