mcp-validator
mcp-validator is a Python testing suite (with reference HTTP/STDIO MCP servers) for validating Model Context Protocol (MCP) server implementations against the MCP specification, including protocol version negotiation and compliance testing for HTTP and STDIO transports. It also includes a framework for testing OAuth 2.1-based authentication for the 2025-06-18 protocol version.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
README describes security-related behaviors for the reference HTTP server/testing environment (e.g., TLS requirement for production with OAuth, WWW-Authenticate headers, CORS/origin validation, DNS rebinding prevention, and optional rate limiting). However, dependency hygiene, secret-handling practices, and exact error-code structure are not verifiable from the provided README alone.
⚡ Reliability
Best When
You have an MCP server implementation (HTTP or STDIO) and want automated, repeatable protocol compliance/regression testing across multiple MCP protocol versions.
Avoid When
You need a turnkey managed service with a hosted endpoint, SDK, or OpenAPI/hosted API rather than a local test runner.
Use Cases
- • Run compliance tests to verify an MCP server correctly implements required MCP behaviors
- • Validate HTTP-based MCP servers (initialization, tools, errors, batching restrictions, session/protocol negotiation)
- • Validate STDIO-based MCP servers including tool discovery and error handling behaviors
- • Test and verify OAuth 2.1 authentication and related HTTP security headers for MCP servers
- • Generate detailed compliance reports for regression testing across MCP protocol versions
Not For
- • Production deployment as an MCP server for end users (it is primarily a validator/testing framework)
- • Replacing an MCP server’s own implementation of OAuth/security logic (it tests/validates, it does not substitute for server auth correctness)
- • Providing a stable hosted API/SaaS interface (this is a local test framework)
Interface
Authentication
Authentication is described for the reference HTTP server and HTTP compliance tests via environment variables (e.g., MCP_OAUTH_REQUIRED_SCOPES). This is not an auth interface for a hosted service; it is part of the validation environment.
Pricing
No pricing information provided; repository appears to be a local open-source testing suite.
Agent Metadata
Known Gotchas
- ⚠ Test execution is command/script driven; an agent may need to orchestrate starting/stopping the reference server during tests.
- ⚠ OAuth-related tests likely require a reachable introspection endpoint or appropriate stubbing; missing external auth dependencies may cause failures unrelated to MCP compliance.
Alternatives
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Scores are editorial opinions as of 2026-03-30.