# Verify Bookends

> Post-edit verification of a short's opening and closing 1.5s. Claude sees a 3-frame strip from each end plus the trimmed transcript text around each end and returns {action:keep}, {action:trim,t0,t1} (inward-only), or {action:drop,reason}. Checks three things — (1) cleanliness (partial words, breath cutoffs, off-shot frames); (2) opening-hook strength (snap t0 inward to a stronger hook line if the first 3s is pure setup); (3) payoff landing (snap t1 to ~80ms past the payoff word when the tail trails into filler). Runs after tighten-pace, before fit-vertical. Inward-only — bookend-trim's outward pass already had its chance. Drops the span only on cleanliness failures requiring >2s of trim — never on hook-weakness alone.

- Skill: `jperrello/verify-bookends` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add jperrello/verify-bookends`
- Raw SKILL.md: https://api.skillmd.com/api/skills/jperrello/verify-bookends/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Docs & Writing
- Author: jperrello (https://skillmd.com/u/jperrello)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/jperrello/verify-bookends

---


# verify-bookends

Last-line defense before a short is committed to fit-vertical. Checks
three things in one Claude call:

1. **Cleanliness** — partial words, breath cutoffs, co-speaker
   interjections, off-shot frames at either end.
2. **Opening-hook strength (VVSA gate)** — the first ~3s is where a
   scrolling stranger swipes away. If the opening is pure setup /
   throat-clearing and a stronger hook line exists within the first 3s,
   snap t0 inward to that line. Hook-weakness alone is never a drop —
   only an inward-trim suggestion.
3. **Payoff landing** — if the tail contains a clear payoff word
   followed by trailing filler ("yeah", "so anyway") or silence, snap
   t1 to ~80ms past the payoff word rather than the sentence boundary.
   Dead air after the payoff costs retention.

Output remains a single `keep`/`trim`/`drop` decision — same I/O
contract, same caller logic in `shorts.sh`.

## Invoke

```
.claude/skills/verify-bookends/verify-bookends.sh <input_clip> <input_trimmed_transcript> <out_decision_json> [VERIFY_BOOKENDS=0 to skip]
```

- `input_clip` — post tighten-pace clip
- `input_trimmed_transcript` — post tighten-pace re-timed transcript
- `out_decision_json` — written JSON: `{"action":"keep"}`, `{"action":"trim","t0":<sec>,"t1":<sec>,"reason":...}`, or `{"action":"drop","reason":...}`

Env: `VERIFY_BOOKENDS=0` makes the skill emit `{"action":"keep","reason":"disabled"}` without calling Claude.

## How

1. ffprobe the clip duration.
2. Slice the trimmed transcript text into a head window (first 1.5s) and a tail window (last 1.5s).
3. ffmpeg out a 3-frame strip from each end (start / mid / end of the 1.5s window).
4. Send both strips + both transcript snippets to `claude -p` (vision-enabled) with explicit inward-only rules.
5. Validate the reply: enforce `0 <= t0`, `t1 <= dur`, `t0 >= 0`, `t1 > t0`. If the proposed trim would remove more than 2.0s of clip duration, downgrade to `{"action":"drop"}`. If the proposed trim would shrink the short below 15s, downgrade to `{"action":"keep","reason":"would shrink below 15s"}`.

## Caller contract

`shorts.sh` reads the JSON. If `action=trim`, it issues a second `cut-clip` + `rebase` against the trimmed transcript, then continues to `fit-vertical`. If `action=drop`, it `continue`s the per-span loop and increments the skipped counter. If `action=keep`, no-op.

## Idempotency

Keyed off `(clip mtime, trimmed-transcript mtime)`. Cached decision written next to `<out>.vbmeta`.