Enter opens the highlighted result. Esc closes.

Claude Fable 5 vs GPT-5.6 Terra

Claude Fable 5 leads GPT-5.6 Terra on coding, 79.3 to 63.9 on the Vibe Coding Index, and GPT-5.6 Terra costs 4.2x less per output token ($12.00 vs $50.00 per million). Updated October 22, 2026; 119 benchmarks have a result for both.

Replace Claude Fable 5 Replace GPT-5.6 Terra
Claude Fable 5Anthropic
Coding
79.3
Overall
79.0
Output $/M
$50.00
109
GPT-5.6 TerraOpenAI
Coding
63.9
Overall
68.1
Output $/M
$12.00
8
vs boards won of 119 shared, 2 tied

Claude Fable 5 or GPT-5.6 Terra: which to pick

Pick Claude Fable 5 for coding: it scores 79.3 on the Vibe Coding Index against 63.9 for GPT-5.6 Terra.

Pick GPT-5.6 Terra for output tokens 4.2x cheaper ($12.00 vs $50.00 per million) and a lower cost per solved task ($0.42 against $2.16).

Model AClaude Fable 5Anthropic79.3/1006 independent benchmarks$2.16 per solved taskModel BGPT-5.6 TerraOpenAI63.9/1006 independent benchmarks$0.42 per solved task
Shared results
119
Claude Fable 5 only
8
GPT-5.6 Terra only
8
Like-for-like categories
8 of 9

Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.

