Add a reaction without a new generate

Add the reaction as an edit. Add reaction clips to a video pulls emotion-tagged B-roll you already have (get_available_broll) and free reaction clips from the Hooks catalog (list_hooks). Insert at the beat with edit_video or compose_video_with_overlay. A shocked face that has to last 12 frames is not a 40-credit Veo take. Do not generate a new person to gasp at a pack you already filmed.

This page is the punchline insert. It is not picture-in-picture talking-head, and it is not a hook-pack billing essay.

Reaction is B-roll with an emotion filter

get_available_broll narrows by emotion: shocked, laughing, excited, and the rest of the tags you actually have rights to. It returns clips you already own — free or purchased. For the wider marketplace, search_broll. list_hooks additionally surfaces free reaction B-roll (kind: 'free') next to premade hook examples and premium marketplace hooks. Premium previews may be watermarked until purchased in the app marketplace.

This is not add B-roll in the broad sense (any illustrating stock). Reaction is a face doing a beat: the gasp after the price, the laugh after the fail, the double-take on the label. Timing is still your job. The tool does not detect comedy.

Cost: free owned clips plus a standard edit operation. Premium hooks have a marketplace price. A generate row has a model sticker — Veo 3.1 is 40 credits for 4/6/8s; Grok Imagine Video is 7 credits at 720p. Use those when you need a shot. A 1-second inset is an insert.

Insert paths:

• Cut in as a full-frame flash (4–8 frames) then back to the product.
• Overlay as a small face if the pack must stay visible — that is closer to PIP, and a different tool if you need a talking-head inset. This page is the reaction flash or cutaway.

Do not generate a synthetic reactor to play a human authority on healthcare, finance, law, or politics. Mashable (21 July 2026) lists synthetic personas presenting as human authorities in those categories as a YouTube inauthentic-content monetization bucket. A stock laugh at a serum is not that. A generated “doctor” gasping at a supplement is. Pick the clip. Do not cast a fake clinician.

N.Y. GBL § 396-b (in force 9 June 2026): ads with a synthetic performer that appears as a human not recognizable as an identifiable person need conspicuous disclosure when they reach NY consumers, with the statute’s exemptions (AP / McDermott / Crowell / Manatt, June 2026). A generated reactor can be that object. A licensed B-roll human is a different rights problem (release), not that statute’s “synthetic performer.” Know which you inserted.

Place it on the beat, then caption the main line

1. Watch the keeper muted. Mark the frame the viewer should feel: price, reveal, spill, the SKU close-up.
2. Browse by emotion. Pick a clip whose eyeline and ratio you can cut. A 16:9 laugh in a 9:16 ad is a crop. Preview.
3. Insert after the beat, not on top of the label if the pack is the product. A reaction that covers the carton is a title-card mistake in face form.
4. Keep it short. A 4-second generated talking head is a new scene. A reaction is punctuation.
5. Caption the main speech, not the reactor’s mouth, unless the joke is that line. Add captions to video after the cut is locked. Two faces with karaoke on the wrong one is noise.

UGC ads often already have a creator face. A second generated face is a crowd. Use a reaction when the creator’s take has no gasp and you will not reshoot. Prefer the creator’s own pickup if you have it — phone, one take, insert. Stock is the fallback, not the brand.

Do not I2V a still of a stock face “to make them more shocked.” You will pay an I2V sticker for a worse likeness and a rights mess. The clip is the performance.

Do not native-audio generate a reactor who says the offer. That is a second ad. Cut back to the pack.

What you are not generating

Refuse these as “reaction” generates:

• A new 8-second Veo of a stranger saying “no way” — you wanted 8 frames of a face you already licensed.
• A lipsync of a celebrity still. Consent and publicity, not a catalog issue.
• A motion-control dance as a stand-in for a laugh. Wrong family.

YouTube Shorts overlay (27 May 2026) still applies if the ad is photoreal AI. Inserting B-roll does not wash the generate it sits in. Disclose the file you made.

The UGC video generator is for the plate. The reaction catalog is for the blink. Mixing them in one prompt is how you recast the product.

Insert, do not recast

The test: if you mute the reaction clip, does the ad still sell? If no, you buried the pack. If yes, the gasp is doing punctuation. Keep it.

Rights on the insert are still rights. A free reaction clip you own is usable in the edit. A premium hook you only previewed is watermarked until you pay the marketplace. A For You screen-record is not in get_available_broll. Do not generate a copy of a stranger’s gasp to dodge a licence; that is a new likeness plus a new bill.

Audio on the reaction clip is usually a problem. A stock laugh track stacked on native-audio dialogue is two rooms. Mute the reaction’s audio unless the joke is the sound. Mix mode on a full laugh under a founder line is the same two-mouth failure as a singing bed. The picture is the punctuation. The soundtrack is already the ad.

If the only reaction you like is 16:9 and the ad is 9:16, crop the reaction as its own small punch — eyes and mouth — not a letterboxed bar. Preview the overlay size. A huge inset that covers the SKU is a title-card mistake. A tiny inset that cannot be read is noise. One beat, one size, then back to the pack.

If you need a seat to drop a shocked clip on the reveal without a new generate, sign up. Browse by emotion. Cut on the beat.

FAQ

Where do reaction clips come from?

get_available_broll (owned clips, emotion filter) and list_hooks (free reaction B-roll and catalog examples). Premium marketplace hooks may be watermarked until purchased. search_broll is the wider library.

Can I generate a custom shocked face instead?

You can, on a generate row, at that row’s credits. This page is the case where you should not. A blink is an insert. Save the generate for the product or the creator.

Will this auto-time the joke?

No. You pick the frame. The tools fetch and composite. Comedy is still an edit.