0.3.1

aerograph-langchain

LangChain callback adapter for AeroGraph.

Automatically records LangChain chain, LLM, tool, and retriever events as AeroGraph trace events.

Installation

When published, you can install the adapter via pip:

pip install aerograph-langchain

For local testing or development, install the packages in editable mode from the repository root:

# Install the core SDK first
pip install -e python/aerograph-sdk

# Install the LangChain adapter
pip install -e python/aerograph-langchain

Usage

Integrating AeroGraphCallbackHandler into your existing LangChain codebase is simple. Setup a FlightRecorder, initialize the handler, and pass it to your chain or model invocations.

Basic Example

import asyncio
from langchain_core.messages import HumanMessage
from langchain_openai import ChatOpenAI
from aerograph_sdk.recorder import FlightRecorder
from aerograph_langchain.handler import AeroGraphCallbackHandler

async def main():
    # 1. Initialize the FlightRecorder pointing to your collector
    recorder = FlightRecorder(
        endpoint="http://localhost:4317",
        project_id="travel-app", # Optional: Routes traces to a specific project (creates it if new)
        actor={"id": "my-agent", "name": "TravelPlanner"}
    )

    # 2. Initialize the AeroGraph callback handler
    handler = AeroGraphCallbackHandler(recorder)

    # 3. Create your LangChain chat model
    model = ChatOpenAI(model="gpt-4o")

    # 4. Invoke the model and pass the handler in callbacks
    response = await model.ainvoke(
        [HumanMessage(content="What are 3 fun things to do in San Francisco?")],
        config={"callbacks": [handler]}
    )
    print(response.content)

if __name__ == "__main__":
    asyncio.run(main())

Advanced Usage with Chains and RAG

You can attach the callback handler at the chain execution level. LangChain automatically propagates the callbacks down to all sub-chains, LLMs, retrievers, and tool invocations.

# Pass the handler to the chain invoke call
result = rag_chain.invoke(
    "How do I configure the server?",
    config={"callbacks": [handler]}
)

Features and Event Mapping

The callback adapter automatically intercepts LangChain execution signals and translates them to canonical AeroGraph TraceEvent types:

• LLM/Chat Starts (on_llm_start, on_chat_model_start) $\rightarrow$ PromptEvent (captures prompt text, model.name, model.provider)
• LLM Ends (on_llm_end) $\rightarrow$ ResponseEvent (captures completion text, streaming telemetry, usage token counts, and duration_ms)
• Tool Starts (on_tool_start) $\rightarrow$ ToolCallEvent
• Tool Ends (on_tool_end) $\rightarrow$ ToolResultEvent (captures output and duration_ms)
• Retriever Runs (on_retriever_start, on_retriever_end) $\rightarrow$ RetrieverEvent (captures source documents, queries, and metadata)
• Errors (on_llm_error, on_tool_error, on_chain_error) $\rightarrow$ ErrorEvent
• LangGraph Node Boundaries (on_chain_start, on_chain_end with langgraph_node metadata) $\rightarrow$ NoteEvent (automatically captures state_before inputs, state_update outputs, step, triggers, path, and checkpoint_ns)
• Custom Events (on_custom_event) $\rightarrow$ StateSnapshotEvent and CheckpointEvent for LangGraph nodes

License

Apache-2.0