agent-loop-browser

Agent Loop Browser

Browser automation for the agent-loop. Use this for:

• Taking screenshots of deployed previews for visual validation
• Filling forms, clicking buttons, navigating pages
• Checking live UI behavior as part of PR verification
• Capturing before/after proof for autonomous PRs

Prerequisites

Prefer the existing Chrome session (logged-in state, extensions, cookies).

DevTools MCP Check

# Check if Chrome DevTools MCP is available
mcporter list chrome-devtools --schema 2>/dev/null || echo "MCP not available"

If MCP is unavailable, fall back to the browser skill's CLI:

# Check browser CLI
command -v browse >/dev/null 2>&1 || echo "browse CLI not installed"

Page Navigation

# Navigate to URL
mcporter call chrome-devtools.navigate_page \
  --args '{"url":"https://github.com/owner/repo/pull/123"}' --output text

# Or with browse CLI
browse goto "https://github.com/owner/repo/pull/123"

Taking Snapshots

# Text snapshot of current page (for understanding layout)
mcporter call chrome-devtools.take_snapshot --args '{}' --output text

# Screenshot for visual proof
mcporter call chrome-devtools.take_screenshot \
  --args '{"filePath":"/tmp/agent-loop-proof.png"}'

Form Filling

# Fill form elements
mcporter call chrome-devtools.fill \
  --args '{"uid":"1_13","value":"text"}' --output text

Click Elements

# Click a button/link
mcporter call chrome-devtools.click \
  --args '{"uid":"1_38"}' --output text

Evaluate Script

# Run JavaScript in page context
mcporter call chrome-devtools.evaluate_script \
  --args '{"function":"() => document.title"}' --output text

# Check CI status from GitHub page
mcporter call chrome-devtools.evaluate_script \
  --args '{"function":"() => document.querySelectorAll('.check-run').length"}' --output text

Visual Validation Workflow

For PR verification requiring UI proof:

1. Navigate to preview/deployed URL
2. Wait for page to load (wait_for text or timeout)
3. Take full-page screenshot → save to /tmp/agent-loop-proof-{pr}.png
4. Compare against expected state (if reference exists)
5. Report: "Visual proof captured at {path}"

# Capture proof
mcporter call chrome-devtools.navigate_page \
  --args '{"url":"https://preview.example.com/pr/123"}' --output text
mcporter call chrome-devtools.wait_for \
  --args '{"text":["Dashboard","Loaded"]}' --output text
mcporter call chrome-devtools.take_screenshot \
  --args '{"filePath":"/tmp/agent-loop-proof-123.png","fullPage":true}'

Failure Handling

Scenario	Action
MCP not available	Log warning, skip browser step
Page not found	Log 404, report broken link
Element not found	Wait 2s, retry once, then skip
Login required	Skip — cannot automate with isolated session
Screenshot fails	Report with page source instead