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

# Step

<a id="literalai.observability.step" />

<a id="literalai.observability.step.Step" />

## Step

```python theme={null}
class Step(Utils)
```

## Using the decorator on a function

If you want to create a step from a function, you should use the `@literalai_client.step` decorator.

The step is automatically ended and sent to the platform when the function returns.

Another advantage of using the decorator is that you get several variables automatically set for you:

* **name**: The name of the step. This is automatically set to the function name.
* **input**: The input of the step. This is automatically set to the arguments of the function.
* **output**: The output of the step. This is automatically set to the return value of the function.

Here is how to use the decorator:

<CodeGroup>
  ```python theme={null}
  @literalai_client.step
  def my_step():
      # do something
  ```
</CodeGroup>

If you want to override the default step parameters, you can pass them to the decorator:

<CodeGroup>
  ```python theme={null}
  @literalai_client.step(id="my-step-id", name="My step", type="run")
  def my_step():
      # do something
  ```
</CodeGroup>

You can access the step object with the `get_current_step` method:

<CodeGroup>
  ```python theme={null}
  @literalai_client.step
  def my_step():
      step = literalai_client.get_current_step()
      # do something
  ```
</CodeGroup>

## Using the `with` statement

If you want to create a step from a block of code, you should use the `with` statement.

The step is automatically ended and sent to the platform when the code exits the `with` block.

<CodeGroup>
  ```python theme={null}
  with literalai_client.step() as step:
      # do something
  ```
</CodeGroup>

If you want to override the default step parameters, you can pass them to the `step` method:

<CodeGroup>
  ```python theme={null}
  with literalai_client.step(id="my-step-id", name="My step", type="run") as step:
      # do something
  ```
</CodeGroup>

## Using the `start_step` method

This method should be used as a last resort because it doesn't automatically end the step.

You must call the `end` method on the step object to end the step and send it to the platform.

<CodeGroup>
  ```python theme={null}
  step = literalai_client.start_step()
  # do something
  step.end()
  ```
</CodeGroup>

You can either pass the step parameters to the `start_step` method, or set them directly on the step object:

<CodeGroup>
  ```python theme={null}
  step = literalai_client.start_step(id="my-step-id", name="My step", type="run")
  step.input = "test input"
  # do something
  step.output = "Hello world"
  step.end()
  ```
</CodeGroup>

## Step parameters

<ParamField path="thread_id" type="uuid">
  The id of the thread
</ParamField>

<ParamField path="id" type="uuid">
  The id of the step. If not provided, a random uuid will be generated. Use
  custom ones to match your own system. Step ids must be unique across your
  project.
</ParamField>

<ParamField path="name" type="string" default="">
  The name of the step (automatically set to the function name if using the
  decorator)
</ParamField>

<ParamField path="type" type="StepType" default="undefined">
  The type of the step. A Step can be one of the following types:

  * `run`: A generic step
  * `tool`: A step that runs a tool
  * `llm`: A step that runs a language model
  * `embedding`: A step that runs an embedding model
  * `retrieval`: A step that retrieves documents
  * `rerank`: A step that reranks documents
  * `undefined`: An undefined step
</ParamField>

<ParamField path="metadata" type="dict" default="{}">
  Metadata associated with the step. This enables you to add custom fields to
  your steps.
</ParamField>

<ParamField path="parent_id" type="uuid">
  The id of the parent step. This enables you to create nested steps.
</ParamField>

<ParamField path="start_time" type="string">
  The start time of the step.
</ParamField>

<ParamField path="end_time" type="string">
  The end time of the step.
</ParamField>

<ParamField path="created_at" type="string">
  The server-side creation time of the step.
</ParamField>

<ParamField path="input" type="dict">
  A dictionary symbolizing an input.
  Prefer using `content` key to store a message.
</ParamField>

<ParamField path="output" type="dict">
  A dictionary symbolizing an output.
  Prefer using `content` key to store a message.
</ParamField>

<ParamField path="tags" type="List[str]" default="[]">
  The tags of the step. This is a complimentary field to the metadata field. It
  enables you to add custom tags to your steps.
</ParamField>

<ParamField path="generation" type="BaseGeneration">
  The generation object associated with the step.
</ParamField>

<ParamField path="attachments" type="List[Attachment]" default="[]">
  The attachments associated with the step.
</ParamField>