# MCP Protocol Conformance

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.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI
- Author: studiomeyer-io
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/studiomeyer-io/mcp-protocol-conformance
- Updated: 2026-10-21
- HTML: https://affpapa.org/en/nevibecode/mcp/mcp-protocol-conformance

## What it 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.

## Requirements
- Needs: Node.js (commands run via npx)

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add protocol-conformance -- npx -y mcp-protocol-conformance
```

### Codex

**Platform CLI**
```bash
codex mcp add mcp-protocol-conformance -- npx -y mcp-protocol-conformance
```

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "mcp-protocol-conformance": {
            "command": "npx",
            "args": [
                "-y",
                "mcp-protocol-conformance"
            ]
        }
    }
}
```

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "mcp-protocol-conformance": {
            "type": "stdio",
            "command": "npx",
            "args": [
                "-y",
                "mcp-protocol-conformance"
            ]
        }
    }
}
```

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add mcp-protocol-conformance npx -y mcp-protocol-conformance
```

## When to use it
- 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
- 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.json` with `manifests/v2.json`.

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