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AnthropicClaude 5 familyLegacyReasoning modelReleased 9 Jun 2026

Claude Fable 5

Previous top-tier model. Prefer claude-fable-5-1 for new work.

Model idclaude-fable-5

Price$10 in, $50 out per 1M tokens

Checked29 September 2026

Knows up to January 2026

1,945events after its cutoff

85 historic, 444 major. 286 days of news.

It launched on 9 June 2026, already missing 128 of them.

Five things it has never heard of

How to call it

7 ways to use Claude Fable 5, with the model id each provider expects.

Providers, model ids, endpoints and docs for Claude Fable 5
ProviderModel idEndpointDocs
Anthropic API (Claude API) claude-fable-5 https://api.anthropic.com/v1/messages platform.claude.com
AWS Bedrock (Messages API / Mantle) anthropic.claude-fable-5 platform.claude.com
Google Cloud Vertex AI claude-fable-5 platform.claude.com
Microsoft Foundry (Azure) claude-fable-5 platform.claude.com
Claude Platform on AWS claude-fable-5 platform.claude.com
OpenRouter anthropic/claude-fable-5 openrouter.ai
Web app claude.ai

Pricing

Prices for Claude Fable 5
Input$10 per 1M tokens
Output$50 per 1M tokens
Cache read$1 per 1M tokens

As published: “per 1M tokens (USD); Batch API 50% off”.

Source: platform.claude.com, checked 29 September 2026.

Specs

Input
Text, images and PDF
Output
Text
Context window
1,000,000 tokens
Max output
128,000 tokens
Open weights
No
Licence
Proprietary
Training cutoff
January 2026
Released
9 June 2026
Status
Legacy
Type
Reasoning model

What stands out

What its maker marketed at launch, and what people found later, each with its source.

  • Strongest cybersecurity capabilities (Mythos 5)

    Anthropic called the Fable 5 / Mythos 5 generation the ‘strongest cybersecurity capabilities of any model in the world’. Mythos 5 runs without safety classifiers for Glasswing defenders.

    Source: anthropic.com

  • Rebuild web apps from screenshots

    First

    Anthropic claims it was the first model to rebuild a web app’s source code from screenshots alone. It also completed Pokemon FireRed using vision only.

    Source: anthropic.com

  • Massive code migrations

    Stripe reported a 50-million-line migration done in one day instead of about two months.

    Source: anthropic.com

  • Novel scientific hypotheses

    In blind comparisons, scientists preferred its molecular-biology hypotheses about 80% of the time over Opus-class models.

    Source: anthropic.com

  • Refusal stop reason with fallbacks

    First

    Safety classifiers can decline a request with stop_reason ‘refusal’. A server-side fallbacks parameter retries on another Claude model.

    Source: platform.claude.com

Four assistants, one scale

Claude Fable 5 is added as a fifth row. Each row runs from what the model knows (graphite) through the months between its cutoff and its launch (hatched) to today (pink).

  1. GPT-6 Astra 271 at launch, 1,863 today
  2. Claude Opus 5.5 372 at launch, 1,795 today
  3. Gemini 4 Hydrogen 1,863 at launch, 1,889 today
  4. Grok 4.7 387 at launch, 1,829 today
  5. Claude Fable 5 128 at launch, 1,945 today
Show as a table
ModelCutoffReleasedMissing at launchMissing today
GPT-6 AstraApril 20263 September 20262711,863
Claude Opus 5.5June 202622 September 20263721,795
Gemini 4 HydrogenMarch 202612 November 20261,8631,889
Grok 4.7May 202621 September 20263871,829
Claude Fable 5January 20269 June 20261281,945

Notes

Superseded by claude-fable-5-1 (same price, cheaper cache reads). Still served; retirement not sooner than 2027-06-09. Sibling claude-mythos-5 (Project Glasswing only, no safety classifiers).

curl https://api.anthropic.com/v1/messages \
 -H "x-api-key: $ANTHROPIC_API_KEY" -H "anthropic-version: 2023-06-01" -H "content-type: application/json" \
 -d '{"model":"claude-fable-5","max_tokens":16000,"messages":[{"role":"user","content":"Hello"}]}'

Sources: