Questions about Cygtree

Does Cygtree work offline?

Yes, entirely. Your boards are ordinary files on your own disk, so the app has nothing to fetch and nowhere to phone. There is one exception and it is not your work: activating a licence key contacts our server once, and after that the app re-checks the key with Polar once on each launch — one request carrying the key and the activation id, no background timer, and nothing about your boards. No answer is not a failure: a paid licence takes no clock, so an offline machine keeps working indefinitely.

Do I need an account?

No. There is no Cygtree account, because there is no Cygtree server holding your work. You type a licence key in once on each computer and that is the whole of it — no sign-in, no password, no session that expires while you are in the middle of something.

Is there a subscription?

No. Cygtree is $20 once and then it is yours. No renewal, no seats, no per-user pricing, and nothing held back behind a higher tier — the trial is the whole app, and so is the version you pay for.

What happens when the three-day trial ends?

Saving stops, and nothing else does. You can still open every board you made, read it, move around it and export it. Nothing is deleted, nothing is hidden and nothing is held — the app simply refuses to write new changes to a board until there is a licence on the machine. The AI features need a licence too, so those stop with the trial. Buy a key and the same install picks up where you left off.

Does Cygtree run on Mac or Linux?

No. Windows 10 and 11, 64-bit, is the only build that exists. The homepage lists macOS and Linux as coming soon, and that is a hope rather than a promise — there is no date, no beta and no commitment behind it. If you are on a Mac today, Cygtree is not for you today.

Do I need an API key?

No. Cygtree holds no API key, asks for none, and has nowhere to put one — there is no key field in the app. It does not resell tokens and it does not run an AI service of any kind.

Can I use my existing Claude or ChatGPT subscription?

Yes, through the command-line agent that plan already gives you. Cygtree launches Claude Code, Codex or Cursor as an ordinary program on your machine, signed into your own account, at your own plan's rates. It never sees your login and never reads or transmits your credentials — it reads those tools' own config files only to list the models they offer. What each one needs and how it is launched is on the AI page.

What does it cost to run the AI?

Nothing extra from us. Cygtree charges nothing for AI, takes no cut of it, and has no meter of its own, because there is no server in the path to meter anything. Your own provider's limits still apply in full, so what Cygtree adds is no limit of its own on top of the one you already pay for.

Do I need an AI at all?

No. With no AI tool installed the board works completely — it is a mind map first, and the AI is something you bolt on if you already pay for one.

Where are my boards stored, and can I open them if Cygtree disappears?

Under %LOCALAPPDATA%\com.cygnuscrane.cygtree\ on your own disk, and yes — they are plain files you can open in a text editor with Cygtree gone. You can move that folder somewhere else. Copy them, back them up, put them on a drive — they behave like any other file, because that is what they are. There is no cloud copy and no sync, so nothing of yours sits somewhere you cannot reach. Export keeps working even with no licence, so a board can always be taken out as a copy or an image. That is not a promise about our future, it is what the files are: the licence says your boards are unaffected if we stop existing.

Does Cygtree send my boards anywhere?

No. There is no sync, no cloud copy and no upload path. When an AI agent reads your board it does so over a connection on your own machine that never leaves it — whatever that agent then sends to its own provider is between you and the plan you pay for.

How many computers can one licence key activate?

A paid key activates on two computers. A trial key activates on one. Two activations is one person on two machines, not two people at once. Reinstalling Windows or swapping the motherboard counts as a different computer, so deactivate before you do either.

What if I get a new PC?

Deactivate the old one first. Open Settings → License in Cygtree on the old computer and press Deactivate this machine; if it reaches Polar the slot frees straight away and your key is unchanged. If it cannot reach Polar nothing is cleared — the slot is still held, deliberately — so do it while you are online rather than assuming it took. If the old computer is gone or dead, remove the activation from your Polar account instead — and if that fails, write to [email protected] and we will try to free the stranded slot for you.

Can I get a refund?

You ask Polar, not us, and Polar decides. Polar Software, Inc. is the merchant of record for every Cygtree order, so a refund is theirs to give — ask through the Polar account portal your purchase created, which you can reach from the account page. Cygnus Crane operates no refund policy of its own and quotes no window; any number we gave you would be a number we do not control. It is also why the three-day trial exists: try the whole app before you spend anything.

What do I get in updates?

Every version 1 release. Versions 1.0 through 1.9, and anything numbered below 2.0, are included in the $20 with no upgrade fee along the way. A version 2, if it ever exists, would be a separate product and a separate purchase.

Does Cygtree track me?

No — the app collects nothing, though this website counts page views. There is no telemetry, no analytics, no usage counters and no crash reports in the software: no code in it reports on you. It does make the connections you ask it to make — the licence check, a link you paste or an agent adds by URL, a voice or dictation model you choose to download, and a YouTube or Vimeo card for as long as it is on screen. Each one is listed in the Privacy Policy, and none of them carries board content or an identifier. The site is a separate matter. It runs Cloudflare Web Analytics, which sets no cookie and assigns no visitor id, and it keeps one thing more — a one-way fingerprint of the address that took a trial, so the same address cannot take a second one. The Privacy Policy lists everything the site holds and how long it holds it.

What is ACP, and is it the same as the other ACP?

ACP here means Zed's Agent Client Protocol, and no — it is not IBM's Agent Communication Protocol. Zed's is the open protocol for talking to coding agents, and Cygtree speaks it, so an agent nobody has written yet can drive a board as soon as you point Cygtree at it, without waiting on us to add support. IBM's is a different specification and has been archived. The two share three letters and nothing else.

Is the connection between the board and the AI a security boundary?

No, and it should not be treated as one. The board tools are served over a connection that never leaves your machine, but any program running as you could in principle reach it. An agent connected over the Agent Client Protocol brings its own file and shell tools, which Cygtree does not sandbox and cannot. Claude Code, Codex and Cursor are launched more tightly than that — their file and shell tools are switched off in this connection — and the AI page sets out exactly what each one can still reach. If you would not let that agent near your disk in a terminal, do not let it near your board.

How do I get support?

Write to [email protected] from the address you bought with. One person answers that mailbox, so this is an endeavour and not a service desk: we will try to reach back out within two business weeks. Try is the honest word, and it is there on purpose.

The trial lasts three days and gives you the whole app. No payment card is asked for at any point. An email address is, because Polar emails the key to it, and one trial is issued per address.

A trial key activates on one computer. A paid key activates on two. Two activations is one person on two machines, not two people at once.

The paid licence is $20 once. It is perpetual, and it covers every release numbered below 2.0 — 1.1, 1.9, 1.10 and anything else in version 1.

A licence is activated once, through our server. After that the app re-validates once on each launch, straight to Polar, carrying only the key and the activation id. A paid licence takes no clock, so a machine that never gets an answer keeps working indefinitely.

The trial carries its own three-day offline allowance. That is a separate clock from the trial itself and happens to be the same length.

When a licence ends, saving to a board is refused. Opening, reading and export all keep working, and no board is deleted, hidden or held.

Deactivating a machine from inside the app frees its slot immediately, provided the app can reach Polar. If it cannot, nothing is cleared and the slot stays held. The key itself is unchanged and can be typed in again anywhere.

Boards are ordinary files on your own disk. There is no cloud, no account and no sync.

Cygtree runs on Windows 10 and 11, 64-bit. There is no macOS build and no Linux build.

Polar Software, Inc. is the merchant of record. Refunds are handled by Polar, and Cygnus Crane operates no refund policy of its own.

Not answered here? Write to [email protected]. A question that had to be asked is a question this page should have answered, so it will end up on it.