llm11

Claude Fable 5.1 with Jev

Claude Fable 5.1 is a model from Anthropic, released 2026-09-01. It costs $10 per million input tokens and $50 per million output tokens, reads up to 1M tokens of context, and writes up to 128,000 tokens in one reply. Through llm11, set model to anthropic/claude-fable-5.1.

Input price
$10 / 1M
Output price
$50 / 1M
Context window
1M tokens
Max output
128K tokens
Cached input
$0.250 / 1M

Read from the provider's prompt cache

Released
2026-09-01
Accepts
text, image, file
Intelligence index
53.4

Artificial Analysis, via the catalogue

Read from the live catalogue and refreshed daily. At blended list price, 3% of the 332 priced models we can call cost more.

Using Claude Fable 5.1 with Jev

Jev is TypeSafe AI's System One model. It reads each request first and decides which model in your pool answers, with a calibrated confidence on that call. Claude Fable 5.1 does the answering when Jev sends it work, or when you name it yourself. Claude Fable 5.1 falls in the llm11-smart band, and the labs and limits it meets make it eligible for that pack. Packs keep a spread of eight models per band, and it is not one of the eight today, so it is only picked when you name it in a custom pool.

Jev is new, so we have not published results for Claude Fable 5.1 with and without it, and this page does not invent any. Every response comes with a receipt that names the model that answered and what it cost against your most expensive model, so you can measure the pairing on your own traffic.

About JevThe System One router

What a request costs

List price arithmetic, the same sum a receipt does. llm11 adds nothing per request; the only fee is on buying credits.

RequestTokens in / outOneA thousand
Short chat turn500 / 200$0.015$15.00
Question over retrieved documents4,000 / 500$0.065$65.00
Long document summary30,000 / 1,000$0.350$350.00

Cheaper models to try

Nearest in price and below Claude Fable 5.1, each within a few points of it on the intelligence index.

Cheaper alternatives to Claude Fable 5.1
ModelInput / 1MOutput / 1MContextIndex
Anthropic Claude Opus 5$5.00$251M50.8
Anthropic Claude Opus 5.5$4.00$201M57.6
Anthropic Claude Sonnet 5.5$2.00$101M56

Call it

Same OpenAI request shape. Naming the model pins it, so nothing is routed, and the answer is still checked.

python

from openai import OpenAI

client = OpenAI(base_url="https://www.llm11.com/v1", api_key="llm11_live_...")

res = client.chat.completions.create(
    model="anthropic/claude-fable-5.1",
    messages=[{"role": "user", "content": "Hello"}],
)

More from Anthropic

Other Anthropic models
ModelInput / 1MOutput / 1MContext
Claude Sonnet 5.5$2.00$101M
Claude Opus 5.5$4.00$201M
Claude Opus 5$5.00$251M
Claude Sonnet 5$2.00$101M
Claude Fable 5$10$501M
Claude Opus 4.8$5.00$251M

All 15 Anthropic models

Questions

What is Claude Fable 5.1 with Jev?
Jev is TypeSafe AI's System One model. It reads each request first and decides which model in your pool answers, with a calibrated confidence on that call. Claude Fable 5.1 does the answering when Jev sends it work, or when you name it yourself. Claude Fable 5.1 falls in the llm11-smart band, and the labs and limits it meets make it eligible for that pack. Packs keep a spread of eight models per band, and it is not one of the eight today, so it is only picked when you name it in a custom pool. Routing decisions are made by Jev, TypeSafe AI's System One model.
Is Claude Fable 5.1 a System One model?
No. Claude Fable 5.1 answers requests. The System One model is Jev, which decides which model answers each one, so the two do different jobs and llm11 uses both.
How much does Claude Fable 5.1 cost?
$10 per million input tokens and $50 per million output tokens. A 4,000 token prompt with a 500 token answer costs about $0.065, so a thousand of them is about $65.00. llm11 passes provider list price through and charges 5% when you buy credits.
What is the Claude Fable 5.1 context window?
1,000,000 tokens, with up to 128,000 tokens in a single reply.
Does Claude Fable 5.1 support tool calling and structured output?
The catalogue lists tool calling, structured output and reasoning controls.
Can I use Claude Fable 5.1 through llm11?
Yes. Set model to anthropic/claude-fable-5.1 on the OpenAI-compatible endpoint and the request goes to it directly, with verification still running.
Does Jev route to Claude Fable 5.1?
Routing decisions are made by Jev, TypeSafe AI's System One model. Claude Fable 5.1 falls in the llm11-smart band, and the labs and limits it meets make it eligible for that pack. Packs keep a spread of eight models per band, and it is not one of the eight today, so it is only picked when you name it in a custom pool.
What is a cheaper alternative to Claude Fable 5.1?
Nearest in price and below it: Anthropic Claude Opus 5 at $5.00 in and $25 out, Anthropic Claude Opus 5.5 at $4.00 in and $20 out and Anthropic Claude Sonnet 5.5 at $2.00 in and $10 out. Nearest in price and below Claude Fable 5.1, each within a few points of it on the intelligence index.