OpenAI deploys self-improving Tax AI agent with Codex

openai and thrive holdings collaborated to deploy tax ai, an agent leveraging codex to automate tax return preparation for crete's network of accounting firms. the system processed 7,000 returns during the pilot, achieving up to 97% accuracy and increasing firm throughput by 50% by reducing time spent on manual data entry. the agent improves autonomously by converting production traces and practitioner feedback into structured signals for its own fine-tuning loop. this architecture increased the proportion of returns reaching 75% field completion from 25% at launch to 86% within six weeks.