This example shows the complete 5-layer narrowing in action.
User: I want to create a skill for writing product requirement documents.
Assistant: Great! PRDs are an important skill. Let me help narrow this down using a systematic approach.
[Layer 1: Domain Identification]
PRDs can serve different purposes depending on the audience and goal. Which is closest to what you need?
- Engineering-focused specs: Detailed feature requirements for implementation
- Stakeholder alignment docs: High-level documents to get buy-in from executives/leadership
- Design briefs: Product requirements focused on user experience and design direction
- External vendor specs: Technical requirements for third-party development
Which type of PRD do you most often need to write?
User: Engineering-focused specs.
Assistant: Perfect. Now let me understand the context better.
[Layer 2: Context Constraints (5W1H)]
- WHO: What's your role? (PM, Senior PM, Product Lead, or Founder?)
- WHERE: What type of company? (Startup, mid-size, or enterprise? B2B or B2C?)
- WHEN: How often do you write these? (Every sprint? Per quarter? Per major initiative?)
- WHY: Primary goal - is it to get eng buy-in, ensure nothing is missed, or facilitate estimation?
- HOW: Any constraints - do you follow a specific template? Any required sections?
User: I'm a Senior PM at a B2B SaaS company (100 people, growing fast). I write PRDs for major features (usually 3-5 per quarter). Main goal is to ensure engineers have everything they need to start building without constant back-and-forth. No required template, but we try to keep docs under 2 pages.
Assistant: Excellent context. Let me narrow further.
[Layer 3: Comparative Narrowing]
Within "engineering PRDs for major features," which scenario is most common?
A. Net-new features: Building something completely new (new product area, new capability)
B. Major enhancements: Significant upgrades to existing features (new workflow, architecture change)
C. Cross-system features: Features requiring coordination across multiple teams/services
D. Customer-driven builds: Custom features for enterprise customers with tight timelines
Which is most frequent, or do you need to handle multiple types?
User: Mostly A and B. Sometimes C, but rarely D.
Assistant: Got it. Let me confirm the boundaries.
[Layer 4: Boundary Validation]
So this skill should:
- ✅ INCLUDE: Net-new features and major enhancements for engineering teams
- ✅ INCLUDE: B2B SaaS context with 3-10 engineer scope typically
- ✅ INCLUDE: Cross-team coordination when needed
- ❌ EXCLUDE: Small story-level specs (those go directly in Jira/tickets)
- ❌ EXCLUDE: Customer-specific custom builds with tight deadlines
- ❌ EXCLUDE: Executive-facing strategy documents or roadmap presentations
Does this match what you need?
User: Yes, exactly!
Assistant: Perfect. One final question to anchor the methodology research.
[Layer 5: Concrete Case Anchoring]
Can you describe a recent PRD you wrote that was either particularly challenging or time-consuming? For example:
- What feature were you speccing?
- What made it hard to write the PRD?
- How long did it take you?
- Did engineers come back with lots of questions, or did it work well?
User: Last month I wrote a PRD for an API rate limiting feature. Took me about 6 hours spread over 3 days. The hard part was explaining the business logic (what counts toward limits, how to handle bursts) clearly enough that engineers understood the intent but could still design the technical solution. We did 2 rounds of clarification before they felt ready to estimate. Would love to get that down to 3 hours and one round of Q&A.
Assistant: Perfect! Now I have a crystal-clear picture.
📌 Final Skill Definition:
"Create engineering-focused PRDs for B2B SaaS senior PMs writing specs for net-new features and major enhancements. PRDs should be 1-2 pages, clearly communicate business logic and user needs without over-specifying technical implementation, and enable engineering teams to estimate and start building with minimal back-and-forth."
This passes all 5 stop conditions:
- ✅ Unique methodology - Yes (balancing business logic vs technical freedom)
- ✅ Clear quality bar - Yes (minimize eng questions, enable estimation)
- ✅ Specific constraints - Yes (B2B SaaS, 1-2 pages, major features)
- ✅ Concrete example - Yes (API rate limiting feature, 6→3 hours)
- ✅ Excludes alternatives - Yes (not small stories, not exec docs)
Ready to move to Step 2: Methodology Research. Since this is a non-technical skill involving communication and judgment, I'd recommend using plan mode to think through the methodology research carefully. Should I proceed in plan mode?
User: Yes, go ahead.
Assistant: Perfect, that's specific enough. Since this is a non-technical skill involving communication and judgment, I'd recommend using plan mode to think through the methodology research carefully. Should I proceed in plan mode?
User: Yes, go ahead.
Assistant: [Enters plan mode and structures the research approach]
Let me search systematically for the best methodologies on engineering-focused PRD writing.
