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

# Google Calendar API

> How Harmonia explicitly synchronizes already scheduled content to an app-created calendar.

Google Calendar is an operator-controlled downstream projection. Temi proposes editorial windows but cannot create or modify external calendar events.

## How Harmonia uses it

Harmonia requests the narrow `calendar.app.created` OAuth scope and creates or reuses a Harmonia-owned calendar. After content has separately reached the application's scheduled state, the operator may explicitly add, update, or remove its calendar event.

The mutation binds to the content item, tenant, calendar, operation, and prior synchronization state. The latest verified projection—or verified absence—is stored on the content item.

## Security and authority

OAuth tokens stay server-side. Harmonia does not request access to unrelated calendars. Calendar synchronization cannot approve content, choose a publication time, or publish a social post.

## Failure behavior

Provisioning and mutations use claims to prevent duplicate calendars or events. Ambiguous provider outcomes are marked uncertain and reconciled instead of blindly repeated. Stale content-item updates are rejected.

## Evidence status

Gateway, OAuth, idempotency, and state-machine behavior have automated coverage. Live use requires authenticated OAuth consent and redacted event reconciliation evidence.

## Relevant files

* `src/lib/googleCalendar.ts`
* `src/lib/calendarSyncState.ts`
* `src/app/api/calendar/google/route.ts`
* `src/app/api/oauth/[platform]/`
* `docs/google-calendar-reference.mdx`