MCP Tools Reference: gmailmcp.googleapis.com

Tool: `label_message`

Adds one or more labels to a specific message in the authenticated user's Gmail account.

To find the message ID, use tools like search_threads or get_thread . If unsure of a user label's ID, use the list_labels tool first to discover available labels and their IDs.

The following sample demonstrate how to use curl to invoke the label_message MCP tool.

Curl Request
curl --location 'https://gmailmcp.googleapis.com/mcp/v1' \ --header 'content-type: application/json' \ --header 'accept: application/json, text/event-stream' \ --data '{ "method": "tools/call", "params": { "name": "label_message", "arguments": { // provide these details according to the tool' s MCP specification } } , "jsonrpc" : "2.0" , "id" : 1 } '

Curl Request

curl  
--location  
 'https://gmailmcp.googleapis.com/mcp/v1' 
  
 \ 
--header  
 'content-type: application/json' 
  
 \ 
--header  
 'accept: application/json, text/event-stream' 
  
 \ 
--data  
 '{ 
 "method": "tools/call", 
 "params": { 
 "name": "label_message", 
 "arguments": { 
 // provide these details according to the tool' 
s  
MCP  
specification  
 } 
  
 } 
,  
 "jsonrpc" 
:  
 "2.0" 
,  
 "id" 
:  
 1 
 } 
 '

Input Schema

Request message for LabelMessage RPC.

LabelMessageRequest

JSON representation
{ "messageId" : string , "labelIds" : [ string ] }

Fields

Fields
`messageId`	`string` Required. The ID of the message to add the labels to.
`labelIds[]`	`string` Required. The IDs of the labels to add. Can be a system label ID (e.g., 'INBOX', 'TRASH', 'SPAM', 'STARRED', 'UNREAD', 'IMPORTANT') or a user-defined label ID. The tool accepts `label_ids` and not label names. Use the list_labels tool to get the corresponding label id to a display name for user-defined labels.

messageId

string

Required. The ID of the message to add the labels to.

labelIds[]

string

Required. The IDs of the labels to add. Can be a system label ID (e.g., 'INBOX', 'TRASH', 'SPAM', 'STARRED', 'UNREAD', 'IMPORTANT') or a user-defined label ID. The tool accepts label_ids and not label names. Use the list_labels tool to get the corresponding label id to a display name for user-defined labels.

Output Schema

Response message for LabelMessage RPC.

Tool Annotations

Destructive Hint: ❌ | Idempotent Hint: ✅ | Read Only Hint: ❌ | Open World Hint: ❌