Outlook plugin: add true reply (thread-preserving) — send_mail-only is too limited

Summary

The Outlook connector/plugin can list and read messages and send new mail via send_mail, but it has no real reply capability (no reply-to-message / thread-preserving send). That makes support and any threaded conversation workflows much less useful than they should be.

Problem

When an agent needs to continue an existing email thread (e.g. OpenAI Support, Trust & Safety, partner tickets), the only available path is to compose a new message with a Re: subject line and hope the remote system matches on subject/case ID.

That does not:

• Set proper In-Reply-To / References headers
• Keep the Microsoft Graph / Outlook conversation thread
• Reliably stay in the vendor’s existing case thread

In practice this leads to:

• Support systems opening new case numbers for each “reply”
• Broken conversation history on both sides
• Agents manually stuffing case IDs into subjects as a brittle workaround
• The connector feeling incomplete for the most common email agent task: reply

Expected behavior

Please add a first-class reply API, for example:

• reply_mail / reply_all taking a messageId (and optional body)
• Optionally forward_mail
• Preserve Graph conversation / internet message headers so replies stay in-thread

Ideal shape:

1. Read message by id
2. Reply (or reply-all) to that message with body
3. Sent item lands in the same conversation thread as a normal Outlook Reply would

Why it matters

Without true reply, Outlook is mostly useful for one-shot outbound and inbox search. For agent workflows that triage and respond inside ongoing threads, missing reply makes the plugin feel half-finished / awkward to use.

Context

• Plugin: Outlook (Microsoft Graph)
• Observed tools: list_mail_messages, get_mail_message, send_mail, get_me
• Missing: reply / reply-all tied to an existing message id

Thanks for considering this — reply support would make Outlook dramatically more useful for agent email ops.

Start by locating the Outlook plugin implementation and the existing list_mail_messages, get_mail_message, send_mail, and get_me tools. Trace how Microsoft Graph messages are read and sent, then define reply or reply-all behavior for a messageId; done means replies preserve the existing Outlook conversation and are covered by tests.