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Documentation Index

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smolagents is Hugging Face’s minimalist Python agent framework — a few hundred lines of code-first agents with tools, memory, and multi-step reasoning. Arize AX captures every smolagent run — agent steps, tool invocations, and the underlying LLM calls — via the openinference-instrumentation-smolagents package.
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smolagents Tracing Tutorial (Google Colab)

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Prerequisites

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Launch Arize AX

  1. Sign in to your Arize AX account.
  2. From Space Settings, copy your Space ID and API Key. You will set them as ARIZE_SPACE_ID and ARIZE_API_KEY below.

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Install

pip install arize-otel \
  openinference-instrumentation-smolagents \
  smolagents openai

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Configure credentials

export ARIZE_SPACE_ID="<your-space-id>"
export ARIZE_API_KEY="<your-api-key>"
export ARIZE_PROJECT_NAME="smolagents-tracing-example"
export OPENAI_API_KEY="<your-openai-api-key>"

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Setup tracing

# instrumentation.py
import os

from arize.otel import register
from openinference.instrumentation.smolagents import SmolagentsInstrumentor

tracer_provider = register(
    space_id=os.environ["ARIZE_SPACE_ID"],
    api_key=os.environ["ARIZE_API_KEY"],
    project_name=os.environ["ARIZE_PROJECT_NAME"],
)

SmolagentsInstrumentor().instrument(tracer_provider=tracer_provider)
print("Arize AX tracing initialized for smolagents.")

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Run smolagents

# example.py

# Importing instrumentation first ensures tracing is set up
# before `smolagents` is imported.
from instrumentation import tracer_provider

from smolagents import CodeAgent, OpenAIServerModel

# OpenAIServerModel reads OPENAI_API_KEY from the environment.
model = OpenAIServerModel(model_id="gpt-5")

agent = CodeAgent(tools=[], model=model)
result = agent.run("Why is the ocean salty? Answer in two sentences.")

print(result)

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Expected output

Arize AX tracing initialized for smolagents.
The ocean is salty because rivers continuously dissolve mineral salts from rocks and soil and carry them to the sea, where they accumulate over millions of years. Water leaves the ocean through evaporation but the salts remain, steadily concentrating until reaching today's roughly 3.5% salinity.

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Verify in Arize AX

  1. Open your Arize AX space and select project smolagents-tracing-example.
  2. You should see a new trace within ~30 seconds containing a CodeAgent.run parent span wrapping per-step Step N spans, an OpenAIModel.generate LLM child span (with the prompt, response, and token usage), and a FinalAnswerTool tool span.
  3. If no traces appear, see Troubleshooting.

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Troubleshooting

  • No traces in Arize AX. Confirm ARIZE_SPACE_ID and ARIZE_API_KEY are set in the same shell that runs example.py. Enable OpenTelemetry debug logs with export OTEL_LOG_LEVEL=debug and re-run.
  • smolagents spans missing but other spans present. SmolagentsInstrumentor().instrument(...) must run before any from smolagents import .... Make sure instrumentation.py is the first import in your entry point.
  • 401 from OpenAI. Verify OPENAI_API_KEY is set and has access to gpt-5. Swap for a model your key can call.
  • Other LLM providers. smolagents supports many backends — HfApiModel() (Hugging Face Inference), LiteLLMModel(...), TransformersModel(...), etc. The same SmolagentsInstrumentor covers them.

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Resources

smolagents Documentation

OpenInference smolagents Instrumentor

smolagents GitHub