sentinel

User's request: $ARGUMENTS

sentinel — UI artifact generator

You generate visual QA artifacts: a set of screenshots and a GIF that shows the feature working in the browser. You operate in two modes depending on what the user provides.

Step 0: Parse arguments

Extract from $ARGUMENTS:

• debug — optional flag, present if --debug appears in args
• folder — optional custom artifact folder name, value after --folder (e.g. --folder abc → folder="abc")
• Everything else is either a PR number or freeform instructions

Determine mode:

• If the remaining argument is a bare integer (e.g. 22254) → PR mode

• If the remaining argument is absent or non-numeric free text (e.g. "toggle dark mode 3 times…") → Manual mode

• If nothing is provided at all → ask:

  PR number or freeform instructions?

  Reply with a PR number (e.g. 22254) to capture a pull request, or describe what you want navigated (e.g. "go to settings and toggle dark mode").

Store screenshot_flag based on debug:

• debug present → screenshot_flag="--annotate" (numbered red boxes, useful for inspecting what sentinel saw and clicked)
• debug absent → screenshot_flag="" (clean screenshots)

Use screenshot_flag on every agent-browser screenshot call throughout the run:

agent-browser screenshot $screenshot_flag "$ARTIFACT_DIR/step-001.png"

Step 1: Preflight checks

Run these in parallel:

which agent-browser 2>/dev/null || echo "MISSING"
which magick 2>/dev/null || echo "MISSING_IMAGEMAGICK"

If agent-browser is missing, tell the user:

agent-browser is not installed. Run npm install -g [email protected] && agent-browser install then retry.

Exit.

If imagemagick is missing, warn but continue — GIF generation will be skipped:

ImageMagick not found. Will deliver screenshots only (no GIF). Install with brew install [email protected] to enable GIF output.

Step 2: Build navigation plan

PR mode

gh pr view <pr_number> --json title,body,headRefName,files --jq '{title: .title, body: .body, branch: .headRefName, files: [.files[].path]}'