Interview Bank

Mastering Claude: From Conversation to Claude Code in 5 Days

D3 Getting Started With Claude Code and Managing Context: Install, Writing CLAUDE.md and "Trim Until You Can't", Permission Modes, Plan Mode's "Explore, Then Plan, Then Write", /clear /compact /rewind, Giving Claude a Verifiable Check

• How do CLAUDE.md and skills divide responsibilities, what goes where, and what goes wrong when CLAUDE.md grows to 500 lines?CLAUDE.md 和 skill 的分工是什么？什么内容该放哪边？一份 CLAUDE.md 写到 500 行会出什么问题？

  Common in ChinaCommon overseasBasic#claude-md#skills#context

  How to reason about it · think before answering

  1. This tests context-cost awareness. 'CLAUDE.md holds rules, skills hold procedures' is the conclusion; derive it from how each is loaded.
  2. Start from load timing: CLAUDE.md enters context in full every session — a fixed cost; a skill keeps only its one-line description resident and loads its body on invocation — a variable cost. Hence short facts that always apply go in CLAUDE.md, occasional multi-step procedures go in skills.
  3. Give the table: commands, non-default style, repo etiquette, environment quirks, and the definition of done belong in CLAUDE.md; deployment runbooks, issue-fixing steps, document generators belong in skills. Multi-step procedures in CLAUDE.md or always-on rules inside a skill are both misplacements.
  4. At 500 lines the failure is dilution, not capacity: important rules drown, adherence drops, and every turn pays for the bloat. Fixes: prune ruthlessly (would removing this cause a mistake?), move occasional content to skills, split path-scoped rules into .claude/rules/ so they load only when matching files are touched.
  5. Follow-ups: a rule that keeps being ignored — prune, then disambiguate, then emphasize; anything that must run every time should be a hook, not a sentence.

  分析过程 · 先想清楚再作答

  1. 这题考的是「上下文成本意识」。答成「CLAUDE.md 放规则、skill 放流程」只是结论，面试官想听你从加载方式推出这个结论。
  2. 拆法从加载时机入手：CLAUDE.md 每次会话整份进入上下文，是固定成本；skill 只有描述那一行常驻，正文在被触发（模型判断相关或用户输入 /name）时才加载，是按需成本。所以「每次都成立的短事实」放 CLAUDE.md，「偶尔才用、一用就是多步」的流程放 skill。
  3. 给判据表：命令、风格差异、仓库礼仪、环境怪癖、完成的判据进 CLAUDE.md；部署流程、修 issue 的固定步骤、某类文档的生成方法进 skill。反过来，CLAUDE.md 里出现了多步流程，或 skill 里放了「每次都要遵守」的规则，都是放错了。
  4. 500 行的问题不是「太长跑不动」，而是稀释：重要规则被淹没，模型的遵守度反而下降，还白白吃掉每轮的窗口。对策是「删到不能再删」（删掉会不会让它犯错？不会就删）、把偶尔用的挪进 skill、按路径拆进 .claude/rules/ 只在碰到匹配文件时加载。
  5. 可预期的追问：「规则它老是不听怎么办」——先删再改再强调；「必须每次执行」的动作根本不该靠 CLAUDE.md，要改成 hook。

  Key points

  • CLAUDE.md loads in full every session — fixed cost; a skill keeps one line resident and loads on demand
  • CLAUDE.md: short always-true facts — commands, style deltas, etiquette, definition of done; skills: occasional multi-step procedures
  • Bloat dilutes: key rules drown, adherence drops, every turn pays
  • Fixes: prune, move occasional content to skills, split path-scoped rules; must-run actions become hooks

  答题要点

  • CLAUDE.md 每次会话整份加载，是固定成本；skill 只常驻一行描述，正文按需加载
  • CLAUDE.md 放每次都成立的短事实：命令、风格差异、规矩、完成判据；skill 放偶尔用的多步流程
  • 写长的后果是稀释：重要规则被淹没、遵守度下降、每轮白付窗口
  • 对策：删到不能再删、偶尔用的进 skill、按路径拆进 rules；必须每次做的改成 hook

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

• What is progressive loading for skills, why does it save context, and how should the description be written?skill 的渐进式加载是怎么回事？为什么能省上下文？description 应该怎么写？

  Common in ChinaCommon overseasIntermediate#skills#context

  How to reason about it · think before answering

  1. This tests the on-demand loading idea and whether you have actually written a skill. The third part separates candidates: a poorly written description makes the skill dead weight.
  2. Mechanism: at session start only each skill's one-line description from the frontmatter is resident; the body loads when the model judges the task relevant or the user types /name. Body length therefore barely affects daily cost, so it can hold long procedures, examples, and caveats.
  3. Contrast with CLAUDE.md: loaded in full every session, a fixed cost; a procedure used twice a week wastes the window the rest of the time. Moving such content into skills is how CLAUDE.md keeps shrinking after pruning.
  4. Writing the description: state what it does plus the phrases a user would say, about a hundred words; too broad triggers on unrelated tasks, too narrow never triggers. Add disable-model-invocation: true for side-effecting workflows so only /name invokes them; $ARGUMENTS takes parameters; allowed-tools pre-approves commands.
  5. Follow-ups: how do you test triggering? Try several natural phrasings and check whether the body loaded. Skill versus subagent: a skill loads a manual into the current context; a subagent opens a separate context to do work; they compose.

