Build with AI
If you use an AI coding assistant such as Claude, ChatGPT, Cursor, or GitHub Copilot to build your integration, give it our LLM-ready reference first. It's a single Markdown file written for language models. It covers setup, the PenPal connection, parent-side callbacks, common workflows, every remote method with its arguments and return types, subtitle format profiles, and the mistakes integrators make most often.
Giving the assistant the full API up front stops it from guessing method names or signatures, so you get working code sooner.
The file is generated from the same function reference as the IFrame Embed docs, so it stays up to date with each release.
How to use it​
| Tool | How to add the docs |
|---|---|
| Claude, ChatGPT, Gemini (chat) | Click Copy Markdown and paste it into the conversation, or attach the downloaded .md file. |
| Claude Code, Codex, other agents | Save the file in your repository (for example docs/closed-caption-creator-iframe.md) and reference it from CLAUDE.md or AGENTS.md. You can also give the agent the URL directly. |
| Cursor | Add the raw URL under Settings → Indexing & Docs → Add Doc, then reference it with @Docs. Or add the downloaded file to your project and @-mention it. |
| GitHub Copilot | Add the file to your repository and reference it from .github/copilot-instructions.md, or attach it in Copilot Chat. |
Raw URL: https://www.closedcaptioncreator.com/docs/llms/iframe-embed.txt
Starter prompt​
Paste this after the docs and change the details to match your stack:
Using the attached Closed Caption Creator IFrame Embed reference, add the caption
editor to my React app:
1. Render the editor iframe on the /captions/:videoId page.
2. Connect with PenPal using the exact iframe origin in allowedOrigins.
3. Load the video from `video.url` and its SRT captions from `video.captionsUrl`.
4. Show the toolbar Save and Close buttons. On Save, export the captions as WebVTT
(as a string, not a download) and PUT them to /api/videos/:videoId/captions.
On Close, navigate back to /videos.
5. Before saving, run QC with a style guide of max 2 lines, 42 characters per line,
and 17 characters per second. Block the save and alert the user if there are errors.
Only use methods listed in the reference.
llms.txt​
We also publish an llms.txt index at https://www.closedcaptioncreator.com/docs/llms.txt, following the llms.txt convention. Agents that support the convention can find the reference on their own.