Claude Fable 5.1 vs Inkling Small

Claude Fable 5.1 leads Inkling Small on coding, 84.2 to 27.3 on the Vibe Coding Index, and Inkling Small costs 41.7x less per output token ($1.20 vs $50.00 per million). Updated October 22, 2026; 78 benchmarks have a result for both.

Replace Claude Fable 5.1 Replace Inkling Small

Claude Fable 5.1Anthropic

Coding: 84.2
Overall: 84.7
Output $/M: $50.00

T Inkling SmallThinking Machines

Coding: 27.3
Overall: 43.6
Output $/M: $1.20

vs boards won of 78 shared

Claude Fable 5.1 or Inkling Small: which to pick

Pick Claude Fable 5.1 for coding: it scores 84.2 on the Vibe Coding Index against 27.3 for Inkling Small.

Pick Inkling Small for output tokens 41.7x cheaper ($1.20 vs $50.00 per million).

Model AClaude Fable 5.1Anthropic84.2/1005 independent benchmarksNo cost per solved task Model BInkling SmallThinking Machines27.3/1004 independent benchmarks$0.16 per solved task

78466

Shared results: 78
Claude Fable 5.1 only: 46
Inkling Small only: 6
Like-for-like categories: 7 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.

Coding
Vibe Coding Index, six public coding benchmarks
Claude Fable 5.1
Claude Fable 5.1 scores 84.2 against 27.3.
5 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Fable 5.1
Claude Fable 5.1 leads, 53.4 against 25.7.
Same board, both measured
Agentic work
AA Agentic Index
Claude Fable 5.1
Claude Fable 5.1 leads, 57.9 against 23.5.
Same board, both measured
Reasoning
GPQA Diamond
Claude Fable 5.1
Claude Fable 5.1 leads, 93.4% against 83.6%.
Same board, both measured
Knowledge
MMLU Pro
Claude Fable 5.1
Claude Fable 5.1 leads, 92.4% against 85.6%.
Same board, both measured
Web design
Design Arena: websites
No call
Only Claude Fable 5.1 has a Design Arena: websites result, 1312.
Directional only
General
Vals Index
No call
Only Inkling Small has a Vals Index result, 27.6%.
Directional only
Long documents
Listed context window
Claude Fable 5.1
Claude Fable 5.1 takes 1M tokens against 524K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Inkling Small
Claude Fable 5.1 $0.035, Inkling Small $0.0010 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Inkling Small has the number, $0.16.
Directional only

At a glance

Coding index: Claude Fable 5.1 84.2 from 5 benchmarks, Inkling Small 27.3 from 4 benchmarks.
Widest category: Math, 41.2 points apart on average over 6 shared benchmarks.
Widest single gap: ProofBench: Claude Fable 5.1 100.0% against Inkling Small 6.0%, 94.0 points apart on a 0 to 100 scale.
Output price: Claude Fable 5.1 $50.00 against Inkling Small $1.20 per million output tokens, 41.7x apart.
Context window: Claude Fable 5.1 takes 1M tokens, Inkling Small 524K.

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
Category	Claude Fable 5.1	Bars	Inkling Small	Ties
Coding	17		0
Intelligence	2		0
Agentic work	5		0
Reasoning	11		0
Math	6		0
Knowledge	10		0
General	27		0
All shared boards	78		0

CodingLike-for-likeSix of these boards feed the Vibe Coding Index170

Coding benchmarks for Claude Fable 5.1 and Inkling Small
Benchmark	Claude Fable 5.1	Inkling Small	Leader
LiveBench coding	97.7%	Not measured	Only Claude Fable 5.1 measured
LMArena WebDev	1743	1409	Claude Fable 5.1
AA Coding Index	81.6	52.9	Claude Fable 5.1
LiveCodeBench (Vals AI)	90.5%	85.9%	Claude Fable 5.1
SWE-bench Verified (Vals AI)	Not measured	82.2%	Only Inkling Small measured
Terminal-Bench 4 (Vals AI)	58.1%	0.0%	Claude Fable 5.1
Vibe Code Bench (Vals AI)	90.3%	19.1%	Claude Fable 5.1
Code migration (Vals AI)	54.6%	13.7%	Claude Fable 5.1
ProgramBench (Vals AI)	7.0%	0.5%	Claude Fable 5.1
IOI (Vals AI)	90.8%	9.3%	Claude Fable 5.1
Terminal-Bench 2.1 (Vals AI)	85.0%	55.1%	Claude Fable 5.1
SWE-bench Multimodal (Vals AI)	61.3%	Not measured	Only Claude Fable 5.1 measured
Vibe Code Bench 1-100 (Vals AI)	28.0%	Not measured	Only Claude Fable 5.1 measured
SkillsBench (Vals AI)	61.5%	33.6%	Claude Fable 5.1
CyberBench (Vals AI)	70.4%	64.1%	Claude Fable 5.1
SciCode	63.1%	49.7%	Claude Fable 5.1
FrontierCode	50.9%	Not measured	Only Claude Fable 5.1 measured
FrontierSWE	56.3%	Not measured	Only Claude Fable 5.1 measured
GSO-Bench	88.2%	Not measured	Only Claude Fable 5.1 measured
WeirdML	92.9%	Not measured	Only Claude Fable 5.1 measured
MirrorCode	73.3%	Not measured	Only Claude Fable 5.1 measured
ALE-Bench	2143.2	Not measured	Only Claude Fable 5.1 measured
LMArena Text: coding	1532	1450	Claude Fable 5.1
LMArena Text: software and IT	1530	1447	Claude Fable 5.1
LMArena WebDev: React	1792	1399	Claude Fable 5.1
LMArena WebDev: HTML	1684	1398	Claude Fable 5.1
LMArena WebDev: from an image	1722	1410	Claude Fable 5.1
Neither model has a result on the other 12 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20

