Cesium Agents : Skill Validator
Overview
This is a validation skill. Run it over any CesiumJS code before declaring it
finished. It is a deterministic checklist: each check has a grep-style trigger,
a verdict, and the skill that holds the fix. The checklist targets CesiumJS
1.124+, where a large set of pre-2023 APIs no longer exist.
CesiumJS 1.124+ is WebGL2 only. Any code that names or assumes WebGL is fine;
any code that names or assumes WebGPU for CesiumJS is wrong.
When to Use
- A CesiumJS snippet was just generated and is about to be presented or
committed.
- Reviewing CesiumJS code from an older tutorial, blog post, or Sandcastle.
- A scene "should work" but renders blank, throws, or leaks, and a structured
pass is needed.
Check 1 : Removed Async-Era APIs (BLOCKER)
Each token below was removed before or within the 1.124 to 1.142 window. Any
match is a hard failure. Verdict: REJECT until fixed.
| Found token |
Status |
Required replacement |
Fix skill |
new Cesium3DTileset( |
removed 1.107 |
await Cesium3DTileset.fromUrl(url) / .fromIonAssetId(id) |
cesium-syntax-3d-tiles |
.readyPromise |
removed 1.107 |
await the async factory |
cesium-core-versioning |
.ready on a tileset/model/provider |
removed 1.107 |
the awaited result is ready |
cesium-core-versioning |
Model.fromGltf( (without Async) |
removed |
Model.fromGltfAsync( |
cesium-syntax-gltf-model |
ModelExperimental |
removed (merged into Model) |
Model |
cesium-syntax-gltf-model |
new CesiumTerrainProvider({ |
removed 1.107 |
await CesiumTerrainProvider.fromUrl(url) |
cesium-syntax-terrain |
createWorldTerrain( (without Async) |
removed 1.107 |
createWorldTerrainAsync( |
cesium-syntax-terrain |
defaultValue( |
removed 1.134 |
a ?? b |
cesium-core-versioning |
new Cesium.Cartesian3.fromDegrees |
throws since 1.139 |
drop new |
cesium-core-coordinates |
terrainExaggeration on Globe |
removed 1.113 |
scene.verticalExaggeration |
cesium-core-versioning |
Check 2 : WebGPU Assumption (BLOCKER)
- Trigger: any reference to a WebGPU backend, context, or toggle for CesiumJS.
- Verdict: REJECT. CesiumJS renders only on WebGL2 in 1.124+.
- Fix skill:
cesium-core-architecture.
Check 3 : Missing ion Token (BLOCKER if ion used)
- Trigger: code uses
fromIonAssetId, IonImageryProvider, world imagery,
world terrain, or OSM Buildings, but never sets Ion.defaultAccessToken.
- Verdict: REJECT. The scene will 401 and the globe will be blank.
- Fix skill:
cesium-syntax-viewer, cesium-impl-cesium-ion.
Check 4 : Async Factory Not Awaited (BLOCKER)
- Trigger: a
from* factory (fromUrl, fromIonAssetId, fromGltfAsync,
fromProviderAsync) whose result is used without await.
- Verdict: REJECT. The variable holds a
Promise, not the object;
scene.primitives.add and property access fail.
- Fix skill:
cesium-core-versioning, cesium-syntax-3d-tiles.
Check 5 : Missing Teardown (WARN)
- Trigger: a
Viewer, Cesium3DTileset, Model, custom Primitive, or
ScreenSpaceEventHandler is created with no destroy() on any cleanup path;
or an addEventListener on a CesiumJS Event with no stored remover.
- Verdict: WARN. Acceptable for a one-shot script, a defect for an app.
- Fix skill:
cesium-core-memory, cesium-errors-memory.
Check 6 : Coordinate Type and Unit (BLOCKER)
- Trigger:
new Cartographic( with degree-magnitude numbers; a Cartographic
assigned to entity.position; a factory called as (latitude, longitude);
degrees passed to new HeadingPitchRoll.
- Verdict: REJECT. The geometry will be misplaced or absent.
- Fix skill:
cesium-errors-coordinates, cesium-core-coordinates.
Check 7 : API Name Verification (BLOCKER)
- Trigger: any CesiumJS class, method, or enum value not confirmed against the
API reference.
- Verdict: REJECT until verified. Hallucinated API names are the highest-risk
defect in generated code.
- Action: WebFetch the name against
https://cesium.com/learn/cesiumjs/ref-doc/ (the SOURCES.md primary source).
