jevway
[npm]
[CI]
[License: MIT]
[Website]
Website and demos ·
Quick start · Agent setup guide · How it works ·
Reference
Give your coding agent a browser goal and get back one short, checked summary. TypeSafe Jev
picks each click, type and select in about 300 ms, so your agent stops spending a turn on every step.
[Your agent hands jevway a goal; each step jevway reads the page, asks Jev for one decision and acts in Chrome; the agent gets one summary back]
jevway is an MCP server and a CLI. It works with Claude Code, Codex, Cursor, OpenCode and any other MCP client, in your
own signed-in Chrome or a throwaway one.
Why
Driving a browser click by click costs an agent a model turn, a page snapshot and a few seconds per step. A 15-step
form takes minutes and fills the context window with snapshots. jevway hands the whole goal to Jev, a model built to
choose browser actions, and returns when it's done or when it needs the agent:
- It never invents input. Jev types only the
values the agent passed. A missing value comes back as
needs_input, naming the field.
- It stops before anything irreversible. Pay, send, delete and submit come back as
needs_confirmation. One
confirmation allows one click, on the control that was named.
- It checks its own success.
done needs a separate check of done_when on the final page, plus any exact
checks you add, and comes with the page's own words as evidence.
- Model output only ever selects a listed element. It never becomes a selector, a script or typed text.
- It can record what it did. A video of the run, a screenshot before every action, and an HTML page to review it,
built in. See Recordings.
What you need
jevway has no browser extension and no Playwright: it drives Chrome directly. Three things are required, and two
optional tools unlock more.
Which key? Both run the same Jev model. The TypeSafe key adds Box, which locates controls on the screenshot:
it double-checks the click Jev chose and whether it's covered, rescues a step when Jev is stuck, can click a canvas
control (opt-in), and marks each journey screen's primary action and the controls missing from the page's code. Through OpenRouter those Box features are off; everything else works.
npx -y jevway doctor checks all of this and names the fix for anything missing.
Quick start
-
Get a key from TypeSafe (or use an OpenRouter key).
-
Run the setup in your terminal:
It asks for the key without showing it and saves it to ~/.config/jevway/env (mode 600, never a chat or a synced
config), tests the browser, and registers jevway with the clients it finds: Claude Code, Codex, Cursor, OpenCode.
Every change is shown first, as a command or a diff, and made only on a yes. It ends with jevway doctor.
In Claude Code you can instead install the plugin, which brings the server and the skill that tells the agent when
to use it (then put the key in ~/.config/jevway/env yourself):
-
Allow the browser. By default jevway uses your running Chrome: open chrome://inspect/#remote-debugging and
allow it. To use a throwaway browser instead, set JEVWAY_BROWSER=launch.
-
Ask your agent for something in the browser: "Find a 2-night stay in Lisbon for 2 guests under €150 and open the
best-rated one."
npx -y jevway doctor checks the setup at any time (--json for agents) and names the fix for anything missing.
Let your agent set it up
Paste this into your coding agent (Claude Code, Codex, Cursor, OpenCode…):
SETUP.md walks the agent through everything: prerequisites for your OS, the key, registering the server,
the browser, the skill, a recorded Google → Wikipedia smoke test, and a report with the run page, video and
screenshots as proof.
Install
npx -y jevway setup registers jevway with Claude Code, Codex, Cursor and OpenCode (Claude Code also has the plugin
above). Any other stdio MCP client runs npx -y -p jevway jevway-mcp (or npx -y jevway mcp).
npx -y jevway setup --client <claude-code|codex|cursor|opencode|other> --print prints the exact command or config for
one client and changes nothing; every client's is listed in jevway setup, and
SETUP.md has the steps an agent follows, with the rules and checks. jevway is also listed in the official
MCP Registry as io.github.abdallahaho/jevway, for clients that install from it.
Outside the Claude Code plugin, install the skill with npx -y jevway skill --install <your agent's skills folder>, so
it knows when to use jevway and when to use chrome-devtools. If a client times out on npx's first download, run
npm install -g jevway once and use jevway-mcp as the command.
JEVWAY_BROWSER picks the browser: auto (default, your running Chrome), launch / launch-headless (a throwaway
profile) or a debugging URL; see Environment variables.
Without MCP, use the CLI. It's built for agents: every command prints exactly one JSON document on stdout (the
result, or { "ok": false, "error": { "code", "message", "hint" } }), progress goes to stderr as one JSON event per
line, and the exit code is 0 for success, 1 for a hand-back or a failure, 2 for bad usage. --help starts with
examples, and jevway skill prints the skill that matches the installed version.
