# Claude Fable 5: pricing, crowd verdict, pros and cons (2026)

> Anthropic's June 2026 Mythos-class flagship: 80.3% on SWE-bench Pro, 11 points clear of every other frontier model

Source: [GLAD-AI-TOR](https://glad-ia-tor.com) · Full page: https://glad-ia-tor.com/tool/claude-fable-5
Arena: llm-models · Crowd score: 63% recommend (4 votes, Bayesian-smoothed) · Price: $50/1M out

First model of Anthropic's Claude 5 family, released 2026-06-09 in a new Mythos class above Opus. Fable 5 is the generally available version, with safety classifiers on dual-use capabilities (cyber, biology, model distillation) that reroute flagged requests to Opus 4.8; Claude Mythos 5 is the same underlying model without those classifiers, reserved for approved organizations via Project Glasswing. API ID claude-fable-5: $10/$50 per 1M tokens, 1M context by default, 128K max output.

## Key facts

- provider: Anthropic
- contextWindow: 1M tokens
- priceIn: $10/1M in
- priceOut: $50/1M out
- modalities: text, vision
- openWeights: no

## Ratings (editorial, 1-5)

- reasoning: 5/5
- coding: 5/5
- writing: 4.5/5
- speed: 2/5
- valueForMoney: 3/5

## Pros

- 80.3% on SWE-bench Pro vs 69.2% for Opus 4.8, 58.6% for GPT-5.5 and 54.2% for Gemini 3.1 Pro, roughly 11 points ahead of the next frontier model
- 95.0% on SWE-bench Verified (Opus 4.8: 88.6%, GPT-5.5: 82.6%) and 29.3% on Cognition's FrontierCode Diamond split, more than double Opus 4.8's 13.4%
- Long-horizon autonomy is the real story: Stripe reported a 50-million-line Ruby codebase migration done in one day instead of 2+ months, and Cursor's CEO calls it state of the art on CursorBench
- Field reports match the benchmarks: HN engineers describe it working 'like an actual engineer' (CRDTs with minimal hand-holding, writing its own fuzzers, one 46x allocation reduction), Simon Willison measured 'several days' worth of work' in a single session
- 1M token context window by default plus 128K output, and state-of-the-art vision on dense documents (29.8% on GDP.pdf vs 24.9% for GPT-5.5 and 22.5% for Opus 4.8)
- Refused-before-output requests are not billed, and server-side fallback to Opus 4.8 with fallback credit is built into the API

## Cons

- Double the price of Opus 4.8 ($10/$50 vs $5/$25) and slow: single requests on hard tasks routinely run many minutes, Simon Willison bluntly calls it 'slow, expensive'
- Dual-use safety classifiers misfire on legitimate work: a medical physicist reported fluid dynamics problems and MRI segmentation code refused as biosecurity risks, with requests silently rerouted to Opus 4.8 (the viral HN thread was titled 'If Claude Fable stops helping you, you'll never know'; Anthropic says under 5% of sessions)
- Rocky launch: US export controls forced Anthropic to suspend access worldwide from June 12 to June 30, 2026, three days after release, with full restoration only on July 1
- Requires 30-day data retention and is not available under zero data retention, a hard blocker for strict-compliance orgs; also no thinking-off mode, raw chain of thought never returned, assistant prefill returns a 400
- Not universally state of the art: GPT-5.5 still leads ARC-AGI-2 (85.0% vs 77.1%), and Andon Labs found unblocked Mythos 5 underperformed both Opus 4.7 and GPT-5.5 on Vending-Bench, with reasoning that optimized for detectability rather than actual harm

## Best for

- long-horizon autonomous agents
- massive refactors and codebase migrations
- frontier research and financial analysis
- vision on dense scientific documents

## Verdict

Take Claude Fable 5 if your workload is genuinely long-horizon: overnight agentic runs, monster migrations, tasks where one multi-hour session replaces days of supervised work. There, the 2x premium over Opus 4.8 pays for itself in task compression, and the benchmarks (80.3% SWE-bench Pro, 11 points clear of the field) are backed by real deployments at Stripe and Cursor. For interactive coding and everyday work, stay on Opus 4.8: 88.6% on SWE-bench Verified at half the price, no classifier misfires, faster turns. Cost-sensitive teams get near-Opus coding from Sonnet 5 at $3/$15 (intro $2/$10 through August 2026). Avoid Fable 5 entirely if your org requires zero data retention or if you work anywhere near biology, medical imaging or security tooling, where the dual-use classifiers still produce false positives and silently swap in Opus 4.8 mid-session.

## Pricing note

Official Anthropic API list price for claude-fable-5: $10/1M input, $50/1M output, single tier with 1M context by default (no long-context premium), 128K max output; requests refused before any output are not billed. Verified against platform.claude.com (Introducing Claude Fable 5) 2026-07.

## Alternatives and head-to-heads

- [Claude Haiku 4.5](https://glad-ia-tor.com/tool/claude-haiku-4-5) (crowd score 67%) · [Claude Fable 5 vs Claude Haiku 4.5](https://glad-ia-tor.com/vs/claude-fable-5-vs-claude-haiku-4-5)
- [Claude Opus 4.7](https://glad-ia-tor.com/tool/claude-opus-4-7) (crowd score 57%) · [Claude Fable 5 vs Claude Opus 4.7](https://glad-ia-tor.com/vs/claude-fable-5-vs-claude-opus-4-7)
- [Claude Sonnet 5](https://glad-ia-tor.com/tool/claude-sonnet-5) (crowd score 57%) · [Claude Fable 5 vs Claude Sonnet 5](https://glad-ia-tor.com/vs/claude-fable-5-vs-claude-sonnet-5)
- [Gemini 3 Pro](https://glad-ia-tor.com/tool/gemini-3-pro) (crowd score 57%) · [Claude Fable 5 vs Gemini 3 Pro](https://glad-ia-tor.com/vs/claude-fable-5-vs-gemini-3-pro)

Full ranking: https://glad-ia-tor.com/hall-of-fame/llm-models

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