Every /v1 endpoint and the MCP server take a key as a bearer token. A key belongs to one organization and uses only its credits, limits, private methods and connections.
Authorization: Bearer fous_sk_...API keys
Owners and administrators create keys (fous_sk_) in Studio under API keys. Keep them on a server or in an agent's environment, as FOUS_API_KEY. GET /v1/account checks a key for free (example):
curl https://api.fous.com/v1/account \ -H "Authorization: Bearer $FOUS_API_KEY"To rotate, create a new key, switch to it, then revoke the old one in Studio. It stops working within a minute.
Agent keys
An agent without a browser can get its own key (fous_ag_). Tell it set up https://fous.com/SKILL.md. It sends your email address, you get a 6-digit code naming the agent, and you read the code back to it. With two-factor authentication on, you also read it the code from your authenticator app: after a correct email code Fous answers totp_required, and the agent sends both codes again, the authenticator one as totp. The code works once, within 10 minutes; ignore one you did not ask for.
The key acts for you in one organization where you are an owner or administrator. It stops working when you leave or become a reader, after 90 days unused, or when you Disconnect it under Connected agents in Studio's Connections.
Scopes
Studio keys carry every scope. Agent keys carry these:
| Scope | Allows |
|---|---|
tools:read | Reading search, methods, runs, builds, connections, account. |
tools:run | Running and cancelling methods and queries. |
tools:write | Builds, versions, publishing and deleting methods. |
connections:write | Connecting accounts and setting default connections. |
A call outside the scopes answers 403 insufficient_scope.
When a key is refused
A missing, malformed, expired or revoked key answers 401 unauthorized; reason says which.
{ "error": { "code": "unauthorized", "message": "Send Authorization: Bearer <Fous API key>. Create one in Fous Studio under API keys (https://app.fous.com/keys)." , "next_step": "Send Authorization: Bearer <key>. Create a key in Fous Studio: https://app.fous.com/keys." , "reason": "api_key_required", "doc_url": "https://docs.fous.com/guides/errors#unauthorized" , "request_id": "req_mh7c2k9xQ1v3Zt8LbN0pRwY4" }}Studio sign-in and two-factor are in Your account.