OpenAI published a research paper detailing the evolution of its Codex platform into the primary AI tool within the company. The paper, titled “The Shift to Agentic AI: Evidence from Codex,” highlights that as of June 11, 2026, Codex accounts for 99.8% of output tokens generated across both Codex and ChatGPT among OpenAI employees.
All departments within OpenAI, including Legal, Finance, and Recruiting, now utilize Codex for work-related tasks. Non-technical departments reached majority Codex usage by April 2026, following earlier adoption by engineering teams. The median employee in a legal role now generates 13 times more monthly output tokens compared to November 2025, while the median researcher’s output has increased over 50 times in the same period.
Growth among non-developer users of Codex has surged, rising 137 times among individual users and 189 times among organizational users since August 2025. Currently, 17.3% of organizational account users outside OpenAI have adopted Codex, contrasting with fewer than 1% of individual users.
The report indicates a significant shift from conversational AI, where users solicit advice, toward agentic AI, where users assign Codex multi-step tasks. “Users are asking Codex to do work, not only to provide advice or information,” the paper states.
OpenAI has cautioned that its internal data may not portray typical trends of enterprise adoption, citing favorable conditions like high organizational commitment and unrestricted usage. Among external organizational users, Codex represents 63.3% of output tokens, while its adoption remains at 16.5% among individual users.
The complexity of tasks submitted to Codex is increasing, with 25.6% of individual users now submitting requests estimated to require over eight hours of human work, compared to just 2.1% in December 2025. Codex boasts over 5 million weekly active users, a more than sixfold increase since February.
