FAQ
What does a run cost?
You pay Anthropic directly for model usage, on your own API key. Rough cost of one run with 6 personas, from our own runs and Tensteps' estimates:
| Model | 6 personas |
| --- | --- |
| claude-fable-5-1 (default) | about $2 |
| claude-opus-5-5 | under $1 |
| claude-sonnet-5-5 | about $0.40 |
| claude-haiku-4-5-20251001 | about $0.20 |
Longer flows cost more. Every run prints an estimate first, and --max-cost refuses to start a run estimated above your limit. Set a spend limit on the key in the Claude Console too.
Is it safe to point at my preview?
Personas really click, type and submit. Before the first run:
- make sure previews don't write to production data or send real emails
- keep payments in test mode and set
guardrails.payment: test_card - list anything off-limits in
guardrails.forbid_actionsandguardrails.forbid_paths
Personas also stay on your site: they can't open other websites unless you allow a host with --allow-host.
Where does my data go?
Screenshots and page text of the site being tested go to Anthropic's API to drive the personas. Typed passwords are masked in reports. Reports stay in your CI run or on your machine. During the pilot, Tensteps runs no servers of its own and receives none of it.
How realistic are the personas?
They're simulated, so treat findings as leads. They're good at noticing where a flow is confusing, slow, broken on a device, or surprising (a fee that appears late, a field that rejects valid input). Every finding links to the replay, so you can judge it yourself in seconds.
Will results change between runs?
The same seed always gives the same persona, device and network. The model's choices vary a little from run to run, so compare runs by what most personas did, not by one session.
Does it work with logins?
Yes: give studies a test account through auth with secret: values. Personas log in when the site asks. Use an account that only exists for testing.
Which CI and hosts are supported?
GitHub Actions with Vercel previews is the guided setup. Any CI can run npx tensteps@beta run --url <preview URL> --yes; GitLab and Bitbucket comments are planned.