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Claude Fable 5 vs GPT-6 Astra

Updated October 21, 2026. 103 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Claude Fable 5 Replace GPT-6 Astra
Claude Fable 5Anthropic
Coding
82.1
Overall
49.6
Output $/M
$50.00
54
GPT-6 AstraOpenAI
Coding
88.7
Overall
52.7
Output $/M
$50.00
47
vs boards won of 103 shared, 2 tied

Decision reading

Pick GPT-6 Astra for coding: it scores 88.7 on the Vibe Coding Index against 82.1 for Claude Fable 5.

Pick Claude Fable 5 when what matters is LiveBench coding or Vibe Code Bench (Vals AI), where it leads.

Model AClaude Fable 5Anthropic82.1/1002 independent benchmarks$2.16 per solved taskModel BGPT-6 AstraOpenAI88.7/1002 independent benchmarksNo cost per solved task
Shared results
103
Claude Fable 5 only
23
GPT-6 Astra only
16
Like-for-like categories
8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

At a glance

Coding index
Claude Fable 5 82.1 from 2 benchmarks, GPT-6 Astra 88.7 from 2 benchmarks.
Widest category
Agentic work, 13.5 points apart on average over 17 shared benchmarks.
Widest single gap
Vending-Bench 2: Claude Fable 5 $5,680 against GPT-6 Astra $15,515, 61.5 points apart on a 0 to 100 scale.
Output price
Both cost $50.00 per million output tokens.
Context window
Claude Fable 5 takes 1M tokens, GPT-6 Astra 1.05M.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
CategoryClaude Fable 5BarsGPT-6 AstraTies
Coding713
Intelligence02
Agentic work710
Reasoning671 tie
Math231 tie
Knowledge51
Web design18
General263
All shared boards54472 ties
CodingLike-for-likeFour of these boards feed the Vibe Coding Index713
Coding benchmarks for Claude Fable 5 and GPT-6 Astra
BenchmarkClaude Fable 5GPT-6 AstraLeader
LiveBench coding98.3%93.7%Claude Fable 5
LMArena WebDev16241774GPT-6 Astra
AA Coding Index76.576.9GPT-6 Astra
LiveCodeBench (Vals AI)89.8%Not measuredOnly Claude Fable 5 measured
SWE-bench Verified (Vals AI)95.0%Not measuredOnly Claude Fable 5 measured
Terminal-Bench 4 (Vals AI)41.4%59.6%GPT-6 Astra
Vibe Code Bench (Vals AI)90.3%89.6%Claude Fable 5
Code migration (Vals AI)55.1%67.7%GPT-6 Astra
ProgramBench (Vals AI)2.0%5.5%GPT-6 Astra
IOI (Vals AI)Not measured100.0%Only GPT-6 Astra measured
Terminal-Bench 2.1 (Vals AI)80.5%87.3%GPT-6 Astra
SWE-bench Multimodal (Vals AI)Not measured43.3%Only GPT-6 Astra measured
Vibe Code Bench 1-100 (Vals AI)Not measured27.6%Only GPT-6 Astra measured
CyberBench (Vals AI)Not measured41.1%Only GPT-6 Astra measured
SciCode61.0%56.5%Claude Fable 5
Terminal-Bench Hard (Artificial Analysis run)62.9%Not measuredOnly Claude Fable 5 measured
FrontierCode53.5%53.3%Claude Fable 5
FrontierSWE47.0%65.5%GPT-6 Astra
GSO-Bench78.4%79.4%GPT-6 Astra
WeirdML91.9%93.3%GPT-6 Astra
MirrorCode63.9%46.7%Claude Fable 5
ALE-Bench2041.32951.3GPT-6 Astra
LMArena Text: coding15181489Claude Fable 5
LMArena Text: software and IT15131474Claude Fable 5
LMArena WebDev: React16311798GPT-6 Astra
LMArena WebDev: HTML16511775GPT-6 Astra
LMArena WebDev: from an image16231726GPT-6 Astra
Neither model has a result on the other 11 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for Claude Fable 5 and GPT-6 Astra
BenchmarkClaude Fable 5GPT-6 AstraLeader
AA Intelligence Index49.652.7GPT-6 Astra
Epoch Capabilities Index163.4168.8GPT-6 Astra
Agentic workLike-for-likePublic boards, shown as published, kept out of the index710
Agentic work benchmarks for Claude Fable 5 and GPT-6 Astra
BenchmarkClaude Fable 5GPT-6 AstraLeader
AA Agentic Index50.751.0GPT-6 Astra
Design Arena: agents building web apps12611372GPT-6 Astra
Design Arena: agents building full-stack apps12801357GPT-6 Astra
Design Arena: agents building mobile apps12641312GPT-6 Astra
Design Arena: agents building Android apps1289Not measuredOnly Claude Fable 5 measured
Design Arena: agents building Godot games12921348GPT-6 Astra
Design Arena: agents building games1285Not measuredOnly Claude Fable 5 measured
Design Arena: HTML slides1277Not measuredOnly Claude Fable 5 measured
Design Arena: PowerPoint slides12951245Claude Fable 5
Design Arena: spreadsheetsNot measured1380Only GPT-6 Astra measured
LiveBench research86.9%85.2%Claude Fable 5
LiveBench browser92.0%84.0%Claude Fable 5
LiveBench long agentic53.2%82.4%GPT-6 Astra
SREBench (Vals AI)Not measured56.9%Only GPT-6 Astra measured
Finance Agent (Vals AI)56.3%53.5%Claude Fable 5
Tax Agent Bench (Vals AI)38.3%20.7%Claude Fable 5
Legal Research Bench (Vals AI)49.5%39.4%Claude Fable 5
Harvey's Legal Agent Benchmark (Vals AI)Not measured7.1%Only GPT-6 Astra measured
Excel Modeling Benchmark (Vals AI)73.7%71.7%Claude Fable 5
BioMysteryBench (Vals AI)Not measured79.3%Only GPT-6 Astra measured
Terminal-Bench-Science (Vals AI)15.7%62.9%GPT-6 Astra
Vals Science IndexNot measured65.1%Only GPT-6 Astra measured
Time Horizon Index (Vals AI)Not measured90.5%Only GPT-6 Astra measured
CUA-bench (Vals AI)Not measured19.2%Only GPT-6 Astra measured
Robo-bench (Vals AI)Not measured23.3%Only GPT-6 Astra measured
τ²-Bench Telecom98.5%Not measuredOnly Claude Fable 5 measured
APEX-Agents63.6%64.7%GPT-6 Astra
Remote Labor Index16.1%20.8%GPT-6 Astra
BALROGNot measured68.3%Only GPT-6 Astra measured
