OpenAI released GPT-5.4 mini and GPT-5.4 nano, their most capable small models optimized for coding, multimodal understanding, and subagents, featuring a 400k context window and over 2x speed compared to GPT-5 mini. The mini model approaches larger GPT-5.4 performance while using only 30% of Codex quota, becoming the default for many coding workflows. Pricing concerns and truthfulness tradeoffs were noted, with mixed third-party evaluations on reasoning and resistance to false premises. OpenAI also addressed behavior tuning issues in a recent update.

Meanwhile, agent infrastructure is evolving with secure code execution and orchestration tools like LangChain's LangSmith Sandboxes and Open SWE, inspired by internal systems at Stripe, Ramp, and Coinbase. Subagents and secure execution are now key product features, with releases like Hermes Agent v0.3.0 showcasing plugin architectures, live Chrome control, and voice mode. Research on attention mechanisms, including Attention Residuals and vertical attention, is gaining traction.