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

# Start a Subscriber Operation

> Add tags to a filtered audience in the background

Add tags to a filtered audience in the background. See [background contact tasks](../../concepts/subscribers#background-tagging) for selection, retry and cancellation behavior.

Requires subscribers:read. Tagging and cancelling a tagging task also require subscribers:tag; creating tag definitions requires tags:write; triggering automations requires automations:trigger. Personal keys retain current company role restrictions. Company keys retain company-scoped authority. Workers recheck authority on every page.

Send `kind: "add_tags"`, a unique `requestKey` and one to twenty-five `tags`. Omit `audience` for all contacts, or supply the same filters as Contacts. `triggerAutomations` defaults to false through API, CLI and MCP; the Contacts tagging action explicitly enables it. Reuse the same key and settings after an interrupted response. A changed request returns `409`.

```json theme={null}
{
  "kind": "add_tags",
  "requestKey": "contacts-september-2026",
  "tags": ["vip"],
  "audience": { "activeOnly": true }
}
```

A `202` response contains `success` and `operation`, including its ID and current state. Invalid inputs return `400`; an operation that cannot be created returns `503`, which you can retry with the same request key.

Missing authentication returns `401`; missing scopes or company access return `403`. An operation outside the selected company is reported as `404`, as is an operation whose retained record no longer exists.