TIL: `No module named` right after an update can mean the process is stale, not the package missing

My Hermes agent started printing this on every turn:

Failed to load bundled provider plugin solstice: No module named 'httpx'

I almost ran pip install httpx. It would have done nothing.

Hermes doesn't run from one venv. Each update builds a fresh environment under ~/.hermes/installs/<id>/environments/<hash>/, and new launches use it. The .venv in the repo had httpx too, and it wasn't the interpreter doing the work either.

httpx was installed in the new environment at 20:51. The gateway had been running since 08:12, and a chat window since the day before. Both were still on the environments they started with, from before the dependency existed.

Ask the running process what it loaded instead of reading launcher scripts:

lsof -p <pid> | grep -o 'environments/[^/]*' | sort -u

The gateway showed an old hash. A fresh process showed the new one. The fix was a restart, with nothing to install:

hermes gateway restart

Then I quit and relaunched the long-lived chat window.

The update log had told me. Its last line said the gateway restart did not finish. I had read the success message and skipped the warning below it.