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 79.3 from 6 benchmarks, GPT-5.6 Terra 63.9 from 6 benchmarks.
Widest category
Agentic work, 14.0 points apart on average over 19 shared benchmarks.
Widest single gap
Kagi LLM Benchmark: Claude Fable 5 91.4% against GPT-5.6 Terra 51.3%, 40.1 points apart on a 0 to 100 scale.
Output price
Claude Fable 5 $50.00 against GPT-5.6 Terra $12.00 per million output tokens, 4.2x apart.
Context window
Claude Fable 5 takes 1M tokens, GPT-5.6 Terra 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-5.6 TerraTies
Coding1721 tie
Intelligence20
Agentic work181
Reasoning1421 tie
Math60
Knowledge110
Web design90
General323
All shared boards10982 ties
CodingLike-for-likeSix of these boards feed the Vibe Coding Index172
Coding benchmarks for Claude Fable 5 and GPT-5.6 Terra
BenchmarkClaude Fable 5GPT-5.6 TerraLeader
LiveBench coding98.3%86.2%Claude Fable 5
LMArena WebDev16241522Claude Fable 5
AA Coding Index76.576.7GPT-5.6 Terra
LiveCodeBench (Vals AI)89.8%85.9%Claude Fable 5
SWE-bench Verified (Vals AI)95.0%95.4%GPT-5.6 Terra
Terminal-Bench 4 (Vals AI)41.4%22.7%Claude Fable 5
Vibe Code Bench (Vals AI)90.3%74.6%Claude Fable 5
Code migration (Vals AI)55.1%47.8%Claude Fable 5
ProgramBench (Vals AI)2.0%0.5%Claude Fable 5
IOI (Vals AI)Not measured87.6%Only GPT-5.6 Terra measured
Terminal-Bench 2.1 (Vals AI)80.5%77.5%Claude Fable 5
Vibe Code Bench 1-100 (Vals AI)Not measured14.8%Only GPT-5.6 Terra measured
SkillsBench (Vals AI)Not measured58.9%Only GPT-5.6 Terra measured
CyberBench (Vals AI)Not measured72.1%Only GPT-5.6 Terra measured
SciCode61.0%55.0%Claude Fable 5
Terminal-Bench Hard (Artificial Analysis run)62.9%62.9%Tie
FrontierCode53.5%41.3%Claude Fable 5
FrontierSWE47.0%Not measuredOnly Claude Fable 5 measured
GSO-Bench78.4%Not measuredOnly Claude Fable 5 measured
WeirdML91.9%78.3%Claude Fable 5
MirrorCode63.9%Not measuredOnly Claude Fable 5 measured
ALE-Bench2041.31951.4Claude Fable 5
LMArena Text: coding15181485Claude Fable 5
LMArena Text: software and IT15131482Claude Fable 5
LMArena WebDev: React16311513Claude Fable 5
LMArena WebDev: HTML16511526Claude Fable 5
LMArena WebDev: from an image16231541Claude Fable 5
SciCodeNot measured10.8%Only GPT-5.6 Terra measured
Neither model has a result on the other 11 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Fable 5 and GPT-5.6 Terra
BenchmarkClaude Fable 5GPT-5.6 TerraLeader
AA Intelligence Index49.642.1Claude Fable 5
Epoch Capabilities Index163.4160.1Claude Fable 5
Agentic workLike-for-likePublic boards, shown as published, kept out of the index181
Agentic work benchmarks for Claude Fable 5 and GPT-5.6 Terra
BenchmarkClaude Fable 5GPT-5.6 TerraLeader
AA Agentic Index50.743.2Claude Fable 5
Design Arena: agents building web apps12611120Claude Fable 5
Design Arena: agents building full-stack apps12801061Claude Fable 5
Design Arena: agents building mobile apps12641111Claude Fable 5
Design Arena: agents building Android apps12841062Claude Fable 5
Design Arena: agents building Godot games1292Not measuredOnly Claude Fable 5 measured
Design Arena: agents building games12851083Claude Fable 5
Design Arena: HTML slides12271058Claude Fable 5
Design Arena: PowerPoint slides12701105Claude Fable 5
LiveBench research86.9%60.4%Claude Fable 5
LiveBench browser92.0%84.0%Claude Fable 5
LiveBench long agentic53.2%48.4%Claude Fable 5
SREBench (Vals AI)Not measured9.5%Only GPT-5.6 Terra measured
Finance Agent (Vals AI)56.3%54.4%Claude Fable 5
Tax Agent Bench (Vals AI)38.3%30.0%Claude Fable 5
Legal Research Bench (Vals AI)49.5%41.4%Claude Fable 5
Excel Modeling Benchmark (Vals AI)73.7%66.2%Claude Fable 5
Terminal-Bench-Science (Vals AI)15.7%10.0%Claude Fable 5
τ²-Bench Telecom98.5%86.3%Claude Fable 5
APEX-Agents63.6%58.2%Claude Fable 5
Remote Labor Index16.1%Not measuredOnly Claude Fable 5 measured
BALROGNot measured53.2%Only GPT-5.6 Terra measured
PostTrainBench41.8%Not measuredOnly Claude Fable 5 measured
Vending-Bench 2$5,680$7,343GPT-5.6 Terra
LMArena Search1229Not measuredOnly Claude Fable 5 measured
Neither model has a result on the other 16 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index142
Reasoning benchmarks for Claude Fable 5 and GPT-5.6 Terra
BenchmarkClaude Fable 5GPT-5.6 TerraLeader
GPQA Diamond93.2%90.9%Claude Fable 5
LiveBench reasoning89.7%90.6%GPT-5.6 Terra
MMMU Pro (Vals AI)89.3%86.5%Claude Fable 5
GPQA Diamond (Artificial Analysis run)92.6%92.5%Claude Fable 5
Humanity's Last Exam (Artificial Analysis run)55.5%42.9%Claude Fable 5
GPQA Diamond (Epoch AI run)85.9%93.3%GPT-5.6 Terra
ARC-AGI98.5%96.5%Claude Fable 5
ARC-AGI-289.2%83.9%Claude Fable 5
SimpleBench81.9%48.9%Claude Fable 5
Chess puzzles47.0%47.0%Tie
Mystery game puzzles52.0%35.0%Claude Fable 5
EBR-bench39.5%Not measuredOnly Claude Fable 5 measured
LMArena Text: hard prompts15071469Claude Fable 5
LMArena Text: expert15341496Claude Fable 5
LMArena Text: hard prompts in English15091465Claude Fable 5
LMArena Vision: diagrams13571295Claude Fable 5
LMArena Vision: homework13611312Claude Fable 5
Kagi LLM Benchmark91.4%51.3%Claude Fable 5
Neither model has a result on the other 4 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index60
Math benchmarks for Claude Fable 5 and GPT-5.6 Terra
BenchmarkClaude Fable 5GPT-5.6 TerraLeader
OTIS Mock AIME100.0%99.7%Claude Fable 5
FrontierMath, tiers 1 to 387.0%86.0%Claude Fable 5
FrontierMath, tier 490.2%70.7%Claude Fable 5
ProofBench95.0%74.0%Claude Fable 5
LMArena Text: math15161465Claude Fable 5
LMArena Text: mathematical work15151478Claude Fable 5
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index110
Knowledge benchmarks for Claude Fable 5 and GPT-5.6 Terra
BenchmarkClaude Fable 5GPT-5.6 TerraLeader
MMLU Pro91.5%86.7%Claude Fable 5
LegalBench (Vals AI)88.6%85.1%Claude Fable 5
CorpFin (Vals AI)71.8%65.3%Claude Fable 5
TaxEval (Vals AI)76.9%76.2%Claude Fable 5
MortgageTax (Vals AI)68.9%67.3%Claude Fable 5
MedCode (Vals AI)56.1%43.4%Claude Fable 5
SimpleQA Verified70.7%43.2%Claude Fable 5
LMArena Text: science15061452Claude Fable 5
LMArena Text: medicine and healthcare14801430Claude Fable 5
LMArena Text: legal and government14981461Claude Fable 5
LMArena Text: business and finance14801448Claude Fable 5
FACTS Benchmark SuiteNot measured52.0%Only GPT-5.6 Terra measured
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index90
Web design benchmarks for Claude Fable 5 and GPT-5.6 Terra
BenchmarkClaude Fable 5GPT-5.6 TerraLeader
Design Arena: websites12951268Claude Fable 5
Design Arena: UI components13161256Claude Fable 5
Design Arena: game dev13351229Claude Fable 5
Design Arena: data viz13041240Claude Fable 5
Design Arena: 3D13181134Claude Fable 5
Design Arena: all code categories13101241Claude Fable 5
Design Arena: SVG13021219Claude Fable 5
Design Arena: ASCII art13291177Claude Fable 5
LiveBench design84.7%76.0%Claude Fable 5
GeneralLike-for-likePublic boards, shown as published, kept out of the index323
General benchmarks for Claude Fable 5 and GPT-5.6 Terra
BenchmarkClaude Fable 5GPT-5.6 TerraLeader
LiveBench data analysis80.5%79.3%Claude Fable 5
Public Benefits Bench (Vals AI)70.4%62.4%Claude Fable 5
SAGE (Vals AI)51.9%47.0%Claude Fable 5
MedScribe (Vals AI)88.5%82.9%Claude Fable 5
Vals Multimodal Index74.2%65.1%Claude Fable 5
IFBench63.5%71.2%GPT-5.6 Terra
Long context reasoning (AA-LCR)82.3%83.0%GPT-5.6 Terra
DTBench98.4%93.3%Claude Fable 5
LMCA61.2%54.9%Claude Fable 5
Surface Evolver Bench95.0%83.8%Claude Fable 5
Furniture assembly35.8%54.2%GPT-5.6 Terra
LMArena Text14911448Claude Fable 5
LMArena Text: instruction following15021456Claude Fable 5
LMArena Text: creative writing14941413Claude Fable 5
LMArena Vision13251271Claude Fable 5
LMArena Text: English14981449Claude Fable 5
LMArena Text: non-English14821441Claude Fable 5
LMArena Text: Chinese15431514Claude Fable 5
LMArena Text: German14861460Claude Fable 5
LMArena Text: Japanese15041454Claude Fable 5
LMArena Text: Korean14871427Claude Fable 5
LMArena Text: French15051466Claude Fable 5
LMArena Text: Spanish14981451Claude Fable 5
LMArena Text: Russian15031452Claude Fable 5
LMArena Text: Polish14941446Claude Fable 5
LMArena Text: multi-turn15041453Claude Fable 5
LMArena Text: longer queries15101454Claude Fable 5
LMArena Text: writing and language15011431Claude Fable 5
LMArena Text: entertainment and media14821418Claude Fable 5
LMArena Vision: English13231272Claude Fable 5
LMArena Vision: Chinese13731337Claude Fable 5
LMArena Vision: reading text13371278Claude Fable 5
LMArena Vision: humor13411236Claude Fable 5
LMArena Vision: creative writing13381248Claude Fable 5
LMArena Document14961472Claude Fable 5
Neither model has a result on the other 11 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-5.6 Terra
BenchmarkClaude Fable 5GPT-5.6 TerraLeader
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-5.6 Terra$0.0080Fits in one request

