Home › Frontier and closed › anthropic

Claude Fable 5.1 anthropic

Closed weights API only frontier listed on OpenRouter 2026-09-01 (54d ago) · source Last verified 2026-10-25 06:51 UTC Docs ↗ OpenRouter ↗

Release timeline

Stages observed by the nightly radar: announced → API only → weights public → served by third parties. Each entry carries the source it was seen at.

  1. 2026-09-01 · API only source
    seeded from the earliest dated observation when first seen · observed 2026-10-07 20:20 UTC

Description

Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work: long code refactors, front-end and visual...

via OpenRouter listing · observed 2026-10-24 21:26 UTC. The listing text is the provider's own description, not an assessment.

Where to run 4 providers · 4 endpoints

Hosted endpoints observed for Claude Fable 5.1, sorted by input price (USD per million tokens). Each row names its observer and date; prices change daily, so check the source before quoting. Cheapest observed input price: $10.00/M.

ProviderModel refContextQuant$/M in$/M outtok/sTTFTToolsStatusObserved
Amazon Bedrock
openrouter
anthropic/claude-fable-5.1 977K unknown $10.00 $50.00 — — yes live 2026-10-24
Anthropic
openrouter
anthropic/claude-fable-5.1 977K unknown $10.00 $50.00 — — yes live 2026-10-24
Azure
openrouter
anthropic/claude-fable-5.1 977K unknown $10.00 $50.00 — — yes live 2026-10-24
Google
openrouter
anthropic/claude-fable-5.1 977K unknown $10.00 $50.00 — — yes live 2026-10-24

No third-party providers observed beyond the lab's own endpoints. Cache-read price $0.25/M (source, observed 2026-10-24).

Facts

Context length1,000,000 tokens (977K) · OpenRouter listing
Modalitiestext + image + file → text
Max completion tokens128,000
Supported parametersinclude_reasoning, max_completion_tokens, max_tokens, reasoning, reasoning_effort, response_format, stop, structured_outputs, tool_choice, tools, verbosity
OpennessClosed weights · closed lab
StageAPI only
Confidencemedium
Pricing (USD per M tokens) in $10.00 · out $50.00 · cache read $0.25
OpenRouter list price (cheapest live endpoint) · source · observed 2026-10-24 21:26 UTC

Open alternatives 5

Nearest open-weights models by modality, context and price on this watch list. Not a quality ranking.

ModelOrgParamsContext$/M inLicenseWhy it is here
Qwen3.5-4B Qwen 4.66B 256K — apache-2.0 vision input
Llama-3.2-11B-Vision-Instruct meta-llama 10.7B — — llama3.2 vision input
Kimi-K3 moonshotai 2.78T 1M $0.23 other similar context (1.05M), cheaper input price ($0.2261/M vs $10/M), vision input
Qwen3-VL-4B-Instruct Qwen 4.44B 256K — apache-2.0 vision input
Qwen3-VL-2B-Instruct Qwen 2.13B 256K — apache-2.0 vision input

Get alerts

Watch the release radar

Email alerts are not open yet; the feeds above are the same data. See feeds for the item schema.

Sources

Radar run: 2026-10-25 06:51 UTC · Last verified 2026-10-25 06:51 UTC