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

# Create Multi-Stage Task

> Create Multi-Stage Task

# Create Multi-Stage Task

This endpoint creates a `multistage` task. Multi-stage tasks are designed to handle complex full-scene labeling that spans multiple annotation types and modalities, and serves as a replacement for Scale’s legacy dependent tasks system (which requires using multiple tasks to fully label a scene).

Use cases for multi-stage tasks include but are not limited to:

* Linking 3D cuboids to their 2D bounding box/polygon projections
* Linking 3D cuboids to relevant top-down annotations
* Conditional labeling (e.g. categorizing scenes based on localization quality to determine whether to label them)<br />

The required parameters for this task are project, attachments, and scene\_format.<br />

The callback\_url is the URL which will be POSTed on task completion, and is described in more detail in the Callback section.

Scale supports the following attachment types for multi-stage tasks:

* (Recommended) Sensor Fusion Scene (.SFS)
* LiDAR frames (.JSON)<br />

<ParamField path="Body Params" type="object">
  <ParamField path="project" type="string" required>
    The name of the project to associate this task with. See the [Projects](/docs/api-reference/projects) Section for more details.

    ***
  </ParamField>

  <ParamField path="batch" type="string">
    The name of the batch to associate this task with. Note that if a batch is specified, you need not specify the project, as the task will automatically be associated with the batch's project. For Scale Rapid projects specifying a batch is required. See [Batches section](/docs/api-reference/batches) for more details.

    ***
  </ParamField>

  <ParamField path="instruction" type="string">
    A markdown-enabled string or iframe embed google doc explaining how to do the task. You can use [markdown](https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet) to show example images, give structure to your instructions, and more.

    ***
  </ParamField>

  <ParamField path="callback_url" type="string">
    The full url (including the scheme `http://` or `https://`) of the callback when the task is completed. See the [Callback section](/docs/api-reference/callbacks) for more details about callbacks.

    ***
  </ParamField>

  <ParamField path="attachments" type="array of strings" required>
    URLs to the scene attachments. Can be a single URL for `.SFS` attachments, or one URL per frame for `.JSON` attachments.

    ***
  </ParamField>

  <ParamField path="scene_format" type="string" required>
    Describes what type of file the attachment is. Can be `sensor_fusion` for `.SFS` attachments or `split_base64` for `.JSON` attachments
  </ParamField>

  <ParamField path="task_blueprint_id" type="string">
    The ID of the blueprint that you would like to use when creating the multi-stage task. If no blueprint is specified, Scale will default to using the project’s most recent active blueprint.
  </ParamField>

  <ParamField path="metadata" type="object">
    A set of key/value pairs that you can attach to a task object. It can be useful for storing additional information about the task in a structured format. Max 10KB.

    ***
  </ParamField>

  <ParamField path="unique_id" type="string">
    A arbitrary ID that you can assign to a task and then query for later. This ID must be unique across all projects under your account, otherwise the task submission will be rejected. See [Avoiding Duplicate Tasks](/docs/api-reference/tasks)[ ](/docs/api-reference/tasks)for more details.

    ***
  </ParamField>

  <ParamField path="priority" type="integer">
    A value of 10, 20, or 30 that defines the priority of a task within a project. The higher the number, the higher the priority.

    ***
  </ParamField>

  <ParamField path="clear_unique_id_on_error" type="boolean">
    If set to be true, if a task errors out after being submitted, the unique id on the task will be unset. This param allows workflows where you can re-submit the same unique id to recover from errors automatically

    ***
  </ParamField>

  <ParamField path="tags" type="array of strings">
    Arbitrary labels that you can assign to a task. At most 5 tags are allowed per task. You can query tasks with specific tags through the task retrieval API.

    ***
  </ParamField>
</ParamField>

```python theme={null}
import requests

# Replace with your actual API key
API_KEY = "your_api_key_here"

# Define the URL for the API endpoint
url = "https://api.scale.com/v1/task/multistage"

# Define the payload for the multi-stage task
payload = {
    "project": "your_project_name_here"
    "instruction": "Annotate the *vehicles* and *pedestrians* in the scene.",
    "callback_url": "https://example.com/callback",
    "attachments": ["https://static.scale.com/uploads/pandaset-demo/scene.sfs"],
    "scene_format": "sensor_fusion",
    "priority": None
}

# Set up the headers for the request
headers = {
    "accept": "application/json",       # Specify that we want the response in JSON format
    "content-type": "application/json"  # Specify the content type of the request
}

# Adding authentication to the POST request
# The auth parameter requires a tuple with the API key and an empty string
response = requests.post(url, json=payload, headers=headers, auth=(API_KEY, ''))

# Print the response text to see the result
print(response.text)
```

```jsx theme={null}
{
  "callback_url": "http://www.example.com/callback",
  "created_at": "2024-01-16T21:03:33.166Z",
  "instruction": "Annotate the *vehicles* and *pedestrians* in the scene.",
  "is_test": false,
  "params": {},
  "status": "pending",
  "task_id": "5a99e20de50d4979ce6d291e",
  "type": "multistage"
}

```