Fable 5 & Mythos 5: The New Top of the Claude Lineup.

Anthropic introduced a new class of models above Opus: Fable 5 and Mythos 5, with 1M-token context and always-on reasoning.

Why 1M context is the headline

Whole codebases, entire knowledge bases, a month of transcripts — in one window. Your RAG setup gets simpler, your pipelines get smarter, and "give Claude everything" stops being a fantasy.

Plumbing still wins

Bigger models don't replace good plumbing. The teams winning are the ones with clean MCP connectors feeding that context window the right data.

Source: Anthropic