PostTrainBench41.8%Not measuredOnly Claude Fable 5 measured
SpireClimbNot measured25.7%Only GPT-6 Astra measured
Vending-Bench 2$5,680$15,515GPT-6 Astra
LMArena Search1229Not measuredOnly Claude Fable 5 measured
Neither model has a result on the other 6 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index67
Reasoning benchmarks for Claude Fable 5 and GPT-6 Astra
BenchmarkClaude Fable 5GPT-6 AstraLeader
GPQA Diamond93.2%Not measuredOnly Claude Fable 5 measured
LiveBench reasoning89.7%92.7%GPT-6 Astra
MysteryMechanism (Vals AI)Not measured53.1%Only GPT-6 Astra measured
MMMU Pro (Vals AI)89.3%Not measuredOnly Claude Fable 5 measured
GPQA Diamond (Artificial Analysis run)92.6%96.3%GPT-6 Astra
Humanity's Last Exam (Artificial Analysis run)55.5%54.7%Claude Fable 5
GPQA Diamond (Epoch AI run)85.9%95.8%GPT-6 Astra
ARC-AGI98.5%98.5%Tie
ARC-AGI-289.2%95.0%GPT-6 Astra
SimpleBench81.9%Not measuredOnly Claude Fable 5 measured
Chess puzzles47.0%74.0%GPT-6 Astra
Mystery game puzzles52.0%84.0%GPT-6 Astra
EBR-bench39.5%76.2%GPT-6 Astra
LMArena Text: hard prompts15071463Claude Fable 5
LMArena Text: expert15341489Claude Fable 5
LMArena Text: hard prompts in English15091464Claude Fable 5
LMArena Vision: diagrams13571297Claude Fable 5
LMArena Vision: homework13611337Claude Fable 5
Neither model has a result on the other 3 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index23
Math benchmarks for Claude Fable 5 and GPT-6 Astra
BenchmarkClaude Fable 5GPT-6 AstraLeader
OTIS Mock AIME100.0%100.0%Tie
FrontierMath, tiers 1 to 387.0%93.7%GPT-6 Astra
FrontierMath, tier 490.2%97.6%GPT-6 Astra
ProofBench95.0%99.0%GPT-6 Astra
LMArena Text: math15161465Claude Fable 5
LMArena Text: mathematical work15151484Claude Fable 5
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index51
Knowledge benchmarks for Claude Fable 5 and GPT-6 Astra
BenchmarkClaude Fable 5GPT-6 AstraLeader
MMLU Pro91.5%Not measuredOnly Claude Fable 5 measured
LegalBench (Vals AI)88.6%Not measuredOnly Claude Fable 5 measured
CorpFin (Vals AI)71.8%Not measuredOnly Claude Fable 5 measured
TaxEval (Vals AI)76.9%Not measuredOnly Claude Fable 5 measured
MortgageTax (Vals AI)68.9%Not measuredOnly Claude Fable 5 measured
MedCode (Vals AI)56.1%48.5%Claude Fable 5
SimpleQA Verified70.7%75.6%GPT-6 Astra
LMArena Text: science15061451Claude Fable 5
LMArena Text: medicine and healthcare14801425Claude Fable 5
LMArena Text: legal and government14981462Claude Fable 5
LMArena Text: business and finance14801439Claude Fable 5
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index18
Web design benchmarks for Claude Fable 5 and GPT-6 Astra
BenchmarkClaude Fable 5GPT-6 AstraLeader
Design Arena: websites12961337GPT-6 Astra
Design Arena: UI components13181394GPT-6 Astra
Design Arena: game dev13361474GPT-6 Astra
Design Arena: data viz13041335GPT-6 Astra
Design Arena: 3D13191501GPT-6 Astra
Design Arena: all code categories13101379GPT-6 Astra
Design Arena: SVG13021431GPT-6 Astra
Design Arena: ASCII art13281359GPT-6 Astra
LiveBench design84.7%82.0%Claude Fable 5
GeneralLike-for-likePublic boards, shown as published, kept out of the index263
General benchmarks for Claude Fable 5 and GPT-6 Astra
BenchmarkClaude Fable 5GPT-6 AstraLeader
Vals IndexNot measured65.0%Only GPT-6 Astra measured
LiveBench data analysis80.5%83.0%GPT-6 Astra
Public Benefits Bench (Vals AI)70.4%Not measuredOnly Claude Fable 5 measured
SAGE (Vals AI)51.9%46.4%Claude Fable 5
MedScribe (Vals AI)88.5%87.9%Claude Fable 5
Vals Multimodal Index74.2%Not measuredOnly Claude Fable 5 measured
IFBench63.5%Not measuredOnly Claude Fable 5 measured
Long context reasoning (AA-LCR)82.3%80.7%Claude Fable 5
DTBench98.4%97.3%Claude Fable 5
LMCA61.2%64.4%GPT-6 Astra
Surface Evolver Bench95.0%Not measuredOnly Claude Fable 5 measured
Furniture assembly35.8%80.0%GPT-6 Astra
LMArena Text14911441Claude Fable 5
LMArena Text: instruction following15021455Claude Fable 5
LMArena Text: creative writing14941420Claude Fable 5
LMArena Vision13251280Claude Fable 5
LMArena Text: English14981447Claude Fable 5
LMArena Text: non-English14821432Claude Fable 5
LMArena Text: Chinese15431489Claude Fable 5
LMArena Text: German14861459Claude Fable 5
LMArena Text: Japanese15041405Claude Fable 5
LMArena Text: Korean14871428Claude Fable 5
LMArena Text: French15051432Claude Fable 5
LMArena Text: Spanish14981422Claude Fable 5
LMArena Text: Russian15031438Claude Fable 5
LMArena Text: Polish14941422Claude Fable 5
LMArena Text: multi-turn15041447Claude Fable 5
LMArena Text: longer queries15101460Claude Fable 5
LMArena Text: writing and language15011437Claude Fable 5
LMArena Text: entertainment and media14821427Claude Fable 5
LMArena Vision: English13231280Claude Fable 5
LMArena Vision: Chinese13731361Claude Fable 5
LMArena Vision: reading text13371292Claude Fable 5
LMArena Vision: humor1341Not measuredOnly Claude Fable 5 measured
LMArena Vision: creative writing13381286Claude Fable 5
LMArena Document1496Not measuredOnly Claude Fable 5 measured
Neither model has a result on the other 10 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Fable 5 and GPT-6 Astra
BenchmarkClaude Fable 5GPT-6 AstraLeader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

