OpenAI introduced a new evaluation suite and research paper on Chain-of-Thought controllability. The company says GPT-5.4 Thinking shows low ability to obscure its reasoning, which supports continued use of CoT monitoring as a safety signal.
OpenAI says GPT-5.4 Thinking and Pro are rolling out gradually across ChatGPT, the API, and Codex. The company positions GPT-5.4 as a unified frontier model for professional work with stronger coding, tool use, and 1M-token context.
OpenAI and Amazon announced a multi-year strategic partnership on February 27, 2026. The deal combines a new Amazon Bedrock-based Stateful Runtime Environment, exclusive third-party AWS distribution for OpenAI Frontier, approximately 2 gigawatts of Trainium capacity, and a $50 billion Amazon investment.
OpenAI Developers published a March 11, 2026 engineering write-up explaining how the Responses API uses a hosted computer environment for long-running agent workflows. The post centers on shell execution, hosted containers, controlled network access, reusable skills, and native compaction for context management.
OpenAI said Codex Security is rolling out in research preview via Codex web. The company positioned it as a context-aware application security agent that reduces noise while surfacing higher-confidence findings and patches.
OpenAI said it will acquire Promptfoo and fold its security and evaluation stack into OpenAI Frontier. The company said Promptfoo will remain open source and current customers will continue to receive support.
OpenAI announced on X that Codex Security has entered research preview. The company positions it as an application security agent that can detect, validate, and patch complex vulnerabilities with more context and less noise.
OpenAI said on X on March 9 that it plans to acquire Promptfoo, an AI security platform, and keep the project open source. The deal strengthens OpenAI Frontier’s agentic testing and evaluation stack.
OpenAI released proof attempts for all 10 First Proof problems and said expert feedback suggests at least five may be correct. The company positioned the result as a test of long-horizon reasoning beyond standard benchmarks.
OpenAI announced $110B in new investment on February 27, 2026, alongside Amazon and NVIDIA partnerships aimed at compute scale. The company tied the move to 900M weekly ChatGPT users, 9M paying business users, and rising Codex demand.
OpenAI says GPT-5.4 Thinking is shipping in ChatGPT, with GPT-5.4 also live in the API and Codex and GPT-5.4 Pro available for harder tasks. The launch packages reasoning, coding, and native computer use into a single professional-work model with up to 1M tokens of context.
OpenAI Developers has updated its GPT-5.4 API prompting guide. The new guidance focuses on tool use, structured outputs, verification loops, and long-running workflows for production-grade agents.