Anthropic

Documentation Index

Fetch the complete documentation index at: https://arize-ax.mintlify.dev/docs/llms.txt

Use this file to discover all available pages before exploring further.

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Prerequisites

• Python 3.10+
• An Arize AX account (sign up)
• An ANTHROPIC_API_KEY from the Anthropic Console

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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-anthropic anthropic

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Configure credentials

export ARIZE_SPACE_ID="<your-space-id>"
export ARIZE_API_KEY="<your-api-key>"
export ARIZE_PROJECT_NAME="anthropic-tracing-example"
export ANTHROPIC_API_KEY="<your-anthropic-api-key>"

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Setup tracing

# instrumentation.py
import os

from arize.otel import register
from openinference.instrumentation.anthropic import AnthropicInstrumentor

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

AnthropicInstrumentor().instrument(tracer_provider=tracer_provider)
print("Arize AX tracing initialized for Anthropic.")

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Run Anthropic

# example.py

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

import anthropic

# The client reads ANTHROPIC_API_KEY from the environment.
client = anthropic.Anthropic()

message = client.messages.create(
    model="claude-sonnet-4-5",
    max_tokens=256,
    messages=[
        {
            "role": "user",
            "content": "Why is the ocean salty? Answer in two sentences.",
        },
    ],
)

print(message.content[0].text)

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Expected output

Arize AX tracing initialized for Anthropic.
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 anthropic-tracing-example.
2. You should see a new trace within ~30 seconds containing a messages.create LLM span with the prompt, response, and token usage attached.
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.
• Anthropic spans missing but other spans present. AnthropicInstrumentor().instrument(...) must run before any import anthropic in the application. Make sure instrumentation.py is the first import in your entry point.
• 401 from Anthropic. Verify ANTHROPIC_API_KEY is set and has access to the model in the example. Swap claude-sonnet-4-5 for a model your key can call.

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Resources