The Action Surface

Listener notes

• On September 10, OpenAI introduced the Agents API in public beta. The service brings the Codex harness to developers, with long-running sessions, tool use, parallel subagents, context compaction, and OpenAI-hosted or partner sandboxes. OpenAI says there is no extra Agents API fee beyond the tokens and tools used; those are the company’s product terms, not an independent performance assessment. 1
• On September 8, a joint CISA, NSA, and FBI advisory alleged that China-based AI companies had run industrial-scale distillation campaigns against U.S. frontier models. The advisory says the activity involved billions of tokens across millions of exchanges since at least late 2024, and recommends anomaly detection, targeted response changes, and cross-provider intelligence sharing. The new event is the government advisory; its attribution and historical claims should be read as the agencies’ assessment. 2
• On September 8, OpenAI published what it says is an AI-produced solution to the Navier–Stokes existence-and-smoothness problem, alongside an analytical write-up and a Lean formalization. Nature reported the announcement and the separate release of related Euler-equation work, but a public claim and a formalized proof are not the same thing as broad mathematical acceptance. 34