Gmail: Update a draft — MCP tool
Gmail MCP tool: Replaces a draft's entire message with new content — the Gmail API has no partial draft edit.
Technical name: update_draft
What task it solves
I want to change what a draft says.
Rewrites a stored draft — new recipients, subject or body — while keeping the same draft id.
When to use it
After the user reviewed a draft and asked for changes. Read it with get_draft first: this call replaces the whole message, so every field to keep must be passed again — omitted fields are dropped, not preserved.
What to provide
draft_id— required.- The complete new state, same fields as create_draft:
to,cc,bcc,subject,body_text/body_html, andthread_id/in_reply_tofor reply drafts.
What it returns
The updated draft (same draft_id; the underlying message id changes).
What changes in Gmail
The draft's previous content is overwritten in the mailbox. The old version is not kept anywhere.
Example request
In my draft to the supplier, change the requested delivery date to 15 September and add Maria to CC — keep the rest as is.
Errors and limitations
Because omitted fields are dropped, "add Maria to CC" requires re-sending everything else too — fetch, merge, then update. A 404 means the draft was sent or deleted meanwhile. Access also depends on token permissions, quotas, and upstream API limits.
Related MCP tools
- Read a draft — the current content to merge with.
- Send a draft — after the update is approved.
Technical details
- Impact: destructive operation
- Group: Drafts
- Description source:
update_draftregistration insrc/tools/drafts.ts - Full technical reference
- All MCP capabilities