regenerate-captures

name	regenerate-captures
description	Regenerate the Starlight website's capture PNGs (hero / agent-pane-focus / activity-focus / git-focus / worktree-spawn / og-image) from the tmux scenario fixtures. Trigger on "regenerate captures", "rebuild capture images", "update hero image", "update agent pane image", "再生成 画像", "キャプチャ更新", and any request that changes `fixtures/scenarios/**` or the seeding logic in `_lib.sh`.

Regenerate Website Capture Images

The website's hero and feature screenshots (website/src/assets/captures/*.png) are generated from real tmux captures driven by fixtures/scenarios/<name>/scenario.sh, not hand-edited images. Any visual change must go through the scenario fixtures → rebuild → re-render pipeline. Never edit a capture PNG directly.

When To Use This Skill

• Changing anything under fixtures/scenarios/ (scenario scripts, _lib.sh, stream files).
• Changing UI code that appears in a capture (row layout, icons, colors, branch label format, activity log rendering, etc.).
• Bumping agent branding (OpenCode icon, Codex label) when the new branding is visible in a capture.

If your change does not affect the visible output (pure logic refactor, test-only change, backend-only fix), skip this skill.

Pipeline Overview

fixtures/scenarios/<name>/scenario.sh
  → sources common/_lib.sh (build_layout seeds 4 panes: MAIN, WAITING, BACKGROUND, ERROR)
  → launches real sidebar binary (`target/release/tmux-agent-sidebar`)
  → `capture` subcommand writes <name>.html into a tmp dir
    → scripts/render-frames.mjs (Playwright) converts .html → .png
      → copied to website/src/assets/captures/<name>.png

For hero, an additional scripts/hero-compose.mjs pass produces og-image.png that is copied to website/public/og-image.png.

Scenario → Output Map

Scenario	Output PNG	Crop
hero	hero.png (+ og-image.png)	full 140×46 canvas
agent-pane-focus	agent-pane-focus.png	rows 0..26, cols 0..46 (agent list)
activity-focus	activity-focus.png	rows 26..46, cols 0..46 (Activity tab)
git-focus	git-focus.png	rows 26..46, cols 0..46 (Git tab)
worktree-spawn	worktree-spawn.png	rows 3..15, cols 0..32 (spawn popup)

All scenarios share build_layout in _lib.sh, so a change to the seeded pane state can affect multiple outputs. Before regenerating, decide which PNGs are actually affected (e.g. a port change only shows in the agent list → hero + agent-pane-focus only; a bottom-tab change → activity-focus or git-focus).

Procedure

1. Preflight

• Must be on the project root.
• cargo, node, tmux on PATH.
• hero must be run from a main checkout — build_layout derives the MAIN pane's branch label from $ROOT via git. Running hero from a feature branch makes the top row read that branch name instead of main.

2. Edit the Scenario Source

• Per-pane seeded state (agent, status, branch, port, bg cmd, wait reason, prompt) lives in build_layout inside fixtures/scenarios/common/_lib.sh.
• Per-scenario composition (which pane is focused, crop region, extra activity log seeding, popup key presses) lives in that scenario's scenario.sh.
• run_fake_agent <pane> <agent> [port] [bg_cmd] — pass "" for port to skip the port listener; pass a non-empty bg_cmd to spawn a sidecar sleep whose argv[0] is the label surfaced by ps-based bg detection.

3. Build The Release Binary

cargo build --release

Scenarios invoke target/release/tmux-agent-sidebar, so a stale debug build will not pick up source changes.

4. Render Only The Affected Scenarios

Prefer a targeted loop over scripts/build-assets.sh (which re-renders everything, ~2–3 min):

TMP="$(mktemp -d -t tas-build.XXXX)"
OUT="$PWD/website/src/assets/captures"
for name in hero agent-pane-focus; do         # edit this list
    mkdir -p "$TMP/$name"
    ./fixtures/scenarios/$name/scenario.sh "$TMP/$name"
    ( cd website && node ../scripts/render-frames.mjs "$TMP/$name" )
    cp "$TMP/$name/$name.png" "$OUT/$name.png"
done

If hero is regenerated, also refresh the og:image:

( cd website && node ../scripts/hero-compose.mjs \
    "$OUT/hero.png" "$OUT/og-image.png" )
cp "$OUT/og-image.png" website/public/og-image.png

Clean up the tmp dir (rm -rf "$TMP").

To regenerate everything in one go, scripts/build-assets.sh is the single source of truth — prefer it over duplicating its logic when the change affects all scenarios.

5. Visual Verification (Mandatory)

Read each regenerated PNG with the Read tool and confirm the intended change is visible and nothing unrelated regressed:

• Did the change you wanted actually land?
• Did the MAIN pane's branch label read main (hero only)?
• Did any row reorder, color shift, or crop-edge artifact appear?
• For hero: the terminal chrome (red/yellow/green window dots) and rounded corners must be intact.

Never ship a capture you have not opened and looked at.

6. Commit

Commit the scenario fixture change and the regenerated PNGs in the same commit so the visual output is always reproducible from git show. Do not commit the scenario change alone; do not regenerate without a fixture change.

Troubleshooting

• terminated by signal 9 during scenario run — a worktree build was copied into the plugin dir without re-signing. This skill builds in the repo itself, so the symlinked plugin dir picks it up for free; only worktrees need the codesign --force --sign - step (see CLAUDE.md → Debugging).
• Sidebar shows wrong branch on top row — you are not on main. Check out main before running the hero scenario.
• Port not shown next to a pane's branch — the port-scan pass only finds ports opened by descendants of the fake agent process. Ensure the 3rd arg to run_fake_agent is a non-empty number.
• Bg-command row body missing — the sidebar requires both @pane_bg_cmd (seeded via _seed_pane bg_cmd=…) and a live process whose argv[0] matches. run_fake_agent … "" "npm run dev" seeds both; drop the 4th arg and the body disappears.
• Rendered PNG is blank or truncated — the sidebar did not finish its first paint before capture ran. start_sidebar already sleeps 2s; longer-starting setups may need an extra pause inside the scenario.

Do Not

• Edit PNGs in an image editor. The pipeline is the source of truth.
• Hand-tune the .html snapshot under the tmp dir — regenerate instead.
• Skip the cargo rebuild. A stale binary is the #1 cause of "why did nothing change?".
• Commit PNG-only changes. If the scenario fixtures did not move, neither should the PNGs.