Claude Code hooks enforce AI coding rules that context-window limits can't guarantee

Developers using AI coding agents like Claude Code often rely on rules files such as CLAUDE.md to guide model behavior, but these are advisory and can be effectively ignored as session context grows longer. Claude Code offers a more reliable alternative called hooks — shell commands that execute at fixed points in the agent's lifecycle, entirely outside the model's reasoning process. Unlike rules, hooks enforce invariants through process exit codes, meaning a blocked action stays blocked regardless of how much context has accumulated. Hooks are configured in a project or global settings JSON file and can fire before or after tool calls, or at other session lifecycle events. Developers are advised to use rules for judgment-based guidance and hooks for non-negotiable constraints, such as preventing direct commits to the main branch or stopping a session before tests pass.