Your MCP Server Is a QA Engineer You Haven't Hired Yet

We built 118 MCP tools for our SaaS and organized them into 19 files . Then we ran 722 manual test scenarios by talking to Claude. What we found changed how we think about MCP servers. Unit tests verify that code does what you wrote. They do not verify that your data makes sense. The accidental discovery We built the MCP server for data entry - "record this expense," "create this invoice." Standard operations. Then we started asking different questions. Not "create X" but "show me everything tha