MadAppGang Browser-Use Plugin Integration
Overview
The browser-use plugin provides headless Chromium screenshot capability as a fallback
when the claude-in-chrome extension is unavailable. When installed alongside designer,
it enables the design-review agent to capture browser screenshots without requiring
the user's Chrome instance to be open.
This skill is optional — all designer plugin functionality works without browser-use installed. browser-use is the fallback for Tier 2 of the three-tier browser capture chain:
- claude-in-chrome (preferred — real Chrome, CSS snapshot, JS execution)
- browser-use (fallback — headless Chromium, screenshot only)
- Error with install options
When to Use
Use this skill when:
- The
design-reviewagent has REFERENCE_TYPE = "browser" (URL reference) - The
design-reviewagent has IMPL_TYPE = "url" (URL implementation) - claude-in-chrome extension is NOT installed or unavailable
- User needs automated screenshot capture without opening Chrome manually
Detection Pattern
Probe the MCP tools directly — no subprocess, no plugin listing. A tool that answers is the only presence check this skill makes:
chrome_available = try mcp__claude-in-chrome__tabs_context_mcp()
→ success: use Tier 1 (claude-in-chrome)
→ error: chrome not available
browser_use_available = try mcp__browser-use__browser_list_sessions()
→ success: use Tier 2 (browser-use)
→ error: neither available → Tier 3 (error)
Screenshot Capture Pattern
When browser-use is available (Tier 2), use this exact sequence:
Step 1: Navigate (creates session automatically)
mcp__browser-use__browser_navigate(url: TARGET_URL)
→ save session_id from response
Step 2: Capture screenshot
mcp__browser-use__browser_screenshot(session_id: SESSION_ID, full_page: False)
→ returns: {"image": "<base64-PNG>", "format": "png", "width": N, "height": N}
→ save BASE64_DATA from response["image"]
Step 3: Decode base64 to file (Python3 is available when browser-use is installed)
Bash:
python3 -c "import base64, sys; open('${OUTPUT_DIR}/filename.png','wb').write(base64.b64decode(sys.argv[1]))" "${BASE64_DATA}"
Step 4: Verify file was created
Bash:
test -f "${OUTPUT_DIR}/filename.png" && echo "ok" || echo "decode_failed"
If decode_failed: close session then stop with error.
Step 5: Close session (ALWAYS — even on error)
mcp__browser-use__browser_close_session(session_id: SESSION_ID)
Note: CSS snapshot extraction (mcp__claude-in-chrome__javascript_tool) is NOT
available in browser-use tier. Skip the reference-css.json step when using browser-use.
Limitations vs claude-in-chrome
| Capability | claude-in-chrome | browser-use |
|---|---|---|
| Screenshot capture | Yes | Yes |
| Full-page screenshot | No (viewport only) | Yes (full_page=True) |
| CSS snapshot (computed styles) | Yes (javascript_tool) | No |
| JavaScript execution | Yes (javascript_tool) | Limited (retry_with_browser_use_agent) |
| User's real Chrome session | Yes | No (separate headless instance) |
| Authenticated sessions | Yes (user's cookies) | No (fresh session) |
| Real DOM state | Yes | DOM index map only |
| Animation disable (before capture) | Yes (CSS injection) | No |
User Notification Template
If NEITHER browser capture method is available, stop with this exact message:
ERROR: No browser capture method available.
Options:
1. Install Claude-in-Chrome extension (preferred — full CSS snapshot support)
→ https://github.com/anthropics/claude-in-chrome
2. Enable browser-use plugin (headless screenshot fallback)
→ /plugin marketplace add browser-use@magus
3. Provide an image file reference instead
→ Re-run with REFERENCE_SOURCE=/path/to/screenshot.png
If browser-use IS available but claude-in-chrome is not, log this info message (do not stop):
INFO: Using browser-use for headless screenshot capture (Tier 2 fallback).
Note: CSS snapshot will not be available — reference-css.json will not be written.