OmniAgent is a Rails engine gem for building application-native AI agents with tools. It provides a small DSL to define agents, model/provider settings, prompt templates, tool schemas, and generation lifecycle callbacks.

• OmniAgent::Agent runtime with provider abstraction and tool-calling loop
• OmniAgent::Tool DSL with JSON-schema-style input definitions
• Prompt composition from ERB files in app/agents/<agent_name>/
• Agent callbacks (before_generation, after_generation)
• Agent and tool tags to support filtering strategies
• OpenAI provider integration out of the box
• Rake tasks and Rails generators for scaffolding

Add these lines to your application's Gemfile:

gem "omni_agent"

Add the provider you're using to the Gemfile as well:

gem "openai"

Then run:

bundle install

1. Install base directories:

bundle exec rails generate omni_agent:install

2. Generate an agent scaffold:

bundle exec rails generate omni_agent:agent ResearchAgent --model gpt-4.1-mini --with-tools WeatherLookup Summarize

3. Add your API key in .env:

OPENAI_ACCESS_TOKEN=your_api_key_here

4. Implement your agent prompt and optional tools under:

app/agents/research_agent/
	research_agent.rb
	prompt.md.erb
	tools/

class ResearchAgent < OmniAgent::Agent
	use_model "gpt-4o-mini"

	before_generation :set_current_user

	def set_current_user
		@user = "Test User"
	end
end

module ResearchAgent::Tools
	class GetWeather < OmniAgent::Tool
		description "Get current weather for a city"
		tags :weather
		metadata category: :utility

		input do
			string :city, description: "City name"
		end

		def execute(city:)
			"Sunny in #{city}"
		end
	end
end

Global defaults can be configured through OmniAgent.configure:

OmniAgent.configure do |config|
	config.default_provider = :openai
	config.default_model = "gpt-4o-mini"
end

bundle exec rspec

Issues and pull requests are welcome.

The gem is available as open source under the terms of the MIT License.