A1 AI engineering company GitHub
Connect the Google Chat MCP server to your AI agent Open source, MIT, on npm. Setup instructions for Claude, Cursor and Codex are in the repository; adoption questions — Telegram. GitHub repository Telegram

Google Chat: Send a message — MCP tool

Google Chat MCP tool: Sends a text message to a space as the authenticated user, optionally into a thread.

Technical name: send_message

What task it solves

I want to post a message into a Google Chat space or thread.

Creates a real message under the authenticated user's name and returns it with name, thread.name and createTime.

When to use it

Use it to notify a room, answer in a thread (thread_name or a stable thread_key), or DM a person (space from find_direct_message). This is a write — the message is immediately visible to the space's members.

What to provide

  • space — required. spaces/<id> or the bare id.
  • text — required. Up to 4096 characters; Chat markup (*bold*, _italic_, code, <users/123> mentions) supported.
  • thread_name / thread_key — optional thread targeting.
  • reply_option — optional. fallback_to_new_thread (default) or or_fail.
  • message_id — optional. Custom id starting with client-, unique per space.

What it returns

The created message with its resource name and thread.

What changes in Google Chat

A new message appears in the space under the authenticated user's name. This creates data; it is not a read.

Example request

Send "Deploy finished ✅" into the release thread of spaces/AAAAAAAAAAA.

Errors and limitations

Needs the chat.messages.create or chat.messages scope and membership in the space. A send is NEVER retried after a 5xx/timeout — check with list_messages before re-sending; reusing a message_id fails with ALREADY_EXISTS, which makes accidental duplicates detectable. Cards (cardsV2) require app authentication and are out of scope. In non-threaded spaces the thread parameters are ignored by the API.

Related MCP tools

Technical details