Question 1

What is playwright-jev?

Accepted Answer

A semantic E2E testing tool built around a Node CLI: playwright-cli observes and performs browser actions, Jev chooses the next step from a code-generated action space, and test code supplies deterministic inputs, assertions, thresholds and the final verdict.

Question 2

What exactly does Jev decide?

Accepted Answer

Only the next action. Jev cannot launch a browser or execute selectors; it returns an actionId from the current observation, and selectors, refs, input values, browser commands and final assertions are all controlled by code. The README credits browser-use/jev-ultrafast for the dynamic indexed action space and speculative fan-out ideas, while the browser layer here is playwright-cli rather than direct CDP.

Question 3

Can I try it without an API key?

Accepted Answer

Yes. Start the bundled login page with python3 -m http.server 4173 --directory examples/demo-app, then run node scripts/cli.mjs examples/login.offline.json --offline. Seeing the demo login pass means the browser startup, page actions and assertions work; it uses preset actions and never calls Jev, so it is not evidence of decision quality.

Question 4

What do the run outcomes mean?

Accepted Answer

passed means Jev chose the completion path and deterministic assertions all passed; failed means a browser action, assertion or tool call failed; blocked means Jev judged the action space cannot progress; review means selection confidence was below the threshold, so the run stops and waits for a human.

Question 5

What should stay in deterministic Playwright tests?

Accepted Answer

Exact amounts, dates, URLs and HTTP status codes; high-risk side effects like payments, deletions and sends; pixel-level visual regressions; and canvas, complex drag, file upload or multi-window flows. The README positions Jev for exploratory E2E with natural-language goals and minor page-structure drift, not those cases.

Question 6

What does a trace record?

Accepted Answer

JSON traces default to outputs/login-trace.json and record page summaries, action candidate counts, the chosen action, probability distributions and per-request jevLatencyMs, jevAttempts and jevUsage, plus total and average Jev time. They do not record input values.

Question 7

What are the requirements and defaults?

Accepted Answer

Node.js 20+, Python 3 and playwright-cli (npm install -g @playwright/cli@latest); if it is not on PATH, set PLAYWRIGHT_CLI. The endpoint defaults to https://api.typesafe.ai/v1/systemone with model jev-latest, overridable via TYPESAFE_ENDPOINT and TYPESAFE_MODEL; npm test runs the repo tests and npm run check checks syntax.

Playwright + Jev E2E

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