TrueFoundry

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Prerequisites

• Python 3.9+
• An Arize AX account (sign up)
• A TRUEFOUNDRY_API_KEY — a Personal Access Token or Virtual Account Token from the Access section of TrueFoundry

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Launch Arize

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-openai 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="truefoundry-tracing-example"
export TRUEFOUNDRY_API_KEY="<your-truefoundry-token>"

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Setup tracing

# instrumentation.py
import os

from arize.otel import register
from openinference.instrumentation.openai import OpenAIInstrumentor

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

OpenAIInstrumentor().instrument(tracer_provider=tracer_provider)
print("Arize AX tracing initialized for TrueFoundry.")

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Run TrueFoundry

# example.py

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

import os

from openai import OpenAI

# Point the OpenAI client at the TrueFoundry AI Gateway endpoint.
client = OpenAI(
    base_url="https://gateway.truefoundry.ai",
    api_key=os.environ["TRUEFOUNDRY_API_KEY"],
)

response = client.chat.completions.create(
    # Models use a `provider-account/model-name` format — the prefix is the
    # provider account configured in your TrueFoundry workspace.
    model="openai/gpt-4.1-mini",
    messages=[
        {
            "role": "user",
            "content": "Why is the ocean salty? Answer in two sentences.",
        },
    ],
)

print(response.choices[0].message.content)

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Expected output

Arize AX tracing initialized for TrueFoundry.
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

1. Open your Arize AX space and select project truefoundry-tracing-example.
2. You should see a new trace within ~30 seconds containing a ChatCompletion LLM span with the prompt, response, and token usage attached. The model name on the span will be the resolved model the gateway routed to (e.g. gpt-4.1-mini-2025-04-14).
3. If no traces appear, see Troubleshooting.

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Troubleshooting

• No traces in Arize. 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.
• TrueFoundry spans missing but other spans present. OpenAIInstrumentor().instrument(...) must run before any import openai. Make sure instrumentation.py is the first import in your entry point.
• 401 from TrueFoundry. Use a TrueFoundry token (Personal Access Token or Virtual Account Token from the Access section), not your OpenAI key. Pass it as the api_key — the OpenAI client sends it as a Bearer token.
• Model not found. Use the provider-account/model-name identifier from your gateway (e.g. openai/gpt-4.1-mini). The prefix is the provider account name configured in your TrueFoundry workspace, not a fixed value — copy the exact model ID from the Playground Code Snippets tab.

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