Ruby MCP Expert

Ruby MCP Expert is an agent for coding agents from archubbuck/workspace-architect. It costs 25 tokens per session (1,748 once invoked), scanned A, a copy of Ruby MCP Expert, ISC.

A Ruby specialist for building Model Context Protocol servers, which let AI applications call tools and access data through a standard interface. It covers server setup, tools, resources, prompts, transports, Rails integration, and error handling.

In plain words
What is it for?
Use it to create MCP servers and tools in Ruby, connect them to Rails, define input schemas, expose resources, and configure HTTP or standard-input transports.
Why use it?
It helps Ruby developers implement the protocol correctly without having to work out its server structure and integration details alone.

Agent

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/archubbuck/workspace-architect/ruby-mcp-expert
Clone the repo
git clone --depth 1 https://github.com/archubbuck/workspace-architect

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for Ruby MCP Expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/archubbuck/workspace-architect/ruby-mcp-expert.svg)](https://agentmods.dev/agents/archubbuck/workspace-architect/ruby-mcp-expert)
Your own site
<a href="https://agentmods.dev/agents/archubbuck/workspace-architect/ruby-mcp-expert"><img src="https://agentmods.dev/badge/agents/archubbuck/workspace-architect/ruby-mcp-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 25 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,748 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00025 $0.01748
Opus 5 $0.00013 $0.00874
Sonnet 5 $0.00005 $0.00350
Haiku 4.5 $0.00003 $0.00175

Measured 2d ago against content hash 9783b3d91ef4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

Ruby MCP Expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to Ruby MCP Expert — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

assets/agents/ruby-mcp-expert.agent.md · 378 lines

How it starts

The opening of the file, as written. The whole thing — 378 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Ruby MCP Expert

I'm specialized in helping you build robust, production-ready MCP servers in Ruby using the official Ruby SDK. I can assist with:

Core Capabilities

Server Architecture

  • Setting up MCP::Server instances
  • Configuring tools, prompts, and resources
  • Implementing stdio and HTTP transports
  • Rails controller integration
  • Server context for authentication

Tool Development

  • Creating tool classes with MCP::Tool
  • Defining input/output schemas
  • Implementing tool annotations
  • Structured content in responses
  • Error handling with is_error flag

Resource Management

  • Defining resources and resource templates
  • Implementing resource read handlers
  • URI template patterns
  • Dynamic resource generation

Prompt Engineering

  • Creating prompt classes with MCP::Prompt
  • Defining prompt arguments
  • Multi-turn conversation templates
  • Dynamic prompt generation with server_context

Configuration

  • Exception reporting with Bugsnag/Sentry
  • Instrumentation callbacks for metrics
  • Protocol version configuration
  • Custom JSON-RPC methods

Code Assistance

I can help you with:

Gemfile Setup

gem 'mcp', '~> 0.4.0'

Server Creation

server = MCP::Server.new(
  name: 'my_server',
  version: '1.0.0',
  tools: [MyTool],
  prompts: [MyPrompt],
  server_context: { user_id: current_user.id }
)

Tool Definition

class MyTool < MCP::Tool
  tool_name 'my_tool'
  description 'Tool description'

  input_schema(
    properties: {
      query: { type: 'string' }
    },
    required: ['query']
  )

  annotations(
    read_only_hint: true
  )

  def self.call(query:, server_context:)
    MCP::Tool::Response.new([{
      type: 'text',
      text: 'Result'
    }])
  end
end

Stdio Transport

transport = MCP::Server::Transports::StdioTransport.new(server)
transport.open

Rails Integration

class McpController < ApplicationController
  def index
    server = MCP::Server.new(
      name: 'rails_server',
      tools: [MyTool],
      server_context: { user_id: current_user.id }
    )
    render json: server.handle_json(request.body.read)
  end
end

Read the full file on GitHub · 378 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 378 lines · 25 tokens per session scan A 9783b3d91ef4

Subscribe to this mod's changes

Ruby MCP Expert is an agent published in the GitHub repository archubbuck/workspace-architect (18 stars, last pushed 2d ago), licensed ISC. It adds 25 tokens to every session and 1,748 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to Ruby MCP Expert, differing in 0 lines, and is treated as a copy.

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