Ag/client conformance

conformance/README.md

@@ -7,7 +7,7 @@ Validates the Ruby SDK's conformance to the MCP specification using [`@modelcont
 - Node.js (for `npx`)
 - `bundle install` completed
 
-## Running the Tests
+## Server Conformance
 
 ### Run all scenarios
 
@@ -64,6 +64,33 @@ bundle exec rake conformance_list
 
 Prints all scenario names that can be passed to `SCENARIO`.
 
+## Client Conformance
+
+The client conformance tests validate `MCP::Client` against the MCP specification by running
+it through scenarios served by the conformance test runner.
+
+### Run all client scenarios
+
+```bash
+npx @modelcontextprotocol/conformance client --suite core --command "ruby conformance/client.rb"
+```
+
+### Run a single scenario
+
+```bash
+npx @modelcontextprotocol/conformance client --scenario initialize --command "ruby conformance/client.rb"
+```
+
+### List available client scenarios
+
+```bash
+npx @modelcontextprotocol/conformance list --client
+```
+
+The conformance runner starts a test server for each scenario, sets the
+`MCP_CONFORMANCE_SCENARIO` environment variable, and invokes the command with the server URL
+as the first argument.
+
 ## SDK Tier Report
 
 The [MCP SDK Tier system](https://modelcontextprotocol.io/community/sdk-tiers) requires SDK
@@ -92,6 +119,7 @@ submissions.
 conformance/
   server.rb              # Conformance server (Rack + Puma, default port 9292)
   runner.rb              # Starts the server, runs npx conformance, exits with result code
+  client.rb              # Conformance client for client-side scenario testing
   expected_failures.yml  # Baseline of known-failing scenarios
   README.md              # This file
 ```

conformance/client.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+# Conformance test client for MCP client testing.
+#
+# Usage: ruby conformance/client.rb <server-url>
+#
+# The scenario name is read from the MCP_CONFORMANCE_SCENARIO environment variable,
+# which is set by the conformance test runner.
+
+$LOAD_PATH.unshift(File.expand_path("../lib", __dir__))
+require "mcp"
+require "mcp/client"
+require "mcp/client/http"
+
+server_url = ARGV[0]
+scenario = ENV["MCP_CONFORMANCE_SCENARIO"]
+
+unless server_url && scenario
+  warn "Usage: MCP_CONFORMANCE_SCENARIO=<scenario> ruby conformance/client.rb <server-url>"
+  exit 1
+end
+
+transport = MCP::Client::HTTP.new(url: server_url)
+client = MCP::Client.new(transport: transport)
+
+case scenario
+when "initialize"
+  client.connect(client_info: { name: "ruby-conformance-client", version: "1.0.0" })
+  client.tools
+  client.close
+when "tools_call"
+  client.connect(client_info: { name: "ruby-conformance-client", version: "1.0.0" })
+  tools = client.tools
+  tool = tools.find { |t| t.name == "add_numbers" }
+  if tool
+    client.call_tool(tool: tool, arguments: { a: 1, b: 2 })
+  end
+  client.close
+else
+  warn "Unknown scenario: #{scenario}"
+  exit 1
+end