Twelfth developer resources
Twelfth API Authentication
Twelfth MCP clients authenticate with a bearer key tied to one workspace. Only a workspace owner or admin can create or revoke these keys. Open Settings → AI & agents, choose Keys & options, give the connection a label, generate the key and copy it immediately; Twelfth displays the complete secret only once.
Send the secret as Authorization: Bearer <key> to https://api.twelfth.ai/mcp. Never place it in a URL, client-side bundle, shared prompt, source-control repository or analytics event. Give every assistant, device or automation its own key so last-used activity and revocation remain attributable.
Rotation and revocation
Create a replacement key, update the one client that uses it, verify the connection, then revoke the old key. Revoke immediately if a device is lost, a collaborator no longer needs access or the secret may have been exposed. A revoked key stops working without changing other connections.