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

# Update Transformation

> Replaces a transformation in a Google Tag Manager workspace with a full resource payload

Replaces a transformation in a Google Tag Manager workspace with a full resource payload. Transformations modify event data in a server-side Google Tag Manager container before it reaches tags. Version and publish to take changes live.

|                       |                             |
| --------------------- | --------------------------- |
| **App**               | Google Tag Manager          |
| **Operation ID**      | `gtm_update_transformation` |
| **Type**              | Action                      |
| **Connection**        | `gtm` (required)            |
| **Credits per run**   | 1                           |
| **Agent / MCP tool**  | Yes                         |
| **Requires approval** | Yes (write operation)       |

## Inputs

| Field                    | Type             | Required | Default | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| ------------------------ | ---------------- | -------- | ------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `account`                | DynamicAccount   | Yes      | -       | Select the Google Tag Manager account.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| `container`              | DynamicAccount   | Yes      | -       | Select the container.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| `workspace`              | DynamicAccount   | Yes      | -       | Select the workspace.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| `transformation`         | DynamicAccount   | Yes      | -       | Select the transformation to update, or provide its ID.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| `transformation_payload` | object or string | Yes      | -       | Full replacement Transformation resource; the update replaces the transformation entirely, so include every field it should keep. Workflow: gtm\_get\_transformation -> edit the payload -> gtm\_update\_transformation. Full Transformation resource (object or JSON string) matching the Google Tag Manager API v2 Transformation spec (server containers). Must include name and type; settings go in parameter. You can copy a transformation from gtm\_list\_transformations and edit it (read-only fields are stripped automatically). |

## Output

**Type**: `Dict`

Returns the updated transformation as provided by the Tag Manager API.