Providers

Rails Agents supports four providers behind one DSL. Pick a provider and model on each agent.

Provider	API key config	Example model
:openai	openai_api_key	"gpt-4o-mini"
:anthropic	anthropic_api_key	"claude-sonnet-4-20250514"
:openrouter	openrouter_api_key	"meta-llama/llama-3.3-70b-instruct:free"
:grok	grok_api_key	"grok-2-latest"

class SupportAgent < RailsAgents::Agent
  provider :openai
  model "gpt-4o-mini"
  description "Answers customer questions."
end

OpenAI

Standard Chat Completions-compatible API. Good default for most agents.

provider :openai
model "gpt-4o-mini"

Set OPENAI_API_KEY or config.openai_api_key.

Anthropic

Best when you need native skills: web search/fetch, code execution, memory, and document skills (:xlsx, :pptx, :docx, :pdf).

provider :anthropic
model "claude-sonnet-4-20250514"
skills :web_search, :xlsx

Set ANTHROPIC_API_KEY or config.anthropic_api_key.

OpenRouter

One API key for hundreds of open-source and commercial models — useful for trying agents without committing to a single vendor.

provider :openrouter
model "meta-llama/llama-3.3-70b-instruct:free"

Set OPENROUTER_API_KEY or config.openrouter_api_key.

Grok (xAI)

provider :grok
model "grok-2-latest"

Set XAI_API_KEY (or GROK_API_KEY) or config.grok_api_key.

Skill support by provider

Skill	Anthropic	Others
:web_search, :web_fetch	Native	Portable Ruby tools
:code_execution, :memory	Native	—
:pptx, :xlsx, :docx, :pdf	Native	—

See Skills for full details.

Default provider

If an agent omits provider, the configured default is used (:openai unless you change it):

RailsAgents.configure do |config|
  config.default_provider = :anthropic
end

You still must set model on each agent.

Next

• Configuration
• Skills