search_mails is much faster — and now supports a date range​

Until now, search_mails always searched both the subject and the message body on classic IMAP servers. On servers without a full-text index (Strato, Fastmail, most shared-hosting providers) that turned every query into a linear scan across the folder — long enough that the Claude client would sometimes hit its timeout and give up.

Starting now, the default is subject-only. For the rare case where you really do want to search the body, two new parameters:

• includeBody: true — also searches the message body. Can be slow on large folders without an index.
• since: "2026-06-01" and before: "2026-07-01" — restricts the search to a date range. Translated directly to IMAP (SINCE / BEFORE) and combines with includeBody.

Microsoft 365 still uses Graph — the switch is transparent there and includeBody now toggles between $filter contains(subject,…) (fast, chronological order) and $search (relevance order, full header + body).

Sent messages now reliably end up in the Sent folder​

On classic IMAP/SMTP, sent messages were delivered correctly but not copied into the mailbox's Sent folder — the mail was only visible on the recipient's side. Fixed. After the SMTP handover, send_mail now performs a best-effort IMAP APPEND into the right Sent folder (detected via the \Sent special-use flag or a list of common names: Sent, Sent Items, INBOX/Sent, INBOX.Sent, INBOX.Sent Items).

Microsoft 365 continues to set saveToSentItems=true on the Graph call — this was never an issue there.

Clear errors instead of timeouts for "Mailbox in use"​

When two sessions open the same IMAP mailbox at the same time, Dovecot (including the default Plesk configuration) temporarily rejects the second with "Mailbox is in use". Until now that arrived at the AI assistant as a generic error.

We now retry internally up to three times with a short backoff — the vast majority of these collisions clear within 250–600 ms. If it doesn't clear, we return a clear message:

The mailbox "Team Support" is currently open in another session. Please try again in a few seconds.

Every error now also carries a correlation ID so we can find the exact request in our logs when you contact support.

All of the above is active on every plan and needs no change in the portal or the AI assistant. Feedback to support@inboxmcp.io.

With help articles, documentation, per-AI-tool guides, this changelog and a roadmap. Available in English and German.

Feedback at support@inboxmcp.io.

Feature set​

• Own mailbox with Microsoft sign-in — sign in through the Microsoft OAuth flow, confirm access. The refresh token is encrypted with an asymmetric envelope scheme before it's stored.
• Shared mailboxes — add a delegate mailbox of a connected Microsoft account without a second sign-in. Before saving, inboxmcp verifies access once via Microsoft Graph; if the check fails, no entry is created.
• Folder hierarchy — nested folders (e.g. Archive/2024/Customers) are correctly resolved in list_folders and every other tool.

MCP tools​

Available immediately — Read: list_mailboxes, list_folders, search_mails, read_mail, read_mail_chunk, get_attachment. Write (Premium / Business): draft_mail, edit_draft, create_folder, move_mails. The remaining write tools send_mail, flag_mail and delete_mail are coming across all providers.

Not yet included​

• Self-service tenant admin consent for Microsoft 365 organisations
• Shared mailboxes with their own sign-in (without a delegate account)

Both are scheduled on the roadmap. More under Connect Microsoft 365.

Feature set​

• MCP endpoint at https://mcp.inboxmcp.io/mcp with OAuth 2.1 and Dynamic Client Registration (RFC 7591). Compatible with Claude Web and Desktop, plus any MCP-conformant client.
• Mailbox connection for IMAP/SMTP (every RFC-3501 mail server — mailbox.org, IONOS, STRATO, Posteo and others) and Microsoft 365 via OAuth.
• Read tools: list_mailboxes, list_folders, search_mails, read_mail, read_mail_chunk, get_attachment (attachment URLs are HMAC-signed and short-lived).
• Write tools (Premium / Business): draft_mail, edit_draft, create_folder, move_mails. More coming.
• Stripe billing: Free (1 mailbox, read-only), Premium (€2.99/mailbox/month), Business (€4.99/mailbox/month) with DPA, audit-log access and tax-compliant invoice.
• Audit log: every tool call is recorded with timestamp, tool, mailbox, client and result.

Security​

Credentials — IMAP/SMTP passwords and OAuth refresh tokens — are encrypted with an asymmetric envelope scheme before they're stored. Recovery from outside is technically impossible. Mail content is never persisted. More under Security & privacy.

Not yet included​

• Write tools send_mail, flag_mail, delete_mail
• Audit log export (CSV / JSON)

Status on the roadmap. Feedback at support@inboxmcp.io.