Models and providers

Pick a model

Form	Example	Provider	Model
Provider and model id	model.openai("gpt-4o")	named	named
Provider and tier	model.mistral.fast	named	from the table below
Tier only	model.balanced	the first provider with a key, in the order of the table	from the table
String	model("anthropic:claude-sonnet-4-6"), model("openai:fast")	named	named, or from the table
Custom endpoint	model.openaiCompatible({ baseURL, model, apiKeyEnv })	any OpenAI-compatible server	named

The same forms work for agentNode({ model }) and for one-off calls with .invoke(). A string also works directly: agentNode({ model: "openai:gpt-4o" }). An unknown provider is an error.

Providers, keys and tiers

Provider	Key	fast	balanced	frontier	creative
anthropic	ANTHROPIC_API_KEY	claude-haiku-4-5	claude-sonnet-4-6	claude-opus-4-8	claude-fable-5
openai	OPENAI_API_KEY	gpt-4o-mini	gpt-4o	gpt-4o	gpt-4o
google	GEMINI_API_KEY or GOOGLE_API_KEY	gemini-2.5-flash	gemini-2.5-flash	gemini-2.5-pro	gemini-2.5-flash
mistral	MISTRAL_API_KEY	mistral-small-latest	mistral-medium-latest	mistral-large-latest	mistral-large-latest
openrouter	OPENROUTER_API_KEY	openai/gpt-4o-mini	openai/gpt-4o-mini	openai/gpt-4o	openai/gpt-4o
minimax	MINIMAX_API_KEY	MiniMax-Text-01	MiniMax-Text-01	MiniMax-Text-01	MiniMax-Text-01
huggingface	HF_TOKEN or HUGGINGFACE_API_KEY	meta-llama/Llama-3.3-70B-Instruct	meta-llama/Llama-3.3-70B-Instruct	meta-llama/Llama-3.3-70B-Instruct	meta-llama/Llama-3.3-70B-Instruct
ollama	AILU_USE_OLLAMA=1	mistral	mistral	mistral	mistral
lmstudio	AILU_USE_LMSTUDIO=1	local-model	local-model	local-model	local-model

A missing key fails the call with the name of the variable to set. AILU_LLM_MOCK=1 turns missing keys into calls to the deterministic offline mock instead.

Local servers need no key but must be switched on: AILU_USE_OLLAMA=1 (with AILU_OLLAMA_BASE_URL for a server not on http://localhost:11434/v1), AILU_USE_LMSTUDIO=1 (with AILU_LMSTUDIO_BASE_URL).

Custom endpoints

model.openaiCompatible points an agent at any server that speaks the OpenAI chat-completions API: vLLM, LM Studio, LiteLLM, Azure OpenAI, a company gateway.

model.openaiCompatible({
  baseURL: "https://gateway.example.com/v1",
  model: "llama-3.1-70b",
  apiKeyEnv: "GATEWAY_API_KEY" // sent as a Bearer token; omit for a keyless server
});

The key is read only from apiKeyEnv. Your OPENAI_API_KEY is never sent to a custom endpoint. Anthropic and Gemini have their own APIs and can't be pointed at a custom URL.