MCP Protocol Conformance — Claude Code MCP server: tests
Run protocol and capability checks against an MCP server, including JSON-RPC, tool schemas, and OAuth 2.1 PKCE. Useful before promoting a build or reviewing changes.
claude mcp add protocol-conformance -- npx -y mcp-protocol-conformanceWhat MCP Protocol Conformance does
MCP Protocol Conformance tests JSON-RPC 2.0, protocol-version negotiation, transport behaviour, OAuth 2.1 PKCE, tool schemas, and advertised capabilities. It also runs tool-call smoke checks and reviews annotations. Results can be rendered as JUnit, JSON, or terminal output; manifests and reports can be compared to detect breaking changes.
The harness connects to a target server over stdio or HTTP. It includes the mcp-conformance CLI and a TypeScript library, and can itself expose 12 read-only tools to an MCP client. It covers specs from 2024-11-05 through 2025-11-25. HTTP checks require spec version 2025-03-26 or later; annotation checks for earlier versions produce warnings.
To add it in Claude Code, run claude mcp add protocol-conformance -- npx -y mcp-protocol-conformance. The target server must be reachable over the transport used for the test, or the run cannot proceed.
What it helps with
- check an MCP server’s JSON-RPC 2.0 compliance
- verify its advertised protocol version
- validate tool schemas and capabilities
- compare manifests or reports for breaking changes
Example prompts for the agent
- Run the full checks against my MCP server over stdio and show the report.
- Check OAuth 2.1 PKCE for my MCP server.
- Compare
manifests/v1.jsonwithmanifests/v2.json.
How to install MCP Protocol Conformance
Platform CLI
claude mcp add protocol-conformance -- npx -y mcp-protocol-conformancePlatform CLI
codex mcp add mcp-protocol-conformance -- npx -y mcp-protocol-conformanceConfig file
{
"mcpServers": {
"mcp-protocol-conformance": {
"command": "npx",
"args": [
"-y",
"mcp-protocol-conformance"
]
}
}
}Config file
{
"servers": {
"mcp-protocol-conformance": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"mcp-protocol-conformance"
]
}
}
}Platform CLI
gemini mcp add mcp-protocol-conformance npx -y mcp-protocol-conformanceStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about MCP Protocol Conformance
How do I install MCP Protocol Conformance in Claude Code?
Run claude mcp add protocol-conformance -- npx -y mcp-protocol-conformance. Claude Code can then connect to the MCP server.
What does MCP Protocol Conformance do?
It tests MCP servers for protocol, transport, OAuth 2.1 PKCE, schema, and capability compliance. It can also compare manifests and reports.
Which MCP specification versions does it support?
It covers versions from 2024-11-05 through 2025-11-25. HTTP tests start with 2025-03-26; older versions run annotation checks in warning-only mode.
