Post
Your inbox has 42,000 unread emails.
Somewhere in there is the K-1 your client sent last Tuesday.
Cairn Post watches your firm's connected mailboxes, filters the noise with rules you can inspect, and sorts what's left by client and type. The morning starts with a short list instead of a raw inbox to triage by hand.
The Problem
Information arrives faster than anyone can file it.
Documents vanish in threads
Clients forward W-2s buried in reply chains mixed with questions, small talk, and "here u go" messages, and the documents quietly get lost while the surrounding context evaporates.
Context dies in the inbox
When a client calls months later asking "why did you do X?", the answer is sitting in an inbox somewhere, and nobody remembers the email or can find it quickly enough to actually answer the question.
Knowledge walks out the door
The senior partner knows every client's quirks, including who needs reminders, who sends phone photos of documents, and who panics every Q4. When they retire, all of that institutional knowledge leaves the firm with them.
Post does not do generic sorting by importance. It reads a forwarded chain from a client's banker as financial correspondence, and knows an IRS notice is still an IRS notice even when the subject line is just "help???"
The Morning Sorting
What one morning of mail becomes.
Filter
Nothing is deleted. Filtered mail stays here, inspectable.
Hold
First contact waits at the gate. A person decides.
Question about your services
Waiting · Held Queue
Classify
AI sorts what rules leave behind. It never hides a message.
Suggested: Returns · flagged return
Suggested: Returns · active filing
Matched via Contacts
Brief
The morning starts here. A short list, not a raw inbox.
2 filtered this week · 1 held · 3 sorted today
How Trust Works
Every sender lands in one of three tiers before AI ever looks at their mail.
Trusted senders are clients Post already knows. Known senders have a real back-and-forth on file. Everyone else waits.
Trusted
A sender matched to a client record, or someone a colleague has marked as trusted by hand.
Known
Not a matched client, but an established back-and-forth: past emails, or mail the firm has already sent them.
Untrusted
First contact, or too little history to place with confidence. Mail waits in the Held Queue until a person reviews it.
A manual decision always sticks. Once someone marks a sender known or trusted, Post does not recompute the tier out from under that call.
Post reads your mail. It doesn't keep a copy.
When AI classification runs, the email's content comes from your mailbox at that moment and is never written back to Post's own database afterward. What stays on file is metadata: the subject, a short preview, who it's from, and what Post decided, never the body of the message.
Post watches. Post understands. Post suggests.
Your team decides and acts.
Not an email client. Doesn't replace Outlook.
Not an auto-responder. Never sends email on the firm's behalf.
Not an autopilot. Every suggestion is a link a person follows and confirms. Nothing routes on its own.
Not a practice management suite. Focused on intake intelligence, not workflow management.
Capabilities
What Post does
Sorts incoming mail into categories accountants use, like tax documents, IRS notices, and client questions, without generic importance scoring
Filters noise with deterministic rules first, and only sends what's left to AI once a firm turns classification on
Holds first-contact senders in a queue until a person acknowledges them, so nothing unfamiliar reaches AI without a decision
Pushes IRS and state notices to the top by a fixed rule that AI cannot override
Connects to Microsoft 365 mailboxes through OAuth, with no inbox forwarding required
Works backward through up to twelve months of mailbox history once a connection starts backfilling
Fetches email content only at classification time and never stores it, keeping metadata, not a copy of the mail
The Ecosystem
The front door to the entire Cairn suite.
Post reads context from six apps across the suite, so a classification can carry the client's active filing, an open document request, or a matched bank account with it. Nothing writes back automatically. Every suggestion is a link a person follows and confirms.
Cairn Post is in active development.
It already reads context from six apps across the suite to sort mail well. We are onboarding firms individually to make sure every implementation is done right.