Intelligence benchmarks for Claude Fable 5.1 and Inkling Small
Benchmark	Claude Fable 5.1	Inkling Small	Leader
AA Intelligence Index	53.4	25.7	Claude Fable 5.1
Epoch Capabilities Index	166.5	150.3	Claude Fable 5.1

Agentic workLike-for-likePublic boards, shown as published, kept out of the index50

Agentic work benchmarks for Claude Fable 5.1 and Inkling Small
Benchmark	Claude Fable 5.1	Inkling Small	Leader
AA Agentic Index	57.9	23.5	Claude Fable 5.1
Design Arena: agents building web apps	1318	Not measured	Only Claude Fable 5.1 measured
Design Arena: agents building full-stack apps	1326	Not measured	Only Claude Fable 5.1 measured
Design Arena: agents building mobile apps	1267	Not measured	Only Claude Fable 5.1 measured
Design Arena: agents building Godot games	1327	Not measured	Only Claude Fable 5.1 measured
Design Arena: PowerPoint slides	1305	Not measured	Only Claude Fable 5.1 measured
Design Arena: spreadsheets	1380	Not measured	Only Claude Fable 5.1 measured
LiveBench research	82.0%	Not measured	Only Claude Fable 5.1 measured
LiveBench browser	100.0%	Not measured	Only Claude Fable 5.1 measured
LiveBench long agentic	80.8%	Not measured	Only Claude Fable 5.1 measured
SREBench (Vals AI)	22.9%	Not measured	Only Claude Fable 5.1 measured
Finance Agent (Vals AI)	58.9%	41.3%	Claude Fable 5.1
Tax Agent Bench (Vals AI)	49.2%	15.4%	Claude Fable 5.1
Legal Research Bench (Vals AI)	55.3%	25.5%	Claude Fable 5.1
Harvey's Legal Agent Benchmark (Vals AI)	Not measured	2.9%	Only Inkling Small measured
Excel Modeling Benchmark (Vals AI)	76.7%	31.8%	Claude Fable 5.1
Terminal-Bench-Science (Vals AI)	40.0%	Not measured	Only Claude Fable 5.1 measured
Time Horizon Index (Vals AI)	63.3%	Not measured	Only Claude Fable 5.1 measured
CUA-bench (Vals AI)	13.2%	Not measured	Only Claude Fable 5.1 measured
Robo-bench (Vals AI)	5.8%	Not measured	Only Claude Fable 5.1 measured
APEX-Agents	68.6%	Not measured	Only Claude Fable 5.1 measured
Remote Labor Index	17.9%	Not measured	Only Claude Fable 5.1 measured
SpireClimb	2.0%	Not measured	Only Claude Fable 5.1 measured
Vending-Bench 2	$5,422	Not measured	Only Claude Fable 5.1 measured
LMArena Search	1246	Not measured	Only Claude Fable 5.1 measured
Neither model has a result on the other 16 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index110

