I kept seeing MCP mentioned everywhere — in Claude Code docs, in Cursor settings, in every "AI engineering stack" post on LinkedIn. I kept nodding like I understood it.
I didn't.
So last week I sat down and built one from scratch. A real MCP server, connected to a real Postgres database, that Claude can actually query. No toy examples. No hand-waving over the hard parts.
This is the full account of what happened — including the two hours I lost to a configuration mistake that had nothing to do with code, and the exact moment the whole thing clicked.
First: what MCP actually is, in one paragraph
