Unblock a session slowed by the sandbox

A blocker report is cheap to write and expensive to act on. This skill front-loads the verification so the report that reaches a maintainer is worth their time.

The measurements quoted below come from a single macOS machine on Claude Code 2.1.220, July 2026. Treat the numbers as illustrative and the method as the point.

Self-diagnosis, all eight checks, before you complain

Run these in order. Each step says what to run, what to read, and what the result lets you conclude. Steps 5b and 5c pay for themselves fastest.

1. Do not trust the sandbox description in your system prompt.