Cossi — AI Chief of Staff

You don't need another to-do app. You need someone who watches your calendar, your inbox, and your relationships — and tells you what matters before you ask.

That's Cossi: a private AI Chief of Staff that runs entirely on your phone. No cloud account. No data harvesting. No waiting to be prompted.

START EVERY DAY AHEAD
Open Cossi to a morning brief built from your real life: today's schedule, a pressure score for the day, the tasks that actually matter, relationships going quiet, and what slipped yesterday. Play it aloud while you get ready.

WALK INTO EVERY MEETING PREPARED
Minutes before each meeting, Cossi hands you a prep brief — the one thing to focus on, drawn from your calendar, prior notes, relationship history, and (if you opt in) recent email threads. After the meeting, capture notes in seconds. That context follows the same people into your next conversation.

GET BOOKED WITHOUT THE BACK-AND-FORTH
Share a booking link in one tap. Cossi finds your open slots, the other person picks a time — it adjusts to their timezone automatically — and the meeting lands on your calendar with a prep task attached. No more "does Tuesday work?"

NEVER LET A RELATIONSHIP GO COLD
Cossi tracks interaction health across meetings and email. When someone important is drifting, your brief flags it — and drafts the reconnect message for you. If tonight's meeting includes someone you haven't spoken to in six weeks, you'll know before you walk in.

AN AGENT THAT ACTS, NOT JUST ANSWERS
"Check my calendar and draft a decline for the 3pm conflict." Cossi's built-in agent reasons through multi-step requests using your data — and asks for approval before changing anything. Voice in, voice out.

YOUR INBOX, TRIAGED
Connect Gmail or any IMAP account. Urgent emails surface in your brief. Replies are drafted and queued for your review — nothing ever sends without your approval.

IT KNOWS YOUR LIMITS
Cossi measures your week's real capacity: committed meeting hours versus available focus time. Overbooked weeks get flagged. Your lightest day gets suggested for deep work. A short work-style questionnaire tunes everything to how you actually operate.

PRIVATE BY ARCHITECTURE
• AI runs on-device — your prompts never touch a server
• Zero telemetry, zero ads, zero tracking
• AES-256-GCM encrypted vault for passwords, keys, and private notes
• Post-quantum authentication (ML-DSA-65) — no password to steal
• One 24-word recovery phrase controls everything; it never leaves your device
• Cloud AI (Claude, OpenAI) is optional and uses your own key
• Privacy policy: https://www.cossiapp.com/privacy

WHAT'S INCLUDED FREE
Morning Brief · Chat · Calendar · Tasks · Encrypted Vault · Post-Quantum Auth

COSSI PRO (optional subscription)
Proactive Chief of Staff notifications · Meeting prep briefs · Relationship intelligence · Email drafting · Booking links · Capacity insights

Built for founders, operators, chiefs of staff, and anyone whose calendar runs their life. Cossi doesn't wait to be asked — it briefs you, preps you, and protects your time.

Your day, already handled.