  分析过程 · 先想清楚再作答

  1. 这题考的是「按需加载」这个设计思想，以及你有没有真写过 skill。第三问是区分度：description 写不好，skill 就形同虚设。
  2. 机制：会话开始时只有每个 skill 的 frontmatter 里那一行 description 常驻上下文；当模型判断当前任务相关、或用户输入 /name 时，正文才被读进来。所以正文长短几乎不影响日常成本，可以放几十步的流程、示例、注意事项。
  3. 对比 CLAUDE.md：它整份每次加载，是固定成本；一周只用两次的流程放进去等于其余时间白占窗口。把这类内容挪到 skill，是「删到不能再删」之后 CLAUDE.md 还能继续变短的主要手段。
  4. description 的写法：说清做什么 + 用户会怎么说（触发词），一百来字；太泛会被无关任务误触发，太窄永远触发不到。有副作用的流程（部署、发消息）加 disable-model-invocation: true 只允许手动 /name 触发。$ARGUMENTS 接参数，allowed-tools 预授权命令。
  5. 可预期的追问：怎么测 skill 有没有被触发？用几个自然语言说法试，看模型是否读了正文；再追问「skill 与 subagent 的区别」——skill 是在当前上下文里加载一份说明书，subagent 是另起一个上下文去做事，两者可以组合。

  Key points

  • Only the description is resident; the body loads on invocation, so body length barely costs
  • CLAUDE.md loads in full each time; moving occasional procedures to skills keeps it short
  • Write the description as what it does plus how users phrase it, about a hundred words
  • Side-effecting workflows get disable-model-invocation; $ARGUMENTS carries parameters

  答题要点

  • 只有 description 常驻，正文在被触发时才加载；正文长短几乎不影响日常成本
  • CLAUDE.md 整份每次加载；偶尔用的流程挪进 skill 是让它继续变短的手段
  • description 写「做什么 + 用户会怎么说」，一百来字，不泛不窄
  • 副作用流程加 disable-model-invocation；$ARGUMENTS 接参数

Mastering Codex and the OpenAI Agents SDK in 5 Days

D2 Codex, Level Up: Cloud Tasks, Code Review, MCP Integration, Custom Instructions, IDE Integration

• MCP servers and skills both extend a coding agent. When do you reach for each, and what goes in the project instruction file instead?MCP server 和 skill 都是在给 coding agent 加能力，什么时候该用哪一个？项目说明文件又放什么？

  Common in ChinaCommon overseasBasic#mcp#skills#coding-agent

  How to reason about it · think before answering

  1. This tests separation of abstraction levels, the tooling-side version of the increasingly common 'function calling vs MCP vs skills' question.
  2. Ask what is being added: access to an external system (tickets, databases, internal services) is MCP, a protocol-level tool; a multi-step procedure (release checklist, migration flow) is a skill, a prompt-level workflow package; conventions to obey every session belong in the instruction file.
  3. Contrast triggers: MCP tools are invoked by the model when it needs data; skills are invoked explicitly by name or matched by description; instruction files are loaded unconditionally at session start.
  4. Conclude: rules in the instruction file, external systems via MCP, procedures as skills; keep each fact in one place to avoid contradictions.
  5. Expect the follow-up: can a skill use MCP tools? Yes; a skill's steps can call for a tool, the layers are orthogonal, not substitutes.

  分析过程 · 先想清楚再作答

  1. 这题考的是抽象层次的区分，是国内面试开始高频出现的「Function Call / MCP / Skills 三者区别」的工具侧版本。
  2. 拆法是问「加的是什么」：加的是访问外部系统的能力（查工单、读数据库、调内部服务）就是 MCP，它是协议层的工具；加的是一套多步骤的做法（发版检查、迁移流程）就是 skill，它是提示词层的流程包；每次会话都要遵守的约定就是项目说明文件。
  3. 再给触发方式的差别：MCP 工具由模型在需要数据时调用；skill 由用户显式点名或由模型按描述匹配；说明文件每次会话开头无条件读入。
  4. 结论落到一句话：规矩归说明文件、外部系统归 MCP、流程归 skill；同一件事只放一处，避免三处互相矛盾。
  5. 可预期的追问：skill 里能不能调 MCP 工具？可以，skill 的步骤里可以要求使用某个工具，两者是正交的层次，不是替代关系。

  Key points

  • MCP adds tools that reach external systems, invoked by the model on demand
  • Skills add multi-step procedures, triggered by name or matched by description
  • The instruction file holds conventions, no-go areas and environment facts read every session
  • The three are orthogonal: rules, external systems, procedures each live in one place; a skill may call for an MCP tool

  答题要点

  • MCP 加的是访问外部系统的工具，由模型按需调用
  • skill 加的是多步骤流程，由用户点名或按描述匹配触发
  • 项目说明文件放每次会话都要遵守的约定、禁区与环境事实
  • 三者正交：规矩、外部系统、流程各放一处，skill 里可以要求用某个 MCP 工具