Deterministic Guardrails: Prompts Steer, Hooks Enforce

Short summary

Prompts alone can't enforce production rules—they only shift probability. The post demonstrates a deterministic hook-based approach that refuses bad edits before they land, combining soft steering (prompt-guided retry loops) with hard gates (PreToolUse blocks). Includes a bash script for blocking mock imports in src/.

• •Prompts are probabilistic requests; hooks are deterministic refusers that can block writes before they land
• •A refactoring loop (generate → check → steer → retry) works better when paired with PreToolUse hooks rather than post-hoc detection
• •Concrete example: blocking mock imports from production code via a hook fired before tool execution

Generated with AI, which can make mistakes.