Pelicans for Opus 4.6 and Codex 5.3 - I don''t have much interesting to say about these models yet to be honest, they''re both incremental improvements on their predecessors and very capable simonwillison.net Opus 4.6 and Codex 5.3 Two major new model releases today, within about 15 minutes of each other. Anthropic released Opus 4.6. Here''s its pelican: OpenAI release GPT-5.3-Codex, albeit only via their Codex app, not …