Add parser compatibility tooling

.agents/skills/chrome-trace/SKILL.md

@@ -20,7 +20,7 @@ Use Playwright with Chromium and the Chrome DevTools Protocol `Tracing` domain t
 
 Do not draw conclusions from FPS alone. Use FPS/frame-time summaries only as the symptom; use trace groups and top events as the explanation.
 
-## Polycss Trace Runners
+## PolyCSS Trace Runners
 
 Use `scripts/trace.mjs` as the front door:
 
@@ -46,7 +46,7 @@ Use `trace.mjs drag` for real `PolyOrbitControls` pointer-drag traces on `nonvox
 
 Use `trace.mjs generic` for arbitrary pages and interactions that are not covered by a polycss bench page.
 
-When interpreting polycss traces, map the result back to the render model:
+When interpreting PolyCSS traces, map the result back to the render model:
 
 - `FunctionCall`, `EventDispatch`, `FireAnimationFrame`: JS/input work. Unexpected sustained per-frame work is suspicious outside imported skeletal animation.
 - `UpdateLayoutTree`, `RecalculateStyles`: style recalculation, often CSS variable or selector invalidation cost.

.agents/skills/compat-hunter/SKILL.md

@@ -0,0 +1,97 @@
+---
+name: compat-hunter
+description: Use when hunting for OBJ/GLB/glTF/VOX parser compatibility issues by streaming candidate models, parsing each immediately, deleting clean files, and retaining only actionable failures, unknown warnings, or unexplained zero-polygon outputs. Especially useful in the polycss repo with scripts/compat-hunter.mjs.
+---
+
+# Compat Hunter
+
+Use this skill when the user wants to keep digging for parser compatibility issues without building a fixed local corpus.
+
+## Workflow
+
+1. In the repo, prefer the reusable script:
+
+   ```bash
+   pnpm compat-hunter -- --max-models 2000
+   ```
+
+   Equivalent explicit form:
+
+   ```bash
+   pnpm --filter @layoutit/polycss-core build
+   node .agents/skills/compat-hunter/scripts/compat-hunter.mjs --max-models 2000
+   ```
+
+2. Let the script stream remote OBJ/GLB/glTF/VOX candidates, parse each model, and discard clean files. Reports are written under `bench/results/`, which is ignored by git.
+
+3. Treat these as known non-actionable unless the user asks to support them:
+   - glTF POINTS/LINES/LINE_LOOP/LINE_STRIP primitives.
+   - Required Draco or meshopt compressed primitives skipped with a warning.
+
+4. Stop and inspect anything classified as:
+   - `throw`
+   - `unknown-warning`
+   - `obj-zero-no-warning`
+   - `glb-zero-no-warning`
+
+5. If an actionable parser issue is found, keep the saved file under the report's `interesting/` directory, add a focused parser test using that behavior, implement the smallest fix, and rerun the focused parser tests plus the hunter on the saved file or source class.
+
+## Useful Commands
+
+Fresh Objaverse and expanded GitHub stream:
+
+```bash
+pnpm compat-hunter -- --max-models 5000 --max-bytes 10mb --timeout-ms 30000
+```
+
+Objaverse only, later shards:
+
+```bash
+pnpm compat-hunter -- --sources objaverse --objaverse-shards 120:220 --max-models 5000
+```
+
+GitHub only:
+
+```bash
+pnpm compat-hunter -- --sources github --max-models 500
+```
+
+Poly Haven only:
+
+```bash
+pnpm compat-hunter -- --sources polyhaven --polyhaven-limit 250 --max-models 200
+```
+
+VOX-heavy GitHub sources:
+
+```bash
+pnpm compat-hunter -- --sources github --github-repos ephtracy/voxel-model@master:vox/,mikelovesrobots/mmmm@master:vox/ --max-models 1000
+```
+
+Local directory:
+
+```bash
+pnpm compat-hunter -- --sources local --local-root /tmp/models --max-models 1000
+```
+
+Keep known-warning files too:
+
+```bash
+pnpm compat-hunter -- --keep-known --max-models 500
+```
+
+Continue after interesting cases:
+
+```bash
+pnpm compat-hunter -- --no-stop-on-interesting --max-models 2000
+```
+
+## Reporting
+
+Summarize the final `report.json` with:
+
+```bash
+pnpm compat-hunter -- --report bench/results/<run>/report.json
+```
+
+In the final response, state the attempted/parsed counts, whether any interesting files were retained, and whether the findings are actionable. Do not imply a clean stream proves full compatibility; it only means this pass found no new actionable parser issue.

.agents/skills/compat-hunter/agents/openai.yaml

@@ -0,0 +1,4 @@
+interface:
+  display_name: "Compat Hunter"
+  short_description: "Stream model parser compatibility hunts"
+  default_prompt: "Use $compat-hunter to stream OBJ/GLB/glTF/VOX models until a parser compatibility issue appears."