If you need a promotional video but lack video-production experience, an AI agent can help turn your idea into a script, visuals, narration, and a finished video. An AI agent is software that follows instructions across several steps and uses tools to complete a task. It coordinates the work, while you decide what the video should say and approve its claims and final version.
For a narrated explainer or product-demo promo, explainroo is my recommended tool. It is a free, open-source kit that lets a coding agent create the video on your computer. You describe the topic, review the result, and ask the agent to make changes. explainroo is designed for illustrated explainers and demos, rather than editing camera footage or making live-action scenes.
Start with one message and one action
A promo works best when it gives viewers a clear reason to care and tells them what to do next. Before you ask an agent to make the video, decide who the video is for and what benefit it should explain, then choose the action you want viewers to take.
Keep the message simple. Introduce a problem or need, then explain the benefit. Show the product or evidence, and end with a call to action. Give the agent approved product facts and brand assets. Review factual claims yourself: the FTC’s advertising guidance says advertising claims must be truthful and supported. Do not let the agent invent prices or performance results. It must not invent customer stories or product features.
Make a promo video with explainroo
explainroo works with coding agents that can run shell commands, including Claude Code, Codex, Pi, OpenCode, and Gemini CLI. It works best with Claude Code. To begin, paste this prompt into your coding agent, replacing the bracketed topic:
Make me a short explainer video about [your topic]. Use explainroo for it: clone the explainroo repository, read its AGENTS.md and follow the steps.After setting up explainroo and creating the video, the agent checks it and gives you an MP4 file. It writes two files: script.md, which contains the narration, and scenes.js, which describes the visuals. A scene can appear on a chosen spoken word, so the illustrations follow the narration.
explainroo uses the Kokoro open voice model to read English narration aloud. It offers American and British voices. Whisper, a speech-recognition tool, marks when each word is spoken so the pictures can appear on cue. Chrome draws the scenes, which can include charts, code, and your own screenshots. You can change the video’s look, pace, and size. Tall, portrait, and square formats include captions that light up word by word.
For a product demo, tell the agent which product to show and where to find its code or website. It rebuilds the product’s screens and shows a mouse pointer clicking and typing as the narration explains them. Give it specific instructions about what to demonstrate, such as the path from opening a feature to completing a task.
The agent cannot watch the finished video. explainroo provides scene stills and a contact sheet. It also includes a layout check for overlapping or cut-off text and a speech check for mispronounced words. Review the MP4 yourself, especially the product details, names, and call to action. Ask the agent for specific changes, such as shortening one scene or making a label easier to read.
Know what explainroo does and does not make
explainroo is suited to narrated explainers and product demos built from drawn scenes and screenshots. It cannot edit existing camera footage. Talking avatars and AI-generated live-action video are also outside its capabilities. It also has no drag-and-drop editor: you describe what to change to your coding agent.
The kit is MIT-licensed and free to use. The coding agent is a separate service with its own pricing. Optional AI illustrations through OpenRouter cost per image. Producing other videos with explainroo has no per-video cost. See example videos and the explainroo documentation before starting.
Check claims, rights, and disclosures before sharing
Before publishing, confirm that the video accurately represents the product and that you have permission to use every logo, screenshot, image, and voice. If the narration includes a testimonial, make sure it reflects a real person’s genuine experience. The FTC’s rule on reviews and testimonials addresses fake or misleading testimonials, including AI-generated ones.
Platform and location determine disclosure rules. YouTube asks creators to disclose realistic AI-generated or altered content in certain cases, such as a realistic event that never happened. Before publishing, check the current rules for your platform and audience, especially if the video depicts realistic people or events.
