Content-Ops Layout v0

content_ops_layout_*_v0 makes content presentation a reviewable LoopX contract. It separates three owners:

• LoopX core owns built-in templates, typed page roles, deterministic compactness thresholds, and acceptance results.
• A writing or platform adapter owns the copy, page selection, narrative structure, author voice, and rendering.
• A renderer owns pixels and emits a compact measurement packet; LoopX does not add an image-processing dependency or ingest draft bodies.

This is a machine-enforced acceptance check, not optional prose guidance.

Template library

loopx content-ops template-list --format json
loopx content-ops template-show \
  --template-id light-serif-longform \
  --format json

The built-in content_ops_layout_template_catalog_v0 currently includes:

• light-serif-longform for dense analytical storytelling;
• monochrome-editorial for high-contrast technical commentary;
• product-brief for problem/mechanism/boundary summaries;
• control-plane-hybrid for prose plus state, gate, and evidence artifacts.

Templates define canvas size, safe area, density limits, page archetypes, and portable style tokens. They do not contain project names, private paths, draft bodies, or provider credentials.

All built-in templates set density.role_overrides.cover.min to 0.82 and max to 0.94. The cover default is intentionally stricter than ordinary pages: at least 82% of the safe-area height must be occupied by meaningful content bounds. Decorative rules, indexes, page numbers, and footers do not count toward that density.

Every built-in template also exposes the same page_sequence defaults:

{
  "first_role": "cover",
  "density_order": "first_page_maximum",
  "interior_min": 0.72
}

The first planned page must be the cover and its measured density must be at least every later page. Pages between the cover and final page use 0.72 as a density floor, or a stricter role/template minimum when one exists. The final page keeps its own closing/CTA role limits so an intentional synthesis page does not need to imitate a dense analytical middle page.

These readability defaults replace cover 0.90–0.98 and interior floor 0.80. Default upper bounds also drop from 0.91–0.94 to 0.88–0.90, depending on template; explicit non-cover role overrides are unchanged. Existing plans are checked against the installed catalog, so an older very full page may now need revision. Cover-first and first-page-maximum obligations are unchanged.

Density measures the vertical content span, not glyph coverage or readability. Do not shrink text, compress line spacing, or add filler to satisfy the floor. The writing adapter must also inspect font size, line length, paragraph rhythm, and code/table hierarchy at phone display size. Respect the owner's page budget: use approved editorial compression or reflow into more pages rather than silently shrinking type. Publishing authority remains unchanged.

Typed plan

Build a plan before rendering:

loopx content-ops layout-plan \
  --item-id plugin-scaling-note \
  --template-id light-serif-longform \
  --page p01:cover:source-system \
  --page p02:argument:source-system \
  --page p03:evidence:source-system \
  --page p04:closing:creator-system \
  --required-role cover \
  --required-role argument \
  --required-role evidence \
  --required-role closing \
  --closing-role closing \
  --generated-at 2026-08-15T12:00:00+08:00 \
  --format json

Roles are typed as cover, argument, mechanism, evidence, boundary, closing, or cta. Project-specific narrative obligations—such as ending in the creator's voice or bridging from one named subject to another—remain in the writing adapter or item-local review plan. LoopX does not universalize them or infer them from prose substrings.

Renderer measurement

The renderer emits content_ops_layout_measurement_v0:

{
  "schema_version": "content_ops_layout_measurement_v0",
  "plan_id": "layout:plugin-scaling-note:light-serif-longform",
  "template_id": "light-serif-longform",
  "pages": [
    {
      "page_id": "p01",
      "asset_ref": "images/p01.jpg",
      "canvas": {"width": 1440, "height": 1920},
      "meaningful_content_bounds": {"top": 154, "bottom": 1364},
      "checks": {
        "overflow": false,
        "collision": false,
        "single_character_line": false
      }
    }
  ]
}

asset_ref must be a relative public-safe reference. Meaningful bounds exclude decorative rules, page numbers, and footers so they cannot make a sparse page look full.

Acceptance

loopx content-ops layout-check \
  --plan-json layout-plan.json \
  --measurement-json layout-measurement.json \
  --format json

content_ops_layout_check_packet_v0 returns pass only when:

• measured page ids exactly match the plan;
• the first page has role cover and is at least as dense as every later page;
• every interior page satisfies the built-in 0.72 density floor;
• all required roles are present and the last page has the planned closing role;
• canvas and density satisfy the selected template and role;
• overflow, collision, and single-character-line checks are explicitly false;
• every renderer safety check is explicitly satisfied.

The packet always keeps autopublish_allowed=false. Layout acceptance never grants provider access, publishing authority, or approval for the content body.