A CSV import that reported failure but had actually succeeded, a 60-second load balancer timeout, and fifty sequential calls to the Mailgun API stacked up inside a loop. The old version of this debugging session takes two hours on a good day: dashboard to codebase to database client and back, assembling the picture piece by piece and holding it all in your head.
With New Relic's MCP server, MongoDB's, and the full codebase live in one Claude Code session, the picture assembles itself. Diagnosed, fixed, and deployed in a single sitting, along with a silent behavior gap no alert would ever have flagged, because from the system's perspective nothing was wrong.