Chapter Briefs (H2 writing cards) [NO PROSE]

Triggers & routing

• Trigger: chapter briefs, H2 briefs, chapter lead plan, section intent, 章节意图, 章节导读, H2 卡片.
• Use when: outline/outline.yml + outline/subsection_briefs.jsonl exist and you want thicker chapters (fewer headings, more logic).

Purpose: turn each H2 chapter that contains H3 subsections into a chapter-level writing card so the writer can:

• add a chapter lead paragraph block (coherence)
• keep a consistent comparison axis across the chapter
• avoid “8 small islands” where every H3 restarts from scratch

This artifact is internal intent, not reader-facing prose.

Why this matters for writing quality:

• Chapter briefs prevent the "paragraph island" failure mode: without a throughline, each H3 restarts and repeats openers.
• Treat throughline and lead_paragraph_plan as decision constraints, not copyable sentences.