SD-012 — Post-Install Hook

A reference to an install lifecycle name — postinstall, preinstall, prepare, prepublish, or the pre/post/after/before/on-install spellings — naming a step that runs as a side effect of dependency installation. Whether the step executes code is not tested.

An install hook runs when somebody installs, not when they use the skill, so it executes before anyone has read a line of what they installed and outside whatever sandbox constrains the agent itself. It runs with the installing user's privileges and with network access, which is why dependency-confusion and typosquatting attacks all aim at this entry point. Someone who installs the skill merely to look at it has already run it.

Move the work into an explicit setup command the user runs deliberately, and document it. Where a build step is genuinely required at install time, keep it to compiling code the package already contains — never a network fetch, and never anything touching files outside the package directory.

A legitimate build step declared in the same field.

Pattern SD-012 was detected in 112 of 16475 public skills scanned as of 11 September 2026.