RubyLLM Ecosystem

Extend RubyLLM with MCP servers, structured schemas, instrumentation, monitoring and community-built tools for production AI apps.

Ecosystem projects are maintained by their respective authors. We list projects for discoverability, but we cannot guarantee the quality, security, maintenance status, or fitness of every listed project.

Table of contents

  1. RubyLLM::Schema
    1. Why Use RubyLLM::Schema?
    2. Key Features
    3. Installation
  2. RubyLLM::MCP
    1. What is MCP?
    2. Key Features
    3. Installation
  3. RubyLLM::Instrumentation
    1. Why Use RubyLLM::Instrumentation?
    2. Key Features
    3. Supported Events
    4. Installation
  4. RubyLLM::Monitoring
    1. Why Use RubyLLM::Monitoring?
    2. Key Features
    3. Installation
  5. RubyLLM::RedCandle
    1. Why Run Models Locally?
    2. Key Features
    3. Installation
    4. Supported Models
  6. OpenTelemetry RubyLLM Instrumentation
    1. Why Use OpenTelemetry Instrumentation?
    2. Key Features
    3. Installation
    4. Usage
  7. Community Projects

After reading this guide, you will know:

  • How RubyLLM::Schema simplifies structured data definition for AI applications
  • What the Model Context Protocol (MCP) is and how RubyLLM::MCP brings it to Ruby
  • How RubyLLM::Instrumentation exposes RubyLLM events through ActiveSupport notifications
  • How RubyLLM::Monitoring provides dashboards and alerts for RubyLLM activity
  • How RubyLLM::RedCandle enables local model execution from Ruby
  • How OpenTelemetry instrumentation for RubyLLM provides observability into your LLM applications
  • Where to find community projects and how to contribute your own

RubyLLM::Schema

Ruby DSL for JSON Schema Creation

RubyLLM::Schema provides a clean, Rails-inspired DSL for creating JSON schemas. It’s designed specifically for defining structured data schemas for LLM function calling and structured outputs.

Why Use RubyLLM::Schema?

When working with LLMs, you often need to define precise data structures for:

  • Structured output formats
  • Function parameter schemas
  • Data validation schemas
  • API response formats

RubyLLM::Schema makes this easy with a familiar Ruby syntax.

Key Features

  • Rails-inspired DSL for intuitive schema creation
  • Full JSON Schema compatibility
  • Support for primitive types, objects, and arrays
  • Union types with any_of
  • Schema definitions and references for reusability

Installation 

gem install ruby_llm-schema

For detailed documentation and examples, visit the RubyLLM::Schema repository.

RubyLLM::MCP

Model Context Protocol Support for Ruby

RubyLLM::MCP brings the Model Context Protocol to Ruby, enabling your applications to connect to MCP servers and use their tools, resources, and prompts as part of LLM conversations.

What is MCP?

The Model Context Protocol is an open standard that allows AI applications to integrate with external data sources and tools. MCP servers can expose:

  • Tools: Functions that LLMs can call to perform actions
  • Resources: Structured data that can be included in conversations
  • Prompts: Predefined prompt templates with parameters

Key Features

  • Multiple transport types (HTTP streaming, STDIO, SSE)
  • Automatic tool integration with RubyLLM
  • Resource management for files and data
  • Prompt templates with arguments
  • Support for multiple simultaneous MCP connections

Installation 

gem install ruby_llm-mcp

For detailed documentation, examples, and usage guides, visit the RubyLLM::MCP documentation.

RubyLLM::Instrumentation

ActiveSupport::Notifications instrumentation for RubyLLM

RubyLLM::Instrumentation is a Rails plugin that instruments RubyLLM events with the built-in ActiveSupport::Notifications API.

Why Use RubyLLM::Instrumentation?

When building LLM applications, you may need custom monitoring, analytics, or logging pipelines based on your RubyLLM activity.

