Gmail MCP: thread reply support missing (regression?)

The built-in Gmail MCP (mcp__claude_ai_Gmail) currently lacks the ability to reply to existing threads. create_draft only supports creating new drafts with to, cc, bcc, subject, and body — there is no thread_id, in_reply_to, or references parameter.

This functionality was previously available but appears to have been removed or regressed.

Expected behavior: create_draft (or a separate reply_to_thread tool) should accept a thread_id parameter to create a draft reply within an existing email thread.

Why this matters: Without thread reply support, users must manually copy-paste draft content into Gmail's UI to reply, breaking the workflow. Setting up a local MCP server as a workaround requires a Google Cloud project with OAuth credentials, which is not possible for users on organization-managed Google Workspace accounts (e.g., universities).