Managing MCP servers in ThinkRail

ThinkRail uses pi's built-in MCP support but has no pi executable. Never run pi mcp add, pi mcp login or other pi commands; edit the configuration files and point the user at Settings › MCP servers for everything that needs them.

Where servers are configured

• User level, pi's agent directory, usually ~/.pi/agent/mcp.json: available in every project.
• This repository, .pi/mcp.json in the worktree, tracked in git. A server defined here does not run until the user approves it in Settings, and any later change to its entry needs approval again. It only loads when the user trusts the project.

Both files use pi's format:

{
  "mcpServers": {
    "docs": { "url": "https://example.com/mcp" },
    "browser": { "command": "npx", "args": ["-y", "@playwright/mcp@0.0.83"] }
  }
}

• Pin package versions in args; never @latest.
• Never write a secret into either file. Reference it as ${ENV_VAR} (from the host's environment) or !command (the command's output, for example !gh auth token), or let the user sign in.
• exposure: deferred (the default here, load the server's tools with tool_search first), direct (a few always-useful tools), or hidden. codemode is treated as deferred.
• Prefer the user-level file for personal servers; only put a server in .pi/mcp.json when the user wants it shared with the repository.

GitHub

GitHub is a recipe, not a preset: its hosted server, authenticated with the user's GitHub CLI sign-in. Add it to the user-level file (Settings › MCP servers offers the same entry under Paste JSON):

{
  "mcpServers": {
    "github": {
      "url": "https://api.githubcopilot.com/mcp/readonly",
      "headers": { "Authorization": "!t=$(gh auth token) && echo \"Bearer $t\"" }
    }
  }
}