Bonus: Top up now and we'll double your first deposit — get x2 credits instantly.
Get Started
Sign Up
Sign Up

Claude Fable 5.1

Up to 30%

Call Claude Fable 5.1 through LLM.API when you want Anthropic-family text generation with unified auth, provider choice, and production-friendly defaults.

Start Using API

What is Claude Fable 5.1?

Claude Fable 5.1 is an Anthropic chat model exposed on LLM.API under id `claude-fable-5-1`. Claude model for demanding reasoning and long-horizon agentic work. Teams use it when they need reliable text generation with text, image inputs and text outputs over an OpenAI-compatible API.

Providers

LLM.API routes Claude Fable 5.1 to the providers below, with discounted effective rates versus list price.

List price by provider ($ / 1M tokens)

InputOutput
anthropic$10 in
$50 out
aws-bedrock$10 in
$50 out
aws-mantle$10 in
$50 out

Provider list prices; the LLM.API discount applies on top.

ProviderPricingContextCapabilities
anthropic30% off—1M tokensvision, tools, streaming, reasoning, web search, JSON, structured
aws-bedrock30% off—1M tokensvision, tools, streaming, reasoning, web search, JSON, structured
aws-mantle30% off—1M tokensvision, tools, streaming, reasoning, web search, JSON, structured

Prices and availability from the LLMAPI catalogue, updated nightly. Last updated 21 Sept 2026.

Try this model

Test Claude Fable 5.1 right here — free to start.

Claude Fable 5.1
Hi! Want to test the model?

Suggestions for your first prompt

Code snippet

Call Claude Fable 5.1 through the OpenAI-compatible API — POST /v1/chat/completions.

python
from openai import OpenAI

client = OpenAI(
    api_key="YOUR_LLMAP_KEY",
    base_url="https://api.llmapi.ai/v1",
)

resp = client.chat.completions.create(
    model="claude-fable-5-1",
    messages=[
        {"role": "system", "content": "You are a precise product assistant."},
        {"role": "user", "content": "Give me three crisp launch checklist items."},
    ],
)
print(resp.choices[0].message.content)
{
  "model": "claude-fable-5-1",
  "messages": [
    {"role": "system", "content": "You are a precise product assistant."},
    {"role": "user", "content": "Give me three crisp launch checklist items."}
  ]
}

5 Core Capabilities

  • Analytical writing

    Produces clear analyses, comparisons, and decision memos from messy source material. Grounded in the model's chat role rather than generic chat claims.

  • Conversational UX

    Maintains coherent multi-turn assistant behavior for product chat surfaces.

  • Multi-step reasoning

    Breaks down complex problems into intermediate steps before answering. Reflects Anthropic positioning for this endpoint.

  • Long-context synthesis

    Summarizes and cross-references information across large prompts when context allows. Relevant for `claude-fable-5-1` workloads on LLM.API.

  • Instruction following

    Follows detailed system and user instructions with strong adherence to format and tone. Tuned to how teams typically call Claude Fable 5.1.

6 Most Valuable Use Cases

  • Multilingual localization drafts for UX copy with Claude Fable 5.1
  • Policy Q&A bots with careful refusal behavior
  • Internal knowledge assistants grounded with your retrieval layer with Claude Fable 5.1
  • Customer support copilots that draft accurate, on-brand replies
  • Data extraction into JSON for downstream systems with Claude Fable 5.1
  • Coding agents for refactors, tests, and PR explanations

Why Build on LLM.API?

One unified API. Every major model. Built-in reliability, cost control, and observability.

  • Intelligent AI Routing

    Automatically route each request to the best model across providers based on latency, cost, and quality—without changing your integration or redeploying code.

    One endpoint, every model.

  • Cost-Aware Execution

    Control spend with per-request cost estimation, smart model selection, and centralized quotas so teams can experiment fast without runaway bills or manual tracking.

    More performance, less spend.

  • Resilient Fallback Flows

    Define automatic, provider-agnostic fallbacks to keep your app up during outages, rate limits, or timeouts—no brittle failover logic scattered through your codebase.

    Never go dark on users.

  • Deep LLM Observability

    Trace every call across providers with logs, metrics, and request replay so you can debug, tune prompts, and optimize model choices from one unified dashboard.

    See every token, everywhere.

  • Task-Level Orchestration

    Describe tasks, not models. LLM.API maps them to the right tools, models, and prompts so you ship complex AI workflows with minimal glue code.

    Think tasks, not models.

  • High-Throughput Batch APIs

    Process millions of inferences efficiently with optimized batch pipelines, concurrency controls, and retry logic—all behind the same simple interface you use for single calls.

    Scale from 1 to millions.

Why run Claude Fable 5.1 on LLM.API?

