PowerShell Exec MCP Server

Instructions

Args:
    code: PowerShell code to execute
    timeout: Command timeout in seconds (1-300, default 60)
    ctx: MCP context for logging and progress reporting

Returns:
    Command output as string

Implementation Reference

• run.py:45-72 (registration)

  Registers the run_powershell tool including its input schema in the ListTools response.

  @server.setRequestHandler(ListToolsRequestSchema)
  async def handle_list_tools():
      return {
          "tools": [
              {
                  "name": "run_powershell",
                  "description": "Execute PowerShell commands securely",
                  "inputSchema": {
                      "type": "object",
                      "properties": {
                          "code": {
                              "type": "string",
                              "description": "PowerShell code to execute"
                          },
                          "timeout": {
                              "type": "integer",
                              "description": "Command timeout in seconds",
                              "minimum": 1,
                              "maximum": 300,
                              "default": 60
                          }
                      },
                      "required": ["code"]
                  }
              }
          ]
      }

• run.py:53-69 (schema)

  Input schema definition for the run_powershell tool.

          "type": "object",
          "properties": {
              "code": {
                  "type": "string",
                  "description": "PowerShell code to execute"
              },
              "timeout": {
                  "type": "integer",
                  "description": "Command timeout in seconds",
                  "minimum": 1,
                  "maximum": 300,
                  "default": 60
              }
          },
          "required": ["code"]
      }
  }

• run.py:74-139 (handler)

  Main handler for run_powershell tool: validates input, executes PowerShell command with timeout handling, returns stdout or errors.

  @server.setRequestHandler(CallToolRequestSchema)
  async def handle_tool_call(request):
      if request.params.name != "run_powershell":
          raise McpError(
              ErrorCode.MethodNotFound,
              f"Unknown tool: {request.params.name}"
          )
  
      code = request.params.arguments.get("code")
      if not isinstance(code, str):
          raise McpError(
              ErrorCode.InvalidParams,
              "code parameter must be a string"
          )
  
      timeout = request.params.arguments.get("timeout", 60)
      if not isinstance(timeout, int) or timeout < 1 or timeout > 300:
          raise McpError(
              ErrorCode.InvalidParams,
              "timeout must be between 1 and 300 seconds"
          )
  
      try:
          process = await asyncio.create_subprocess_exec(
              "powershell",
              "-NoProfile",
              "-NonInteractive",
              "-Command",
              code,
              stdout=subprocess.PIPE,
              stderr=subprocess.PIPE,
              text=True
          )
  
          stdout, stderr = await asyncio.wait_for(
              process.communicate(),
              timeout=timeout
          )
  
          if process.returncode != 0:
              raise McpError(
                  ErrorCode.InternalError,
                  stderr or "Command failed with no error output"
              )
  
          return {
              "content": [
                  {
                      "type": "text",
                      "text": stdout
                  }
              ]
          }
  
      except asyncio.TimeoutError:
          process.kill()
          raise McpError(
              ErrorCode.Timeout,
              f"Command timed out after {timeout} seconds"
          )
      except Exception as e:
          raise McpError(
              ErrorCode.InternalError,
              str(e)
          )