YNAB MCP Server

Instructions

This tool performs a lightweight API call to verify that:
- The MCP server is running
- The YNAB access token is valid
- The YNAB API is reachable

Returns:
    JSON string with health status and connection info

Implementation Reference

• src/ynab_mcp/server.py:718-757 (handler)

  The main handler function for the 'health_check' tool. Decorated with @mcp.tool() which registers it as an MCP tool. It checks YNAB API connectivity by fetching budgets and returns a JSON status.

  @mcp.tool()
  async def health_check() -> str:
      """Check server health and YNAB API connectivity.
  
      This tool performs a lightweight API call to verify that:
      - The MCP server is running
      - The YNAB access token is valid
      - The YNAB API is reachable
  
      Returns:
          JSON string with health status and connection info
      """
      try:
          logger.info("Running health check")
          client = get_ynab_client()
  
          # Make a lightweight API call to verify connectivity
          budgets = await client.get_budgets()
  
          return json.dumps(
              {
                  "status": "healthy",
                  "api_connected": True,
                  "budgets_count": len(budgets),
                  "message": "YNAB MCP server is running and API is accessible",
              },
              indent=2,
          )
      except Exception as e:
          logger.error(f"Health check failed: {e}", exc_info=True)
          return json.dumps(
              {
                  "status": "unhealthy",
                  "api_connected": False,
                  "error": str(e),
                  "message": "YNAB MCP server is running but API is not accessible",
              },
              indent=2,
          )