ServiceNow MCP Server

Instructions

Implementation Reference

• src/servicenow_mcp/tools/change_tools.py:758-858 (handler)

  The core handler function for the 'approve_change' tool. It validates parameters, queries the approval record for the change request, updates the approval to 'approved', and advances the change request state to 'implement' via ServiceNow Table API.
  def approve_change( auth_manager: AuthManager, server_config: ServerConfig, params: Dict[str, Any], ) -> Dict[str, Any]: """ Approve a change request in ServiceNow. Args: auth_manager: The authentication manager. server_config: The server configuration. params: The parameters for approving a change request. Returns: The result of the approval. """ # Unwrap and validate parameters result = _unwrap_and_validate_params( params, ApproveChangeParams, required_fields=["change_id"] ) if not result["success"]: return result validated_params = result["params"] # Get the instance URL instance_url = _get_instance_url(auth_manager, server_config) if not instance_url: return { "success": False, "message": "Cannot find instance_url in either server_config or auth_manager", } # Get the headers headers = _get_headers(auth_manager, server_config) if not headers: return { "success": False, "message": "Cannot find get_headers method in either auth_manager or server_config", } # First, find the approval record approval_query_url = f"{instance_url}/api/now/table/sysapproval_approver" query_params = { "sysparm_query": f"document_id={validated_params.change_id}", "sysparm_limit": 1, } try: approval_response = requests.get(approval_query_url, headers=headers, params=query_params) approval_response.raise_for_status() approval_result = approval_response.json() if not approval_result.get("result") or len(approval_result["result"]) == 0: return { "success": False, "message": "No approval record found for this change request", } approval_id = approval_result["result"][0]["sys_id"] # Now, update the approval record to approved approval_update_url = f"{instance_url}/api/now/table/sysapproval_approver/{approval_id}" headers["Content-Type"] = "application/json" approval_data = { "state": "approved", } if validated_params.approval_comments: approval_data["comments"] = validated_params.approval_comments approval_update_response = requests.patch(approval_update_url, json=approval_data, headers=headers) approval_update_response.raise_for_status() # Finally, update the change request state to "implement" change_url = f"{instance_url}/api/now/table/change_request/{validated_params.change_id}" change_data = { "state": "implement", # This may vary depending on ServiceNow configuration } change_response = requests.patch(change_url, json=change_data, headers=headers) change_response.raise_for_status() return { "success": True, "message": "Change request approved successfully", } except requests.exceptions.RequestException as e: logger.error(f"Error approving change: {e}") return { "success": False, "message": f"Error approving change: {str(e)}", }
• src/servicenow_mcp/tools/change_tools.py:91-97 (schema)

  Pydantic BaseModel defining the input schema for the approve_change tool, including required change_id and optional approver_id and approval_comments.
  class ApproveChangeParams(BaseModel): """Parameters for approving a change request.""" change_id: str = Field(..., description="Change request ID or sys_id") approver_id: Optional[str] = Field(None, description="ID of the approver") approval_comments: Optional[str] = Field(None, description="Comments for the approval")
• src/servicenow_mcp/utils/tool_utils.py:521-527 (registration)

  Registration of the 'approve_change' tool in the central tool definitions dictionary used by the MCP server, linking the handler function, input schema, return type, description, and serialization method.
  "approve_change": ( approve_change_tool, ApproveChangeParams, str, "Approve a change request", "str", # Tool returns simple message ),
• src/servicenow_mcp/tools/__init__.py:23-32 (registration)

  Re-export of the approve_change handler from change_tools.py in the tools package __init__, making it available for import.
  from servicenow_mcp.tools.change_tools import ( add_change_task, approve_change, create_change_request, get_change_request_details, list_change_requests, reject_change, submit_change_for_approval, update_change_request, )
• src/servicenow_mcp/tools/change_tools.py:107-159 (helper)

  Shared helper function used by approve_change (and other tools) to unwrap, validate input parameters against the Pydantic schema, and handle common parameter formatting issues.
  def _unwrap_and_validate_params(params: Any, model_class: Type[T], required_fields: List[str] = None) -> Dict[str, Any]: """ Helper function to unwrap and validate parameters. Args: params: The parameters to unwrap and validate. model_class: The Pydantic model class to validate against. required_fields: List of required field names. Returns: A tuple of (success, result) where result is either the validated parameters or an error message. """ # Handle case where params might be wrapped in another dictionary if isinstance(params, dict) and len(params) == 1 and "params" in params and isinstance(params["params"], dict): logger.warning("Detected params wrapped in a 'params' key. Unwrapping...") params = params["params"] # Handle case where params might be a Pydantic model object if not isinstance(params, dict): try: # Try to convert to dict if it's a Pydantic model logger.warning("Params is not a dictionary. Attempting to convert...") params = params.dict() if hasattr(params, "dict") else dict(params) except Exception as e: logger.error(f"Failed to convert params to dictionary: {e}") return { "success": False, "message": f"Invalid parameters format. Expected a dictionary, got {type(params).__name__}", } # Validate required parameters are present if required_fields: for field in required_fields: if field not in params: return { "success": False, "message": f"Missing required parameter '{field}'", } try: # Validate parameters against the model validated_params = model_class(**params) return { "success": True, "params": validated_params, } except Exception as e: logger.error(f"Error validating parameters: {e}") return { "success": False, "message": f"Error validating parameters: {str(e)}", }