Claude

Claude Fable 5.1

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Anthropic's updated frontier model improving across the board on agentic coding, long-running agent workflows, and knowledge work. More concise in plans and summaries than Fable 5.

Context
1Mtokens
Max output
128Ktokens
Latency
~22ms
Released
2026-09-01

Pricing

$ / 1M tokens
Input
$10.00/M
Output
$50.00/M
Cache Read
$0.25/M
Write (5m)
$12.50/M
Write (1h)
$20.00/M

Capabilities

7 listed
  • Chat
  • Tool Use
  • Reasoning
  • Vision
  • Coding
  • Analysis
  • Long Context

Code examples

POST /v1/chat/completions
python
from openai import OpenAI

client = OpenAI(
    api_key="your_api_key",
    base_url="https://api.modelstack.cc/v1",
)

response = client.chat.completions.create(
    model="claude-fable-5-1",
    messages=[{"role": "user", "content": "Hello!"}],
)
print(response.choices[0].message.content)

Related models

Frequently asked questions

How is Claude Fable 5.1 billed on ModelStack?expand_more
ModelStack bills based on actual request usage. Input, output, cache, and any other applicable rates follow the live pricing table on this page. Final request costs are available in the console.
What are the context window and maximum output for Claude Fable 5.1?expand_more
Claude Fable 5.1 has a 1M context window and supports up to 128K of output.
How can I call Claude Fable 5.1 through ModelStack?expand_more
Use the model ID `claude-fable-5-1` with any OpenAI-compatible SDK pointed at the ModelStack API — see the code examples above for Python, Node.js, and cURL.
Which capabilities does Claude Fable 5.1 support?expand_more
Claude Fable 5.1 supports: Chat, Tool Use, Reasoning, Vision, Coding, Analysis, Long Context.