graph TD A[Start: Receive top-20-niches] --> B[Initialize Keyword Collection] B --> C[Select First Niche] C --> D[Call Skill #218: Brainstorm Keywords] D --> E[Store Keywords + Commentary] E --> F{More Niches?} F -->|Yes| G[Select Next Niche] G --> D F -->|No| H[Call Skill #223: Process All Keywords] H --> I[Filter to 3-5 Keywords per Niche] I --> J[Remove Commentary] J --> K[Format Final Output] K --> L[End: Return keywords-for-20-niches]