Open source. Built for Codex. / Meet Jev Use

JEV USE / NAVIGATION FOR CODEX

Give your agent
a sense of direction.

From a goal to the right page. Jev navigates browser tabs and desktop apps, checking the result as it goes.

Start building Explore the API

Your browser. Your session. One navigation call.

Illustrative navigation workflow in three retro computer windows: observe a page, select an eligible link, and verify arrival. — JEV.NAVIGATE / ILLUSTRATIVE WORKFLOW01 — 03

A small API.
A clear division of work.

01 Codex sets the goal

02 Jev chooses the way

03 The runtime verifies

LESS BACK AND FORTH

Set the destination.
Let Jev take it from there.

A whole browser journey runs in one call, without a host-model turn between every hop.

01 / OBSERVE

Start with what’s there.

Jev selects from links and controls observed on the current page. The route comes from the live interface.

02 / NAVIGATE

Keep the journey moving.

Define the goal, scope, and hop limit once. Jev follows eligible links and revalidates them before navigating.

03 / VERIFY

Know when you’ve arrived.

Check the destination URL, heading, or your own postcondition. If the journey stops, get a classified reason and fallback.

ONE FACTORY. TWO METHODS.

Small enough to learn.
Ready to go places.

Read the API docs

Use your existing Codex browser provider.
Initialize Jev once, then reuse the session.

const jev = await createJevBrowser({ browser });

const result = await jev.navigate({
  tab,
  startUrl: 'https://docs.example.com',
  targetUrl: 'https://docs.example.com/guide',
  targetHeading: 'Getting started',
  goal: 'Find the getting-started guide.',
  sameOrigin: true,
  maxHops: 12
});

Observed links. Bounded scope. Verified arrival.

BUILT WITH BOUNDARIES

A useful agent knows
when to stop.

A result you can inspect, even when the next step needs you.

See the navigation contract

Scope stays explicit.: Keep journeys on the same origin, restrict paths, and set a maximum number of hops.
Completion is checked.: A successful action isn’t enough. The destination or step postcondition has to match.
Fallbacks have a reason.: Login, interaction boundaries, loops, and verification errors return distinct guidance.

FROM YOUR MACHINE TO THE WEB

Your next journey
starts here.

Install the skill. Connect your browser.
Give Jev somewhere to go.

Full installation guide

Install for Codex

git clone https://github.com/vlad-terin/jev-use.git
cd jev-use

# Add TYPESAFE_API_KEY to your local .env file
npm test
npm run install:codex -- --env-file .env

Requires Node.js 22+, a compatible Codex browser provider, and a TypeSafe API key ↗.

The installer stores your environment-file path. The key stays in your local file.

A FEW GOOD QUESTIONS

Before you go.

Does Jev replace my browser tools?

Jev works with a compatible Codex browser provider. Codex provides the browser and computer-use tools; Jev selects observed targets and runs bounded journeys with verification.

What gets sent to TypeSafe?

The runtime sends authorized observed page text and link metadata to TypeSafe for selection. Use it with pages and data you are authorized to process. Your API key stays in your local environment file.

Can I run several journeys at once?

Yes. jev.navigations() supports 1–12 independent browser jobs at a time, using distinct tabs. Desktop and interactive jobs run at concurrency 1 because they share input focus.

Is Jev Use open source?

Yes. Jev Use is MIT licensed. Read, modify, and run the code from GitHub. A TypeSafe API key is required for model selection; see TypeSafe for its service terms and pricing.

Give your agent a sense of direction.

Set the destination.Let Jev take it from there.