Claude Fable 5$0.035Fits in one request
GPT-6 Astra$0.035Fits in one request

Same cost

Repository review

50K input + 3K output tokens

Claude Fable 5$0.650Fits in one request
GPT-6 Astra$0.650Fits in one request

Same cost

Agent loop

200K input + 10K output tokens

Claude Fable 5$2.50Fits in one request
GPT-6 Astra$2.50Fits in one request

Same cost

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of Claude Fable 5 and GPT-6 Astra
SpecificationAnthropic Claude Fable 5OpenAI GPT-6 Astra
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedJune 9, 2026September 4, 2026
Context window1M1.05M
Input $/Mtok$10.00$10.00
Output $/Mtok$50.00$50.00
Coding index82.188.7
Independent measurements behind it22
Cost per solved task$2.16Not computable
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Fable 5 better than GPT-6 Astra for coding?

Pick GPT-6 Astra for coding: it scores 88.7 on the Vibe Coding Index against 82.1 for Claude Fable 5. Pick Claude Fable 5 when what matters is LiveBench coding or Vibe Code Bench (Vals AI), where it leads.

Which is cheaper, Claude Fable 5 or GPT-6 Astra?

Claude Fable 5 costs $10.00 per million input tokens and $50.00 per million output tokens; GPT-6 Astra costs $10.00 and $50.00. Cost per solved task is known for Claude Fable 5 only.

Which has the bigger context window, Claude Fable 5 or GPT-6 Astra?

GPT-6 Astra, with 1.05M tokens against 1M.

How many benchmarks is the Claude Fable 5 vs GPT-6 Astra comparison based on?

103 benchmarks have a result for both models as of October 21, 2026. Claude Fable 5's coding index rests on 2 independent benchmarks and GPT-6 Astra's on 2. Where only one model has a result, the page says so instead of naming a winner.

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