Interview Bank

Mastering Claude: From Conversation to Claude Code in 5 Days

D4 Extending Claude Code: Hooks (Deterministic) vs. CLAUDE.md (Advisory), Skills, Subagents, Plugins, Wiring Up an MCP Server, CLI Tools First

• Why are hooks more reliable than rules in CLAUDE.md? What belongs in each? Give one rule you would move from CLAUDE.md to a hook.为什么 hooks 比 CLAUDE.md 里的规则更可靠？各适合放什么？举一个你会从 CLAUDE.md 挪到 hook 的例子。

  Common in ChinaCommon overseasBasic#hooks#claude-md

  How to reason about it · think before answering

  1. This tests the systemic position of advisory versus deterministic, not feature recall. 'Hooks are scripts that run automatically' is a description; explain why model adherence is not program execution.
  2. Breakdown: CLAUDE.md enters the model's context as text and the model decides after reading — adherence is high but not total, drops as the file grows, and can be lost after compaction. A hook is a script Claude Code itself runs unconditionally at fixed lifecycle points (PreToolUse, PostToolUse, Stop), with the exit code deciding whether to block, independent of the model's judgment.
  3. One-line rule: actions that allow zero exceptions become hooks; preferences that usually apply stay in CLAUDE.md. The inverse also holds — delete rules the model follows by default, convert must-always rules into hooks, and the file shrinks.
  4. Make the example concrete: 'run lint and tests before committing' is occasionally skipped as text; as a Stop hook, failing tests exit 2 and the model receives the summary and keeps fixing. 'Never edit migrations/' becomes a PreToolUse hook matching Edit|Write that exits 2 on a path hit.
  5. Follow-ups: risks? Hooks are code running on your machine — a cloned repo's hooks execute, and headless mode shows no trust dialog; a Stop hook is overridden after 8 consecutive blocks to prevent loops.

  分析过程 · 先想清楚再作答

  1. 这题考的是「建议 vs 确定性」的系统位置，不是背功能名。答「hooks 是自动执行的脚本」只是描述，要说清为什么模型的遵守率不等于程序的执行率。
  2. 拆法：CLAUDE.md 的内容作为文字进入模型上下文，由模型读后决定怎么做——遵守率高但不是百分之百，文件越长越低，压缩后还可能丢失。hook 是 Claude Code 程序在固定生命周期点（PreToolUse / PostToolUse / Stop 等）无条件运行的脚本，由退出码决定拦不拦，与模型的判断无关。
  3. 判据一句话：一次例外都不能有的动作做成 hook；通常应该这样的偏好写进 CLAUDE.md。反向操作也成立：CLAUDE.md 里模型已经默认遵守的删掉，必须百分之百的换成 hook，文件就短了。
  4. 例子要具体：「提交前跑 lint 与测试」——作为文字它偶尔会被跳过；做成 Stop hook，测试不过 exit 2，模型收到失败摘要继续修，直到通过；「不许改 migrations/」做成 PreToolUse hook 匹配 Edit|Write，路径命中就 exit 2。
  5. 可预期的追问：hook 有没有风险？有——它是代码，跑在你机器上，clone 陌生仓库时别人的 hook 会执行，无头模式没有信任对话框；Stop hook 连续 8 次阻止后会被放行防死循环。

  Key points

  • CLAUDE.md is text the model reads and then decides on — high but not total adherence
  • A hook is a script the program runs unconditionally at lifecycle points; the exit code decides, not the model
  • Zero-exception actions become hooks; usual preferences stay in CLAUDE.md
  • Examples: pre-commit tests as a Stop hook; a migrations deny as a PreToolUse hook

  答题要点

  • CLAUDE.md 是送进上下文的文字，由模型读后决定，遵守率高但不是百分之百
  • hook 是程序在固定生命周期点无条件跑的脚本，退出码决定拦不拦，与模型判断无关
  • 一次例外都不能有的做 hook；通常应该这样的写 CLAUDE.md
  • 例：提交前测试改成 Stop hook；禁改 migrations 改成 PreToolUse hook