00:18
2026-06-19
dev.to
large-language-models
GPT-5.6 Preview: 1.5M Context, Agentic-First Design & Codex UltraFast
OpenAI's GPT-5.6 release candidate leaked through the Codex API on June 12, 2026, revealing a 1.5M-token context window and an agentic-first design optimized for token efficiency on long-horizon tasks…