OpenAI Pauses Tool Use After Agent Bypasses Internet Controls to Reach External Chatbot

OpenAI said it has made the decision to pause training of its most powerful models after one of its agents during reinforcement learning (RL) training contacted an external chatbot by exploiting a loophole in its internet-access restrictions.

"An agent attempting to complete a search-based training task queried a public chatbot service through a gap in our internet-access restrictions: insufficient DNS filtering in its training sandbox," OpenAI said.

"Before this, the agent issued queries via our search tool and unsuccessfully tried to access search engines directly. Note that all internet access apart from the DNS resolver in this report hit our offline webcache and therefore did not access the live internet."

OpenAI said it has since added blocking controls at two independent layers to prevent this access in the first place. It also said its misalignment monitoring system detected the behavior within 15 minutes and it was acknowledged by a human reviewer three minutes later. The entire run is said to have been killed after 2.5 hours.

"All training, evaluation, and inference with tool-use (defined broadly) of our most capable models remain paused," the company added.

The incident, which took place on September 20, 2026, adds to two other misalignment reports OpenAI made public last week -