<!-- Extension API v0 — pre-1.0. Interfaces may change without notice until P2 seals the custom-code format. First-party extensions track HEAD. -->

# `design.extpage.add`

Add an installed extension's page to the workspace draft under /ek/{slug} (owner-changeable path); the page renders the extension's composite through the active theme.

- **scope**: `design:write`
- **storefront-visible** (bumps the catalog generation): no
- **destructive**: no

## Payload

| field | type | required | notes |
|---|---|---|---|
| `workspace` | string (/^(main\|ws_[A-Z0-9]{26})$/, default "main") | no |  |
| `ext` | string (/^[a-z0-9-]+\.[a-z0-9-]+$/, ≤80 chars) | yes |  |
| `slug` | string (/^[a-z0-9-]{1,32}$/) | yes |  |
| `path` | string (/^\/ek\/[a-z0-9-]{1,40}$/) | no |  |
| `expectedRev` | integer (1..9007199254740991) \| null | no |  |

### JSON Schema

```json
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "workspace": {
      "default": "main",
      "type": "string",
      "pattern": "^(main|ws_[A-Z0-9]{26})$"
    },
    "ext": {
      "type": "string",
      "maxLength": 80,
      "pattern": "^[a-z0-9-]+\\.[a-z0-9-]+$"
    },
    "slug": {
      "type": "string",
      "pattern": "^[a-z0-9-]{1,32}$"
    },
    "path": {
      "type": "string",
      "pattern": "^\\/ek\\/[a-z0-9-]{1,40}$"
    },
    "expectedRev": {
      "default": null,
      "anyOf": [
        {
          "type": "integer",
          "minimum": 1,
          "maximum": 9007199254740991
        },
        {
          "type": "null"
        }
      ]
    }
  },
  "required": [
    "ext",
    "slug"
  ],
  "additionalProperties": false
}
```