[FEATURE] Gmail MCP Connector: Add mark_as_read (remove UNREAD label) tool

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

The Gmail MCP connector currently lacks the ability to mark emails as read. This means automated workflows (e.g. scheduled email digest tasks in Cowork) that summarise and process emails cannot complete the final step of marking them as read after processing.

Proposed Solution

Requested tool: unlabel_thread or a dedicated mark_as_read tool that removes the UNREAD system label from a thread or message.

Similar feature requests: #28575 (attachment support), #27567 (multi-account support)

Alternative Solutions

Manually marking them is currently the only option

Priority

High - Significant impact on productivity

Feature Category

MCP server integration

Use Case Example

Use case: Scheduled Cowork tasks that check Gmail and summarise action items should be able to mark processed emails as read automatically, without requiring manual user intervention.

Additional Context

_No response_