PPTX Slide Specification

Author final coordinates directly in layout_tree. No renderer may decide placement, shrink text, or infer layout after the audit.

Required contract

• The root JSON contains summary and slides.
• Every slide has a stable id, a message-led title, an accessibility reading order, and a complete layout_tree.
• A layout tree declares slide size, root group, id-keyed groups and objects, final inch bboxes, styles, z-indexes, and classifications.
• Every meaningful object has id, kind, role, classification, content, style, bbox, and z_index.
• Production summary contains an explicit layout_policy (safe margin, content bottom, footer top, minimum gap) and accessibility metadata.

Authoring rules

1. Use stable readable IDs, absolute groups, and positive inch dimensions.
2. Keep normal content inside the safe margin and above the footer rail. Only background layout_design objects may be full bleed.
3. Use native text, shape, line, table, and image objects. Recreate labels and values from any supporting visual as native objects.
4. Give meaningful images alt text. Record source_ref for sourced claims.
5. Keep content text at 9 pt or greater; shorten, resize, or split dense content before reducing type.
6. Use shared grids, consistent gaps, explicit color, explicit font size, and an intentional z-order.

Build contract

A task-local builder starts from a blank slide layout and maps all bboxes with Inches(...). Explicitly set wrapping, disabled auto-size, text insets, anchors, alignment, fonts, colors, line settings, image aspect ratio, and hidden-slide state. Reject zero or negative geometry before adding an object.

See references/layout-contract.md for the compact schema and repair guidance.