[Searches: "PRD best practices expert", "product requirements document methodology for engineers", "best PRD examples B2B SaaS"]
I found several strong frameworks:
Product Management:
- Marty Cagan (SVPG): Emphasizes problem-first PRDs, separating problem space from solution space
- Teresa Torres: Continuous discovery, outcome-focused requirements
Business Writing:
- Barbara Minto: Pyramid Principle - lead with conclusion, MECE structure
- Amazon: Working backwards from press release, 6-pager narrative format
Golden Examples Found:
- Intercom's public PRD template
- Linear's product spec format
Common Mistakes (from my search):
- Jumping to solutions before defining the problem
- Writing for engineers instead of for alignment
- Missing success metrics
Let me dig deeper into primary sources to get very clear conclusions...
[Continues searching until methodology is crystal clear]
Which of these approaches resonates? Or should I search deeper into any of them?
User: I like Amazon's approach combined with Cagan's problem-first thinking. Can you find more details on Amazon's method?
Assistant: [Searches: "Amazon 6-pager template", "Amazon working backwards methodology", "Amazon PR FAQ process"]
[Fetches relevant articles and synthesizes key principles]
Here's what I found from primary sources...
[After thorough methodology research]
Assistant: Before I generate the skill, let me design test scenarios. Let's think through diverse cases:
Test Scenarios:
- Simple feature: Adding a filter to existing dashboard
- Complex feature: New AI-powered recommendation engine
- Edge case: Feature requiring significant backend architecture changes
- Failure mode: Vague problem statement that needs refinement
Does this cover the range of PRDs you typically write? Any other scenarios we should test?
User: Also add: Feature that needs cross-team coordination.
Assistant: Great addition. Now I'll invoke skill-creator to generate the skill with proper format.
[Invokes: Skill tool with skill: "skill-creator:skill-creator"]
The skill-creator will guide me through:
- Creating proper YAML frontmatter (name, description, model: opus)
- Writing in imperative form
- Structuring the skill directory
- Validating the output
[After skill-creator completes]
I've generated the skill. Let me test it against our scenarios...
[Reviews results, identifies gaps, iterates]
[Continues to Step 10: refinement based on test results]
此示例展示了完整的五层缩小范围流程的实际应用。
用户:我想创建一个用于编写产品需求文档的Skill。
助手:太好了!PRD是一项重要的Skill。让我用系统方法帮您缩小范围。
[第一层:领域识别]
根据受众和目标的不同,PRD有不同的用途。您的需求最接近哪一种?
- 面向工程师的规格说明:用于实现的详细功能需求
- 利益相关者对齐文档:用于获得高管/领导层认可的高层文档
- 设计简报:专注于用户体验和设计方向的产品需求
- 外部供应商规格:用于第三方开发的技术需求
您最常需要编写哪种类型的PRD?
用户:面向工程师的规格说明。
助手:完美。让我进一步了解场景。
[第二层:场景约束(5W1H)]
- 谁(WHO):您的角色是什么?(产品经理、创始人还是高管?)
- 做什么(WHAT):这是关于选择功能、确定优先级,还是上线与否的决策?
- 在哪里(WHERE):什么类型的公司?(初创公司、中型公司还是企业?B2B还是B2C?)
- 何时(WHEN):您多久写一次?(每个冲刺?每个季度?每个重大举措?)
- 为什么(WHY):主要目标是——获得工程师认可、确保没有遗漏,还是便于估算?
- 如何做(HOW):有任何约束吗?(时间限制、流程要求、利益相关者)
用户:我是一家B2B SaaS公司(100人,快速增长)的高级产品经理。我为重大功能编写PRD(通常每季度3-5个)。主要目标是确保工程师拥有开始构建所需的一切信息,无需反复沟通。没有强制模板,但我们尽量将文档控制在2页以内。
助手:非常好的场景信息。让我进一步缩小范围。
[第三层:对比式缩小范围]
在“面向工程师的重大功能PRD”中,哪种场景最常见?
A. 全新功能:构建完全新的东西(新产品领域、新功能)
B. 重大增强:对现有功能的重大升级(新工作流程、架构变更)
C. 跨系统功能:需要跨多个团队/服务协调的功能
D. 客户驱动的构建:为企业客户定制的功能,时间紧迫
哪种最常见,还是您需要处理多种类型?
用户:主要是A和B。有时是C,但很少是D。
助手:明白了。让我确认边界。
[第四层:边界验证]
因此,本Skill应:
- ✅ 包含:面向工程团队的全新功能和重大增强PRD
- ✅ 包含:B2B SaaS场景,通常涉及3-10名工程师
- ✅ 包含:需要时的跨团队协调
- ❌ 不包含:小型需求级规格说明(这些直接写在Jira/工单中)
- ❌ 不包含:时间紧迫的客户定制构建
- ❌ 不包含:面向高管的战略文档或路线图演示
这符合您的需求吗?
