Video Editing with Claude and Codex: What a Kapara Battle Taught Us

The battle: same footage, same words, no cuts

Rina from Only in Israel spoke to camera and said, in each round, how she wanted to be edited: an elegant round with a carousel of her videos around her, a viral round with her name huge behind her, and a round of live commands, "zoom", "neon", "cut". Both tools got the same file and the same transcript, with one hard rule: no cutting, trimming or speed changes. So the two versions run in perfect sync, Claude on top and Codex on the bottom, and you can see word for word who did what.

We'll leave the verdict to you. What you can take from the battle is how to work well with both tools.

What they can actually do

Neither of them is an editing app with a timeline. They write code that edits for you, so they're good at whatever you can describe in words and timings:

• Styled captions in any font, color and size, with keywords highlighted.
• An effect that lands on a word: say "Instagram" and the icon pops on that exact frame.
• Text behind the speaker: the name huge in the background, the head in front of it.
• Color and mood: warm, cinematic, black and white, neon or spotlight.
• Motion: zooms, shakes, flashes and glitches, exactly where they belong.

Honestly, the limits: there's no timeline to drag, so you need to know how to describe. Renders take a few minutes and sometimes need a fix round. Effects like a carousel behind the speaker need clean footage: a simple background and even light.

Two ways to give instructions: voice or prompt

By voice, inside the video. You say on camera what you want, like Rina did in the battle, and the tool transcribes and edits to match. It's striking and fun to watch, but it's only one way.

By written prompt. You film normally, without a word about the edit, and write the style, the effect for each word and the opening hook in the chat. That's how most everyday edits are done.

The workflow in five steps

1. Film it right. Medium shot, you in the center, room on the sides, a clean background and even light. Half a second of silence before and after each sentence.
2. Ask for a transcript with a timestamp for every word. Every word-triggered effect is built on it.
3. Describe it in plain words, by prompt or by voice, like you would to a human editor: "when I say X, do Y".
4. Still frames before the render. A few frames catch a mistake in seconds, not after a ten-minute render.
5. One focused fix round: one list with every note, not a drip.

The prompts

Editing by written prompt, when nothing is said about the edit in the video:

I'm uploading a raw talking-head video. Edit it like this:

STYLE: warm, cinematic color. Clean and premium, not busy.
CUTS: remove every silence longer than 0.3s. Keep every word I say.
HOOK: first 2 seconds, a big title at the top: "[your hook]"
CAPTIONS: one line, bold white, the key word of each sentence in gold.
ON WORDS:
- when I say "[word]", pop [an icon / an image] next to my shoulder
- on every punchline, a quick zoom-in
- on "[word]", a white flash

Before rendering the full video, show me still frames from the key moments.

The battle prompt, when the instructions are spoken inside the video. We locked the length only for a fair comparison; in a normal edit you can ask it to cut silences too.

I'm uploading a raw talking-head video.
In the video, I tell you out loud how I want it edited.
Listen to what I say and edit it exactly the way I describe,
with every effect landing on the exact word I say it.

RULES:
1. Do NOT cut, trim, extend, or change the speed of the footage.
   The output must be exactly the same length as the input, frame for frame.
2. Only add layers on top: captions, graphic elements, effects, color, zooms.
3. Keep the original audio exactly as it is.
4. Before rendering the full video, show me still frames from the key moments.
5. After rendering, check the output length and confirm it matches the input.

Here is exactly what I say in the video:
[paste your words here]

Tips that save hours

• One word per effect. "When I say boom" works far better than "add some action in the middle".
• Always ask for frames before the render. A one-second check saves a full render.
• Make it check itself: "check the length is right and that no word is missing".
• Bigger captions than you think, because everything looks smaller on a phone.
• One effect at a time, so when something breaks, you know what.
• It's fine to say no: "this looks cheap, make it subtler" is great feedback.

How to build your own editing style

When everyone edits with the same tools, style is what sets you apart. Here's how to build one without being an editor:

1. Start from references: 2–3 reels whose editing you love, to understand what exactly grabbed you.
2. Ask for a breakdown: font, words on screen, cutting pace, color, motion and sound.
3. Pick one signature that's only yours: a gold keyword, a zoom on every question, a handwritten caption.
4. Write three "always" rules and three "never" rules.
5. Every effect needs a reason: a zoom marks a punchline, a flash marks a transition, silence marks a key moment.
6. Test it on three different videos, calm and energetic. Whatever breaks in one of them leaves the style.
7. Save it as a Skill and keep improving: every repeated note goes into the skill, and every version beats the last.

The reference breakdown prompt:

I'm uploading 3 reels whose editing style I love.
Break down each one, frame by frame:
- captions: font, size, position, words on screen at once, highlight color
- cutting pace: average seconds per cut, how silences are handled
- color: the overall look
- motion: which effects, and on which moments (hook, punchline, CTA)
- sound: music, sound effects, silence

Then write me ONE style card that combines what they have in common,
plus 3 "always" rules and 3 "never" rules.
Don't copy any of them. Give me something that feels like mine.

The save-my-style prompt:

Save the editing style we just built as a Skill called "my-style".
Include the style card, the always/never rules,
and every correction I gave you in this chat.
From now on, when I say "edit in my-style", use it.

What to install

• Claude Code or Codex: the tools that edit. You can ask them to install everything else.
• FFmpeg: the free engine that processes the video.
• Whisper: transcription with an exact timestamp for every word.
• Remotion: for higher-end motion graphics, with official skills for Claude Code. Install: npx skills add remotion-dev/skills