Agent Browser Plugin

The Agent Browser plugin adds browser automation and visual QA skills backed by the agent-browser CLI.

Install

Install the plugin package alongside @sentry/junior:

pnpm add @sentry/junior @sentry/junior-agent-browser

Runtime setup

Add the package name to the plugin set exported from plugins.ts:

plugins.ts

import { defineJuniorPlugins } from "@sentry/junior";

export const plugins = defineJuniorPlugins(["@sentry/junior-agent-browser"]);

Config

No plugin config is required.

Plugin-specific setup

This plugin adds three skills and installs a browser runtime into the sandbox snapshot:

• /agent-browser for general browser interaction
• /visual-web-qa for evidence-driven visual checks
• /demo-video for edited demo, walkthrough, and explainer videos with Remotion

Rebuild the sandbox snapshot after you enable the plugin so browser commands work in new sandboxes.

Use /agent-browser for general browser interaction:

/agent-browser Open https://example.com, capture a screenshot, and summarize what is on the page.

Use /visual-web-qa when a frontend or docs change needs scoped browser evidence:

/visual-web-qa Verify the updated docs navigation in light and dark themes, then share the evidence.

Use /demo-video for a product presentation rather than a raw browser recording:

/demo-video Make a 90-second walkthrough of this app with UI captures and narration. Keep the story about what users can do.

The demo workflow reuses captures and unchanged narration during revisions. It times camera moves, highlights, and captions to the spoken words, and it checks the rendered export before delivery. Music is optional and must come from a track you supply or have a license for. It does not install Remotion or FFmpeg. Use compatible dependencies in a separate artifact project and check the applicable Remotion license. Generated narration needs an enabled TTS plugin or another available speech workflow; supplied audio also works. No production changes are needed to make a video.

Verify

1. Run /agent-browser with a simple open-and-snapshot request.
2. Run /visual-web-qa against a reachable local or preview page.
3. Confirm both turns can execute agent-browser commands successfully.
4. Confirm visual QA reports the exact target, scoped result, and successfully shared screenshot or video evidence.

Failure modes

• command not found: agent-browser: the plugin runtime did not load. Confirm the plugin is registered and rebuild the sandbox snapshot.
• Browser launch fails during the turn: the snapshot browser runtime is missing or incomplete. Rebuild the sandbox snapshot after enabling the plugin.
• Stale element references like @e*: the DOM changed after the snapshot was taken. Run a fresh snapshot -i after navigation or UI updates.
• Page appears incomplete: the page had not finished loading before the next action. Wait explicitly with agent-browser wait --load networkidle before interacting.
• Visual QA is blocked: no local server or preview URL is reachable. Start the repo-native development server or provide a preview URL, then retry.

Next step

Continue with Plugins to build provider-specific extensions or review Security Hardening for production controls.