rstack

Captures before/after screenshots of web pages or elements for visual comparison. Use when user says "take before and after", "screenshot comparison", "visual diff", "PR screenshots", "compare old and new", or needs to document UI changes. Accepts two URLs (file://, http://, https://) or two image paths.

Use when multiple workflows duplicate the same operational logic, when deciding what belongs in actions vs shared services, or when refactoring repeated operational blocks across domain flows. Use when adding new features that share mechanics with existing ones.

Records visual proof while testing UI behavior — the agent tests the app hands-on via computer use while a screen recording with structured test/assertion annotations captures the session — then posts the video and a results summary to the requested destination. Use when changed runtime behavior needs observable verification, including headless environments (scripted screenshots and probes) and non-UI changes (measured numbers, output pairs).

Run the greploop workflow with the @greptile-apps trigger when the normal trigger refuses a large PR. Requires the greploop skill installed alongside this entrypoint.

Address Greptile feedback on a PR, MR, or shelved changelist through bounded review and fix cycles. Use when the task includes a Greptile review loop. Supports the alternate @greptile-apps trigger for large PRs.

Isolate repository edits in a Git worktree before starting a feature, fix, or documentation change. Preserve a worktree already assigned to the same task. Read-only reviews and investigations do not need a new worktree.

Cut AI tells from text you write or edit for a human reader (commit messages, PR titles and bodies, docs, code comments, replies). Apply before committing, posting, or sending; leave prose you didn't touch alone.