TurnKit

Ruby AI agent runtime with durable turns, tools, skills, and Rails persistence.

Installation

Add this line to your application's Gemfile:

gem "turnkit"

Run:

bundle install

Quick Start

Set a provider key, then ask an agent:

export ANTHROPIC_API_KEY=...

require "turnkit"

agent = TurnKit::Agent.new(
  name: "helper",
  instructions: "Answer briefly."
)

turn = agent.conversation.ask("Explain Ruby blocks in one sentence.")
puts turn.output_text

Usage

Create a conversation:

agent = TurnKit::Agent.new(
  name: "writer",
  instructions: "Write clear release notes."
)

conversation = agent.conversation(subject: "v1 launch")
conversation.say("Mention faster tool execution.")

turn = conversation.run!
puts turn.output_text

Create a tool:

class SaveReport < TurnKit::Tool
  description "Save a report."
  parameter :title, :string, required: true
  parameter :body, :string, required: true

  def self.ends_turn? = true
  def self.completion_message(result) = "Saved #{result.fetch("report_id")}."

  def call(title:, body:, context:)
    { report_id: "rep_1", title: title, body: body }
  end
end

Use the tool:

agent = TurnKit::Agent.new(
  name: "reporter",
  instructions: "Save reports when asked.",
  tools: [SaveReport]
)

turn = agent.conversation.ask("Save a short status report.")
puts turn.output_text

Add skills:

skill = TurnKit::Skill.from_file("skills/research.md")

agent = TurnKit::Agent.new(
  name: "researcher",
  skills: [skill]
)

Delegate to sub-agents:

writer = TurnKit::Agent.new(
  name: "writer",
  description: "Draft concise copy."
)

editor = TurnKit::Agent.new(
  name: "editor",
  sub_agents: [writer]
)

turn = editor.conversation.ask("Ask the writer for three headlines.")
puts turn.output_text

Install Rails persistence:

bin/rails generate turnkit:install
bin/rails db:migrate

Configure Rails:

# config/initializers/turnkit.rb
TurnKit.store = TurnKit::ActiveRecordStore.new
TurnKit.default_model = "claude-sonnet-4-5"
TurnKit.timeout = 300

Reconcile stale turns:

TurnKit.reconcile_stale!

Options

Configure defaults globally:

TurnKit.default_model = "claude-sonnet-4-5"
TurnKit.max_iterations = 25
TurnKit.timeout = 300
TurnKit.max_depth = 3
TurnKit.max_tool_executions = 100
TurnKit.cost_limit = nil

Override defaults per agent:

agent = TurnKit::Agent.new(
  name: "analyst",
  model: "gpt-4.1-mini",
  max_iterations: 10,
  timeout: 60,
  cost_limit: 0.25
)

Option	Description
default_model	Default model for new turns.
client	Client adapter for model calls.
store	Store for conversations and turns.
max_iterations	Maximum model calls per turn.
timeout	Maximum seconds per root turn.
max_depth	Maximum sub-agent nesting depth.
max_tool_executions	Maximum tool calls per root turn.
cost_limit	Maximum cost per root turn.

Contributing

Open bug reports and pull requests on GitHub:

https://github.com/samuelcouch/turnkit

Run tests:

bundle exec rake test

License

See the MIT License.