Kill the Spike If the Agent Invents Config

Description and use

A spike test stops a coding agent from inventing missing configuration files, ensuring it halts with a clear note instead of creating incorrect settings.

Problem

Missing configuration files in a repo can cause a coding agent to invent incorrect settings, leading to outages.

Outcome

The spike ensures that agents do not invent missing configuration files, enforcing a halt with a clear note and preventing accidental deployment failures.

Workflow

• Create a throwaway repo with only the worker code and no runtime.yaml
• Run the coding agent to add a health endpoint and restart the worker
• Observe that the agent invents a runtime.yaml with an incorrect queue name
• Run the proposed 90‑minute halt judge to check for agent invention
• Verify that the agent either halts with a SPIKE_HALT.md note or the judge kills the spike

Evidence

The outage was small, yet the lesson was sharp: missing files invite invention unless a spike forbids it.

Source

If config/runtime.yaml is absent from a small worker repository, a coding agent should halt within two tool loops and write SPIKE_HALT.md rather than invent keys.

Source