## TL;DR

Move BUILDKITE_ADDITIONAL_HOOKS_PATHS onto the agent container itself so the agent picks it up at startup and propagates it, instead of setting it per command container.

## Steps

1. Move BUILDKITE_ADDITIONAL_HOOKS_PATHS onto the agent container itself so the agent picks it up at startup and propagates it, instead of setting it per command container. If you set it per-container for secrets injection on command containers only, restructure so the agent-level value covers what you need. This is a regression from the #3944 change, so pin or test agent upgrades when you rely on hook paths.

## When to use

You are seeing this: The reporter diagnosed it: the agent now overrides the variable on each bootstrap container with its own startup-env value, discarding the per-container value. Use this skill when you run into "Buildkite: BUILDKITE_ADDITIONAL_HOOKS_PATHS ignored after agent upgrade".

## When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

## Versions

Versions mentioned in the source: past v3.127.1. If you are on something much newer or older, the details may have shifted.

## Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.