Kill Switch

Problem

An in-band stop hook that the agent's own loop checks at the start of each iteration only works if the agent's loop is still alive and cooperating. If the model is wedged inside a long tool call, infinite-looping on a degenerate state, or running tools that ignore process signals, the in-band stop never fires. Killing the operating-system process is a brutal fallback that loses provenance and any chance to run compensating actions. Without a stop primitive outside the agent's own control flow, operator authority disappears the moment the agent stops checking in.

Solution

Signed revocation token or feature flag checked on every step from a shared store the agent runtime cannot bypass. On revocation, the agent halts: no further model calls, no further tool calls; in-flight effects are compensated where possible. Killing the OS process is the fallback, but loses provenance.

When to use

• An agent runs tools or model calls that can cause real harm if it goes wedged.
• Out-of-band halt must be guaranteed even when the agent loop ignores in-band signals.
• A signed revocation token or feature flag can be checked from a store the runtime cannot bypass.