Anthropic launched Claude Fable 5 and Claude Mythos 5 with 1M context and 128k max output.

Default million-token context and always-on adaptive thinking make long-context behavior a baseline for these Claude models.

Fable is widely released, Mythos is limited to Project Glasswing, so builders have different availability paths for the same context profile.

• Jun 11, 2026OpenAI modelcard diff shows the API docs navigation content removed.
• Jun 11, 2026OpenAI pricing page removed visible API pricing content for GPT-5.5, GPT-5.4, and realtime.
• Jun 11, 2026Claude Fable 5 and Claude Mythos 5 use the tokenizer introduced with Claude Opus 4.7.

This is the world we build in. It moves this fast. We move with it.