AWS FIS MCP Server

Instructions

Start a new AWS FIS experiment based on an experiment template.

Args:
    template_id: ID of the experiment template to use
    region: AWS region to use (default: us-east-1)
    client_token: Optional client token for idempotency
    
Returns:
    JSON string containing the started experiment information

Implementation Reference

• aws_fis_mcp/tools.py:180-212 (handler)

  The handler function that implements the core logic of the 'start_experiment' tool. It uses boto3 to call AWS FIS start_experiment API, handles client token, serializes datetime objects, and returns JSON response.

  @require_write_mode
  def start_experiment(template_id: str, region: str = "us-east-1", client_token: Optional[str] = None) -> str:
      """
      Start a new AWS FIS experiment based on an experiment template.
      
      Args:
          template_id: ID of the experiment template to use
          region: AWS region to use (default: us-east-1)
          client_token: Optional client token for idempotency
          
      Returns:
          JSON string containing the started experiment information
      """
      try:
          fis = boto3.client('fis', region_name=region)
          
          # Generate a client token if not provided
          if not client_token:
              client_token = str(uuid.uuid4())
          
          response = fis.start_experiment(
              experimentTemplateId=template_id,
              clientToken=client_token
          )
          
          # Get the raw experiment data and serialize datetime objects
          experiment = response.get('experiment', {})
          serialized_experiment = _serialize_datetime(experiment)
          
          return json.dumps(serialized_experiment, indent=2)
      except Exception as e:
          return f"Error starting experiment: {str(e)}"

• aws_fis_mcp/server.py:29-29 (registration)

  Registration of the 'start_experiment' handler function as a tool in the FastMCP server application.

  app.tool()(start_experiment)

• aws_fis_mcp/tools.py:34-51 (helper)

  Helper function used by start_experiment to recursively serialize datetime objects to ISO strings in the response.

  def _serialize_datetime(obj: Any) -> Any:
      """
      Recursively serialize datetime objects to ISO format strings.
      
      Args:
          obj: Object that may contain datetime objects
          
      Returns:
          Object with datetime objects converted to ISO format strings
      """
      if isinstance(obj, datetime):
          return obj.isoformat()
      elif isinstance(obj, dict):
          return {key: _serialize_datetime(value) for key, value in obj.items()}
      elif isinstance(obj, list):
          return [_serialize_datetime(item) for item in obj]
      else:
          return obj

• aws_fis_mcp/tools.py:19-31 (helper)

  Decorator applied to start_experiment to enforce write mode requirement for destructive operations.

  def require_write_mode(func):
      """Decorator to require write mode for destructive operations."""
      @wraps(func)
      def wrapper(*args, **kwargs):
          if not _WRITE_MODE_ENABLED:
              return json.dumps({
                  "error": "Write operations are disabled",
                  "message": f"The '{func.__name__}' operation requires write mode. Please restart the server with --allow-writes flag to enable write operations.",
                  "operation": func.__name__,
                  "read_only_mode": True
              }, indent=2)
          return func(*args, **kwargs)
      return wrapper

• aws_fis_mcp/server.py:7-19 (registration)

  Import statement that brings the start_experiment function into the server module for registration.

  from aws_fis_mcp.tools import (
      list_experiment_templates,
      get_experiment_template,
      list_experiments,
      get_experiment,
      start_experiment,
      stop_experiment,
      create_experiment_template,
      delete_experiment_template,
      list_action_types,
      generate_template_example,
      set_write_mode,
  )