Substack Post Writer

Draft a post from what the user actually has, then package every field Substack needs.

Before drafting

Read references/voice-rules.md, references/anti-fabrication.md, references/platform-limits.md.
Read ~/.substack-skills/voice-profile.md and ~/.substack-skills/story-bank.md if they exist.

Build each section from the user's outline, message, Story Bank, or files. Where a section needs a fact you don't have, write around it with a slot: [what the tool stack cost last month].
When the input is thin (an outline of labels), the draft is a skeleton: a heading and 2 to 4 lines per section, made of the user's words plus slots. Still a draft, never a refusal.
Working length 1,000 to 2,500 words unless the user sets one.
Clipping check: Gmail clips emails over 102KB. If the user's target or past style is over about 6,000 words, or image-heavy, say so before drafting and offer: split into a series, cut, or accept that email readers see "View entire message".

--mode package skips drafting and packages an existing draft.