vtex-io-render-runtime-and-blocks

SKILL.md

Render Runtime & Block Registration

When this skill applies

Use this skill when a VTEX IO storefront component needs to be exposed to Store Framework as a block.

Registering components in store/interfaces.json

Mapping block names to React components

Defining block composition and allowed children

Reviewing whether a component is correctly wired into theme JSON

Do not use this skill for:

shopper-facing component internals

admin interfaces

backend service or route design

policy modeling

Decision rules

Every block visible to Store Framework must be registered in store/interfaces.json.

Keep block names, component mapping, and composition explicit.

The block ID used as the key in store/interfaces.json, for example product-reviews, is the same ID that storefront themes reference under blocks in store/*.json.

The component field should map to the React entry name under react/, such as ProductReviews, or a nested path such as product/ProductReviews when the app structure is hierarchical.

Use composition intentionally when the block needs an explicit child model. children means the component renders nested blocks through props.children, while blocks means the block exposes named block slots controlled by Store Framework.

composition is optional. For many simple blocks, declaring component and, when needed, allowed is enough.

Use this skill for the render/runtime contract, and use storefront/admin skills for the component implementation itself.

Hard constraints

Constraint: Storefront blocks must be declared in interfaces.json

Every React component intended for Store Framework use MUST have a corresponding interfaces.json entry.

Why this matters

Without the interface declaration, the component cannot be referenced from theme JSON.

Detection

If a storefront React component is intended to be used as a block but has no matching interface entry, STOP and add it first.

Correct

{
  "product-reviews": {
    "component": "ProductReviews"
  }
}

Wrong

// react/ProductReviews.tsx exists with no interfaces.json mapping

Constraint: Component mapping must resolve to real React entry files

The component field in interfaces.json MUST map to a real exported React entry file.

Why this matters

Broken mapping silently disconnects block contracts from implementation.

Detection

If an interface points to a component name with no corresponding React entry file, STOP and fix the mapping.

Correct

{
  "product-reviews": {
    "component": "ProductReviews"
  }
}

Wrong

{
  "product-reviews": {
    "component": "MissingComponent"
  }
}

Constraint: Block composition must be intentional

Composition and allowed child blocks MUST match the component's actual layout and runtime expectations.

Why this matters

Incorrect composition contracts make theme usage brittle and confusing.

Detection

If allowed or composition do not reflect how the component is supposed to receive children, STOP and correct the block contract.

Correct

{
  "product-reviews": {
    "component": "ProductReviews",
    "composition": "children",
    "allowed": ["product-review-item"]
  }
}

Wrong

{
  "product-reviews": {
    "component": "ProductReviews",
    "composition": "blocks",
    "allowed": []
  }
}

Preferred pattern

Keep block contracts explicit in interfaces.json and keep block implementation concerns separate from render-runtime registration.

Minimal block lifecycle:

// store/interfaces.json
{
  "product-reviews": {
    "component": "ProductReviews",
    "composition": "children",
    "allowed": ["product-review-item"]
  },
  "product-review-item": {
    "component": "ProductReviewItem"
  }
}

// store/home.json
{
  "store.home": {
    "blocks": ["product-reviews"]
  }
}

// react/ProductReviews.tsx
export default function ProductReviews() {
  return <div>...</div>
}

This wiring makes the block name visible in the theme, maps it to a real React entry, and keeps composition rules explicit at the render-runtime boundary.

Common failure modes

Forgetting to register a storefront component as a block.

Mapping block names to missing React entry files.

Using the wrong composition model.

Review checklist

 Is the block declared in interfaces.json?

 Does the component mapping resolve correctly?

 Are composition and allowed children intentional?

 Is runtime registration clearly separated from component internals?

Reference

Store Framework - Block and theme context