Newsletter Writer

Write product update emails and feature announcement newsletters. Handles subject lines, preview text, email structure, and audience-appropriate content.

Input Resolution

Resolve the argument (if provided) in this order:

1. Path to an existing marketing brief (.md containing "Executive Summary" or "Key Messages") -> marketing brief
2. Path to an existing blog post (.md with blog post structure) -> blog post
3. Path to an existing changelog (.md with Added/Fixed/Changed sections or CHANGELOG.md) -> changelog
4. Matches GitHub URL or #\d+ pattern -> PR
5. Contains ... or .. -> git ref range
6. Resolves to existing file/directory -> codebase feature
7. Otherwise -> freeform text

If no argument is provided, ask: "What should the newsletter cover? You can provide a marketing brief, blog post, changelog, PR URL/number, git ref range, file/directory path, or just describe the update."

If multiple interpretations match, confirm with the user.