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Promote unstable docs for Haystack 2.20 (#10080)
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2025-11-13 18:00:45 +01:00

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---
title: "CohereChatGenerator"
id: coherechatgenerator
slug: "/coherechatgenerator"
description: "CohereChatGenerator enables chat completions using Cohere's large language models (LLMs)."
---
# CohereChatGenerator
CohereChatGenerator enables chat completions using Cohere's large language models (LLMs).
<div className="key-value-table">
| | |
| --- | --- |
| **Most common position in a pipeline** | After a [ChatPromptBuilder](../builders/chatpromptbuilder.mdx) |
| **Mandatory init variables** | `api_key`: The Cohere API key. Can be set with `COHERE_API_KEY` or `CO_API_KEY` env var. |
| **Mandatory run variables** | `messages` A list of [`ChatMessage`](../../concepts/data-classes/chatmessage.mdx) objects |
| **Output variables** | `replies`: A list of [`ChatMessage`](../../concepts/data-classes/chatmessage.mdx) objects <br /> <br />`meta`: A list of dictionaries with the metadata associated with each reply, such as token count, finish reason, and so on |
| **API reference** | [Cohere](/reference/integrations-cohere) |
| **GitHub link** | https://github.com/deepset-ai/haystack-core-integrations/tree/main/integrations/cohere |
</div>
This integration supports Cohere `chat` models such as `command`,`command-r` and `comman-r-plus`. Check out the most recent full list in [Cohere documentation](https://docs.cohere.com/reference/chat).
## Overview
`CohereChatGenerator` needs a Cohere API key to work. You can set this key in:
- The `api_key` init parameter using [Secret API](../../concepts/secret-management.mdx)
- The `COHERE_API_KEY` environment variable (recommended)
Then, the component needs a prompt to operate, but you can pass any text generation parameters valid for the `Co.chat` method directly to this component using the `generation_kwargs` parameter, both at initialization and to `run()` method. For more details on the parameters supported by the Cohere API, refer to the [Cohere documentation](https://docs.cohere.com/reference/chat).
Finally, the component needs a list of `ChatMessage` objects to operate. `ChatMessage` is a data class that contains a message, a role (who generated the message, such as `user`, `assistant`, `system`, `function`), and optional metadata.
### Tool Support
`CohereChatGenerator` supports function calling through the `tools` parameter, which accepts flexible tool configurations:
- **A list of Tool objects**: Pass individual tools as a list
- **A single Toolset**: Pass an entire Toolset directly
- **Mixed Tools and Toolsets**: Combine multiple Toolsets with standalone tools in a single list
This allows you to organize related tools into logical groups while also including standalone tools as needed.
```python
from haystack.tools import Tool, Toolset
from haystack_integrations.components.generators.cohere import CohereChatGenerator
# Create individual tools
weather_tool = Tool(name="weather", description="Get weather info", ...)
news_tool = Tool(name="news", description="Get latest news", ...)
# Group related tools into a toolset
math_toolset = Toolset([add_tool, subtract_tool, multiply_tool])
# Pass mixed tools and toolsets to the generator
generator = CohereChatGenerator(
tools=[math_toolset, weather_tool, news_tool] # Mix of Toolset and Tool objects
)
```
For more details on working with tools, see the [Tool](../../tools/tool.mdx) and [Toolset](../../tools/toolset.mdx) documentation.
### Streaming
This Generator supports [streaming](guides-to-generators/choosing-the-right-generator.mdx#streaming-support) the tokens from the LLM directly in output. To do so, pass a function to the `streaming_callback` init parameter.
## Usage
You need to install `cohere-haystack` package to use the `CohereChatGenerator`:
```shell
pip install cohere-haystack
```
#### On its own
```python
from haystack_integrations.components.generators.cohere import CohereChatGenerator
from haystack.dataclasses import ChatMessage
generator = CohereChatGenerator()
message = ChatMessage.from_user("What's Natural Language Processing? Be brief.")
print(generator.run([message]))
```
With multimodal inputs:
```python
from haystack.dataclasses import ChatMessage, ImageContent
from haystack_integrations.components.generators.cohere import CohereChatGenerator
# Use a multimodal model like Command A Vision
llm = CohereChatGenerator(model="command-a-vision-07-2025")
image = ImageContent.from_file_path("apple.jpg")
user_message = ChatMessage.from_user(content_parts=[
"What does the image show? Max 5 words.",
image
])
response = llm.run([user_message])["replies"][0].text
print(response)
# Red apple on straw.
```
#### In a Pipeline
You can also use `CohereChatGenerator` to use cohere chat models in your pipeline.
```python
from haystack import Pipeline
from haystack.components.builders import ChatPromptBuilder
from haystack.dataclasses import ChatMessage
from haystack_integrations.components.generators.cohere import CohereChatGenerator
from haystack.utils import Secret
pipe = Pipeline()
pipe.add_component("prompt_builder", ChatPromptBuilder())
pipe.add_component("llm", CohereChatGenerator())
pipe.connect("prompt_builder", "llm")
country = "Germany"
system_message = ChatMessage.from_system("You are an assistant giving out valuable information to language learners.")
messages = [system_message, ChatMessage.from_user("What's the official language of {{ country }}?")]
res = pipe.run(data={"prompt_builder": {"template_variables": {"country": country}, "template": messages}})
print(res)
```