Explain Video Generator

Append a chunk of explainer markup to an open explainer stream. Chunks accumulate into one growing document — never resend earlier content. Viewers see it render live. Returns remaining budget. Your first successful append returns the explainer's link, so make it a real playback buffer — an opening section, not just a title slide. Send the link to the user as a non-blocking progress update, then continue appending immediately.

Attach a picture the user supplied or you generated in the conversation to an open explainer stream, so an ordinary image slide can show it. You need a file reference with a download link. Returns the attachment id to write on an image item: <item type="image" attachment="<id>" anchor="..." title="..."></item>, with no prompt. Call it before the append_explainer_chunk that names the slide — an append naming an id that is not an upload of this explainer is refused. Up to 12 pictures per explainer (each reply says how many more it can take), 8 MB each, png/jpeg/webp/gif; they do not count toward the generated-image cap. If the file only comes as a bare reference with no download link (uploads from the ChatGPT mobile app do), the call fails: build the explainer without that picture, never invent an id.

Finalize an open explainer stream. Call this when you are done pushing — the explainer stops showing as generating and narration becomes playable for viewers.

Open an explainer stream where YOU author the content. Scrimba creates an empty explainer and renders whatever explainer markup you push — live, as you push it. Use this for custom narration, mermaid diagrams, LaTeX maths, precisely composed code walkthroughs, and side-by-side before/after diffs of changed code. Returns: a stream_token for pushing and the complete explainer markup contract — no link yet. The explainer's link arrives in your first successful append_explainer_chunk result; make that first append a real playback buffer (an opening section, not just a title slide), then send the link to the user as a non-blocking progress update and keep appending (anyone who opens it can watch, no account needed, and holders of the link can claim ownership from the page). The result is large — more than 50KB — so if your client stores or truncates large tool results, use any storage or file tools you have to extract it in full. Read the contract to the end before pushing.