AI provider settings

Every setting below is read once at startup and requires a restart to change. Built-in defaults are overridden by nonempty environment values. Unknown FANOUT_ names fail startup; platform-injected service names are tolerated. Custom names use FANOUT_ plus a clear name, adding the area only when it clarifies. Vendor credentials and endpoints keep the vendor’s documented names.

Fanout also recognizes ANTHROPIC_API_KEY, ANTHROPIC_BASE_URL, OPENAI_API_KEY, and OPENAI_BASE_URL. Other vendor/tool variables are ignored; only the explicitly selected AI provider’s key and endpoint are used.

Environment variable	Type	Default
`ANTHROPIC_API_KEY` or `ANTHROPIC_API_KEY_FILE`	string · secret	—
`ANTHROPIC_BASE_URL`	string	—
`FANOUT_AI_MODEL`	string	—
`FANOUT_AI_PROVIDER`	string	—
`OPENAI_API_KEY` or `OPENAI_API_KEY_FILE`	string · secret	—
`OPENAI_BASE_URL`	string	—

Notes

`ANTHROPIC_API_KEY`

Required when FANOUT_AI_PROVIDER is anthropic.

`ANTHROPIC_BASE_URL`

Defaults to https://api.anthropic.com. Fanout appends /v1/messages, preserving any gateway path prefix. Use an HTTP(S) base URL without embedded credentials, a query, or a fragment.

`FANOUT_AI_MODEL`

Overrides the provider’s default: claude-sonnet-5-5 for Anthropic and gpt-6.1-sol for OpenAI. The OpenAI provider expects a reasoning model supporting reasoning.encrypted_content for stateless Responses replay. A 400 rejecting encrypted content is reported as a server-side configuration error; choose a compatible reasoning model with FANOUT_AI_MODEL.

`FANOUT_AI_PROVIDER`

Enables chat by selecting exactly anthropic or openai. Empty disables chat.

`OPENAI_API_KEY`

Required when FANOUT_AI_PROVIDER is openai.

`OPENAI_BASE_URL`

Defaults to https://api.openai.com/v1. Fanout appends /responses, preserving the API version and any gateway path prefix. Use an HTTP(S) base URL without embedded credentials, a query, or a fragment.