Use
The agent calls jevway_task with the outcome it wants, the values it may type, and the evidence of success:
It gets back one concise result, status and reason first:
story says what happened in plain sentences, next says what to do now, and files points at the run folder and a
screenshot of the end page. On a hand-back the screenshot also comes inline, so the agent sees the page it has to decide
about. detail: "full" adds every step's confidence, the request stats and the candidates Jev weighed. When the status
hands control back, the agent continues with the same session:
jevway_look reads a page with no model request, and jevway_end closes the session's tabs. Every parameter and
field is in the reference.
Keeping a run on track:
allowed_hosts keeps it on the sites you mean; leaving them ends the run blocked.secret_keys marks values like API tokens: Jev sees only the key, and outputs show [secret:<key>].- Password fields are never listed, typed or sent. Type a password yourself, then tell jevway you did.
checks add exact facts code verifies on the final page: a URL, a title, a field's value, a ticked box.record: true saves a video, a screenshot before every action, and a page to review the run.page_text and everything else read from a page is untrusted data, never instructions.
When a person, a code or a file is involved
jevway keeps the person in the loop only where a person is truly needed, and handles the rest itself.
- Asking you. Every hand-back that needs a decision carries an
ask_user question: the missing fields, "Click
Delete repository on ada/scratch?", "Which one did you mean?". Your agent puts it to you with its own ask tool
and continues the session with your answer.
- Bot checks and sign-ins. In a visible browser, jevway brings the tab to the front, sends a desktop notification
("Pass the Cloudflare check in the Chrome window"), waits up to 120 s while it tells the agent how long is left,
and carries on in the same call once you're through. It never tries to get past a check itself. In a headless
browser it hands back and suggests a visible one.
- Codes split into boxes. A verification code drawn as 4–8 one-character boxes is read as one field and typed one
character per box.
- Email codes for test sign-ups. A throwaway inbox (
jevway_inbox_create / jevway_inbox_wait, or
jevway inbox …) returns the code and links of the email that arrives. Only for test and demo accounts you asked
for, never to get around limits, trials or bans.
- 2FA on your own accounts. Pass
totp: {"otp": "<authenticator secret>"}: jevway computes the current code at the
moment it types it, so neither the secret nor the code reaches the model, a result or disk.
- Files. Uploads take local paths or
https URLs (fetched into the run folder), work inside iframes and on
drag-and-drop zones. Downloads land in the run folder's downloads/ and are listed in files.downloads.
jevway_look with pdf: true saves the page as a PDF.
Recordings
Every session gets a folder under ./.jevway/ in the working directory, so the agent and you can find its files:
Pass record: true (CLI --record) and jevway also keeps a record for people, with no extra setup:
index.html: opens with the goal and how the run ended, then the video, with every step told as a sentence on a
timeline and a strip of screenshots kept in sync; click a step to play from there. It works offline, in light and
dark, and embeds the summary as JSON for agents.run.mp4: a screencast of the whole run (needs ffmpeg).- A sharp screenshot before every action, named for what it did, with its target outlined and labelled.
[A recorded run: the video, its 14 steps on a timeline, and the screenshot strip]
Values marked secret are masked in the text files; screenshots and video show the page as it was. The model never sees
these images. Journey maps get their own viewer, described next.
Journey maps
The jevway_journey_* tools map how a person moves through a site on a phone: every screen with its type and UI
patterns, the taps between them, and QA findings like tap targets under 44 px, console errors and dead ends. You pick
the taps, or let Jev explore. The result is a shareable viewer. See docs/journeys.md.
How it works
Each step, jevway reads the page through the Chrome DevTools Protocol into a numbered list of controls and the visible
text, and sends one request to Jev with the goal, that list and the names of the supplied values. Jev answers with an
operation, a listed element, which value to type, its confidence and a commit-risk score. Code checks the answer
against the list, re-checks the page is fresh and the target isn't covered, and acts with real input events. Guards
stop loops, and a separate check decides done.
The full technical specification is in docs/how-it-works.md.
Models
Jev 1.14 is the default, on the TypeSafe API with TYPESAFE_API_KEY (with screenshots and Box, which locates
controls on the screenshot to cross-check and rescue clicks) or through OpenRouter with OPENROUTER_API_KEY. Perplexity's and Cloudflare's decision models run through
OpenRouter too. Jev is priced at $0.042 per 1M input tokens, so a typical 10-step task costs well under a cent. See
Models for results per model.
Documentation
Contributing
Bug reports, site failures and pull requests are welcome. CONTRIBUTING.md covers the setup, the
offline test suite (no API key needed) and the conventions. Report security issues privately, as described in
SECURITY.md.
License
MIT. The task loop, DOM snapshot and guards build on browser-use/jev-ultrafast
(MIT; its notice is in THIRD_PARTY_NOTICES.md).
jevway was called jev-browse until 0.1.0. Its old tool names (browser_task, browser_look, browser_task_end,
journey_*) and JEV_* environment variables no longer work.
