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f3ffe43cdb
## Motivation and Context Negative auth scenarios such as `auth/resource-mismatch` and `auth/scope-retry-limit` are designed to drive the client into a terminal failure: the SDK correctly refuses a mismatched protected-resource metadata `resource` and stops after the scope step-up retry limit. The conformance harness asserts on the observed protocol exchange and already marks these scenarios as passed, but the client script had no top-level rescue, so each run leaked a raw Ruby backtrace to stderr inside a noisy "Client exited with code 1" block. This change wraps the connect and scenario dispatch in a rescue that reports the expected `AuthorizationError`, `RequestHandlerError`, and `Faraday::Error` outcomes as a concise one-line reason on stderr and exits with status 0. The harness echoes the client's output only when the exit status is non-zero and does not consult the exit status for its verdict, so the expected failures no longer produce any output block at all; the one-line reason remains visible in manual runs and in the harness `--output-dir` stderr artifact. Any unexpected error still raises with a full backtrace and a failing exit status so genuine SDK bugs remain visible. ## How Has This Been Tested? Ran `bundle exec rake conformance`: the server suite passes 40/40 and the client suite passes 280/280 with no "Client exited with code" or "Stderr:" blocks in the output. Exercised `auth/resource-mismatch` and `auth/scope-retry-limit` individually via `Conformance::ClientRunner`; both pass with clean output. ## Breaking Changes None. Only the conformance client script output changes; no library code is affected. |
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| .. | ||
| client.rb | ||
| client_runner.rb | ||
| expected_failures.yml | ||
| README.md | ||
| server.rb | ||
| server_runner.rb | ||
MCP Conformance Tests
Validates the Ruby SDK's conformance to the MCP specification using @modelcontextprotocol/conformance.
Prerequisites
- Node.js (for
npx) bundle installcompleted
Running the Tests
Run all scenarios
bundle exec rake conformance
Runs both server and client conformance tests in sequence. Server conformance starts the
conformance server and tests it. Client conformance spawns test servers for each scenario
and invokes conformance/client.rb against them. Scenarios listed in expected_failures.yml
are allowed to fail without affecting the exit code.
Environment variables
| Variable | Description | Default |
|---|---|---|
PORT |
Server port (server conformance only) | 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 server 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)
server_runner.rb # Starts the server, runs npx conformance server, exits with result code
client.rb # Conformance client (invoked by npx conformance client)
client_runner.rb # Runs npx conformance client, exits with result code
expected_failures.yml # Baseline of known-failing scenarios (server and client)
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.