Notes on what we observe when we check MCP servers, and the fixes for what we find.https://mcpcheckup.com/https://mcpcheckup.com/blog/observed-unsigned-faq/https://mcpcheckup.com/blog/observed-unsigned-faq/Five real protocol-level causes behind an "observed-unsigned" MCP Checkup report — four in a server's own setup, one a bug in our probe that we found and fixed. Each with a curl self-test and a fix.Tue, 01 Sep 2026 00:00:00 GMT