feat: add LangGraph agent and tool adapter for CrewAI integration

- Introduced LangGraphAgentAdapter to facilitate interaction with LangGraph agents.
- Implemented methods for task execution, context handling, and tool configuration.
- Created LangGraphToolAdapter to convert CrewAI tools into LangGraph-compatible format.
- Enhanced error handling and logging for task execution and streaming processes.
This commit is contained in:
lorenzejay
2025-04-09 16:28:21 -07:00
parent c9508821fa
commit 2cc5b0cb11
2 changed files with 303 additions and 0 deletions

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from typing import Any, AsyncIterable, Dict, List, Optional
from langchain_core.messages import ToolMessage
from langgraph.checkpoint.memory import MemorySaver
from langgraph.prebuilt import create_react_agent
from pydantic import Field, PrivateAttr
from crewai.agents.agent_adapters.base_agent_adapter import BaseAgentAdapter
from crewai.agents.agent_adapters.langgraph.langgraph_tool_adapter import (
LangGraphToolAdapter,
)
from crewai.agents.agent_builder.base_agent import BaseAgent
from crewai.tools.agent_tools.agent_tools import AgentTools
from crewai.tools.base_tool import BaseTool
from crewai.utilities import Logger
from crewai.utilities.converter import Converter
from crewai.utilities.events import crewai_event_bus
from crewai.utilities.events.agent_events import (
AgentExecutionErrorEvent,
AgentExecutionStartedEvent,
)
class LangGraphAgentAdapter(BaseAgentAdapter):
"""Adapter for LangGraph agents to work with CrewAI."""
model_config = {"arbitrary_types_allowed": True}
_logger: Logger = PrivateAttr(default_factory=lambda: Logger())
_tool_adapter: LangGraphToolAdapter = PrivateAttr()
_graph: Any = PrivateAttr(default=None)
_memory: Any = PrivateAttr(default=None)
_max_iterations: int = PrivateAttr(default=10)
function_calling_llm: Any = Field(default=None)
step_callback: Any = Field(default=None)
# Config parameters for LangGraph
model: str = Field(default="gpt-4o")
verbose: bool = Field(default=False)
def __init__(
self,
role: str,
goal: str,
backstory: str,
tools: Optional[List[BaseTool]] = None,
llm: Any = None,
max_iterations: int = 10,
**kwargs,
):
"""Initialize the LangGraph agent adapter."""
super().__init__(
role=role,
goal=goal,
backstory=backstory,
tools=tools,
llm=llm or self.model,
**kwargs,
)
self._tool_adapter = LangGraphToolAdapter(tools=tools)
self._max_iterations = max_iterations
self._setup_graph()
def _setup_graph(self) -> None:
"""Set up the LangGraph workflow graph."""
try:
# Initialize memory for the agent
self._memory = MemorySaver()
# Convert CrewAI tools to LangGraph/LangChain compatible tools
converted_tools = self._tool_adapter.converted_tools
# Create the agent graph with ReAct pattern
self._graph = create_react_agent(
model=self.llm, # Pass as model parameter
tools=converted_tools,
checkpointer=self._memory,
)
except ImportError as e:
self._logger.log(
"error", f"Failed to import LangGraph dependencies: {str(e)}"
)
raise
except Exception as e:
self._logger.log("error", f"Error setting up LangGraph agent: {str(e)}")
raise
def _build_system_prompt(self) -> str:
"""Build a system prompt for the LangGraph agent."""
return f"""You are {self.role}.
Your goal is: {self.goal}
Your backstory: {self.backstory}
When working on tasks, think step-by-step and use the available tools when necessary.
"""
def execute_task(
self,
task: Any,
context: Optional[str] = None,
tools: Optional[List[BaseTool]] = None,
) -> str:
"""Execute a task using the LangGraph workflow."""
self.create_agent_executor(tools)
try:
task_prompt = task.prompt() if hasattr(task, "prompt") else str(task)
if context:
task_prompt = self.i18n.slice("task_with_context").format(
task=task_prompt, context=context
)
crewai_event_bus.emit(
self,
event=AgentExecutionStartedEvent(
agent=self,
tools=self.tools,
task_prompt=task_prompt,
task=task,
),
)
# Set up a session ID for this task
session_id = f"task_{id(task)}"
# Configure the invocation
config = {"configurable": {"thread_id": session_id}}
# Invoke the agent graph with the task prompt
result = self._graph.invoke({"messages": [("user", task_prompt)]}, config)
print("result", result)
# Get the final response
messages = result.get("messages", [])
last_message = messages[-1] if messages else None
final_answer = ""
print("final_answer", final_answer)
if isinstance(last_message, dict):
final_answer = last_message.get("content", "")
