System Information MCP Server

Instructions

Implementation Reference

• src/sysinfo/server.py:95-111 (handler)

  The primary handler function for the 'get_network_status' tool. Decorated with @mcp.tool for automatic registration in the FastMCP server. It invokes get_network_info() from collectors, formats the output, and returns a ToolResult with text content.

  @mcp.tool
  def get_network_status() -> ToolResult:
      """Get network configuration and connectivity - interfaces, IPs, DNS, VPN status.
      
      Complete network diagnostics including external connectivity and VPN detection.
      Essential for troubleshooting network issues and security analysis.
      """
      info_sections = []
      info_sections.append("# Network Status")
      info_sections.append(f"*Generated: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}*\n")
      
      try:
          info_sections.extend(get_network_info())
      except Exception as e:
          info_sections.append(f"⚠️ **Network detection error**: {str(e)}")
      
      return text_response("\n".join(info_sections))

• src/sysinfo/collectors.py:442-487 (helper)

  The core helper function get_network_info() that implements the network status logic: enumerates network interfaces with psutil.net_if_addrs(), retrieves gateway/DNS info platform-specifically, fetches external IP via AWS checkip, detects VPN via interface names, and compiles markdown-formatted info list.

  def get_network_info() -> List[str]:
      """Get network interface and connectivity information"""
      info = []
      info.append("\n## 🌐 Network")
      
      # Network interfaces
      net_interfaces = psutil.net_if_addrs()
      net_stats = psutil.net_if_stats()
      
      for interface, addresses in net_interfaces.items():
          if interface.startswith('lo') or interface.startswith('utun'):
              continue  # Skip loopback and tunnels for main display
          
          stats = net_stats.get(interface)
          if stats and stats.isup:
              info.append(f"\n### {interface}")
              info.append(f"- **Status**: {'Up' if stats.isup else 'Down'}")
              
              for addr in addresses:
                  if addr.family.name == 'AF_INET':  # IPv4
                      info.append(f"- **IPv4**: {addr.address}")
                      if addr.netmask:
                          info.append(f"  - **Netmask**: {addr.netmask}")
                  elif addr.family.name == 'AF_INET6':  # IPv6
                      if not addr.address.startswith('fe80'):  # Skip link-local
                          info.append(f"- **IPv6**: {addr.address}")
      
      # Gateway and DNS
      gateway = _get_default_gateway()
      if gateway:
          info.append(f"\n- **Default Gateway**: {gateway}")
      
      dns_servers = _get_dns_servers()
      if dns_servers:
          info.append(f"- **DNS Servers**: {', '.join(dns_servers[:3])}")
      
      # External IP
      external_ip = _get_external_ip()
      info.append(f"- **External IP**: {external_ip}")
      
      # VPN Detection
      vpn_status = _detect_vpn(net_interfaces, net_stats)
      info.append(f"- **VPN Status**: {vpn_status}")
      
      return info

• src/sysinfo/server.py:95-111 (registration)

  The @mcp.tool decorator on get_network_status() handles tool registration in the FastMCP instance created earlier in the file.

  @mcp.tool
  def get_network_status() -> ToolResult:
      """Get network configuration and connectivity - interfaces, IPs, DNS, VPN status.
      
      Complete network diagnostics including external connectivity and VPN detection.
      Essential for troubleshooting network issues and security analysis.
      """
      info_sections = []
      info_sections.append("# Network Status")
      info_sections.append(f"*Generated: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}*\n")
      
      try:
          info_sections.extend(get_network_info())
      except Exception as e:
          info_sections.append(f"⚠️ **Network detection error**: {str(e)}")
      
      return text_response("\n".join(info_sections))