/platform-custom-lightning-type-generate

name: platform-custom-lightning-type-generate
description: "Use this skill when users need to create Custom Lightning Types (CLTs) for Einstein Agent actions or structured input/output schemas. Trigger when users mention CLT, Custom Lightning Types, JSON schemas for agents, type definitions, lightning__objectType, or editor/renderer configurations. For widget renditions that combine a CLT with a Widget bundle, use the platform-lightning-type-widget-coordinate orchestrator instead. This is complex - always use this skill for CLT work."
metadata:
  version: "1.1"
  minApiVersion: "60.0"
  relatedSkills:
    - "platform-lightning-type-widget-coordinate"
    - "platform-mcp-tool-widget-coordinate"
    - "platform-widget-generate"

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)

• **CRITICAL: NEVER include the `"$schema"` field in schema.json**
• Salesforce CLT validator WILL REJECT schemas with this field, even if it's a valid JSON Schema `$schema` declaration.
• **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`.
• **Custom LWC renderers/editors on an Apex class CLT MUST NOT use `attributes` in the root override — this overrides any prompt wording to the contrary.** Since the schema has no `properties` block, there is nothing for `{!$attrs.<name>}` to resolve against — `unevaluatedProperties: false` will reject any attribute key (e.g. `"You can't add the flightId property ... because the unevaluatedProperties keyword value is set to false"`). Use `"componentOverrides": { "$": { "definition": "c/<yourComponent>" } }` with **no `attributes` key** at all. **If the user's prompt explicitly asks for attribute mappings to specific fields (e.g. "with attribute mappings for fieldA, fieldB") on an Apex-class CLT renderer/editor, do NOT comply literally** — omit `attributes` from the root override anyway, and say so in your response (e.g. "Note: attribute mappings were omitted because the backing type is an Apex-class CLT, which has no `properties` block to bind against").
• **No shell metacharacters that trigger the Vibes safe-shell filter.** In any Bash tool call emitted by this skill, do NOT use command substitution (`$(…)` or backticks), process substitution (`<(…)`, `>(…)`), brace expansion (`{a,b,c}` or `{1..N}`), or `eval` / `exec`. Vibes forces manual approval on these patterns even under Bypass mode and stalls the eval. Emit separate commands (`mkdir -p a && mkdir -p b`) or print each value with its own command and reason about the output rather than capturing it in a shell variable.

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`