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Accounts and usage

Quatern's commands work without an account. The agent, the part that writes and adapts code from plain English, needs either a free Quatern account (sign in with GitHub) or your own Anthropic API key.

Quatern account Your own Anthropic key
How Sign in with GitHub ANTHROPIC_API_KEY, or store a key with quatern login
Cost Free monthly allowance Billed to your Anthropic account
Default model Claude Sonnet 5.5 Claude Opus 5.5
Requests go to Quatern's API, which forwards them to Anthropic Straight to Anthropic
Usage shown in whoami Yes No

Sign in with GitHub

quatern login

Choose 1 (or press Enter). Quatern shows a code and opens GitHub. Enter the code there and approve:

Your code: ABCD-1234
Enter it at https://github.com/login/device (opening your browser)…
signed in as octocat; token stored at ~/.quatern/credentials (readable by you only)
  • Quatern asks GitHub only for read access to your public profile (read:user).
  • On a computer without a browser, use quatern login --no-browser and open https://github.com/login/device anywhere.
  • New sign-ups need a GitHub account at least 30 days old.
  • In the REPL, the same flow is /login or /login github.

Free monthly usage

A Quatern account includes 400,000 tokens a month of agent usage.

  • Input and output tokens both count, including cached prompt tokens.
  • The allowance resets at 00:00 UTC on the 1st of each month.
  • Only the agent uses tokens. Verification, deploys, doctor and every other command run on your computer and are free.

Check what's left:

$ quatern whoami
Quatern account as octocat via https://api.quatern.co (token from ~/.quatern/credentials)
model: claude-sonnet-5-5 (default for Quatern accounts)
312,400 of 400,000 tokens left this month (resets November 1)

quatern doctor shows the same line under agent.

Limits

When You see
The month's allowance is used up Free usage for this month is used up. Resets November 1. You can also set ANTHROPIC_API_KEY to use your own key.
Too many requests in a short time rate limited: ... wait a minute and try again
The agent reaches its turn cap on one request [agent] stopped after 40 turns (agent_max_turns)
Your plan doesn't include the chosen model [agent] <model> is not available on your plan; using <fallback>, and the request continues

A Quatern account can use Claude Sonnet 5.5 and Claude Haiku 4.5. To use another model, such as Opus, use your own key.

Use your own Anthropic key

Create a key in the Anthropic Console, then either set it in your environment:

export ANTHROPIC_API_KEY=sk-ant-...

To keep it, add the line to ~/.zshrc or ~/.bashrc (on Windows, to ~/.bashrc in your WSL distribution).

…or store it with Quatern:

quatern login --anthropic-key

Anthropic API key:
stored at ~/.quatern/credentials (readable by you only)

With your own key, requests go straight to Anthropic. Usage, billing and rate limits are your Anthropic account's, and Quatern doesn't track them.

Which credential wins. If more than one is set, Quatern uses the first of: QUATERN_API_KEY, then ANTHROPIC_API_KEY, then the stored sign-in or key. When you store a sign-in while an environment variable is set, Quatern warns you that the variable takes precedence.

Choose the model

Signed in with Default
Quatern account claude-sonnet-5-5
Your own key claude-opus-5-5

Override it, in order of precedence:

  1. --model on quatern agent
  2. The QUATERN_MODEL environment variable
  3. runtime.agent_model in ~/.quatern/config.json (default "auto", meaning the defaults above)
$ QUATERN_MODEL=claude-haiku-4-5 quatern whoami
...
model: claude-haiku-4-5 (QUATERN_MODEL)

whoami and logout

quatern whoami shows how the agent is connected, the model and where it came from, and on a Quatern account, the tokens left this month. It exits 1 when you're not signed in:

$ quatern whoami
not signed in. Run quatern login, or set ANTHROPIC_API_KEY to use your own key.

quatern whoami --json gives the same information for scripts.

quatern logout removes the stored sign-in or key:

$ quatern logout
signed out: removed the Quatern sign-in at ~/.quatern/credentials

If ANTHROPIC_API_KEY is still set, Quatern says so: the agent keeps working until you unset it.

Account problems

Message What to do
your Quatern sign-in is no longer valid. Run quatern login. Sign in again.
Your Quatern account is disabled. Contact [email protected]. Email us. Your own key still works.
Quatern has reached today's limit of new sign-ups. Try again after 00:00 UTC. Try tomorrow, or use your own key.
cannot reach ... Check your connection. Everything except the agent keeps working offline.

Privacy

Stays on your computer: recordings, calibrations, maps, stacks, receipts, logs, REPL history and timings. Quatern doesn't upload any of them.

Sent when you use the agent: your request, a one-line note with the selected robot, its config path and the deploy target, and the text results of the tools the agent runs (for example a verification report computed on your computer). In the tour, the agent also gets the recording's id and length, the goal, and the reference modules' parameters.

Where it goes:

  • With a Quatern account, to Quatern's API, which forwards it to Anthropic. Quatern doesn't log prompts or responses. It stores one usage record per request (account, model, token counts, status and time).
  • With your own key, straight to Anthropic.

Your account: from GitHub, Quatern stores your GitHub id, your username, and your email address if GitHub shares it. Your sign-in token is stored on your computer in ~/.quatern/credentials, readable only by you; Quatern's servers keep only a hash of it.

For the full policy, see the Privacy Policy.