What are your most useful agent hooks?
I started using the stop hook in most of my projectes, so I don't need to trust the agent to "remember" it has validate its changes.
My hook uses git to check if there are changed files. If there are some it runs a few scripts and if they fail their output is piped back to the agent.
I always had git hooks in place that would run typecheck, linting and unit tests (only the ones related to the changes), but in my current workflow my agents don't commit themselves.
Usually it is me doing the commits and I often got annoyed when there were still broken tests or linting issues left to fix, so I switched to using agent hooks to run pretty much what I have in my lint-staged config.
Some downsides to this approach:
You need to be aware of this and not ask the agent about a codebase that is currently in a dirty state or it would start cleaning up the issues after it answered you.
This isn't watertight either. I once had a run where Sonnet 4.6 couldn't fix the linting issue so it changed my oxlint config instead.
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Are you using agent hooks?
Which ones do you find most useful?