# Capabilities (https://www.cal-sdk.com/docs/reference/capabilities)

Before you offer a feature, such as "edit this and following" or a video link, you'll want to know the user's calendar can do it. Every provider has a `capabilities` object that tells you. calsdk also uses it to pick fallbacks, the conformance suite runs only the tests a provider declares, and these docs build the [provider comparison](/docs/providers) from it.

```ts
calendar.capabilities.events.recurrenceScopeThisAndFollowing; // true, false, 'unknown' or { condition }
```

## Values [#values]

| Value | Meaning |
| --- | --- |
| `true` | Always supported |
| `false` | Never supported |
| `'unknown'` | The provider cannot tell ahead of time. Not the same as unsupported |
| `{ condition: string }` | Supported only under the condition, such as `'Teams meetings need a work or school account.'` |

## Flags [#flags]

<TypeTable
  type={{
    'events.details': { type: 'Capability', description: 'Events keep the title and description they are written with. Booking tools name events from a template instead.', required: true },
    'events.allDay': { type: 'Capability', description: 'Create all-day events.', required: true },
    'events.recurrence': { type: 'Capability', description: 'Create and read recurring series.', required: true },
    'events.recurrenceScopeThisAndFollowing': { type: 'Capability', description: "Change or delete this and later occurrences with `scope: 'thisAndFollowing'`.", required: true },
    'events.serverSideExpansion': { type: 'Capability', description: '`expandRecurring: true` returns occurrences, computed by the provider or by calsdk for it.', required: true },
    'events.attendees': { type: 'Capability', description: 'Invite and read attendees.', required: true },
    'events.conference': { type: 'Capability', description: '`createConference: true` creates a video link.', required: true },
    'events.reminders': { type: 'Capability', description: 'Set reminders.', required: true },
    'events.color': { type: 'Capability', description: 'Set event colors.', required: true },
    'events.etag': { type: 'Capability', description: 'Events carry `etag` and writes honor `ifMatch`.', required: true },
    'events.search': { type: 'Capability', description: 'Free-text search with `query` on `listEvents`.', required: true },
    freeBusy: { type: 'Capability', description: 'A free/busy endpoint. Without one, calsdk computes free/busy from events.', required: true },
    sync: { type: 'Capability', description: 'Fetch changes since a cursor with `syncEvents`.', required: true },
    webhooks: { type: 'Capability', description: 'Push notifications. Part of the contract, not implemented by any provider yet.', required: true },
  }}
/>