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Comparison · 3 models · Updated Nov 2, 2026

Claude Fable 5.1 vs DeepSeek V4.1 Flash 1017 vs GPT-6 Astra

DeepSeek V4.1 Flash 1017 comes out ahead, 79 to 68 and 66 on our weighted score, and it is the cheaper option too.

  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. Our pick

    DeepSeek

    DeepSeek V4.1 Flash 1017

    Released Oct 17, 2026New

    79/100
    • ECI158.8
    • Price$0.15 / $0.60
    • Context1M
    Full specs Remove DeepSeek V4.1 Flash 1017

  3. OpenAI

    GPT-6 Astra

    Released Sep 4, 2026New

    68/100
    • ECI169.1
    • Price$10.00 / $50.00
    • Context1.05M
    Full specs Remove GPT-6 Astra
01 — Verdict

DeepSeek V4.1 Flash 1017 is our pick

DeepSeek V4.1 Flash 1017 is the better all-round choice, scoring 79/100 against GPT-6 Astra (68) and Claude Fable 5.1 (66). It leads on price. GPT-6 Astra wins on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT-6 AstraCapabilities Index (ECI): GPT-6 Astra 169.1 · Claude Fable 5.1 166.4 · DeepSeek V4.1 Flash 1017 158.8
  • Lowest priceDeepSeek V4.1 Flash 1017DeepSeek V4.1 Flash 1017 $0.263 · Claude Fable 5.1 $20.00 · GPT-6 Astra $20.00 per 1M tokens (3:1 blend)
  • Longest contextGPT-6 AstraGPT-6 Astra 1,050,000 · Claude Fable 5.1 1,000,000 · DeepSeek V4.1 Flash 1017 1,000,000 tokens
  • Widest inputsClaude Fable 5.1 and GPT-6 AstraClaude Fable 5.1: Text, Images, PDFs · DeepSeek V4.1 Flash 1017: Text, Images · GPT-6 Astra: Text, Images, PDFs
  • Self-hostingDeepSeek V4.1 Flash 1017Publishes downloadable weights (MIT)
How the score is built
MeasureWeightClaude Fable 5.1DeepSeek V4.1 Flash 1017GPT-6 Astra
CapabilityCapabilities Index (ECI)50%9787100
Price25%0740
Inputs & features15%807080
Context window10%606061
Overall100%66/10079/10068/100
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 DeepSeek V4.1 Flash 1017 vs GPT-6 Astra specifications side by side
SpecificationClaude Fable 5.1AnthropicDeepSeek V4.1 Flash 1017DeepSeekGPT-6 AstraOpenAI
Capability
Capabilities Index (ECI)166.4158.8169.1 (best)
ECI rank#6 of 165#19 of 165#1 of 165 (best)
GPQA DiamondGraduate-level science questions—93.2%95.8% (best)
FrontierMath Tiers 1–3Research-level mathematics90.2%71.2%93.7% (best)
OTIS Mock AIME 2024–2025Competition mathematics100% (best)99.4%100% (best)
SimpleQA VerifiedShort factual questions70.8%42.5%75.6% (best)
Price per million tokens
Input$10.00$0.15 (best)$10.00
Output$50.00$0.60 (best)$50.00
Cached input$0.25$0.003 (best)$1.00
Blended (3:1)$20.00$0.263 (best)$20.00
Long-context rateSame rateSame rateOver 272K: $20.00 / $75.00
Price sourceOfficial Anthropic APIOfficial DeepSeek APIOfficial OpenAI API
Limits
Context window1,000,000 tokens1,000,000 tokens1,050,000 tokens (best)
Max output128,000 tokens384,000 tokens (best)128,000 tokens
Inputs and features
TextYesYesYes
ImagesYesYesYes
PDFsYesNoYes
AudioNoNoNo
VideoNoNoNo
ReasoningYeslow · medium · high · xhigh · maxYeslow · high · maxYeslow · medium · high · xhigh · max
Tool callingYesYesYes
Structured outputYesYesYes
Availability
WeightsProprietaryOpenMITProprietary
API model IDclaude-fable-5-1deepseek-flashgpt-6-astra
API providers3740 (best)37
ReleasedSep 1, 2026Oct 17, 2026Sep 4, 2026
Knowledge cutoffJun 2026May 2025Apr 30, 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
  • DeepSeek V4.1 Flash 1017$2.70
  • GPT-6 Astra$200.00
04 — Questions

Which should you choose?

