Outlook Assistant v3.7.3 — E2E Sweep: 25 Real-World Fixes

What’s new in v3.7.3#

This release is the result of a manual end-to-end sweep against a live personal Outlook.com mailbox — every tool, every action permutation, every reasonable param shape. 48 findings filed across 7 GitHub issues (#159 tracker, #160-#165 by theme); 25+ fixes shipped here. v3.7.4 picks up two more (#168, #169) that surfaced in re-verification.

I’ll spare the line-by-line — see the CHANGELOG for the full list. The highlights:

MCP boundary chokepoint#

Every MCP client delivers params slightly differently. Some send arrays as JSON strings; some send booleans as "true" / "false"; some send numbers as decimal-formatted strings. Pre-3.7.3, each tool handler tried to deal with this individually, and the work was inconsistent. The visible failures were random: manage-rules isEnabled was silently ignored, update-email ids iterated character-by-character (one call → 400+ Graph errors), apply-category categories array literally didn’t work via MCP at all.

utils/schema-coerce.js handles it now. Single function, walks the tool’s inputSchema, coerces each value, hands the handler real JS types. 36 unit + integration tests covering each coercion path. Add a tool, no extra coercion code needed.

Strict unknown-param rejection#

Same idea — additionalProperties: false on every tool’s input schema. Typo a param and you get “Unknown param ‘verbosit’. Valid params: format, count, …” instead of silently ignoring it. Param-name aliases let backwards-compatible names continue to work (manage-event takes id or eventId; manage-rules takes displayName to match Graph’s field name; manage-category takes deprecated set and categoryId; etc.).

File output everywhere#

attachments download outputDir, export target=message outputDir, export target=conversation outputDir — all now honour the param. Default to os.tmpdir() rather than the current working directory (which was rarely what callers wanted). Auto-create the target directory if it doesn’t exist. Kept the deprecated savePath alias.

IDs on creates#

folders create and manage-rules create previously didn’t surface the new resource’s ID. The agent had to list, find by name, hope the name was unique. v3.7.3 adds **ID**: <id> to the response and surfaces it in _meta.

Identity in auth about#

Before: token diagnostics, scopes, expiry, last refresh — no indication of which mailbox. After: displayName <email> at the top of the block via a single GET /me. Surprisingly hard to live without once you have it.

Safety-belt warnings#

OUTLOOK_MAX_EMAILS_PER_SESSION and OUTLOOK_ALLOWED_RECIPIENTS are off by default — sensible for tool authors but error-prone if you forget to set them and start sending real email. Server startup now warns when they’re unset and prints a copy-paste snippet. Ships a .mcp.json.example with both pre-wired.

Other notable fixes#

• read-email strips zero-width tracking-pixel chars (U+200B..U+200F, U+2060, U+FEFF) — was bloating tokens by hundreds of chars on Gmail-relayed messages.
• set-auto-replies enabled=false properly transitions scheduled → disabled (was previously a silent no-op).
• set-auto-replies enabled=true (no schedule) on personal accounts now warns when Graph silently coerces the request to disabled.
• manage-contact list uses $count: true and shows “Showing N of M” with a skip: N hint when more pages exist.
• find-meeting-rooms and get-mail-tips distinguish “feature not available on this account type” from generic permission errors.

This is the largest single release of fixes Outlook Assistant has had. The mailbox sweep was 12 hours of pure regression-finding and the resulting 25-ish fixes are a significant trust upgrade — the small things that used to surprise you no longer surprise you.