Claude Fable 5 is live
BetterToken updated Claude Fable 5 on June 9, 2026 for Claude Code, long-running agent tasks, complex software engineering, and intensive knowledge work.
Release date: June 9, 2026
BetterToken has updated the Claude Fable 5 model entry. Check the model plaza for the currently available model ID, then configure it through the Claude Code or external-tool setup guide that matches your client.
Anthropic officially introduced Claude Fable 5 on June 9, 2026 and describes it as a new generation of intelligence for the hardest knowledge work and coding problems. Anthropic says Fable 5 is a Mythos-class model built for longer, more complex, more asynchronous work, especially long-running agents, complex software engineering, knowledge work, and vision-heavy workflows.
Highlights
- Stronger long-running agent work: Anthropic says Fable 5 can operate for longer in Claude Code or an agent harness, planning across stages, executing, and checking its own work
- Better fit for complex software engineering: The model is positioned for large migrations, complex implementations, multi-day autonomous sessions, and engineering tasks that need less direct supervision
- Improved knowledge work and vision: Fable 5 targets complex analysis, document reasoning, charts, tables, PDFs, and other visual materials
- More active self-checking: Anthropic emphasizes that Fable 5 validates its own work more thoroughly, which helps when you hand off a task and review the result later
- New safeguards: For sensitive areas such as cybersecurity, biology, and chemistry, Anthropic applies safeguards and fallback behavior; some requests may be answered by Claude Opus 4.8 instead
Setup guidance
If you use Claude Code, start with the Claude Code setup guide.
- Claude Code:
https://bettertoken.ai - OpenAI-compatible API:
https://bettertoken.ai/v1
Use the model name currently shown in the model plaza. Do not hardcode a model name that is not shown there.