agent-browser derive-client skill generates API clients from HAR traffic

Introduced 2026-07-19 · score 0.93

HOW TO USE IT

When reverse-engineering a site’s internal API, load the derive-client skill and record the browser flows you need in a HAR. Use the HAR to identify endpoints, derive a standalone client or CLI, and verify its calls against the live API.

agent-browser skills get derive-client

agent-browser network har start --content text
# Exercise the site flows to capture
agent-browser network har stop /tmp/site.har

agent-browser network har start --content all

WHY THIS HELPS

Generate a reusable API client while reverse-engineering a site's internal API.

REQUIREMENTS AND LIMITATIONS

Version: v0.32.3
derive-client (required): Skill name for the workflow that derives an internal API client from recorded browser traffic.
--content text: Default mode; embeds text-like response bodies, up to 2 MB per body.
--content all: Embeds all response bodies; binary bodies are base64-encoded. Mutually exclusive with other --content modes.
--content none: Disables response-body embedding. Mutually exclusive with other --content modes.
<output.har>: Path where `network har stop` saves the HAR.
Prerequisite: Install agent-browser and a discovery skill with `npx skills add vercel-labs/agent-browser`; the agent-browser CLI serves the version-matched skill content.
Prerequisite: If the site requires login, log in before starting the HAR; the skill says session cookies are exported separately.
Prerequisite: Exercise each client flow at least twice with different inputs; verify every generated function against the live API.

FIRST-PARTY EVIDENCE

Check the installed version and the source before using it. Entry JSON

Report a problem with this card

Tools change faster than your agent’s training data.

Changes

agent-browser derive-client skill generates API clients from HAR traffic