fix: carve out check-only examples from the render requirement

docs/new-example-prompt.md required every example to produce a deliberate
render and wire gallery metadata and assets, with no exception. Eight of the
59 examples ship no render, no gallery.json entry, and no hero asset — an
established, deliberate category the authoring prompt did not acknowledge, so
the prompt described a rule the repository does not follow. CLAUDE.md stated
it more strongly still: "their renders ship in the site gallery", of all 59.

State the exception in both, keyed to a criterion rather than a list of the
eight so it stays true as the set changes: an example is check-only when its
witness is a data or state fact that no scene redesign can make visible — a
datablock name, an RNA attribute's presence, a post-exit sidecar, a topology
count, export metadata — so the render would be identical whether the API
held or broke. The existing "redesign the scene until failure would be
visible" instruction is the test to attempt first; the exception is for
contracts that are invisible, not renders that are hard.

CLAUDE.md now says 51 of 59 ship a render, and records that a check-only
example wires only the plugin manifest entry, the smoke catalog row, and its
README.

Verified on disk: exactly eight examples have no gallery.json entry
(coincident-vert-weld, eval-mesh-datablock-name, exit-pre-sidecar,
gn-bundle-roundtrip, mesh-automasking-settings, ngon-triangulate,
unapplied-scale-gltf, vse-linear-modifiers); all eight have a
tests/smoke/catalog.json row, none takes --output, and each carries at least
one falsifier flag. Smoke coverage is unaffected.

Closes #146

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: TMHSDigital <154358121+TMHSDigital@users.noreply.github.com>

Author: TMHSDigital

CLAUDE.md

@@ -105,12 +105,25 @@ AI asset pipeline track: `decimate_to_budget.py`, `convex_hull_collider.py`, `lo
 Runnable scripts at `examples/<name>/`, each asserting a real API contract with
 deterministic checks (exit non-zero on failure) and optionally rendering a still via
 `--output`. All of them run headless on Blender 5.2 LTS and 4.5 LTS in `blender-smoke.yml` (5.1 on the weekly cron, the `needs-5.1` PR label, or manual dispatch);
-their renders ship in the site gallery at `docs/gallery/`. `examples/gallery.json` is the
-gallery's source of truth. When authoring a new one, copy the anatomy of
+**51 of the 59 ship a render in the site gallery** at `docs/gallery/`. The other
+eight are **check-only**: they carry no `--output` path, no gallery entry, and no
+hero asset. The criterion is whether the contract is expressible in pixels. An
+example is check-only when its witness is a data or state fact that no scene
+redesign can make visible — a datablock name, an RNA attribute's presence, a
+post-exit sidecar, a topology count, export metadata — so a render would look
+identical whether the API held or broke. That is a category, not a shortcut: a
+subject whose render *could* be made legible must be rendered, per
+`docs/new-example-prompt.md`. Smoke coverage is unaffected; every check-only
+example still carries a `tests/smoke/catalog.json` row and a falsifier.
+`examples/gallery.json` is the
+gallery's source of truth. When authoring a new gallery example, copy the anatomy of
 `examples/bmesh-gear/` (script structure, README shape, dark-studio render recipe) and
 wire all of: gallery.json entry, `.cursor-plugin/plugin.json` examples array (CI-gated),
 a `tests/smoke/catalog.json` row, a README gallery row, hero webp (1280×720) in
 `docs/gallery/assets/` + preview webp (1200×675), then run `python scripts/build_gallery.py`.
+A check-only example wires only the `.cursor-plugin/plugin.json` entry, the
+`tests/smoke/catalog.json` row, and its README — it is deliberately absent from
+`examples/gallery.json` and `docs/gallery/`.
 Renders must conform to the gallery look spec at `docs/VISUAL-STYLE.md`.
 Render paths gate framing through the shared helper `examples/gallery_framing.py` —
 imported via a `__file__`-relative `sys.path` shim, the repo's only

docs/new-example-prompt.md

@@ -49,6 +49,21 @@ you write code:
   to infer what contract is being demonstrated. If the render would look the same
   whether the API worked or not, redesign the scene until failure would be visible.
 
+**The check-only exception.** A small, established category of examples ships with
+no render at all: no `--output` path, no `examples/gallery.json` entry, no hero or
+preview asset, no `docs/gallery/` page. The criterion is whether the contract is
+expressible in pixels. An example is check-only when its witness is a data or state
+fact that *no* scene redesign can make visible — a datablock name, the presence or
+absence of an RNA attribute, a post-exit sidecar file, a topology count, export
+metadata — so the render would be identical whether the API held or broke. The
+"redesign the scene until failure would be visible" instruction above is the test:
+attempt it first, and only when it cannot succeed in principle does the example
+become check-only. The exception is for contracts that are invisible, not for
+renders that are hard. Eight of the 59 examples currently qualify, and `CLAUDE.md`
+carries the same rule. A check-only example is otherwise a full example: it still
+asserts a real contract, still exits non-zero on failure, still carries a falsifier,
+and still takes a `tests/smoke/catalog.json` row so it runs on every PR.
+
 Where an API diverges between 4.5, 5.1, and 5.2, asserting each side's actual contract is
 part of the witness—version-gate explicitly and document the divergence rather than
 papering over it. Version-gate on the `bpy.app.version` tuple, not
@@ -73,12 +88,16 @@ The example must:
   witnesses, what failure it would catch, and any version-gated divergence between
   4.5 LTS, 5.1, and 5.2 LTS;
 - produce a deliberate, well-framed render rather than a mockup, primitive dump, or
-  placeholder.
+  placeholder — unless it meets the check-only exception above, in which case it
+  ships no render and no gallery entry, and the PR body says which criterion put it
+  there.
 
 Complete every integration required for a shipped example. Infer the exact current
 shape from neighboring examples and repository configuration, including the example
 directory, README, gallery metadata and assets, plugin manifest, smoke catalog
-(`tests/smoke/catalog.json`), top-level README, and generated gallery pages. After regenerating the gallery with
+(`tests/smoke/catalog.json`), top-level README, and generated gallery pages. A
+check-only example skips the gallery metadata, assets, and generated pages — it wires
+the plugin manifest, the smoke catalog row, and its README, and nothing else. After regenerating the gallery with
 `python scripts/build_gallery.py`, read the **generated** output character by
 character—not only `examples/gallery.json` source fields. Open
 `docs/gallery/index.html` and `docs/gallery/<name>/index.html` and inspect the