If it does not exist, the code is wrong.
Check 8 : Continuous Render on a Static Scene (WARN)
- Trigger: a static or rarely-changing scene with no
requestRenderMode: true.
- Verdict: WARN. Not a defect, but a battery and GPU cost.
- Fix skill:
cesium-core-performance.
Verdict Rule
- Any BLOCKER unresolved : REJECT the code. Do not present it as done.
- Only WARN items : ACCEPT with the warnings stated to the user.
- All checks clear : ACCEPT.
NEVER report CesiumJS code as complete while a Check 1 to 4, 6, or 7 failure
stands.
Quick Scan Order
Run Check 1, 2, 3, 4 first; they are the fastest to grep and the most common.
Then Check 6 and 7. Check 5 and 8 last; they are WARN-level.
Reference Files
references/methods.md : every check as a grep-ready pattern with verdict
and fix skill.references/examples.md : worked validations of three code snippets, one
rejected and rewritten, one warned, one accepted.references/anti-patterns.md : the failure modes of validation itself, such
as trusting a plausible but hallucinated API name.
Related Skills
cesium-core-versioning : the full removed-API migration detail.cesium-core-architecture : the WebGL2-only fact.cesium-errors-coordinates : coordinate type and unit failures.cesium-core-memory : teardown requirements.cesium-agents-scene-architect : the setup decisions this validator checks.
Sources
Built on the project research base (docs/research/vooronderzoek-cesium.md)
and the verified CHANGES.md matrix, against the CesiumJS API Reference on the
approved sources, 2026-05-20.
1---2name: cesium-agents-skill-validator3description: Use when CesiumJS code has just been generated or reviewed and must be checked before it is called done, to catch deprecated APIs and common defects, or when auditing CesiumJS code from an older source. Detects the removed synchronous patterns (readyPromise, the url constructor option, ModelExperimental, defaultValue, new on a Cartesian factory), WebGPU assumptions, missing ion tokens, missing destroy() calls, and coordinate-type mistakes. Runs a deterministic checklist and routes each failure to the skill that fixes it. Keywords: validate CesiumJS code, review Cesium code, is this Cesium code correct, deprecated CesiumJS API, readyPromise, ModelExperimental, defaultValue removed, check before commit, CesiumJS code quality, lint Cesium, did I use the right API, audit Cesium scene, why might this code fail.4license: MIT5---67# Cesium Agents : Skill Validator89## Overview1011This is a validation skill. Run it over any CesiumJS code before declaring it12finished. It is a deterministic checklist: each check has a grep-style trigger,13a verdict, and the skill that holds the fix. The checklist targets CesiumJS141.124+, where a large set of pre-2023 APIs no longer exist.1516CesiumJS 1.124+ is WebGL2 only. Any code that names or assumes WebGL is fine;17any code that names or assumes WebGPU for CesiumJS is wrong.1819## When to Use2021- A CesiumJS snippet was just generated and is about to be presented or22 committed.23- Reviewing CesiumJS code from an older tutorial, blog post, or Sandcastle.24- A scene "should work" but renders blank, throws, or leaks, and a structured25 pass is needed.2627## Check 1 : Removed Async-Era APIs (BLOCKER)2829Each token below was removed before or within the 1.124 to 1.142 window. Any30match is a hard failure. Verdict: REJECT until fixed.3132| Found token | Status | Required replacement | Fix skill |33|-------------|--------|----------------------|-----------|34| `new Cesium3DTileset(` | removed 1.107 | `await Cesium3DTileset.fromUrl(url)` / `.fromIonAssetId(id)` | `cesium-syntax-3d-tiles` |35| `.readyPromise` | removed 1.107 | `await` the async factory | `cesium-core-versioning` |36| `.ready` on a tileset/model/provider | removed 1.107 | the awaited result is ready | `cesium-core-versioning` |37| `Model.fromGltf(` (without `Async`) | removed | `Model.fromGltfAsync(` | `cesium-syntax-gltf-model` |38| `ModelExperimental` | removed (merged into `Model`) | `Model` | `cesium-syntax-gltf-model` |39| `new CesiumTerrainProvider({` | removed 1.107 | `await CesiumTerrainProvider.fromUrl(url)` | `cesium-syntax-terrain` |40| `createWorldTerrain(` (without `Async`) | removed 