Add support for custom LLM implementations

Co-Authored-By: Joe Moura <joao@crewai.com>
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Devin AI
2025-03-04 17:09:17 +00:00
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# Custom LLM Implementations
CrewAI now supports custom LLM implementations through the `BaseLLM` abstract base class. This allows you to create your own LLM implementations that don't rely on litellm's authentication mechanism.
## Using Custom LLM Implementations
To create a custom LLM implementation, you need to:
1. Inherit from the `BaseLLM` abstract base class
2. Implement the required methods:
- `call()`: The main method to call the LLM with messages
- `supports_function_calling()`: Whether the LLM supports function calling
- `supports_stop_words()`: Whether the LLM supports stop words
- `get_context_window_size()`: The context window size of the LLM
## Example: Basic Custom LLM
```python
from crewai import BaseLLM
from typing import Any, Dict, List, Optional, Union
class CustomLLM(BaseLLM):
def __init__(self, api_key: str, endpoint: str):
super().__init__() # Initialize the base class to set default attributes
self.api_key = api_key
self.endpoint = endpoint
self.stop = [] # You can customize stop words if needed
def call(
self,
messages: Union[str, List[Dict[str, str]]],
tools: Optional[List[dict]] = None,
callbacks: Optional[List[Any]] = None,
available_functions: Optional[Dict[str, Any]] = None,
) -> Union[str, Any]:
# Implement your own logic to call the LLM
# For example, using requests:
import requests
headers = {
"Authorization": f"Bearer {self.api_key}",
"Content-Type": "application/json"
}
# Convert string message to proper format if needed
if isinstance(messages, str):
messages = [{"role": "user", "content": messages}]
data = {
"messages": messages,
"tools": tools
}
response = requests.post(self.endpoint, headers=headers, json=data)
return response.json()["choices"][0]["message"]["content"]
def supports_function_calling(self) -> bool:
# Return True if your LLM supports function calling
return True
def supports_stop_words(self) -> bool:
# Return True if your LLM supports stop words
return True
def get_context_window_size(self) -> int:
# Return the context window size of your LLM
return 8192
```
## Example: JWT-based Authentication
For services that use JWT-based authentication instead of API keys, you can implement a custom LLM like this:
```python
from crewai import BaseLLM, Agent, Task
from typing import Any, Dict, List, Optional, Union
class JWTAuthLLM(BaseLLM):
def __init__(self, jwt_token: str, endpoint: str):
super().__init__() # Initialize the base class to set default attributes
self.jwt_token = jwt_token
self.endpoint = endpoint
self.stop = [] # You can customize stop words if needed
def call(
self,
messages: Union[str, List[Dict[str, str]]],
tools: Optional[List[dict]] = None,
callbacks: Optional[List[Any]] = None,
available_functions: Optional[Dict[str, Any]] = None,
) -> Union[str, Any]:
# Implement your own logic to call the LLM with JWT authentication
import requests
headers = {
"Authorization": f"Bearer {self.jwt_token}",
"Content-Type": "application/json"
}
# Convert string message to proper format if needed
if isinstance(messages, str):
messages = [{"role": "user", "content": messages}]
data = {
"messages": messages,
"tools": tools
}
response = requests.post(self.endpoint, headers=headers, json=data)
return response.json()["choices"][0]["message"]["content"]
def supports_function_calling(self) -> bool:
# Return True if your LLM supports function calling
return True
def supports_stop_words(self) -> bool:
# Return True if your LLM supports stop words
return True
def get_context_window_size(self) -> int:
# Return the context window size of your LLM
return 8192
```
## Using Your Custom LLM with CrewAI
Once you've implemented your custom LLM, you can use it with CrewAI agents and crews:
```python
# Create your custom LLM instance
jwt_llm = JWTAuthLLM(
jwt_token="your.jwt.token",
endpoint="https://your-llm-endpoint.com/v1/chat/completions"
)
# Use it with an agent
agent = Agent(
role="Research Assistant",
goal="Find information on a topic",
backstory="You are a research assistant tasked with finding information.",
llm=jwt_llm,
)
# Create a task for the agent
task = Task(
description="Research the benefits of exercise",
agent=agent,
expected_output="A summary of the benefits of exercise",
)
# Execute the task
result = agent.execute_task(task)
print(result)
```
## Advanced Usage: Function Calling
If your LLM supports function calling, you can implement the function calling logic in your custom LLM:
```python
def call(
self,
messages: Union[str, List[Dict[str, str]]],
tools: Optional[List[dict]] = None,
callbacks: Optional[List[Any]] = None,
available_functions: Optional[Dict[str, Any]] = None,
) -> Union[str, Any]:
import requests
headers = {
"Authorization": f"Bearer {self.jwt_token}",
"Content-Type": "application/json"
}
# Convert string message to proper format if needed
if isinstance(messages, str):
messages = [{"role": "user", "content": messages}]
data = {
"messages": messages,
"tools": tools
}
response = requests.post(self.endpoint, headers=headers, json=data)
response_data = response.json()
# Check if the LLM wants to call a function
if response_data["choices"][0]["message"].get("tool_calls"):
tool_calls = response_data["choices"][0]["message"]["tool_calls"]
# Process each tool call
for tool_call in tool_calls:
function_name = tool_call["function"]["name"]
function_args = json.loads(tool_call["function"]["arguments"])
if available_functions and function_name in available_functions:
function_to_call = available_functions[function_name]
function_response = function_to_call(**function_args)
# Add the function response to the messages
messages.append({
"role": "tool",
"tool_call_id": tool_call["id"],
"name": function_name,
"content": str(function_response)
})
# Call the LLM again with the updated messages
return self.call(messages, tools, callbacks, available_functions)
# Return the text response if no function call
return response_data["choices"][0]["message"]["content"]
```
## Implementing Your Own Authentication Mechanism
The `BaseLLM` class allows you to implement any authentication mechanism you need, not just JWT or API keys. You can use:
- OAuth tokens
- Client certificates
- Custom headers
- Session-based authentication
- Any other authentication method required by your LLM provider
Simply implement the appropriate authentication logic in your custom LLM class.