tencentcloud-agentobs-sdk-langchain

中文文档

Observability SDK for LangChain / LangGraph: automatically intercepts LangChain callback and LangGraph node lifecycle events, converts them into OTel spans conforming to the Tencent Cloud CLS GenAI Trace specification, and uploads directly to Tencent Cloud CLS.

• Zero intrusion: one setup() call (or LangChainInstrumentor().instrument()) completes instrumentation — no changes to business code
• Faithful trace tree: each graph.invoke() produces a complete trace with an entry → agent → step → chat / tool hierarchy that mirrors the framework's real call structure
• Concurrency safe: parent-child relationships are derived from the framework's parent_run_id — parallel tool calls and nested sub-agents just work
• Compliance ready: three content capture modes (full / truncate / off) for strict data-residency requirements
• Full metrics: token usage, finish_reason, tool error classification, ReAct round tracking

Installation

pip install tencentcloud-agentobs-sdk-langchain

Runtime dependencies are installed automatically. The key ones:

• langchain-core > 0.1.0 — the target framework being instrumented
• tencentcloud-cls-sdk-python >= 1.0.8 — CLS upload client

For LangGraph agents you additionally need langgraph, and for LLM calls a provider integration such as langchain-openai.

Requires Python >= 3.9.

Quick Start

A single setup() handles all initialization:

import os
from tencentcloud_agentobs_sdk_langchain import setup, CLSConfig

# 1. Configure your LLM provider (managed by LangChain, not this SDK)
os.environ["OPENAI_API_KEY"] = "sk-xxxx"

# 2. Enable CLS observability (must be called before running any agent)
# Option A: all from environment variables
setup()

# Option B: explicit CLSConfig (unset fields fall back to env vars)
setup(CLSConfig(
    endpoint="ap-guangzhou.cls.tencentcs.com",
    topic_id="xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
    secret_id="your_secret_id",
    secret_key="your_secret_key",
))

# 3. Use LangChain / LangGraph as usual
from langchain_core.tools import tool
from langchain_openai import ChatOpenAI
from langgraph.prebuilt import create_react_agent

@tool
def get_weather(city: str) -> str:
    """Look up the weather for a city."""
    return {"Beijing": "Sunny, 26C"}.get(city, "Sunny, 25C")

agent = create_react_agent(ChatOpenAI(model="gpt-4o-mini"), tools=[get_weather])
result = agent.invoke({"messages": [("user", "What's the weather in Beijing?")]})
print(result["messages"][-1].content)

setup() creates a TracerProvider, attaches the CLSCloudExporter, registers instrumentation, and returns the provider (useful if you need to attach additional processors).

Manual wiring (advanced)

from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import BatchSpanProcessor
from tencentcloud_agentobs_sdk_langchain import LangChainInstrumentor
from tencentcloud_agentobs_sdk_langchain.cls_cloud_exporter import CLSCloudExporter

provider = TracerProvider()
provider.add_span_processor(BatchSpanProcessor(CLSCloudExporter()))
LangChainInstrumentor().instrument(tracer_provider=provider)

Configuration

All fields resolve with the priority: explicit CLSConfig value > environment variable > built-in default.

SDK logs are written to cls_sdk.log (configurable via CLS_SDK_LOG_FILE / CLS_SDK_LOG_LEVEL), using a rotating file handler.

Span hierarchy

For a LangGraph create_react_agent, one invoke() produces:

entry  enter_application
└ agent  invoke_agent
  ├ step  react round_1
  │  ├ chain  call_model
  │  ├ chain  RunnableSequence
  │  │  ├ chain  Prompt
  │  │  └ chat   <model>
  │  ├ chain  should_continue
  │  └ tool   execute_tool <name>        (one per parallel tool call)
  └ step  react round_2
     └ ...

The tree faithfully reflects LangChain's real callback nesting: chat is nested under its RunnableSequence, tool executions attach directly under the current step, and each entry into the LangGraph agent node opens a new ReAct step.

Examples

See example.py for a minimal end-to-end quick start (LangGraph ReAct agent + setup()).

License

Apache-2.0. See LICENSE.