Converge the screened direction pool into a small, discussion-ready shortlist, writing `output/trace/IDEA_SHORTLIST.md`. **Trigger**: idea shortlist, shortlist directions, brainstorm shortlist, 方向 shortlist. **Use when**: you already have a direction pool and screening table and want the strongest 3
Converge the screened direction pool into a small, discussion-ready shortlist, writing `output/trace/IDEA_SHORTLIST.md`. **Trigger**: idea shortlist, shortlist directions, brainstorm shortlist, 方向 shortlist. **Use when**: you already have a direction pool and screening table and want the strongest 3-5 directions for the final memo.