ruby-sdk/conformance

MCP Conformance Tests

Validates the Ruby SDK's conformance to the MCP specification using @modelcontextprotocol/conformance.

Prerequisites

• Node.js (for npx)
• bundle install completed

Running the Tests

Run all scenarios

bundle exec rake conformance

Starts the conformance server, runs all active scenarios against it, prints a pass/fail summary for each scenario, and exits with a non-zero status code if any unexpected failures are detected. Scenarios listed in expected_failures.yml are allowed to fail without affecting the exit code.

Environment variables

Variable	Description	Default
PORT	Server port	9292
SCENARIO	Run a single scenario by name	(all)
SPEC_VERSION	Filter scenarios by spec version	(all)
VERBOSE	Show raw JSON output when set	(off)

# Run a single scenario
bundle exec rake conformance SCENARIO=ping

# Use a different port with verbose output
bundle exec rake conformance PORT=3000 VERBOSE=1

# Start the server on a specific port
bundle exec rake conformance_server PORT=3000

Start the server and test separately

# Terminal 1: start the server
bundle exec rake conformance_server

# Terminal 2: run all scenarios
npx @modelcontextprotocol/conformance server --url http://localhost:9292/mcp

# Terminal 2: run a single scenario
npx @modelcontextprotocol/conformance server --url http://localhost:9292/mcp --scenario ping

Keeps the server alive between test runs, which avoids the startup overhead when iterating on a single scenario. Stop the server with Ctrl+C when done.

List available scenarios

bundle exec rake conformance_list

Prints all scenario names that can be passed to SCENARIO.

SDK Tier Report

The MCP SDK Tier system requires SDK maintainers to self-assess and report results to the SDK Working Group via modelcontextprotocol/modelcontextprotocol issues.

To generate a full tier assessment report, use the /mcp-sdk-tier-audit slash command from the modelcontextprotocol/conformance repository with the conformance server running:

# Terminal 1 (this repository): start the conformance server
bundle exec rake conformance_server

# Terminal 2 (conformance repository): run the tier audit skill as a slash command in Claude Code
/mcp-sdk-tier-audit /path/to/modelcontextprotocol/ruby-sdk http://localhost:9292/mcp

The skill evaluates conformance pass rate, issue label taxonomy, triage metrics, documentation coverage, and policy compliance, then produces a markdown report suitable for tier advancement submissions.

File Structure

conformance/
  server.rb              # Conformance server (Rack + Puma, default port 9292)
  runner.rb              # Starts the server, runs npx conformance, exits with result code
  expected_failures.yml  # Baseline of known-failing scenarios
  README.md              # This file

Known Limitations

Known-failing scenarios are registered in conformance/expected_failures.yml. They are allowed to fail without affecting the exit code and are tracked to catch regressions. These are shown in the output of bundle exec rake conformance.