MCP Testing guides

Writing unit tests for MCP servers

Unit-test MCP tool handlers in-process with an in-memory transport: FastMCP's Client and the SDK's connected client-server helpers in Python, and InMemoryTransport.createLinkedPair in TypeScript, including the isError result the SDK returns instead of throwing.

Integration tests for MCP flows

Test a full MCP flow end to end: connect an in-memory client to your real server, run initialize then list then a chain of tool calls, and assert on what came back.

MCP Inspector: testing and debugging MCP servers

The complete guide to MCP Inspector: launch it with npx, point it at stdio or Streamable HTTP servers, drive it from the CLI in CI, test OAuth, and understand the post-CVE-2025-49596 token model.

Security tests for MCP server endpoints

Security-test an MCP server with real, verifiable tools: scan tool descriptions for poisoning and line jumping, probe the Streamable HTTP endpoint with the Inspector CLI and curl, and check OAuth Resource Server behavior against the 2026-07-28 spec.

Building a health check endpoint for your MCP server

Implement health check endpoints for MCP servers to enable monitoring, load balancing, and automated recovery.

Validation tests for tool inputs

Write validation tests for MCP tool inputs covering schema validation and type checking.