Ruby LLM

RubyLLM provides one beautiful Ruby API for all LLM providers. Same interface whether using GPT, Claude, Gemini, or local Ollama models.

1. One API for Everything

# Chat with any provider - same interface
chat = RubyLLM.chat(model: 'gpt-4.1')
chat = RubyLLM.chat(model: 'claude-sonnet-4-5')
chat = RubyLLM.chat(model: 'gemini-2.0-flash')

# All return the same RubyLLM::Message object
response = chat.ask("Hello!")
puts response.content

2. Configuration First

Always configure API keys before use:

# config/initializers/ruby_llm.rb
RubyLLM.configure do |config|
  config.openai_api_key = ENV['OPENAI_API_KEY']
  config.anthropic_api_key = ENV['ANTHROPIC_API_KEY']
  config.gemini_api_key = ENV['GEMINI_API_KEY']
  config.request_timeout = 120
  config.max_retries = 3
end

3. Tools Are Ruby Classes

Define tools as RubyLLM::Tool subclasses with description, param, and execute:

class Weather < RubyLLM::Tool
  description "Get current weather for a location"
  param :latitude, type: 'number', desc: "Latitude"
  param :longitude, type: 'number', desc: "Longitude"

  def execute(latitude:, longitude:)
    # Return structured data, not exceptions
    { temperature: 22, conditions: "Sunny" }
  rescue => e
    { error: e.message }  # Let LLM handle errors gracefully
  end
end

chat.with_tool(Weather).ask("What's the weather in Berlin?")

4. Rails Integration with acts_as_chat

Persist conversations automatically:

class Chat < ApplicationRecord
  acts_as_chat
end

chat = Chat.create!(model: 'gpt-4.1')
chat.ask("Hello!")  # Automatically persists messages

5. Streaming with Blocks

Real-time responses via blocks:

chat.ask("Tell me a story") do |chunk|
  print chunk.content  # Print as it arrives
end

1. Build a new AI feature (chat, embeddings, image generation)
2. Add Rails chat integration (acts_as_chat, Turbo Streams)
3. Implement tools/function calling
4. Add streaming responses
5. Debug an LLM interaction
6. Optimize for production
7. Something else

Wait for response, then read the matching workflow.

After reading the workflow, follow it exactly.

# 1. Does it load?
bin/rails console -e test
> RubyLLM.chat.ask("Test")

# 2. Do tests pass?
bin/rails test test/models/chat_test.rb

# 3. Check for errors
bin/rails test 2>&1 | grep -E "(Error|Fail|exception)"

Report to user:

• "Config: API keys loaded"
• "Chat: Working with [model]"
• "Tests: X pass, Y fail"

All in references/:

Getting Started: getting-started.md Core Features: chat-api.md, tools.md, streaming.md, structured-output.md Rails: rails-integration.md Capabilities: embeddings.md, image-audio.md Infrastructure: providers.md, error-handling.md, mcp-integration.md Quality: anti-patterns.md

All in workflows/: