Connect Idea to Motion to Antigravity and you can ask for a video the same way you ask for anything else. Antigravity writes the script, plans each scene and writes the animation code; we synthesize the voiceover, time it to the words, render the animation and hand back an MP4. It speaks Streamable HTTP directly, so connecting is one config entry carrying an API key in an Authorization header.
Generate a connection key if this client needs one, then add the server.
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Generate a connection key
Add it to Antigravity
~/.gemini/antigravity/mcp_config.json
{
"mcpServers": {
"ideatomotion": {
"serverUrl": "https://api.ideatomotion.com/mcp",
"headers": {
"Authorization": "Bearer vai_YOUR_KEY"
}
}
}
}Generate a key above to replace vai_YOUR_KEY.
serverUrl, not url. Restart after saving.The exact names Antigravity reads, and what happens when one of them is wrong.
Antigravity reads its MCP servers from a JSON file — ~/.gemini/antigravity/mcp_config.json. The entry goes under mcpServers, with the endpoint in serverUrl. Those names are not what every other client uses, and getting one wrong is not an error, it is silence: the file parses, Antigravity starts, and the server never appears.
Narration is synthesized on your own ElevenLabs, Cartesia or Sarvam AI key. Silent motion graphics need none.
Idea to Motion generates the voiceover on your own text-to-speech account. Add an ElevenLabs, Cartesia or Sarvam AI key — it's stored encrypted and never shown again. Rendering is blocked until a key is connected.
Where the line between your assistant and the platform falls, and why it falls there.
Ask for a video from Antigravity's agent panel the same way you ask for a change to the code — the tool calls run beside your editor, and you approve the plan there.
Type it into the agent panel, in the same thread you use for code.
“Make a 45-second widescreen explainer about how our API rate limiting works.”
What comes back
The ways this goes wrong, and most of them go wrong silently.
Open it from the agent panel: … → MCP Servers → Manage → View raw config. Antigravity picks up MCP servers on launch, so restart after saving before deciding the entry is wrong. The likeliest cause is the endpoint field: Antigravity takes serverUrl, so an entry copied from Cursor or Claude Code carries a url it will quietly ignore.
Check the names in ~/.gemini/antigravity/mcp_config.json. The entry belongs under mcpServers, and the endpoint goes in serverUrl. These differ between clients — some read mcpServers, some servers, some context_servers — and a wrong one is not an error: the file parses, Antigravity starts, and the server is simply never loaded. Copy the snippet in step 1 rather than adapting one from another client's documentation.
A key that is wrong, truncated or revoked gets a 401, and most clients report that as a failed connection rather than as an auth problem. Keys are shown once and stored hashed, so there is no way to read an old one back — generate a fresh one in step 1, then paste the new key over the old one in the config and reload Antigravity. Paste the whole vai_ string including the prefix; the old key can be revoked from the same panel.
~/.gemini/antigravity/mcp_config.json is the file Antigravity reads for this; a copy anywhere else is never opened. Create it if it does not exist yet, keep the surrounding JSON valid — a trailing comma takes the whole file down, not just this entry — and reload Antigravity, which reads MCP config at startup.
Narration and transcription run on your own ElevenLabs, Cartesia or Sarvam AI key rather than ours, so a narrated or recorded video needs one connected — step 2 on this page, or the set_voice_key tool from inside Antigravity. Silent motion graphics need no voice key at all, so "make it a silent motion graphic instead" is a valid way past this.