Willison keynote: Claude Opus 4.5 and GPT-5.1 mark 2026 LLM trends
Simon Willison delivered the closing keynote at WeAreDevelopers World Congress North America in San Jose, summarizing key LLM trends and releases in 2026 so far. He highlighted the November 2025 releases of Claude Opus 4.5 and GPT-5.1, which enabled coding agents like Claude Code and Codex to cross a threshold of practical usability. The talk is available on YouTube with annotated slides and notes.
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Simon Willison
On Friday I gave the closing keynote at the WeAreDevelopers World Congress North America in San Jose. I tied together the key trends from the past year into a chronological exploration of everything that happened in 2026. The video is on YouTube ; here are my annotated slides and notes to accompany the talk. # I'm going to give a lightning tour of everything that has happened so far in 2026. The year isn't over yet! # For me, 2026 started a couple of months earlier in November 2025. # November saw the release of two important models: Claude Opus 4.5 and GPT-5.1. As is usually the case with new models, these were incremental improvements on the models that came before them. But every now and then when a model improves, it crosses an invisible line where something that didn't really work starts working. In this case, the thing that started working was their coding agents. Claude Code had been around since February 2025, Codex was a little younger. These two new models, when paired with t
