The Missive MCP server can create and update email drafts through compose_draft, but it cannot attach files. Missive support confirmed this limit on September 29, 2026.

Please add a way to upload files and attach them to new or existing drafts through MCP. The draft should show the file names and attachments before the email is sent.

For example, an AI assistant could create a report or PDF on my computer, then prepare an email with that file attached in Missive. I could review the draft and approve the email without adding the file by hand.