ClaudeAgent

Ruby SDK for building AI-powered applications with the Claude Agent SDK. Wraps the Claude Code CLI with idiomatic Ruby interfaces for one-shot queries, multi-turn conversations, permissions, hooks, and MCP tools.

Requirements

Ruby 3.2+
Claude Code CLI v2.0.0+

Installation

gem "claude_agent"

Quick Start

One-Shot Query

require "claude_agent"

turn = ClaudeAgent.ask("What is the capital of France?")
puts turn.text
puts "Cost: $#{turn.cost}"

Multi-Turn Conversation

ClaudeAgent.chat do |c|
  c.say("Fix the bug in auth.rb")
  c.say("Now add tests for the fix")
  puts "Total cost: $#{c.total_cost}"
end

Streaming

ClaudeAgent.ask("Explain Ruby blocks") { |msg| print msg.text_content }

Global Configuration

ClaudeAgent.configure do |c|
  c.model = "claude-sonnet-4-5-20250514"
  c.permission_mode = "acceptEdits"
  c.max_turns = 10
end

# Or set individual fields
ClaudeAgent.model = "claude-sonnet-4-5-20250514"

Permissions

ClaudeAgent.permissions do |p|
  p.allow "Read", "Grep", "Glob"
  p.deny "Bash", message: "Shell access disabled"
  p.deny_all
end

Hooks

ClaudeAgent.hooks do |h|
  h.before_tool_use(/Bash/) { |input, ctx| { continue_: true } }
  h.after_tool_use { |input, ctx| { continue_: true } }
end

MCP Tools

server = ClaudeAgent::MCP::Server.new(name: "calc") do |s|
  s.tool("add", "Add two numbers", { a: :number, b: :number }) do |args|
    args[:a] + args[:b]
  end
end

ClaudeAgent.register_mcp_server(server)

Documentation

Guide	Description
Getting Started	Installation, first queries, multi-turn basics
Configuration	Global config, Options, sandbox, agents, env vars
Conversations	Multi-turn API, TurnResult, callbacks, tool tracking
Queries	One-shot interfaces: ask, query_turn, query
Permissions	PermissionPolicy DSL, can_use_tool, queue mode
Hooks	HookRegistry DSL, hook events, input types
MCP Tools	In-process tools, servers, schemas, elicitation
Events	EventHandler, typed callbacks, event layers
Messages	All 22 message types, 8 content blocks, pattern matching
Sessions	Session discovery, mutations, forking, resume
Client	Low-level bidirectional API (advanced)
Errors	Error hierarchy and handling patterns
Logging	Debug logging, custom loggers, log levels
Architecture	Internal design, data flow, module map

Development

bin/setup                          # Install dependencies
bundle exec rake                   # Tests + RBS + RuboCop
bundle exec rake test              # Unit tests
bundle exec rake test_integration  # Integration tests (requires CLI v2.0.0+)
bundle exec rubocop                # Lint
bin/console                        # IRB with gem loaded

License

MIT License - see LICENSE.txt

claude_agent

Runtime