  • Unified AI Routing

    Reach Claude Fable 5.1 and sibling models through one OpenAI-compatible endpoint.

  • Cost Control

    Practical: Compare provider price points and keep spend visible as you scale Claude Fable 5.1.

  • Reliability Layer

    Production: Retry and route across configured providers when a single upstream blips.

  • Observability

    Production: Trace prompts, tokens, and errors for Claude Fable 5.1 alongside the rest of your stack.

  • Drop-in SDKs

    Keep using familiar OpenAI client patterns with base URL https://api.llmapi.ai/v1.

  • Model Breadth

    Swap Claude Fable 5.1 for chat, media, or embedding alternatives without rewriting auth.

When to Use — When NOT to Use

Use it if...

  • You need a general-purpose text model for assistants, agents, or content workflows (Claude Fable 5.1)
  • Your prompts benefit from the model's family strengths (reasoning, speed, or cost) (Claude Fable 5.1)
  • You want OpenAI-compatible chat completions through a single LLM.API key (Claude Fable 5.1)
  • You need provider failover options exposed for this model id (Claude Fable 5.1)

Avoid if...

  • Your use case depends on unpublished proprietary benchmarks not listed here
  • You need guaranteed real-time hard latency SLAs without benchmarking the provider
  • You require on-prem only deployment with no cloud inference
  • You need pure embedding, OCR, or media generation instead of chat

BENCHMARKS

Claude Fable 5.1 benchmark scores

Intelligence index

This model53.
Tracked median24.

Scale: 0-100 index points

Output speed

This model67 t/s

Scale: 0-400 tokens per second

Reference price per 1M tokens

Input$10.00
Output$50.00

Bars compare input and output list prices for this model.

Artificial Analysis Intelligence Index53
Median index across all tracked models24
Output speed67 tokens/s
Reference input price$10.00 / 1M tokens
Reference output price$50.00 / 1M tokens

Independent scores published by Artificial Analysis (source). Reference prices are provider list prices, not LLM.API pricing.

RELIABILITY

Claude Fable 5.1 uptime, last 30 days

30-Day Uptime
97.55%
Past Incidents (30d)
13
Error rate (24h)
8.20%

Last 30 days

19/30 days operational | 97.55% uptime

Availability tracked for this model. Full history on the LLM Uptime Status page or the status hub. LLM.API routes around provider outages automatically.

COMMUNITY

What developers say about Claude models

Summarised from publicly published developer and community reviews of this model family. Opinions are the sources’, not LLM.API’s, and may not be specific to Claude Fable 5.1.

  • Reviewers consistently rank the Opus tier at or near the frontier for coding and agentic work, and several note the price/performance gap to rivals has narrowed.
  • A recurring complaint in community round-ups is verbosity — strong reasoning, but long answers and heavy token use unless you constrain output.
  • Teams report the Sonnet/Haiku tiers as the practical default for volume, keeping Opus for planning and hard debugging.

SOURCES

Frequently Asked Questions

  • What is the context length for Claude Fable 5.1?

    Reported context for Claude Fable 5.1 is 1M tokens. Always verify the active provider row if multiple providers are listed.

  • What are limitations of Claude Fable 5.1?

    Like other API models, Claude Fable 5.1 can be wrong, incomplete, or uneven on edge cases. Validate outputs for high-stakes use. Media/OCR/STT models additionally depend on input quality.

  • Is Claude Fable 5.1 a chat model?

    Yes—Claude Fable 5.1 is exposed as a chat/completions-style endpoint on LLM.API.

  • What is Claude Fable 5.1?

    Claude model for demanding reasoning and long-horizon agentic work. On LLM.API it is addressed as `claude-fable-5-1`.

  • Can I use tools or structured outputs with Claude Fable 5.1?

    Tool and/or structured-output flags appear on one or more providers for this model—confirm in the providers table.

  • When should I choose Claude Fable 5.1?

    Your prompts benefit from the model's family strengths (reasoning, speed, or cost) — especially when you specifically need Claude Fable 5.1.

  • Where is the canonical page for Claude Fable 5.1?

    https://llmapi.ai/models/anthropic-claude-fable-5-1/

  • Does Claude Fable 5.1 support streaming?

    Yes—at least one listed provider advertises streaming.

  • Which providers serve Claude Fable 5.1?

    LLM.API currently lists: anthropic, aws-bedrock. Availability can vary by region and account.

  • How is Claude Fable 5.1 priced on LLM.API?

    Listed pricing metadata shows: In $10.00 / 1M tokens · Out $50.00 / 1M tokens. LLM.API may offer discounted effective rates (illustrative ~30% callout vs list when available).. Confirm live rates in the LLM.API dashboard or docs before production budgeting.

COMPARE

Competitive Models

Get one key to every model

Swap your API key. Keep your code.

Start for free Talk to sales