# IMPLEMENTATION.md — Fix Guard Plugin Derailment

## Changes Made
- `plugins/automaton-guard/plugin.ts:60-65`: Replaced `client.chat()` injection with `throw new Error()`

## How It Works
- When an edit is blocked, the guard now throws an error instead of injecting synthetic user messages
- This prevents derailing the agent's context mid-operation
- The harness handles the error cleanly without contaminating message history
- The error message still includes actionable instructions for creating/transitioning tasks