Key Features

  • Event instrumentation for key RubyLLM operations
  • Native integration with ActiveSupport::Notifications
  • Event hooks for chat completion, tools, embeddings, images, moderation, and transcription
  • Easy integration with existing Rails observability stacks

Supported Events

  • complete_chat.ruby_llm when RubyLLM::Chat#ask is called
  • execute_tool.ruby_llm when a tool call is executed
  • embed_text.ruby_llm when RubyLLM::Embedding.embed is called
  • paint_image.ruby_llm when RubyLLM::Image.paint is called
  • moderate_text.ruby_llm when RubyLLM::Moderation.moderate is called
  • transcribe_audio.ruby_llm when RubyLLM::Transcription.transcribe is called

Installation 

gem install ruby_llm-instrumentation

For detailed documentation and examples, visit the RubyLLM::Instrumentation repository.

RubyLLM::Monitoring

RubyLLM monitoring within your Rails application

RubyLLM::Monitoring is a Rails engine that provides a dashboard for cost, throughput, response time, and error aggregations. It also supports configurable alerts through channels such as email or Slack.

Why Use RubyLLM::Monitoring?

When running RubyLLM-powered features in production, you need ongoing visibility into performance, cost, and failure patterns.

Key Features

  • Captures events from RubyLLM::Instrumentation
  • Dashboard metrics for cost, throughput, latency, and error rates
  • Rule-based alerting for operational thresholds and regressions

Installation 

gem install ruby_llm-monitoring

For detailed documentation and examples, visit the RubyLLM::Monitoring repository.

RubyLLM::RedCandle

Local LLM Execution with Quantized Models

RubyLLM::RedCandle enables local LLM execution using quantized GGUF models through the Red Candle gem. Unlike other RubyLLM providers that communicate via HTTP APIs, RubyLLM::RedCandle runs models directly in your Ruby process using Rust’s Candle library.

Why Run Models Locally?

Running LLMs locally offers several advantages:

  • Zero latency: No network round-trips to external APIs
  • No API costs: Run unlimited inferences without usage fees
  • Complete privacy: Your data never leaves your machine
  • Offline capable: Works without an internet connection

Key Features

  • Local inference with hardware acceleration (Metal on macOS, CUDA for NVIDIA GPUs, or CPU fallback)
  • Automatic model downloading from HuggingFace
  • Streaming support for token-by-token output
  • Structured JSON output with grammar-constrained generation
  • Multi-turn conversation support with automatic history management

Installation 

gem install ruby_llm-red_candle

Note: The underlying red-candle gem requires a Rust toolchain for compiling native extensions.

Supported Models

RubyLLM::RedCandle supports various quantized models including TinyLlama, Qwen2.5, Gemma-3, Phi-3, and Mistral-7B. Models are automatically downloaded from HuggingFace on first use.

For detailed documentation and examples, visit the RubyLLM::RedCandle repository.

OpenTelemetry RubyLLM Instrumentation

Observability for RubyLLM Applications

opentelemetry-instrumentation-ruby_llm adds OpenTelemetry tracing to RubyLLM, enabling you to send traces to any compatible backend (Langfuse, Datadog, Honeycomb, Jaeger, Arize Phoenix and more).

Why Use OpenTelemetry Instrumentation?

When running LLM applications in production, you need visibility into:

  • Which models are being called and how they perform
  • The flow of conversations and tool calls
  • How long each step takes and where time is spent
  • Token usage for cost tracking and optimization
  • Tool call selection, execution, and results
  • Error rates and failure modes

This gem provides all of this automatically, with minimal setup and without having to manually add tracing code to your application.

Key Features

  • Automatic tracing for chat completions and tool calls
  • Token usage tracking (input and output)
  • Tool call spans with arguments and results
  • Error recording with exception details
  • Works with any OpenTelemetry-compatible backend
  • Follows the OpenTelemetry GenAI Semantic Conventions

Installation 

gem install opentelemetry-instrumentation-ruby_llm

Usage 

OpenTelemetry::SDK.configure do |c|
  c.use 'OpenTelemetry::Instrumentation::RubyLLM'
end

For detailed documentation, setup instructions, and examples, visit the OpenTelemetry RubyLLM Instrumentation repository.

Community Projects

The RubyLLM ecosystem is growing! If you’ve built a library or tool that extends RubyLLM, we’d love to hear about it. Consider:

  • Opening a PR to add your project to this page
  • Sharing it in our GitHub Discussions
  • Using the ruby-llm topic on your GitHub repository

Together, we’re building a comprehensive ecosystem for LLM-powered Ruby applications.