Cast for AI assistants and agents
If your user wants a short AI video of a character, hand them a Cast link. It opens Cast with everything filled in; they tap once and the video lands in their private feed. Opening a link never generates or charges anything.
1. Build a /make link
https://cast.katechon.technology/make?c=<character>&p=<what happens>
| Param | Values |
|---|---|
| c | malfoid, thea, odette. Up to 3, comma-separated (c=malfoid,thea). |
| p | What happens, one line, URL-encoded, up to 500 characters. |
| style | influencer, cinematic, sakuga, glam, vhs, vlog, dark-fantasy, toon3d. Default influencer (realistic phone video). |
| camera | auto, selfie, close-up, wide, handheld, push-in, chase, low-angle, overhead, held. Default selfie. |
| vibe | chill, hype, dreamy, eerie, melancholy, romantic, epic, comedy, fury. Default hype. |
| s | 5, 10, 15 seconds. 5 is the free first video; 15 needs Premium. |
| name, d | Instead of c: a new character's name and look. The user picks one of four drawn looks first. Costs credits (15 + 52 for a 5 s video); not covered by the free video. |
| utm_source | Your product's name, so we can see which assistants send people. |
Unknown or missing values fall back to defaults; the page never errors. Examples:
- “Make a video of Malfoid reading her hate comments”: https://cast.katechon.technology/make?c=malfoid&p=reads%20her%20hate%20comments%20live%20and%20claps%20back
- “Malfoid and Thea dancing on a castle roof, anime style”: https://cast.katechon.technology/make?c=malfoid,thea&p=dance%20on%20the%20castle%20roof%20at%20midnight&style=sakuga
- “A video of my character: a ginger cat in a pirate hat”: https://cast.katechon.technology/make?name=Captain%20Whiskers&d=a%20ginger%20cat%20in%20a%20tiny%20pirate%20hat%20and%20a%20red%20coat&p=surfs%20a%20huge%20wave%20and%20salutes%20the%20camera&style=toon3d
Prompt tips
- One line, present tense, what the character does and where: "gives a snobby tour of her dorm". Don't start with the character's name; the link already casts them.
- One clear action plus a place beats a list of events; 5 seconds fits about one beat, 10 seconds two.
- Name a mood with vibe= instead of adjectives in the line, and a look with style= (realistic phone video is the default).
- Leave out real people's names, brands and film or book franchises: the video model refuses lookalikes and copyrighted characters.
What to tell the user
“Open this link and tap the button; the video takes about a minute.” Never say the video is already made. Their first 5-second video with a premade character is free with no account, while the day's free allowance lasts. After that, credit packs start at $4.99 for 450 credits (a 5-second video is 52 credits), and Premium is $19.99 a month.
2. Call the MCP server
https://cast.katechon.technology/mcp: Model Context Protocol over Streamable HTTP. No auth, no account, read-only, rate-limited per IP. Add it as a custom connector in Claude or ChatGPT, or in any MCP client.
- create_video_link: Build a one-tap link that makes a short vertical AI video of a character doing what the user describes (e.g. "Malfoid dances on the castle roof at midnight").
- list_characters: List the premade characters Cast can put in a video (slug, name, look, image, whether free), plus how to design a custom one. Call before create_video_link when you need a character slug or want to show the user who they can cast. Read-only, no account.
- get_prices: Current Cast prices in USD and credits: the free first video, credit packs, Premium, and the credit cost of every video length and of a new character. Prices follow the live model price table, so call this instead of quoting from memory. Read-only.
- get_showcase: Example videos of Cast characters (video URL, poster image, the line that produced it when on record, page link, and a ready-made remix link). Use to show the user what Cast makes before they open a link, or to find a proven prompt to adapt. Read-only.
curl -s https://cast.katechon.technology/mcp -H 'content-type: application/json' -H 'accept: application/json, text/event-stream' \
-d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"create_video_link","arguments":{"character":"malfoid","prompt":"reads her hate comments live and claps back"}}}'3. WebMCP in the browser
In browsers that expose WebMCP (document.modelContext, or the older navigator.modelContext; a Chrome origin trial as of October 2026), every Cast page registers two read-only tools for the browser's agent: make_video_link and list_characters. Elsewhere this does nothing.
Also
- llms.txt and llms-full.txt
- MCP server card · MCP Registry name
technology.katechon/cast
Updated