Claude Fable vs Claude Opus
The within-Claude question. Fable 5.1 landed on 1 September 2026 at $10 and $50 per million tokens, exactly twice Opus 5, and Anthropic still tells you to start on Opus for most workloads. Fable 5.1 is the escalation path for demanding reasoning and long-horizon agentic runs, and its cache reads cost a quarter of a percent of the input price, which changes the maths on long repeated contexts. Escalate when you can point at a task Opus actually fails.
| Claude Fable | Claude Opus | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Current release | Fable 5.1 | Opus 5 |
| Tier | Frontier | Frontier |
| Context | 1M | 1M |
| Cost | Frontier price | Premium |
| Modalities | text, vision | text, vision |
| Open weights | No | No |
Cost is a tier, not a quote, providers change prices often. Check Anthropic and Anthropic before you commit. Last updated 2026-09-04.
Which one to pick
Demanding reasoning and long-horizon agentic work, when Opus at high effort still falls short
Reach for it when- The genuinely hardest problems where being right dominates cost
- Work you cannot easily verify yourself
Agentic coding and multi-step engineering work, near the ceiling, at half the price
Reach for it when- Almost everything else. It is the better price-to-capability trade
- High-volume agentic work where the 2x multiplier compounds
Related comparisons
- Claude Fable vs GPT AstraThe top of the market, and the two land within 48 hours of each other: Fable 5.1 on 1 September 2026, GPT-6 Astra on the 3rd.
- Claude Opus vs GPT AstraThe practical version of the frontier question, because Opus 5 costs half what Astra does, $5 and $25 per million tokens against $10 and $50, and Anthropic recommends it as the default for most workloads.
- Claude Opus vs GPT SolTwo mid-frontier models at almost the same price, now that GPT-6 Astra sits above Sol and Claude Fable 5.1 sits above Opus.
- Claude Opus vs Gemini ProTwo different bets.
- Claude Opus vs GrokBoth are pitched at agentic coding.
- Claude Opus vs Claude SonnetThe one most Claude users get wrong by defaulting up.