Eval-Driven Development

• Key points are in the visual diagram above.

Understanding Eval-Driven Development helps you build reliable, scalable agent applications instead of fragile demos.

Think of Eval-Driven Development as a specialized capability in your Eval Engineering & Observability engineering toolkit.

Scenario

A production team in Eval Engineering & Observability uses Eval-Driven Development to handle a real user request — reducing manual work and improving response quality with proper validation and logging.

Solution

In Eval Engineering & Observability, apply Eval-Driven Development to this scenario: A production team in Eval Engineering & Observability uses Eval-Driven Development to handle a real user request — reducing manual work and improving response quality with proper validation and logging. Identify the inputs, run the technique, validate the output, and note one thing you would monitor in production.

Do this before moving to the next module — reading alone is not enough.

Open the Code Walkthrough below and run it locally. Change one parameter related to Eval-Driven Development (e.g. model, temperature, top_k, or tool name), observe the difference in output, and write 2–3 sentences explaining what changed.

Highlighted lines show where Eval-Driven Development happens in the code.

1# Eval-Driven Development — minimal example2from openai import OpenAI3
4client = OpenAI()  # create API client5
6# Ask the model to explain this topic7response = client.chat.completions.create(  # core API call for Eval-Driven Development8    model="gpt-4o-mini",9    messages=[10        {"role": "system", "content": "You explain eval-driven development clearly."},11        {"role": "user", "content": f"What is eval-driven development?"},12    ],13    temperature=0,14)15print(response.choices[0].message.content)  # show output for debugging

• Skipping evaluation for Eval-Driven Development before production
• No logging or tracing around eval driven development steps
• Ignoring cost and latency implications

Quick recap — the most important points from this module.