Anthropic's newest Mythos-class flagship — improves on Fable 5 across the board, biggest gains in agentic coding and long-running agentic workflows. 1M context, 128K output, vision, file input, adaptive thinking.
Modalities
Text+Image → Text
Below release
Not established
Weights
Not published
Where it sits in the catalogue Kyma measures
Every number against every text model Kyma prices per token — a stated rule, not a chosen line-up.
$13.50
output $67.50
median $0.977 · best $0.0494
$67.50
per 1M tokens generated
median $3.531 · best $0.2164
Not measured yet
6 observations since 2026-09-03
median 96.2% · best 100.0%
Not measured
probe median, one fixed prompt
median 40.8 tok/s · best 308.3 tok/s
Not measured
probe median, to a complete answer
median 2.50 s · best 0.52 s
1M
max output 128,000
published by Anthropic, not measured here
Tick above each rail is this model, below it the other 69. Dashed rule is the field median, solid is its best. Better is left; the axis stops at the 90th percentile, so a few models sit past its right edge.
Usage
How much this model is actually called here.
Rank
#109
of 113 active models
Tokens served
33
all-time
Platform share
0.0%
of all tokens
Pricing
Pay per token. Cached input bills at this model’s own cached rate, listed below.
+ Estimate your workload− Estimate your workload
Estimated monthly cost
$1,823
$60.75 / day on Claude Fable 5.1
Same workload on:
Estimates use list pricing. Actual bills depend on real token counts, and every response includes its exact cost.
How it compares
Against the peers people actually weigh it against.
| Spec | Claude Fable 5.1 | Claude Fable 5 | Claude Sonnet 5 |
|---|---|---|---|
| Input /1M | $13.50 | $13.50 | $2.70 |
| Output /1M | $67.50 | $67.50 | $13.50 |
| Context | 1M | 1M | 1M |
| Tools | Yes | Yes | Yes |
| Reasoning | Yes | Yes | Yes |
| Throughput | Not measured | 15.5 tok/s | 17.9 tok/s |
Quick start
Up and running in under two minutes.
- 1
Create an API key
Sign up and grab a key from the dashboard — $0.50 free credit, no card required.
Get API key → - 2
Make your first request
Drop in your key and send a chat completion — fully OpenAI-compatible.
curl https://kymaapi.com/v1/chat/completions \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "claude-fable-5.1", "messages": [ {"role": "user", "content": "Explain prompt caching in one paragraph."} ] }' - 3
Stream responses
Add
"stream": trueto receive tokens as they arrive.curl https://kymaapi.com/v1/chat/completions \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "claude-fable-5.1", "stream": true, "messages": [{"role": "user", "content": "Hello!"}] }'
FAQ
Common questions about this model.
What is the context window of Claude Fable 5.1?
How much does the Claude Fable 5.1 API cost?
Does Claude Fable 5.1 support function calling?
Are the weights for Claude Fable 5.1 publicly available?
Is Claude Fable 5.1 ever served below the precision its creator released it at?
How do I use Claude Fable 5.1?
More models by Anthropic
| Model | Context | Input | Output |
|---|---|---|---|
| 1M | $6.75 | $33.75 | |
| 1M | $13.50 | $67.50 | |
| 1M | $2.70 | $13.50 | |
| 1M | $13.50 | $67.50 | |
| 1M | $6.75 | $33.75 | |
| 1M | $4.05 | $20.25 | |
| 200K | $1.35 | $6.75 |