1.107 | `createWorldTerrainAsync(` | `cesium-syntax-terrain` |41| `defaultValue(` | removed 1.134 | `a ?? b` | `cesium-core-versioning` |42| `new Cesium.Cartesian3.fromDegrees` | throws since 1.139 | drop `new` | `cesium-core-coordinates` |43| `terrainExaggeration` on `Globe` | removed 1.113 | `scene.verticalExaggeration` | `cesium-core-versioning` |4445## Check 2 : WebGPU Assumption (BLOCKER)4647- Trigger: any reference to a WebGPU backend, context, or toggle for CesiumJS.48- Verdict: REJECT. CesiumJS renders only on WebGL2 in 1.124+.49- Fix skill: `cesium-core-architecture`.5051## Check 3 : Missing ion Token (BLOCKER if ion used)5253- Trigger: code uses `fromIonAssetId`, `IonImageryProvider`, world imagery,54 world terrain, or OSM Buildings, but never sets `Ion.defaultAccessToken`.55- Verdict: REJECT. The scene will 401 and the globe will be blank.56- Fix skill: `cesium-syntax-viewer`, `cesium-impl-cesium-ion`.5758## Check 4 : Async Factory Not Awaited (BLOCKER)5960- Trigger: a `from*` factory (`fromUrl`, `fromIonAssetId`, `fromGltfAsync`,61 `fromProviderAsync`) whose result is used without `await`.62- Verdict: REJECT. The variable holds a `Promise`, not the object;63 `scene.primitives.add` and property access fail.64- Fix skill: `cesium-core-versioning`, `cesium-syntax-3d-tiles`.6566## Check 5 : Missing Teardown (WARN)6768- Trigger: a `Viewer`, `Cesium3DTileset`, `Model`, custom `Primitive`, or69 `ScreenSpaceEventHandler` is created with no `destroy()` on any cleanup path;70 or an `addEventListener` on a CesiumJS `Event` with no stored remover.71- Verdict: WARN. Acceptable for a one-shot script, a defect for an app.72- Fix skill: `cesium-core-memory`, `cesium-errors-memory`.7374## Check 6 : Coordinate Type and Unit (BLOCKER)7576- Trigger: `new Cartographic(` with degree-magnitude numbers; a `Cartographic`77 assigned to `entity.position`; a factory called as `(latitude, longitude)`;78 degrees passed to `new HeadingPitchRoll`.79- Verdict: REJECT. The geometry will be misplaced or absent.80- Fix skill: `cesium-errors-coordinates`, `cesium-core-coordinates`.8182## Check 7 : API Name Verification (BLOCKER)8384- Trigger: any CesiumJS class, method, or enum value not confirmed against the85 API reference.86- Verdict: REJECT until verified. Hallucinated API names are the highest-risk87 defect in generated code.88- Action: WebFetch the name against89 `https://cesium.com/learn/cesiumjs/ref-doc/` (the SOURCES.md primary source).90 If it does not exist, the code is wrong.9192## Check 8 : Continuous Render on a Static Scene (WARN)9394- Trigger: a static or rarely-changing scene with no `requestRenderMode: true`.95- Verdict: WARN. Not a defect, but a battery and GPU cost.96- Fix skill: `cesium-core-performance`.9798## Verdict Rule99100- Any BLOCKER unresolved : REJECT the code. Do not present it as done.101- Only WARN items : ACCEPT with the warnings stated to the user.102- All checks clear : ACCEPT.103104NEVER report CesiumJS code as complete while a Check 1 to 4, 6, or 7 failure105stands.106107## Quick Scan Order108109Run Check 1, 2, 3, 4 first; they are the fastest to grep and the most common.110Then Check 6 and 7. Check 5 and 8 last; they are WARN-level.111112## Reference Files113114- `references/methods.md` : every check as a grep-ready pattern with verdict115 and fix skill.116- `references/examples.md` : worked validations of three code snippets, one117 rejected and rewritten, one warned, one accepted.118- `references/anti-patterns.md` : the failure modes of validation itself, such119 as trusting a plausible but hallucinated API name.120121## Related Skills122123- `cesium-core-versioning` : the full removed-API migration detail.124- `cesium-core-architecture` : the WebGL2-only fact.125- `cesium-errors-coordinates` : coordinate type and unit failures.126- `cesium-core-memory` : teardown requirements.127- `cesium-agents-scene-architect` : the setup decisions this validator checks.128129## Sources130131Built on the project research base (`docs/research/vooronderzoek-cesium.md`)132and the verified `CHANGES.md` matrix, against the CesiumJS API Reference on the133approved sources, 2026-05-20.
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