# preview_sync

Behavior, inputs, outputs and permissions for preview_sync.

Source: https://docs.getridian.com/developers/tools/preview_sync/
Language: en
Reviewed: 2026-10-06

This reference is generated from the published tool contract.

## Behavior and boundaries

Checks whether a one-way sync from one of the user's calendars into another could be created, without creating anything. It reports both calendars, whether it could be created, and every blocker it found — all of them, not just the first. It deliberately does not state how many events would be copied: that is not computed, so it is not claimed. A sync copies continuously, not once. A positive preview is not a reservation: the same checks run again when create_sync writes, and conditions can change in between.

## Permissions

Granted scopes, accounts, calendars and visibility rules limit access. Workspace administrators do not automatically gain access to other users’ accounts.

`sync:read`

[Consent and boundaries](https://docs.getridian.com/developers/authentication/)

## Input

```json
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "sourceCalendarId": {
      "type": "string",
      "minLength": 1
    },
    "targetCalendarId": {
      "type": "string",
      "minLength": 1
    }
  },
  "required": [
    "sourceCalendarId",
    "targetCalendarId"
  ],
  "additionalProperties": false
}
```

## Output

```json
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "ok": {
      "type": "boolean",
      "const": true
    },
    "source": {
      "type": "object",
      "properties": {
        "id": {
          "type": [
            "string",
            "null"
          ]
        },
        "name": {
          "type": [
            "string",
            "null"
          ]
        }
      },
      "required": [
        "id",
        "name"
      ],
      "additionalProperties": false
    },
    "target": {
      "type": "object",
      "properties": {
        "id": {
          "type": [
            "string",
            "null"
          ]
        },
        "name": {
          "type": [
            "string",
            "null"
          ]
        }
      },
      "required": [
        "id",
        "name"
      ],
      "additionalProperties": false
    },
    "direction": {
      "type": "string",
      "const": "one_way"
    },
    "canCreate": {
      "type": "boolean"
    },
    "blockers": {
      "type": "array",
      "items": {
        "type": "string"
      }
    },
    "effect": {
      "type": "string",
      "const": "ongoing_copy_unknown_volume"
    }
  },
  "required": [
    "ok",
    "source",
    "target",
    "direction",
    "canCreate",
    "blockers",
    "effect"
  ],
  "additionalProperties": false
}
```

## Errors and retries

Check the tool result for errors. Do not blindly retry writes after a timeout. Check the current resource or send status first.

[Error handling](https://docs.getridian.com/developers/errors/)