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Comparison · 2 models · Updated Nov 2, 2026

Claude Fable 5.1 vs Inkling Small

Too close to call on our weighted score (Inkling Small 68, Claude Fable 5.1 66). The right pick depends on what you value most.

  1. Anthropic

    Claude Fable 5.1

    Released Sep 1, 2026

    66/100
    • ECI166.4
    • Price$10.00 / $50.00
    • Context1M
    Full specs Remove Claude Fable 5.1

  2. Thinking Machines

    Inkling Small

    Released Jul 30, 2026

    68/100
    • ECI150.5
    • Price$0.58 / $1.44
    • Context1.05M
    Full specs Remove Inkling Small

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01 — Verdict

Too close to call

It is close. Our weighted score puts them within 2 points (Inkling Small 68/100, Claude Fable 5.1 66/100), so choose by what matters most for your work: Claude Fable 5.1 for raw capability, Inkling Small on price and Inkling Small for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityClaude Fable 5.1Capabilities Index (ECI): Claude Fable 5.1 166.4 · Inkling Small 150.5
  • Lowest priceInkling SmallInkling Small $0.795 · Claude Fable 5.1 $20.00 per 1M tokens (3:1 blend)
  • Longest contextInkling SmallInkling Small 1,048,576 · Claude Fable 5.1 1,000,000 tokens
  • Widest inputsSame inputsClaude Fable 5.1: Text, Images, PDFs · Inkling Small: Text, Images, Audio
  • Self-hostingInkling SmallPublishes downloadable weights (Apache-2.0)
How the score is built
MeasureWeightClaude Fable 5.1Inkling Small
CapabilityCapabilities Index (ECI)50%9777
Price25%052
Inputs & features15%8070
Context window10%6061
Overall100%66/10068/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

Claude Fable 5.1 vs Inkling Small specifications side by side
SpecificationClaude Fable 5.1AnthropicInkling SmallThinking Machines
Capability
Capabilities Index (ECI)166.4 (best)150.5
ECI rank#6 of 165 (best)#58 of 165
GPQA DiamondGraduate-level science questions—88.5%
FrontierMath Tiers 1–3Research-level mathematics90.2% (best)46.3%
OTIS Mock AIME 2024–2025Competition mathematics100% (best)90.0%
SimpleQA VerifiedShort factual questions70.8% (best)19.1%
Price per million tokens
Input$10.00$0.58 (best)
Output$50.00$1.44 (best)
Cached input$0.25$0.116 (best)
Blended (3:1)$20.00$0.795 (best)
Long-context rateSame rateSame rate
Price sourceOfficial Anthropic APIOfficial Thinking Machines API
Limits
Context window1,000,000 tokens1,048,576 tokens (best)
Max output128,000 tokens1,048,576 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesNo
AudioNoYes
VideoNoNo
ReasoningYeslow · medium · high · xhigh · maxYeslow · medium · high · xhigh · max
Tool callingYesYes
Structured outputYesNo
Availability
WeightsProprietaryOpenApache-2.0
API model IDclaude-fable-5-1thinkingmachines/Inkling-Small
API providers37 (best)12
ReleasedSep 1, 2026Jul 30, 2026
Knowledge cutoffJun 2026—
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • Claude Fable 5.1$200.00
  • Inkling Small$8.68
04 — Questions

Which should you choose?

Which is better: Claude Fable 5.1 or Inkling Small?

It is close. Our weighted score puts them within 2 points (Inkling Small 68/100, Claude Fable 5.1 66/100), so choose by what matters most for your work: Claude Fable 5.1 for raw capability, Inkling Small on price and Inkling Small for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Claude Fable 5.1 or Inkling Small?

Inkling Small is cheaper at $0.58 input / $1.44 output per million tokens (official Thinking Machines API price). Claude Fable 5.1 costs $10.00 input / $50.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $0.795 per million tokens for Inkling Small versus $20.00 for Claude Fable 5.1 (25× as much).

Which scores higher on benchmarks?

Claude Fable 5.1 scores higher on the Capabilities Index (ECI): Claude Fable 5.1 166.4 (#6 of 165) and Inkling Small 150.5 (#58 of 165). Their confidence ranges do not overlap (163.6–170.8 vs 147.7–152.4), so the gap is a real one. On individual benchmarks: FrontierMath Tiers 1–3 — Claude Fable 5.1 90.2%, Inkling Small 46.3%; OTIS Mock AIME 2024–2025 — Claude Fable 5.1 100%, Inkling Small 90.0%; SimpleQA Verified — Claude Fable 5.1 70.8%, Inkling Small 19.1%.

Which is better for coding?

There are no published SWE-bench Verified results for Claude Fable 5.1 and Inkling Small yet, so there is no like-for-like coding score. On overall capability, Claude Fable 5.1 leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Which has the bigger context window?

Inkling Small has the largest context window at 1,048,576 tokens, against 1,000,000 for Claude Fable 5.1. Maximum output per response: Claude Fable 5.1 up to 128,000, Inkling Small up to 1,048,576 tokens.

Which can read images, PDFs, audio or video?

Claude Fable 5.1 accepts text, images and PDFs; Inkling Small accepts text, images and audio. They handle the same number of input types.

Are any of these open source?

Inkling Small publishes its weights (Apache-2.0) and can be self-hosted; Claude Fable 5.1 is proprietary.

Which is newer?

Claude Fable 5.1 is the newest, released Sep 1, 2026. Inkling Small came out Jul 30, 2026. Knowledge cutoff: Claude Fable 5.1 Jun 2026.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.

05 — Keep comparing

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