Claude Fable 5
Anthropic's Mythos-tier flagship for software engineering, research, and knowledge work — now routable through CC Switch with the same Anthropic-compatible API you already use.
What is Fable 5?
Released June 9, 2026, Fable 5 is Anthropic's most capable public model to date — a Mythos-class generalist that leads across coding, vision, science, and long-form reasoning. A new safety layer may block certain high-risk replies; in rare cases sensitive queries are answered by Opus 4.8 instead.
Specs & pricing
One-million-token context, up to 128K output tokens. API list price is $10 per million input and $50 per million output — roughly double Opus 4.8. Cached prompt reads get a 90% discount. Sampling knobs like temperature are gone; use prompts for tone and the effort parameter (low → max) to balance depth, speed, and cost.
How to access it
Official paths include Claude paid plans, the Claude API (model ID claude-fable-5), AWS, Google Cloud, and aggregators like OpenRouter (anthropic/claude-fable-5). On CC Switch, point your existing Anthropic client at our base URL and pass --model=claude-fable-5 — no SDK changes required.
Prompting that works
Fable 5 follows instructions more literally than earlier models — be explicit about role, context, task, output format, and hard constraints. For agentic workflows, put the full spec in the first message instead of dribbling requirements. Want variety without temperature? Ask for it in the prompt.