Which is better: Claude Fable 5.1, DeepSeek V4.1 Flash 1017 or GPT-6 Astra?

DeepSeek V4.1 Flash 1017 is the better all-round choice, scoring 79/100 against GPT-6 Astra (68) and Claude Fable 5.1 (66). It leads on price. GPT-6 Astra wins on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Claude Fable 5.1, DeepSeek V4.1 Flash 1017 or GPT-6 Astra?

DeepSeek V4.1 Flash 1017 is cheaper at $0.15 input / $0.60 output per million tokens (official DeepSeek API price). Claude Fable 5.1 costs $10.00 input / $50.00 output per million tokens (official Anthropic API price); GPT-6 Astra costs $10.00 input / $50.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $0.263 per million tokens for DeepSeek V4.1 Flash 1017 versus $20.00 for Claude Fable 5.1 (76× as much) and $20.00 for GPT-6 Astra (76× as much).

Which scores higher on benchmarks?

GPT-6 Astra scores higher on the Capabilities Index (ECI): GPT-6 Astra 169.1 (#1 of 165), Claude Fable 5.1 166.4 (#6 of 165) and DeepSeek V4.1 Flash 1017 158.8 (#19 of 165). The confidence ranges of the top two overlap (165.9–174.3 vs 163.6–170.8), so treat the gap as small. On individual benchmarks: FrontierMath Tiers 1–3 — GPT-6 Astra 93.7%, Claude Fable 5.1 90.2%, DeepSeek V4.1 Flash 1017 71.2%; OTIS Mock AIME 2024–2025 — Claude Fable 5.1 100%, GPT-6 Astra 100%, DeepSeek V4.1 Flash 1017 99.4%; SimpleQA Verified — GPT-6 Astra 75.6%, Claude Fable 5.1 70.8%, DeepSeek V4.1 Flash 1017 42.5%.

Which is better for coding?

There are no published SWE-bench Verified results for Claude Fable 5.1, DeepSeek V4.1 Flash 1017 and GPT-6 Astra yet, so there is no like-for-like coding score. On overall capability, GPT-6 Astra leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.

Which has the bigger context window?

GPT-6 Astra has the largest context window at 1,050,000 tokens, against 1,000,000 for Claude Fable 5.1 and 1,000,000 for DeepSeek V4.1 Flash 1017. Maximum output per response: Claude Fable 5.1 up to 128,000, DeepSeek V4.1 Flash 1017 up to 384,000, GPT-6 Astra up to 128,000 tokens.

Which can read images, PDFs, audio or video?

Claude Fable 5.1 accepts text, images and PDFs; DeepSeek V4.1 Flash 1017 accepts text and images; GPT-6 Astra accepts text, images and PDFs. Claude Fable 5.1 handles the widest range of inputs.

Are any of these open source?

DeepSeek V4.1 Flash 1017 publishes its weights (MIT) and can be self-hosted; Claude Fable 5.1 and GPT-6 Astra is proprietary.

Which is newer?

DeepSeek V4.1 Flash 1017 is the newest, released Oct 17, 2026. GPT-6 Astra came out Sep 4, 2026; Claude Fable 5.1 came out Sep 1, 2026. Knowledge cutoff: Claude Fable 5.1 Jun 2026, DeepSeek V4.1 Flash 1017 May 2025, GPT-6 Astra Apr 30, 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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