> ## 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.

# Errors & limits

> What a failed Nowadays MCP tool call looks like, and how requests are rate limited.

A failed tool call returns an error the agent can read, describing what went
wrong. There are four kinds worth knowing.

| Failure               | What it means                                                                                                                           |
| --------------------- | --------------------------------------------------------------------------------------------------------------------------------------- |
| Not authenticated     | Your OAuth session expired or was revoked. Reconnect — see [Connecting](/mcp/connecting).                                               |
| Organization required | Your account belongs to more than one organization and none is selected. Call `select_organization` first.                              |
| Not found             | The event does not exist, **or** it isn't accessible to you. The two are indistinguishable by design.                                   |
| Rejected write        | A field failed validation, the event is cancelled, or the change would drop agenda sessions. See [Writing events](/mcp/writing-events). |

<Note>
  A not-found error is returned for both missing and inaccessible events on
  purpose, so you never learn whether another organization's event exists. Don't
  treat it as proof that an id is invalid — only that it isn't readable by you.

  Every rejected write means **nothing was written**, so it is always safe to
  correct the call and retry without first checking what partially landed.
</Note>

## Visibility, not just errors

Tools act **as you**. An agent reaches exactly the events your Nowadays account
can open, so a tool returning fewer events than you expect is usually
permissions, not a bug — enterprise events are private to their creator and their
approvers by default.

## Rate limits

Requests are rate limited **per user**, across every MCP client you have
connected. Limits are approximate and enforced on a best-effort basis.

Exceeding the limit returns a rate-limit error. Back off and retry, increasing
the delay on repeated failures, and spread bulk work out rather than firing many
calls at once.

If you have a legitimate need for a higher limit,
[contact us](mailto:support@nowadays.ai) — limits may be raised on request.