Claude Fable 5.1

LiveAnthropic
Model IDclaude-fable-5-1

Claude Fable 5.1 by Anthropic: 1M context, 128K max output, with Vision, Function Calling, Reasoning, Prompt Caching, Response Schema, Streaming, Web Search. Via KumoAPI, Input (prompt) costs 10 Credits / M tokens. Compatible with Anthropic Messages: swap the base URL and you are connected.

VisionFunction CallingReasoningPrompt CachingResponse SchemaStreamingWeb Search
Get startedTry in Playground
Context window
1Mtokens
1,000,000
Max output
128Ktokens
128,000
7-day uptime
—
Not yet probed
Measured throughput
—
Real traffic, last 7 days · output side

Capabilities

Listed exactly as the catalog flags them, including what this model does not support.

7 of 15 supported

VisionVision

Natively multimodal: captioning, classification, visual Q&A, chart and screenshot understanding. Images are converted to tokens at the input rate.

Function CallingFunction Calling

Connect the model to external tools and APIs: it decides when to call which function and with what arguments, your code runs it. Force or forbid calls with tool_choice.

ReasoningReasoning

The model thinks before answering, which markedly improves multi-step planning and reasoning for coding, math and data analysis. Thinking tokens bill at the output rate.

Prompt CachingPrompt Caching

Repeated prefixes (system prompts, long documents) hit the cache: reads cost far less than input, writes are priced by retention time.

Response SchemaResponse Schema

Constrain output to a JSON Schema you provide for predictable, type-safe results without parsing free text.

StreamingStreaming

Tokens arrive over SSE as they are generated; the first frame is forwarded immediately with no buffering. Claude Code, Codex and similar tools depend on this.

Web SearchWeb Search

Vendor-hosted live web retrieval; the model decides when to search and cites sources.

AudioAudioNot supported

Audio input or speech output.

VideoVideoNot supported

Video input understanding or video generation.

File InputFile InputNot supported

Upload PDFs and other documents directly; the model reads the whole document with native vision.

RealtimeRealtimeNot supported

Bidirectional low-latency voice / text sessions over WebSocket.

SessionSessionNot supported

Server-side multi-turn context (e.g. previous_response_id in Responses) so you need not resend history.

MediaMediaNot supported

Image / video / music generation endpoints.

Multipart FormMultipart FormNot supported

multipart/form-data file-upload requests.

Binary ResponseBinary ResponseNot supported

Endpoints that return raw audio / image bytes.

Protocols & code samples

Change the base URL to KumoAPI, keep everything else. Native protocols pass straight through; “adapted” ones are translated by the gateway.

Claude Code setup guide

Anthropic SDK or any Messages-protocol client: point base_url at https://api.kumoapi.com and use a KumoAPI key.

curl https://api.kumoapi.com/v1/messages \
  -H "x-api-key: $SOLEAPI_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{
    "model": "claude-fable-5-1",
    "max_tokens": 1024,
    "messages": [{"role": "user", "content": "Explain prompt caching in one sentence"}]
  }'

Full price list

List price → KumoAPI price per channel, every pricing dimension, nothing hidden.

ItemUnitAnthropic list priceKumoAPI ×1
Input (prompt)per 1M tokens$10.0010 Credits
Output (completion)per 1M tokens$50.0050 Credits
Cache readper 1M tokens$0.250.25 Credits
Cache write · 5 minper 1M tokens$12.5012.5 Credits
Cache write · 1 hourper 1M tokens$20.0020 Credits
Web search (general)per 1K calls$10.0010 Credits

“Off” is computed at 1 Credit = ¥1 and today’s rate: 1 − channel multiplier × (1 Credit in the list currency).

FAQ

How much does the Claude Fable 5.1 API cost?

Via KumoAPI, Input (prompt) costs 10 Credits / M tokens, with 1 Credit = ¥1.

What are the context window and output limit of Claude Fable 5.1?

Context window 1M tokens, up to 128K tokens per response.

Does Claude Fable 5.1 support function calling and structured outputs?

Function calling with tool_choice control is supported; structured outputs (JSON Schema) are supported.

How do I use Claude Fable 5.1 in Claude Code?

Set ANTHROPIC_BASE_URL=https://api.kumoapi.com, ANTHROPIC_API_KEY to your KumoAPI key and ANTHROPIC_MODEL=claude-fable-5-1, then run claude. No config files to edit.

One API key for Claude Fable 5.1 and 30+ models

Free credits on sign-up, pay as you go, no monthly fee.

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