What is eval-driven development: How to ship high-quality agents without guessing

Eval-driven development (EDD) is a methodology designed to improve the quality and reliability of applications powered by large language models (LLMs) by using evaluations as a core aspect of the development process. Unlike traditional testing that relies on a limited set of examples and binary pass/fail results, EDD involves defining quality criteria in advance, scoring changes across multiple dimensions, and using these scores to guide development decisions. EDD functions as a continuous loop where evaluation criteria are refined as business needs change, ensuring that every modification to the system is assessed against a consistent standard before deployment. This approach allows for clear identification of the impact of changes, helping to prevent regressions and optimize the system based on measurable outcomes. By integrating evaluations directly into CI/CD pipelines, EDD offers a structured framework for managing quality at every stage of development, from initial prompt modifications to production monitoring. Braintrust, a tool supporting EDD, provides infrastructure for managing datasets, scoring, and release controls, enabling teams to maintain alignment between development and production criteria and ensuring that changes are validated against defined quality standards.