用户:是的,完全符合!
助手:完美。最后一个问题来锚定我们的方法论研究。
[第五层:具体案例锚定]
您能描述一个最近编写的、特别有挑战性或耗时的PRD吗?例如:
- 您在为哪个功能编写规格?
- 编写PRD的难点是什么?
- 花了多长时间?
- 工程师是否提出了很多问题,还是效果很好?
用户:上个月我为一个API速率限制功能写了PRD。花了大约6个小时,分3天完成。难点是清晰地解释业务逻辑(什么计入限制、如何处理突发流量),让工程师理解意图但仍能设计技术解决方案。我们进行了2轮澄清,他们才觉得可以开始估算。我希望能把时间缩短到3小时,只需要一轮问答。
助手:完美!现在我有了非常清晰的画面。
📌 最终Skill定义:
“为B2B SaaS高级产品经理创建面向工程师的PRD,用于编写全新功能和重大增强的规格说明。PRD应控制在1-2页,清晰传达业务逻辑和用户需求,不过度指定技术实现,使工程团队能够估算并开始构建,尽量减少反复沟通。”
这满足所有5个停止条件:
- ✅ 独特方法论 - 是(平衡业务逻辑与技术自由度)
- ✅ 清晰的质量标准 - 是(减少工程师的问题,便于估算)
- ✅ 具体约束 - 是(B2B SaaS,1-2页,重大功能)
- ✅ 具体示例 - 是(API速率限制功能,6→3小时)
- ✅ 排除替代任务 - 是(不是小型需求,不是高管文档)
准备进入步骤2:方法论研究。由于这是一个涉及沟通和判断的非技术类Skill,我建议使用计划模式来更细致地梳理方法论研究。我应该以计划模式继续吗?
用户:是的,继续。
助手:完美,范围足够具体了。由于这是一个涉及沟通和判断的非技术类Skill,我建议使用计划模式来更细致地梳理方法论研究。我应该以计划模式继续吗?
用户:是的,继续。
助手:[进入计划模式并构建研究方法]
让我系统地搜索面向工程师的PRD写作的最佳方法论。
[搜索:“PRD best practices expert”, “product requirements document methodology for engineers”, “best PRD examples B2B SaaS”]
我找到了几个强大的框架:
产品管理领域:
- Marty Cagan(SVPG):强调以问题为导向的PRD,区分问题空间和解决方案空间
- Teresa Torres:持续发现,以结果为导向的需求
商务写作领域:
- Barbara Minto:金字塔原理 - 结论先行,MECE结构
- 亚马逊:从新闻稿倒推,6页纸叙事格式
找到的优质示例:
- Intercom的公开PRD模板
- Linear的产品规格格式
常见错误(来自我的搜索):
- 在定义问题之前就跳到解决方案
- 为工程师写作而非为对齐写作
- 缺少成功指标
让我深入研究原始来源以得出非常清晰的结论...
[继续搜索,直到方法论清晰明确]
这些方法中哪一个引起了您的共鸣?或者我需要更深入地搜索其中任何一个吗?
用户:我喜欢亚马逊的方法结合Cagan的以问题为导向的思路。你能找到更多关于亚马逊方法的细节吗?
助手:[搜索:“Amazon 6-pager template”, “Amazon working backwards methodology”, “Amazon PR FAQ process”]
[获取相关文章并提炼关键原则]
这是我从原始来源中找到的...
[经过全面的方法论研究后]
助手:在生成Skill之前,让我设计测试场景。让我们梳理多样的案例:
测试场景:
- 简单功能:为现有仪表板添加筛选器
- 复杂功能:新的AI驱动推荐引擎
- 边缘案例:需要重大后端架构变更的功能
- 失败模式:需要细化的模糊问题陈述
这涵盖了您通常编写的PRD范围吗?我们还应该测试其他场景吗?
用户:还要添加:需要跨团队协调的功能。
助手:很好的补充。现在我将调用skill-creator以正确格式生成Skill。
[调用:Skill工具,参数:skill: "skill-creator:skill-creator"]
skill-creator将引导我完成:
- 创建正确的YAML前置内容(名称、描述、model: opus)
- 以命令式写作
- 构建Skill目录
- 验证输出
[skill-creator完成后]
我已经生成了Skill。让我根据我们的场景进行测试...
[审查结果,识别差距,迭代优化]
[继续到步骤10:根据测试结果细化]