elif hasattr(last_message, "content"):
final_answer = getattr(last_message, "content", "")
return (
final_answer
or "Task execution completed but no clear answer was provided."
)
except Exception as e:
self._logger.log("error", f"Error executing LangGraph task: {str(e)}")
crewai_event_bus.emit(
self,
event=AgentExecutionErrorEvent(
agent=self,
task=task,
error=str(e),
),
)
raise
async def stream_task(
self,
task: Any,
context: Optional[str] = None,
tools: Optional[List[BaseTool]] = None,
) -> AsyncIterable[Dict[str, Any]]:
"""Stream the execution of a task."""
self.create_agent_executor(tools)
try:
task_prompt = task.prompt() if hasattr(task, "prompt") else str(task)
if context:
task_prompt = self.i18n.slice("task_with_context").format(
task=task_prompt, context=context
)
# Set up a session ID for this task
session_id = f"task_{id(task)}"
# Configure the invocation
config = {"configurable": {"thread_id": session_id}}
# Stream the execution
inputs = {"messages": [("user", task_prompt)]}
for item in self._graph.stream(inputs, config, stream_mode="values"):
message = item.get("messages", [])[-1] if "messages" in item else None
if (
message is not None
and hasattr(message, "tool_calls")
and getattr(message, "tool_calls", None)
):
tool_calls = getattr(message, "tool_calls", [])
if tool_calls and len(tool_calls) > 0:
yield {
"is_task_complete": False,
"require_user_input": False,
"content": f"Using tool: {tool_calls[0].name}",
}
elif isinstance(message, ToolMessage):
content = getattr(message, "content", "Tool execution complete")
yield {
"is_task_complete": False,
"require_user_input": False,
"content": f"Tool result: {content[:50]}...",
}
elif message is not None:
# Final response or intermediary thinking
content = getattr(message, "content", str(message))
yield {
"is_task_complete": True,
"require_user_input": False,
"content": content,
}
except Exception as e:
self._logger.log("error", f"Error streaming LangGraph task: {str(e)}")
yield {
"is_task_complete": True,
"require_user_input": False,
"content": f"Error: {str(e)}",
}
def create_agent_executor(self, tools: Optional[List[BaseTool]] = None) -> None:
"""Configure the LangGraph agent for execution."""
if tools:
self.configure_tools(tools)
# No need for a separate executor in LangGraph
def configure_tools(self, tools: Optional[List[BaseTool]] = None) -> None:
"""Configure tools for the LangGraph agent."""
if tools:
all_tools = list(self.tools or []) + list(tools or [])
self._tool_adapter.configure_tools(all_tools)
# We need to recreate the graph with the new tools
self._setup_graph()
def get_delegation_tools(self, agents: List[BaseAgent]) -> List[BaseTool]:
"""Implement delegation tools support for LangGraph."""
agent_tools = AgentTools(agents=agents)
return agent_tools.tools()
def get_output_converter(
self, llm: Any, text: str, model: Any, instructions: str
) -> Any:
"""Convert output format if needed."""
return Converter(llm=llm, text=text, model=model, instructions=instructions)
def _parse_tools(self, tools: List[BaseTool]) -> List[BaseTool]:
"""Parse and validate tools."""
return tools
def configure_structured_output(self, task) -> None:
"""Configure the structured output for LangGraph."""
# This will be implemented in a separate improvement
pass

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class LangGraphToolAdapter:
"""Adapts CrewAI tools to LangGraph-compatible format"""
def __init__(self, tools: Optional[List[BaseTool]] = None):
self.tools = tools or []
self.converted_tools = []
def configure_tools(self, tools: List[BaseTool]) -> None:
"""Convert CrewAI tools to LangGraph tools"""
self.tools = tools
self.converted_tools = self._convert_tools(tools)
def _convert_tools(self, tools: List[BaseTool]) -> List[Any]:
"""
Convert CrewAI tools to LangGraph-compatible tools
LangGraph expects tools in langchain_core.tools format
"""
from langchain_core.tools import Tool
converted_tools = []
for tool in tools:
# Create a wrapper function that matches LangGraph's expected format
def tool_wrapper(*args, tool=tool, **kwargs):
# Extract inputs based on the tool's schema
if len(args) > 0 and isinstance(args[0], str):
return tool.run(args[0])
elif "input" in kwargs:
return tool.run(kwargs["input"])
else:
return tool.run(**kwargs)
# Create a LangChain Tool
converted_tool = Tool(
name=tool.name, description=tool.description, func=tool_wrapper
)
converted_tools.append(converted_tool)
return converted_tools