ActionmcpBLOCK
Rails Engine with MCP compliant Spec.
Overview
From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.
ActionMCP is a Ruby gem focused on providing Model Context Protocol (MCP) capability to Ruby on Rails applications, specifically as a server.
ActionMCP is designed for production Rails environments and does not support STDIO transport. STDIO is not included because it is not production-ready and is only suitable for desktop or script-based use cases. Instead, ActionMCP is built for robust, network-based deployments.
The client functionality in ActionMCP is intended to connect to remote MCP servers, not to local processes via STDIO.
It offers base classes and helpers for creating MCP applications, making it easier to integrate your Ruby/Rails application with the MCP standard.
With ActionMCP, you can focus on your app's logic while it handles the boilerplate for MCP compliance.
Introduction
Model Context Protocol (MCP) is an open protocol that standardizes how applications provide context to large language models (LLMs).
Think of it as a universal interface for connecting AI assistants to external data sources and tools.
MCP allows AI systems to plug into various resources in a consistent, secure way, enabling two-way integration between your data and AI-powered applications.
This means an AI (like an LLM) can request information or actions from your application through a well-defined protocol, and your app can provide context or perform tasks for the AI in return.
ActionMCP is targeted at developers building MCP-enabled Rails applications. It simplifies the process of integrating Ruby and Rails apps with the MCP standard by providing a set of base classes and an easy-to-use server interface.
Protocol Support
ActionMCP targets the released MCP 2025-11-25 protocol. Older protocol versions and unreleased draft versions are not accepted. Core handling includes:
- JSON-RPC 2.0 transport layer
- Capability negotiation during initialization
- Error handling with proper error codes (-32601 for method not found,
63e5f3aaf10dOBSERVED · 2026-10-07Exposed tools (11)
8 read · 3 write · 0 destructive.
| Tool | Risk | Description |
|---|---|---|
README | read | Custom desc |
add | write | Add two numbers together |
analyze_code | read | Analyze code for potential improvements |
analyze_csv | read | Analyze a CSV file |
calculate_sum | read | Calculate the sum of two numbers |
calculate_sum_with_precision | read | Calculate the sum of two numbers with specified precision |
code | read | Code to explain |
create_github_issue | write | Create a GitHub issue |
execute_command | write | Run a shell command |
language | read | Programming language |
test.txt | read | A test file |
Trust audit
BLOCKgrade D · trust 64/100 Do not install this without reading the findings. The audit found something that could harm you or your machine.
| Layer | What it checks | Result |
|---|---|---|
| L0 | Provenance & inventory | PASS |
| L1 | Static analysis of the code | FAIL |
| L2 | Instruction surface (what it tells the agent) | PASS |
| L3 | Class-specific surface | PASS |
| L4 | Behavioural (sandbox) | SKIPPED |
What the source does
- Filesystem
- none-observed
- Network
- declared (4 observation(s))
- Shell
- declared (1 observation(s))
- Dependencies
- not all pinned
- Secrets in source
- found
Findings (23)
atob( ... new Function(
export DATABASE_URL="postgresql://ubuntu:password@localhost/actionmcp_test"
"--bind", "http://127.0.0.1:#{@options[:port]}", "--config", rackup ]"--bind", "http://127.0.0.1:#{port}",# bundle exec falcon serve --bind http://127.0.0.1:62770 mcp/config.ru
DATABASE_URL: postgresql://ubuntu:password@localhost/actionmcp_test
test.sqlite3
.annotaterb.yml
.release-please-manifest.json
.rubocop.yml
.ruby-version
.keep
ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../../Gemfile", __dir__)$LOAD_PATH.unshift File.expand_path("../../../lib", __dir__)destination File.expand_path("../../../../../tmp/generator_test_output", __dir__)destination File.expand_path("../../../../../tmp/generator_test_output", __dir__)destination File.expand_path("../../../../../tmp/generator_test_output", __dir__)bundle exec falcon serve --bind http://127.0.0.1:62770 --config mcp_vanilla.ru
bundle exec falcon serve --bind http://0.0.0.0:62770 --config mcp/config.ru
`))}}var Ct;var et=S(()=>{Ct={major:4,minor:3,patch:5}});function Dg(r){if(r==="")return!0;if(r.length%4!==0)return!1;try{return atob(r),!0}catch{return!1}}function $_(r){if(!Fv.test(r))return!1;let irender text: "🏴☠️ REBELLION REGISTERED 🏴☠️"
"👁️🗨️ #{time_ago_in_words(Time.current - seconds.seconds)} in this digital prison, #{client_ref}."@types/bun, @types/node, typescript, vite
Gates applied: critical_finding, no_behavioural_pass.
63e5f3aaf10dfull audit observations/trust-audit/mcp-server/seuros__actionmcp.json · Report an issue / request a re-scanAudit history
Every audit this server has had. A grade with a past is a grade somebody is still checking.
| Date | Source | Verdict | Grade | Score | Change |
|---|---|---|---|---|---|
| 2026-10-07 | 63e5f3aaf10d | BLOCK | D | 64 | first audit |
Questions
What is the Actionmcp MCP server?
Rails Engine with MCP compliant Spec.
What tools does Actionmcp expose?
11 in total: 8 read-only, 3 that write, and 0 that can delete or overwrite. Every one is listed on this page with its risk.
Is Actionmcp safe to connect to an agent?
No — not without reading the findings first. The audit graded it D (64/100) and found 2 critical or high issues in the source. Each one is listed on this page with the file and line it is on.
What credentials does Actionmcp need?
No credential environment variables were found in its source, so it appears to need none.
How current is this page?
The grade is for one exact copy of the source (63e5f3aaf10d), read on 2026-10-07. The repository is watched and re-audited when it changes.