brain-mcp

Instructions

Implementation Reference

• brain_mcp/server/server.py:119-158 (handler)

  The `list_principles` tool is defined within the `_register_principles` function in `brain_mcp/server/server.py`. It uses the `mcp.tool()` decorator for registration and reads principles via `get_principles()`.

  @mcp.tool()
  def list_principles() -> str:
      """
      List your configured principles.
      Principles are loaded from the YAML/JSON file specified in config.toml.
      """
      principles = get_principles()
  
      if not principles:
          return "No principles configured. Add a principles file to config.toml."
  
      # Support both flat list and nested dict formats
      section = principles.get("principles", principles)
  
      if isinstance(section, list):
          output = ["## Your Principles\n"]
          for i, p in enumerate(section, 1):
              if isinstance(p, dict):
                  name = p.get("name", f"Principle {i}")
                  desc = p.get("description", p.get("definition", ""))[:200]
                  output.append(f"**{i}. {name}**")
                  output.append(f"> {desc}\n")
              else:
                  output.append(f"**{i}.** {p}\n")
          return "\n".join(output)
  
      elif isinstance(section, dict):
          output = ["## Your Principles\n"]
          for key in sorted(section.keys()):
              principle = section[key]
              if isinstance(principle, dict):
                  name = principle.get("name", key)
                  definition = principle.get("definition", "")[:200]
                  output.append(f"**{key.upper()}. {name}**")
                  output.append(f"> {definition}\n")
              else:
                  output.append(f"**{key}**: {principle}\n")
          return "\n".join(output)
  
      return "Principles format not recognized."