Claude Fable 5
The newest Anthropic model — first Mythos-class made generally available.
What is Claude Fable 5?
Claude Fable 5 is the Anthropic frontier model with a 200,000 tokens (1M with extended thinking) context window, released 2026-06-09. Tagline: The newest Anthropic model — first Mythos-class made generally available..
Pricing detail. Released alongside Mythos 5 on June 9, 2026 as the publicly-available member of the new Mythos class. Premium per-token pricing on the Anthropic API; available everywhere Opus 4.8 ships.
How I use it inside the Agent OS. Selected from Agent OS for the highest-stakes one-shot work — replacing Opus 4.8 as the safety net on hard prompts. Bench scoring pending.
What I built with Claude Fable 5
Every model on Goldie Bench gets the same fixed prompt set — one shot, single HTML file out — and I score the result 0–10 inside the Agent Operating System. Here's what Claude Fable 5 shipped on the bench: 0 one-shot demos across 200,000 tokens (1M with extended thinking) of context. Of those, 0 are scored against the field with my honest 0–10 from the source guides at agentos.guide.
Strengths
- Anthropic's most capable publicly-available model — vendor claim: 'capabilities exceed those of any model we've ever made generally available'
- Tops external SWE-bench Verified at 95.0% in Julian's three-dragons writeup
- Top-tier plan quality (9.1/10) on Kilo's plan-vs-build rubric
Trade-offs
- No goldiebench per-task scores yet — bench rank pending a published head-to-head guide
- Premium pricing; Fusion premium panel reportedly out-scores it at half the API cost
Best for
- Mission-critical one-shot builds where you want Anthropic's newest reasoning
- Long-context work using extended thinking up to 1M tokens
- Plan-heavy multi-step tasks where intelligence in the plan matters more than the build
Every demo by Claude Fable 5
0 live demos, sorted by category. Click any tile to play the actual one-shot result. Verdicts and 0–10 scores are pulled from the source guides where I posted them publicly.
Head-to-heads with Claude Fable 5
Direct comparisons against every other scored model on the bench:
Claude Fable 5 vs Opus 4.8 Claude Fable 5 vs GLM-5.2 Claude Fable 5 vs Grok Claude Fable 5 vs Qwen 3.7 Claude Fable 5 vs Kimi K2.7Read more on agentos.guide: /claude-fable-5, /claude-fable-5-use-cases, /claude-5-agent-os, /claude-5-ai-seo, /claude-hermes-olympus-protocol
Run this stack yourself.
Every demo on this bench was built inside the Agent Operating System — one prompt, one shot, single HTML file out. The Agent OS, the prompts, the templates, the weekly walkthroughs and 3,600+ founders shipping with it every day all live inside the AI Profit Boardroom.