AI

AI in Letos is optional. Until you turn it on, you won’t see any AI button and nothing is sent anywhere.

Who answers

In Settings → AI → Provider you choose what handles AI features:

Provider	Where it runs	What you need
Local model (on this device)	on your computer, nothing leaves it	a Mac with Apple Silicon and at least 16 GB RAM, a model download (about 5 GB)
Claude API	at Anthropic	your own API key
OpenAI API	at OpenAI	your own API key
Custom endpoint (OpenAI-compatible)	wherever you specify	an address, a model, a key if needed
Claude CLI (signed-in subscription)	at Anthropic, via your installed claude	Claude Code signed in with your subscription
Codex CLI (signed-in subscription)	at OpenAI, via your installed codex	Codex CLI signed in with your subscription

Local model

The local model (Gemma 4 E4B) is downloaded once from Hugging Face and then runs right inside Letos, with no internet. The text of your e-mails and tasks never leaves your computer. It works only in the desktop app on a Mac with Apple Silicon; on weaker hardware it would answer slowly.

Claude CLI and Codex CLI

If you have Claude Code or Codex CLI installed and signed in with your subscription, Letos finds it on its own and uses it (it runs claude -p / codex exec). If it finds the CLI but it isn’t signed in, it shows “not signed in” and suggests claude auth login / codex login. A Connect chip then appears next to the AI button and opens Settings → AI.

API keys

In the computer and iPhone apps an API key is stored only in the system keychain — never in the database — and isn’t synced to other devices. In the web version the key is stored encrypted on the Letos server, which uses it for AI requests; you’re asked for consent before it’s saved the first time. Delete it with Delete saved key.

iPhone

On the iPhone, AI doesn’t run on the device. You have two options. Either in Settings, under AI (custom endpoint), find the My computer card and click Use My computer — AI then answers on your Mac and requests travel between your devices encrypted (on the Mac turn on Use this computer as AI for my devices). Or enter your own OpenAI-compatible endpoint, model and API key. Without one of the two, AI features stay hidden on the iPhone.

Consent to sending content

For any provider outside your device, Letos first asks with one shared consent, Send data off this device: to whom (e.g. Anthropic · api.anthropic.com), what is sent (the text of e-mails you have processed, tasks, goals, notes, up to 20 sent e-mails for your writing style…) and why. It asks when you save the provider in Settings → AI or the first time you use an AI button.

• Allow — the consent covers this provider; for a custom endpoint only the saved address.
• Decline — nothing is sent and the feature stays off. You aren’t asked again; the AI button shows a short note with Allow….
• Close (Esc) — not a decision; you’ll be asked next time.
• Consents given earlier stayed valid (“Allowed earlier”).
• Decisions about API providers sync to your other devices; for the Claude CLI and Codex CLI they apply to this computer only.
• Change it any time in Settings → Privacy. When revoking you can tick Also delete the stored API key (off by default).

Our sync server never sees AI content — it goes straight from your device to the provider.

What AI can do

• Mail: Summarize thread, Smart snooze ✨, sorting into Action / FYI / Newsletter, Draft a follow-up, Write with AI (a reply draft in the tone you choose), rewriting text and Check grammar (local model only).
• Quick replies: in the top bar next to the Reply button, the More reply options menu (▾) has Reply with an AI suggestion, shortcut ⌥ R. It opens a reply and suggests three short texts right away. The item appears only when AI is ready. Clicking a suggestion inserts that text into the reply, which you edit. When the suggestions run out, the Suggest quick replies button above the text in the compose window offers another set. Nothing is sent without you. If you use a provider outside your device, the same consent applies as for the rest of AI.
• Tasks: Extract tasks ✨ from an e-mail, ✨ Suggest subtasks, ✨ Estimate with AI, ✨ Capture from free text and ✨ Solve with AI — the result is added to the task note under the heading “Řešení (AI)”; nothing is overwritten.
• Goal planning: Plan with AI turns a goal into a concrete plan — see below.
• Overviews: summaries of the day and the week.

AI never sends or deletes anything on its own. You always review and confirm suggestions.

Thread summaries are stored on the device; clear them in Settings → AI.

Plan with AI

On a yearly goal (in the Year view, on the goal card and in its detail) or while creating a new goal you’ll find Plan with AI. You answer five questions — what you want to achieve, why, how you’ll know it’s done, by when, and how much time a week you can give it — and AI drafts, in three steps:

1. the goal rewritten to be concrete and measurable (your own words stay visible next to it),
2. one milestone for each remaining quarter,
3. 3–6 first tasks for the first two weeks with time estimates; the first one is a small step for the next few days.

You then see everything on one review screen: edit, untick, remove or reorder any row. Rows from AI carry a Suggested by AI label. Nothing is saved until you press Add selected; then only the ticked rows are added, and a single Undo takes the whole plan back. If the tasks don’t fit your time for two weeks, the last ones are unticked and Letos tells you.

• Who drafts it: the local model is offered first. A provider outside your device only if you’ve already given it consent, and before the first step you see what is sent: just the goal title, why, your answers and the titles of your other goals. Nothing from mail or the calendar.
• If a draft fails, Letos does not switch to another provider on its own. You choose: try again, use a template, or a provider you’ve already allowed.
• Done when: the goal’s measure is saved as a “Done when: …” line in the goal’s note and shows in its detail.
• Health and money: such goals can be planned too — steps are phrased as habits, and the draft says it isn’t professional advice.
• Time blocks (optional): on the review screen you can look for free time in Google Calendar. Letos only uses busy/free information and the working hours from Settings. Only the blocks you tick are written to the calendar. Without Google Calendar you get dates only.
• Without AI (AI off, iPhone, web) the same steps work with templates — see Tasks.

In the Weekly review each goal has an optional AI: suggest next steps — 1–3 tasks for the coming week and, if the goal is behind, one suggested change (move a milestone, shrink the scope, add time). Nothing changes on its own: you add only what you tick. Besides the goal title, why and date, this step also sends the titles of that goal’s steps (done this week and open), step counts and the titles of your other goals — with a provider outside your device this is spelled out under the button. Notes, mail and the calendar are never sent.