First public beta of MailChat for Thunderbird.

Default drafts-only mode blocks sending from the chat. Optional autonomous sending requires explicit activation in both the Windows installer and Thunderbird settings, plus compose.send permission.

Search and read local mail, download selected attachments, prepare new drafts and native replies with account signature and RFC-linked predecessor history. Missing history fails explicitly. Exact draft content and permissions are checked before autonomous sending; uncertain sends are not retried automatically.

Requirements: Windows, Thunderbird 153+, Node.js 22+ and Codex desktop with local MCP support. Download the required Windows bridge and installation instructions from https://github.com/andrea199/mailchat-for-thunderbird/releases/tag/v1.4.0-beta.1 . The XPI alone is not sufficient.

Nine automated mock/HTTP/installer tests passed. Real Thunderbird/Codex end-to-end testing remains outstanding. Beta release, independent project, MIT license.