System Information MCP Server

Instructions

Implementation Reference

• src/system_info_mcp/server.py:35-44 (handler)

  Handler function for the get_cpu_info_tool, registered via @app.tool() decorator. Delegates execution to the get_cpu_info helper function with provided parameters.

  @app.tool()
  def get_cpu_info_tool(interval: float = 1.0, per_cpu: bool = False) -> Dict[str, Any]:
      """Retrieve CPU usage and information.
  
      Args:
          interval: Measurement interval in seconds (default: 1.0)
          per_cpu: Include per-CPU core breakdown (default: false)
      """
      return get_cpu_info(interval=interval, per_cpu=per_cpu)

• src/system_info_mcp/server.py:35-35 (registration)

  Registration of the get_cpu_info_tool via FastMCP @app.tool() decorator.

  @app.tool()

• src/system_info_mcp/tools.py:22-78 (helper)

  Core helper function implementing the CPU information retrieval logic using psutil library. Includes parameter validation, CPU stats collection, frequency, load average, and optional per-CPU breakdown. Cached with 2-second TTL.

  @cache_result("cpu_info", ttl=2)
  def get_cpu_info(interval: float = 1.0, per_cpu: bool = False) -> Dict[str, Any]:
      """Retrieve CPU usage and information."""
      try:
          # Validate parameters
          if interval <= 0:
              raise ValueError("Interval must be a positive number")
  
          # Get CPU percentage (this call blocks for the interval)
          cpu_percent = psutil.cpu_percent(interval=interval)
  
          # Get per-CPU percentages if requested
          per_cpu_percent = None
          if per_cpu:
              per_cpu_percent = psutil.cpu_percent(interval=0, percpu=True)
  
          # Get CPU counts
          cpu_count_logical = psutil.cpu_count(logical=True) or 0
          cpu_count_physical = psutil.cpu_count(logical=False) or 0
  
          # Get CPU frequency
          try:
              cpu_freq = psutil.cpu_freq()
              cpu_freq_current = safe_float(cpu_freq.current if cpu_freq else 0)
              cpu_freq_max = safe_float(cpu_freq.max if cpu_freq else 0)
          except (AttributeError, OSError):
              cpu_freq_current = 0.0
              cpu_freq_max = 0.0
  
          # Get load average (Unix-like systems only)
          try:
              if hasattr(os, 'getloadavg'):
                  load_avg = os.getloadavg()
                  load_average = [round(avg, 2) for avg in load_avg]
              else:
                  load_average = [0.0, 0.0, 0.0]
          except (AttributeError, OSError):
              load_average = [0.0, 0.0, 0.0]
  
          result = {
              "cpu_percent": round(cpu_percent, 1),
              "cpu_count_logical": cpu_count_logical,
              "cpu_count_physical": cpu_count_physical,
              "cpu_freq_current": cpu_freq_current,
              "cpu_freq_max": cpu_freq_max,
              "load_average": load_average,
          }
  
          if per_cpu_percent is not None:
              result["per_cpu_percent"] = [round(p, 1) for p in per_cpu_percent]
  
          return result
  
      except Exception as e:
          logger.error(f"Error getting CPU info: {e}")
          raise