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Cover image for Automating RAG Regression Tests with an AI-Driven Evaluator (AI Builder + Copilot Studio)
Bala Madhusoodhanan
Bala Madhusoodhanan

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Automating RAG Regression Tests with an AI-Driven Evaluator (AI Builder + Copilot Studio)

Intro:
We built a lightweight regression-testing pipeline for our Retrieval-Augmented Generation (RAG) agent using Power Automate, Copilot Studio (or Execute Agent), and an AI Builder evaluation prompt. The goal: turn a curated set of knowledge-base (KB) questions into a repeatable test pack, run them automatically after KB or instruction changes (or model upgrades), and deliver deterministic pass/fail reports to the product owner.

How it works (high level):
Work with the product owner to define a small, focused regression pack: representative KB questions + the expected/desired responses or required attributes (formatting, tone, required facts). Keep these single-turn questions to start.

Update a row with the result (Pass/Fail, metrics, evaluator JSON).
After loop: aggregate results, calculate pass rate, and send a report to the product owner (email/Teams/Files).

The evaluation prompt (core idea) We used an evaluator prompt that positions the LLM as an impartial critic and returns a strict JSON evaluation. This is inspired by proven LLM-as-judge patterns and gives us a deterministic, machine-readable output to gate deployments.

  • Output is machine-readable (JSON/CSV) so results can be tracked and automated.
  • Each test shows scores and a short reason so the product owner sees why something failed.
  • Clear PASS/FAIL and a short failure reason make go/no-go decisions easy. Every result links back to the original test case so fixes are quick to find.
  • Include run info (date, model/KB version) so failures can be reproduced.
  • Show a one-line summary (e.g., "28/30 passed — 93%") for a fast health check.
  • Prioritize failures by impact so the product owner knows what to fix first.
  • Attach remediation notes (short next steps) so engineers know how to resolve issues.

A clear, structured evaluation report turns a flood of agent outputs into actionable intelligence — empowering product owners to make fast, confident decisions about content changes, model updates, and releases.

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