Generating Custom Lightning Type

## When to Use This Skill

Use this skill when you need to:
- Create Custom Lightning Types (CLTs) for structured inputs/outputs
- Generate JSON Schema-based type definitions for Lightning Platform
- Configure CLTs for Einstein Agent actions
- Set up editor and renderer configurations for custom UI
- Troubleshoot deployment errors related to Custom Lightning Types

## Specification

# CustomLightningType Metadata Specification

## Overview & Purpose
Custom Lightning Types (CLTs) are JSON Schema-based type definitions used by the Lightning Platform (including Einstein Agent actions) to describe structured inputs/outputs and drive editor/renderer experiences.

## Configuration
- **Choose referenced CLT pattern for nested objects** - When you need a **reusable** or **separately deployed** nested type, create a CLT for that shape and reference it with `"lightning:type": "c__<CLTName>"`. That string is the referenced type’s **`lightning:type` value / FQN / registered identifier** — not the JSON Schema `title`.
- **Choose standard Lightning types** when the structure is simple and can be expressed with properties and supported primitive `lightning:type` identifiers.
- **Choose Apex class types** (`@apexClassType/...`) when the structure already exists server-side and you want the Apex class to define the shape.
- **Include editor/renderer config** only when you need custom UI behavior (custom LWC input/output components). Otherwise, omit.

## Critical Rules (Read First)
- **Root object schemas MUST include**:
  - `"type": "object"`
  - `"title"`
  - `"lightning:type": "lightning__objectType"`
  - `"unevaluatedProperties": false`
- `"unevaluatedProperties"` is enforced as `false` by the CLT metaschema. Do not set it to `true`.
- **Root object schemas MUST NOT include** `"examples"` when `"unevaluatedProperties": false` is set.
- **Nested objects (inside `properties`) MUST NOT set** `"lightning:type": "lightning__objectType"`.
    - Nested objects can be: references to other CLTs using `c__<CLTName>` syntax.
- **List/array properties are highly restricted by the CLT metaschema**:
  - **CRITICAL LIMITATION**: the CLT metaschema may reject the `items` keyword entirely. Treat `items` as **disallowed by default**.
  - **Root-level arrays** (direct children of the root `properties`):
    - **MUST include** `"lightning:type": "lightning__listType"`
    - **MUST NOT include** `"items"`
    - **OPTIONAL** `"type": "array"`
  - **Nested arrays** (arrays inside nested objects) are the most common failure:
    - **MUST include** `"type": "array"`
    - **MUST NOT include** `"lightning:type": "lightning__listType"`
    - **MUST NOT include** `"items"`
- **When `"unevaluatedProperties": false` is set, any unknown keyword will fail validation**. Prefer removing keywords over relaxing strictness.
- **Apex class CLTs are minimal**:
  - Include **only** `title`, `description` (optional), and `lightning:type` set to `@apexClassType/...`.
  - Do **not** add `type`, `properties`, `required`, or `unevaluatedProperties`.

## Additional CLT Metaschema Validations
- **Org namespace validation**: titles/descriptions and other string fields may be validated to ensure you are not using an org namespace in places that are disallowed.
- **Lightning type validation**: CLTs are validated to prevent referencing internal namespaces (for example, disallowing types from internal namespaces like `sfdc_cms` where not permitted).
- **Object type validation**: the CLT root is validated to ensure `lightning:type` is exactly `lightning__objectType`