# LabelStudioCallbackHandler

> **Class** in `langchain_community`

📖 [View in docs](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler)

Label Studio callback handler.
Provides the ability to send predictions to Label Studio
for human evaluation, feedback and annotation.

## Signature

```python
LabelStudioCallbackHandler(
    self,
    api_key: Optional[str] = None,
    url: Optional[str] = None,
    project_id: Optional[int] = None,
    project_name: str = DEFAULT_PROJECT_NAME,
    project_config: Optional[str] = None,
    mode: Union[str, LabelStudioMode] = LabelStudioMode.PROMPT,
)
```

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| `api_key` | `Optional[str]` | No | Label Studio API key (default: `None`) |
| `url` | `Optional[str]` | No | Label Studio URL (default: `None`) |
| `project_id` | `Optional[int]` | No | Label Studio project ID (default: `None`) |
| `project_name` | `str` | No | Label Studio project name (default: `DEFAULT_PROJECT_NAME`) |
| `project_config` | `Optional[str]` | No | Label Studio project config (XML) (default: `None`) |
| `mode` | `Union[str, LabelStudioMode]` | No | Label Studio mode ("prompt" or "chat") (default: `LabelStudioMode.PROMPT`) |

## Extends

- `BaseCallbackHandler`

## Constructors

```python
__init__(
    self,
    api_key: Optional[str] = None,
    url: Optional[str] = None,
    project_id: Optional[int] = None,
    project_name: str = DEFAULT_PROJECT_NAME,
    project_config: Optional[str] = None,
    mode: Union[str, LabelStudioMode] = LabelStudioMode.PROMPT,
)
```

| Name | Type |
|------|------|
| `api_key` | `Optional[str]` |
| `url` | `Optional[str]` |
| `project_id` | `Optional[int]` |
| `project_name` | `str` |
| `project_config` | `Optional[str]` |
| `mode` | `Union[str, LabelStudioMode]` |


## Properties

- `DEFAULT_PROJECT_NAME`
- `api_key`
- `url`
- `payload`
- `ls_client`
- `project_name`
- `project_config`
- `mode`
- `project_id`
- `ls_project`
- `parsed_label_config`
- `from_name`
- `to_name`
- `value`
- `input_type`

## Methods

- [`add_prompts_generations()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/add_prompts_generations)
- [`on_llm_start()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_llm_start)
- [`on_chat_model_start()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_chat_model_start)
- [`on_llm_new_token()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_llm_new_token)
- [`on_llm_end()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_llm_end)
- [`on_llm_error()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_llm_error)
- [`on_chain_start()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_chain_start)
- [`on_chain_end()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_chain_end)
- [`on_chain_error()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_chain_error)
- [`on_tool_start()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_tool_start)
- [`on_agent_action()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_agent_action)
- [`on_tool_end()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_tool_end)
- [`on_tool_error()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_tool_error)
- [`on_text()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_text)
- [`on_agent_finish()`](https://reference.langchain.com/python/langchain-community/callbacks/labelstudio_callback/LabelStudioCallbackHandler/on_agent_finish)

---

[View source on GitHub](https://github.com/langchain-ai/langchain-community/blob/4b280287bd55b99b44db2dd849f02d66c89534d5/libs/community/langchain_community/callbacks/labelstudio_callback.py#L78)