version: "1.0.0"

Screenshot Debugging Skill

Purpose

Diagnose terminal screenshot corruption caused by incomplete terminal-state updates.

When to Use

• SVG screenshots show stale or overlaid text.
• Live WebSocket output looks correct but /screenshot.svg does not.
• Issues appear with full-screen TUIs (tmux/vim/less).

Procedure

1. Capture terminal bytes

• Capture PTY output around the failing action.

1. Replay into the Go tracker

• Feed bytes through internal/terminalstate (go-te based).
• Confirm whether buffer state diverges from expected terminal behavior.

1. Check preprocessing/filtering

• Validate DA filtering and any partial-sequence buffering logic.

1. Check dirty/refresh logic

• Verify tracker updates happen before screenshot cache decisions.

1. Add regression coverage

• Add a focused Go test and (when useful) fuzz corpus seed.

1. Verify

• Run make check and re-test the real scenario.

Notes

• Prefer reproductions from real PTY captures over synthetic minimal sequences.
• If rendering differs only in dashboard thumbnails, inspect SSE activity gating and screenshot cache TTL/invalidations.