> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nowadays.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Writing events

> The rules create_event and update_event enforce, and the refusals worth planning for.

`create_event` and `update_event` are not plain CRUD. This page covers the
behavior behind the arguments — the parts that will surprise an agent that
assumes otherwise.

## Creating

`create_event` returns the new event's `id` and `grantedTo`:

```json theme={null}
{ "id": "3f2b8c1a-…", "grantedTo": 3 }
```

`grantedTo` is how many people can now see the event. You are one of them; the
rest are your approvers.

<Warning>
  **`grantedTo: 0` means the event exists but nobody can see it.** Enterprise
  events are private by default and visibility is derived from the creator's
  group memberships — so a user who belongs to no group produces an invisible
  event. It is not an error and the event is real; an administrator needs to add
  that user to a group. Check this value rather than assuming success means the
  event is usable.
</Warning>

The organization comes from your session, so it is never an argument.

## Updating

`update_event` takes only the fields you are changing, under `changes`. Three
rules govern every update:

<AccordionGroup>
  <Accordion title="Omitted means unchanged; null means cleared">
    A field you leave out is not touched. Sending `null` clears it. That
    distinction is deliberate — there is no way to accidentally blank a field by
    omitting it, and no way to clear one by guessing at an empty value.
  </Accordion>

  <Accordion title="All or nothing">
    If any field is rejected, **nothing is written** and the error lists every
    problem at once. A rejected update therefore always leaves the event
    untouched, so it is safe to correct and retry without checking what
    partially landed.
  </Accordion>

  <Accordion title="Some fields are derived, not writable">
    `location` is derived from `formattedLocations`, and event dates from the
    union of your guestroom nights and agenda date ranges. Neither is accepted as
    input — send the inputs and the derived values follow.
  </Accordion>
</AccordionGroup>

### Editing the agenda

The agenda is edited by **operation**, not by replacement. Send
`agendaOperations` with `add`, `update` or `remove`, each addressed by a session
`id` from a prior `get_event`:

```json theme={null}
{
  "agendaOperations": [
    { "op": "update", "sessionId": "a1b2…", "session": { "startTime": "09:30" } },
    { "op": "remove", "sessionId": "c3d4…" },
    {
      "op": "add",
      "session": {
        "title": "Closing keynote",
        "dates": ["2027-03-17"],
        "startTime": "16:00",
        "endTime": "17:00"
      }
    }
  ]
}
```

Replacing the whole agenda to change one session is both expensive and an easy
way to silently drop the ones you forgot, so there is no way to do it. An unknown
`sessionId` is an error rather than a silent no-op.

### Two refusals worth planning for

**A cancelled event cannot be edited.** Reopen it in Nowadays first.

**Shrinking the agenda dates is refused if any session would lose a date.** The
affected sessions are named in `orphanedSessions`:

```json theme={null}
{
  "message": "Those agenda dates would drop sessions…",
  "orphanedSessions": [
    {
      "sessionId": "a1b2…",
      "title": "Kickoff",
      "droppedDates": ["2027-03-14"],
      "fullyOrphaned": true
    }
  ]
}
```

The dashboard drops such sessions after an "are you sure" prompt. An agent has no
equivalent prompt, so the write is refused instead — move or remove the sessions
deliberately, then retry.

## Limits

A single call is bounded so one request cannot monopolise the service:

| Field                                   | Limit                      |
| --------------------------------------- | -------------------------- |
| `agendaOperations`                      | 200 per request            |
| `formattedLocations`                    | 50 per request             |
| `decisionFactors`, `additionalServices` | 50 values each             |
| `accommodations`                        | 400 nights                 |
| `meetingRoomDates`                      | 50 ranges, each ≤ 366 days |
| Free-text fields                        | 1,000 characters           |
| `name`                                  | 100 characters             |

Exceeding one is rejected with the offending field named, and — as always —
nothing is written.