Release 0.5.0 — sending mail

Sending over SMTP

For classic IMAP mailboxes the assistant now uses the SMTP credentials you registered when adding the mailbox. To, CC, BCC, subject and body work as expected; you can send HTML and plain-text bodies together so the recipient's client picks the format that fits. Replies thread cleanly into the original conversation and quote the previous message — same behaviour you already know from drafts.

Sending over Microsoft 365 — including shared mailboxes

Microsoft mailboxes go out through the Graph API. For your own mailbox nothing else is needed — once you enable "Allow sending" when connecting it, the assistant can send directly. For shared (delegate) mailboxes the assistant sends AS the shared mailbox itself, so the recipient sees "info@yourcompany.com" as sender, not your personal Microsoft account.

The usual Microsoft permission applies: the connected user account needs Send-As rights on the shared mailbox. If it doesn't, Microsoft rejects the send — and the assistant gets a clean error message with a hint at what to do, instead of a cryptic stack trace.

SMTP is now optional

When adding an IMAP mailbox you can now simply skip the SMTP fields. A checkbox "Allow sending from this mailbox" controls whether SMTP details are even collected.

If you skip SMTP and the assistant later tries to send, it gets a direct answer: "Sending is not allowed for this mailbox. SMTP credentials are missing — add them in the portal to enable sending." No cryptic timeouts, no silent failures.

Per-mailbox, by design

For Microsoft 365 (own and shared) the connect dialog now has its own checkbox "Allow sending from this mailbox". It's off by default — mailboxes you connect only to read stay read-only. You can flip it on later in the mailbox details without re-running OAuth.

It works the other way too: turn sending off later — for instance because the assistant should only listen for a while — and the next send attempt comes back as "Sending is currently disabled for this mailbox."

Clean errors, always

While we were at it, we tidied up error behaviour across the whole MCP surface: every unexpected exception is now caught centrally, answered with a plain-English explanation, and tagged with a unique correlation ID. When something goes wrong you can copy that ID into a support ticket and we find the matching trace in our logs in seconds rather than minutes.

What's next

With sending, drafting, iterating and moving in place the main write actions are now all covered. Next we focus on the remaining classic mail verbs — flagging (read, important, starred) and moving to trash — and on broader Microsoft-side providers for customers who run more than "just" Outlook.

As always, we'd love to hear how you use the assistant and where things creak: hi@inboxmcp.io.