Outlook export

Outlook's own OAuth connector needs Microsoft's app-review process, the same story as Gmail's. Until that clears, gnt prebrain --outlook reads a portable Outlook export instead, no approval required, no gnt server ever in the read path.

Produce the export

Outlook has no single-click whole-mailbox export to a portable format. What it does support natively is per message: open a message in Outlook on the web or new Outlook for Windows, open the message actions menu, and choose Download → Download as EML (Outlook on the web) or Save as (new Outlook for Windows). Each one writes a single .eml file. Repeat across the messages you want scanned, put them all in one folder, then point --outlook at that folder.

For more than a handful of messages, script it against the Graph API instead: GET /me/messages/{id}/$value returns a message's raw MIME content, exactly what a .eml file holds. Loop it over a folder's message ids and write each response to its own file.

Not supported: classic Outlook for Windows' Import/Export wizard, which only writes .pst, Microsoft's proprietary binary mailbox format. Parsing it would mean reverse-engineering a closed binary format instead of reading a documented text one, so --outlook never attempts it. If a .pst file is all you have, open it in classic Outlook and use the per-message export above, or bridge it through another mail client that can read PST and export EML or mbox.

mbox works too, if you already have one

Outlook itself never produces an .mbox file, but if you bridged the mailbox through a tool that does (syncing it over IMAP into another mail client and exporting from there, for example), point --outlook at that single file instead of a folder. It's detected automatically and read the same way --gmail reads a Takeout export.

Scope it with flags

Bound the date range and sender with --outlook-since/--outlook-until (YYYY-MM-DD) and --outlook-from (comma-separated addresses or domains). A malformed date skips the walker entirely rather than silently running it unscoped.

Code
$ gnt prebrain --outlook ~/Exports/outlook-eml \
    --outlook-since 2026-01-01 \
    --outlook-from acme.com

Found 96 candidate chunks:
  Outlook export: 96 chunks across 19 files

What it reads, and what it never does

Same parsing and thread reconstruction as the Gmail export walker: messages are reconstructed into threads using each message's Message-ID, In-Reply-To, and References headers, HTML bodies are converted to plain text, and quoted history a reply carries along is stripped, so a long thread doesn't get reprocessed once per reply.

Attachments are never opened. If a message has one, its filename is kept for context and nothing else about it is read.

Same as every other prebrain walker: everything above happens on your device before the privacy gate runs, and only masked text ever reaches extraction.