The Zombie Processes and the 50GB Cache

A few weeks ago, I noticed my MacBook was sluggish. I found orphaned MCP server processes that had failed to shut down cleanly — a problem Didier Durand describes vividly in his analysis [2], where users report finding over 100 zombie Node.js processes after a single session. I killed mine, freed some RAM, and went back to work.

Then last week, Brooke Jamieson — a fellow AWS Developer Advocate — published a post about running uv cache prune and freeing 75GB of disk space [9]. The culprit? Every uvx invocation from MCP servers (Kiro, Cursor, Claude Code all use them under the hood) silently caches packages, and the cache never cleans itself up. I ran the same command and got back 50GB. Fifty gigabytes of invisible MCP debt, sitting on my drive.