面试题库

7 天 Agent Skills：把经验做成可复用能力

D1 Skills 是什么：SKILL.md 规范、目录结构与三阶段渐进式加载

• Agent Skills 解决的是什么问题？它和把所有规范写进一个大的提示词文件有什么区别？What problem do Agent Skills solve, and how are they different from putting every convention into one big instruction file?

  国内高频海外高频基础#agent-skills#context-engineering

  分析过程 · 先想清楚再作答

  1. 这题的区分度在你有没有说出「按需」两个字。只答「skill 是可复用的提示词」的人，等于没答，因为那句话对提示词模板同样成立。
  2. 先给分工：工具补的是能力缺口，模型本来做不到的事；技能补的是经验缺口，模型做得到但不知道你们这儿怎么做。这一刀切下去，后面的论证才站得住。
  3. 再给机制差异：常驻指令文件每次会话全量进上下文，skill 平时只露 name 与 description，命中才展开正文。前者的成本是固定的，后者的成本是按需的。
  4. 接着算代价：二十条规范写满六千 token 的系统提示，五十轮会话要重复计费三十万 token；更贵的是注意力被不相干的规则稀释，做第三件事时被第十七条干扰。
  5. 最后给判据，这是面试官真正想听的一句：这条经验是不是每次都用得上？是就写进常驻指令文件，不是就做成 skill。
  6. 可预期的追问是「那提示词模板呢」。答案是谁来挑：模板是你手动选的，skill 是模型读着 description 自己选的，触发权在模型手里。

  How to reason about it · think before answering

  1. The discriminator is whether you say on demand. Answering skills are reusable prompts says nothing, because that is equally true of a prompt template.
  2. Start with the split: tools fill a capability gap the model cannot cross on its own; skills fill an experience gap where the model can do the task but not the way your team does it.
  3. Then the mechanism: a persistent instruction file enters context in full every session, while a skill exposes only name and description until something matches and its body is loaded.
  4. Quantify the cost: twenty conventions at six thousand tokens of system prompt bill three hundred thousand tokens over a fifty-turn session, and the attention dilution costs more than the money.
  5. Close with the rule of thumb interviewers want: if the guidance applies every single time, it belongs in the persistent instruction file; otherwise make it a skill.
  6. Expected follow-up: what about prompt templates? The difference is who chooses. You pick a template; the model picks a skill by reading descriptions.

  答题要点

  • 工具补能力缺口，技能补经验缺口，这是两件事，不要混着答。
  • 常驻指令文件成本固定且每轮重发，skill 的正文只在命中时才进上下文。
  • 把不相干的规范全塞进系统提示，除了花钱还会稀释注意力，让模型被无关规则干扰。
  • 判据是「是不是每次都用得上」：是就常驻，不是就做成 skill。
  • 和提示词模板的关键差别是触发权在模型手里，靠的是 description。

  Key points

  • Tools close capability gaps, skills close experience gaps. Do not blur the two.
  • A persistent instruction file costs the same tokens every turn; a skill body only enters context when it matches.
  • Dumping unrelated conventions into the system prompt both costs money and dilutes attention.
  • The test is whether the guidance applies every time: if yes it stays resident, if no it becomes a skill.
  • Unlike a prompt template, a skill is selected by the model itself from its description.