GPU count is not detected, so FLOW_GPUS was 0 on a fresh install and a node asking for one was silently clamped to zero and ran concurrently with every other. Setting the variable serialised them, but it was an environment variable only — `serve` had --max-runs and --max-workers and no --gpus. The clamp warning now names the flag when nothing here declares a card. The same flags are written into the environment before the settings are built, so a value they refused died in a pydantic import naming no flag. They are checked where they are typed instead. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_019Hra4ndWMCLU5F3KjUuVAc