GPT-5.6 Terra costs less

Repository review

50K input + 3K output tokens

Claude Fable 5$0.650Fits in one request
GPT-5.6 Terra$0.136Fits in one request

GPT-5.6 Terra costs less

Agent loop

200K input + 10K output tokens

Claude Fable 5$2.50Fits in one request
GPT-5.6 Terra$0.520Fits in one request

GPT-5.6 Terra costs less

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-5.6 Terra
SpecificationAnthropic Claude Fable 5OpenAI GPT-5.6 Terra
MakerAnthropicOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedJune 9, 2026July 9, 2026
Context window1M1.05M
Input $/Mtok$10.00$2.00
Output $/Mtok$50.00$12.00
Coding index79.363.9
Independent measurements behind it66
Cost per solved task$2.16$0.42
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Fable 5 better than GPT-5.6 Terra for coding?

Pick Claude Fable 5 for coding: it scores 79.3 on the Vibe Coding Index against 63.9 for GPT-5.6 Terra. Pick GPT-5.6 Terra for output tokens 4.2x cheaper ($12.00 vs $50.00 per million) and a lower cost per solved task ($0.42 against $2.16).

Which is cheaper, Claude Fable 5 or GPT-5.6 Terra?

Claude Fable 5 costs $10.00 per million input tokens and $50.00 per million output tokens; GPT-5.6 Terra costs $2.00 and $12.00. Per solved SWE-bench Verified task, Claude Fable 5 costs $2.16 and GPT-5.6 Terra $0.42.

Which has the bigger context window, Claude Fable 5 or GPT-5.6 Terra?

GPT-5.6 Terra, with 1.05M tokens against 1M.

How many benchmarks is the Claude Fable 5 vs GPT-5.6 Terra comparison based on?

119 benchmarks have a result for both models as of October 22, 2026. Claude Fable 5's coding index rests on 6 independent benchmarks and GPT-5.6 Terra's on 6. Where only one model has a result, the page says so instead of naming a winner.

Compare next

Embed this comparison on your site

Free under CC BY 4.0, while the source link stays visible. Preview the frame · Terms and other embeds

<iframe src="https://llmbenchmark.ai/embed/compare/claude-fable-5-vs-gpt-5-6-terra" title="Claude Fable 5 vs GPT-5.6 Terra, LLMBenchmark.ai" width="100%" height="360" style="border:0;max-width:100%" loading="lazy"></iframe>
<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/claude-fable-5-vs-gpt-5-6-terra">LLMBenchmark.ai, Claude Fable 5 vs GPT-5.6 Terra</a></p>