Topic
Deterministic fixtures that pin protocol edge cases so compiling refactors cannot silently break a wire contract.
A dev.to author running Microsoft's agent-hooks conformance kit got 69 passes, 4 skips and 0 failures on its reference harness. That covers one host, while the launch demo names eight frameworks and the claims table has three rows.
Reality
MCP's 2026-07-28 revision deletes the initialize handshake and Mcp-Session-Id, so a server must answer each request from what arrives with it. A developer who rebuilt the spec against 708 tests wrote one test whose only job is proving no state leaks between server instances.
Reality
One engineer who built services on AWS, GCP and Alibaba Cloud puts about 90% of cloud services in a commodity bucket that is safe to abstract. A platform team has to normalize errors and pagination for that share, and services with a real cost or capability edge stay native.
Reality
A conformance suite hashed a repository, killed mutmut, cosmic-ray, Stryker and PIT at the instant a source file went dirty, then hashed again. One of the four came back mutated, and a plain SIGTERM was enough to do it.
Reality
The finalized Streamable HTTP transport mirrors tool arguments into Mcp-Param-* headers. A bad suffix, an excluded type, or an unreachable annotation kills the tool definition, so validate before tools/list.
Reality