When --on is specified, the first argument is a formula name: gt sling shiny --on gt-abc123 This applies the formula to existing work, creating wisp scaffolding that shapes execution of the target bead. Changes: - Add Formula field to SlungWork wisp type - Add --on flag to gt sling command - Verify both bead and formula exist before slinging - Update dry-run output to show formula info 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>