Wrapping Hermes Agent with agent-stack: six tiny libs for the boring parts
The day my agent silently broke
A customer pinged me on a Tuesday. The reply from my agent looked fine. The tool call underneath did not. One field flipped from user_id to userId after a model swap, and my tool call started returning empty objects instead of throwing. The agent kept going. The user kept asking why their lookup felt off. I found out three days later from a support ticket.
That bug was not in the agent loop. The loop was perfect. The bug was around it. Argument shape changed. No one caught it because there was no snapshot to compare against. No validator to fail fast. No trace to diff.
That story is why I built agent-stack. Six small libs, one repo, one install. Each one fixes one thing that goes wrong outside the agent loop.
