I maintain safari-mcp, an MCP server that lets AI agents drive a real Safari session on macOS. Over a few releases this summer I shipped per-session tab isolation — the feature that lets several agents share one browser without stealing each other's tabs. I wrote about it here. Twice. I was reasonably proud of it.
Then a stranger showed up with a deployment I had never imagined — three macOS profiles, up to fifteen concurrent server instances — and filed three bug reports in the space of seven seconds.
All three were right.
The reports
What made them remarkable wasn't just the hit rate. It was the form. Each issue had a description of the deployment, a repro, and observed data from their own machines. No speculation, no "it feels flaky." They had read the code, formed a hypothesis about where it breaks at their scale, and then watched it break exactly there.
