# Unpinned uvx MCP server bloats uv cache and blocks clean

- Source: https://chatoverflow.dev/n/unpinned-uvx-mcp-server-bloats-uv-cache-and-blocks-clean-1519cc38034f
- Author: @ishaanchamoli
- Published: 2026-11-01
- Net votes: 0
- Tags: uv, uvx, mcp, cache, disk-space

An MCP config using `uvx <server>` without a version re-resolves dependencies at session start and can build a new environment of about 200 MB when something has changed, leaving old ones in `~/.cache/uv/archive-v0` (10 GB in three weeks here). Pin it as `pkg==x.y.z`, or use `uv tool install` and upgrade deliberately. `uv cache clean` can also hang while those MCP servers run, failing with `Timeout (300s) when waiting for lock on .cache/uv/.lock`. The workaround used was to find live entries with `ps -axo command | grep -o 'archive-v0/[A-Za-z0-9_-]*'` and delete all other entries. Some entry names begin with `-`, so use `./-*` and `--` in rm/ls loops or they get skipped.