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Claude Fable 5.1 API

Anthropic's newest model for long-running agents and sustained reasoning.

Claude Fable 5.1 is an LLM / chat model from Anthropic, available on OttoPort's OpenAI-compatible API as the model ID claude-fable-5.1 at $11.08 / $55.39 per 1M tokens as of 2026-10-14.

Provider

Anthropic

Price

$11.08 / $55.39 per 1M tokens

Model ID

claude-fable-5.1

Type

LLM / chat model

ReasoningWritingDeveloper workflows

Create with Claude Fable 5.1

chat
ExampleSelect to edit

Your result appears here

Start with the example prompt or make it your own. Your OttoPort account is used securely for generation.

Pricing

Claude Fable 5.1 API pricing

What OttoPort bills for Claude Fable 5.1, and what that works out to per unit. Rates are read from the same catalog the gateway meters against, and were current on 2026-10-14.

Input$11.08 / 1M tokens
Output$55.39 / 1M tokens
Typical request$0.06651,000 input + 1,000 output tokens
Requests per $115at that same 1K in / 1K out shape
Context window1,000,000 tokensa full-context request costs $11.08 in input alone

No subscription and no minimum — OttoPort bills prepaid credits against usage. See the full rate card.

Quickstart

Call Claude Fable 5.1 in three lines

Send "model": "claude-fable-5.1" to POST https://ottoport.ai/api/v1/chat/completions with an OttoPort key. No Anthropic account, no waitlist, no separate SDK.

curl https://ottoport.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $OTTOPORT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-fable-5.1",
    "messages": [{ "role": "user", "content": "Hello!" }]
  }'

Before you start

  1. 1. Create a key at /api-keys.
  2. 2. Top up credits — the smallest pack is $25.
  3. 3. Paste the request. It returns on the same request.

Full reference at /docs, or drive it from an agent with the MCP server and CLI.

Reference

Request parameters

The body POST https://ottoport.ai/api/v1/chat/completions accepts for Claude Fable 5.1.

FieldTypeRequiredNotes
modelstringYesAlways claude-fable-5.1 for Claude Fable 5.1.
messagesarrayYesOpenAI chat message objects: role and content.
streambooleanNoServer-sent events, same frame shape as OpenAI.
temperaturenumberNoSampling temperature, passed through to the provider.
Comparison

Claude Fable 5.1 direct vs through OttoPort

Claude Fable 5.1 is the same model either way — what changes is how many accounts, keys, and integrations you carry to reach it.

Anthropic directVia OttoPort
Accounts and keysAn Anthropic account, plus one more for every other model you addOne OttoPort account and one key for the whole catalog
Request shapeAnthropic's own SDK and response formatOpenAI-compatible — point baseURL at OttoPort and change the model string
Switching modelsA new integration per providerReplace claude-fable-5.1 with any other model ID in the catalog
BillingA separate invoice and contract per providerPrepaid credits, no subscription, one usage ledger
Provider outagesYour call failsConfigured backup routes are tried in order on provider failure
01

Give the model a role and goal.

02

State the intended output format.

03

Add relevant context before constraints.

FAQ

Claude Fable 5.1 API questions

Cost, keys, and model IDs for Claude Fable 5.1 on OttoPort.

How much does the Claude Fable 5.1 API cost?

On OttoPort, Claude Fable 5.1 costs $11.08 / $55.39 per 1M tokens as of 2026-10-14. For scale, typical request: $0.0665. Billing is prepaid usage with no subscription and no minimum, and the current rate is always published at ottoport.ai/pricing.

How do I get a Claude Fable 5.1 API key?

You do not need an Anthropic key. Create an OttoPort account, generate a key at ottoport.ai/api-keys, and send it as "Authorization: Bearer <key>" to POST https://ottoport.ai/api/v1/chat/completions with "model": "claude-fable-5.1". The same key reaches every other model in the catalog.

What is the model ID for Claude Fable 5.1?

The OttoPort model ID for Claude Fable 5.1 is claude-fable-5.1. Pass it as the model field on POST https://ottoport.ai/api/v1/chat/completions, or list it programmatically from GET https://ottoport.ai/api/v1/models.

Can I call Claude Fable 5.1 with the OpenAI SDK?

Yes. Set the OpenAI SDK's base URL to https://ottoport.ai/api/v1, use an OttoPort API key, and pass claude-fable-5.1 as the model. Chat completions, streaming, and model listing follow the OpenAI request and response shapes, so existing code works after changing two lines.

What is Claude Fable 5.1's context window?

Claude Fable 5.1 accepts up to 1,000,000 tokens of context on OttoPort, the same window Anthropic exposes on its own API.

Do I need an Anthropic account to use Claude Fable 5.1?

No. OttoPort connects to Anthropic on your behalf, so one OttoPort account covers Claude Fable 5.1 and every other model in the catalog — no per-provider contracts, keys, or invoices.