Reasoning benchmarks for Claude Fable 5.1 and Inkling Small
Benchmark	Claude Fable 5.1	Inkling Small	Leader
GPQA Diamond	93.4%	83.6%	Claude Fable 5.1
LiveBench reasoning	91.7%	Not measured	Only Claude Fable 5.1 measured
MysteryMechanism (Vals AI)	47.8%	Not measured	Only Claude Fable 5.1 measured
MMMU Pro (Vals AI)	90.6%	Not measured	Only Claude Fable 5.1 measured
GPQA Diamond (Artificial Analysis run)	93.7%	89.5%	Claude Fable 5.1
Humanity's Last Exam (Artificial Analysis run)	59.1%	33.3%	Claude Fable 5.1
GPQA Diamond (Epoch AI run)	Not measured	88.5%	Only Inkling Small measured
ARC-AGI	97.5%	84.0%	Claude Fable 5.1
ARC-AGI-2	90.0%	40.1%	Claude Fable 5.1
Chess puzzles	48.0%	Not measured	Only Claude Fable 5.1 measured
Mystery game puzzles	58.0%	6.0%	Claude Fable 5.1
EBR-bench	57.1%	Not measured	Only Claude Fable 5.1 measured
LMArena Text: hard prompts	1528	1423	Claude Fable 5.1
LMArena Text: expert	1544	1441	Claude Fable 5.1
LMArena Text: hard prompts in English	1522	1429	Claude Fable 5.1
LMArena Vision: diagrams	1343	1251	Claude Fable 5.1
LMArena Vision: homework	1345	1257	Claude Fable 5.1
Neither model has a result on the other 5 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index60

Math benchmarks for Claude Fable 5.1 and Inkling Small
Benchmark	Claude Fable 5.1	Inkling Small	Leader
OTIS Mock AIME	100.0%	90.0%	Claude Fable 5.1
FrontierMath, tiers 1 to 3	90.2%	46.3%	Claude Fable 5.1
FrontierMath, tier 4	87.8%	17.1%	Claude Fable 5.1
ProofBench	100.0%	6.0%	Claude Fable 5.1
LMArena Text: math	1531	1459	Claude Fable 5.1
LMArena Text: mathematical work	1541	1441	Claude Fable 5.1
Neither model has a result on the other 7 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index100

Knowledge benchmarks for Claude Fable 5.1 and Inkling Small
Benchmark	Claude Fable 5.1	Inkling Small	Leader
MMLU Pro	92.4%	85.6%	Claude Fable 5.1
LegalBench (Vals AI)	88.5%	83.0%	Claude Fable 5.1
CorpFin (Vals AI)	Not measured	69.6%	Only Inkling Small measured
TaxEval (Vals AI)	76.0%	75.5%	Claude Fable 5.1
MortgageTax (Vals AI)	70.8%	62.3%	Claude Fable 5.1
MedCode (Vals AI)	53.5%	37.9%	Claude Fable 5.1
SimpleQA Verified	70.8%	19.1%	Claude Fable 5.1
LMArena Text: science	1532	1428	Claude Fable 5.1
LMArena Text: medicine and healthcare	1531	1413	Claude Fable 5.1
LMArena Text: legal and government	1514	1415	Claude Fable 5.1
LMArena Text: business and finance	1493	1413	Claude Fable 5.1
Neither model has a result on the other 7 boards here

Web designDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared

Web design benchmarks for Claude Fable 5.1 and Inkling Small
Benchmark	Claude Fable 5.1	Inkling Small	Leader
Design Arena: websites	1312	Not measured	Only Claude Fable 5.1 measured
Design Arena: UI components	1336	Not measured	Only Claude Fable 5.1 measured
Design Arena: game dev	1381	Not measured	Only Claude Fable 5.1 measured
Design Arena: data viz	1344	Not measured	Only Claude Fable 5.1 measured
Design Arena: 3D	1392	Not measured	Only Claude Fable 5.1 measured
Design Arena: all code categories	1335	Not measured	Only Claude Fable 5.1 measured
Design Arena: SVG	1300	Not measured	Only Claude Fable 5.1 measured
Design Arena: ASCII art	1323	Not measured	Only Claude Fable 5.1 measured
LiveBench design	83.4%	Not measured	Only Claude Fable 5.1 measured

GeneralLike-for-likePublic boards, shown as published, kept out of the index270

General benchmarks for Claude Fable 5.1 and Inkling Small
Benchmark	Claude Fable 5.1	Inkling Small	Leader
Vals Index	Not measured	27.6%	Only Inkling Small measured
LiveBench data analysis	80.3%	Not measured	Only Claude Fable 5.1 measured
Public Benefits Bench (Vals AI)	74.9%	59.4%	Claude Fable 5.1
SAGE (Vals AI)	48.5%	32.7%	Claude Fable 5.1
MedScribe (Vals AI)	91.3%	84.1%	Claude Fable 5.1
Vals Multimodal Index	Not measured	50.0%	Only Inkling Small measured
Long context reasoning (AA-LCR)	85.3%	75.7%	Claude Fable 5.1
DTBench	97.6%	Not measured	Only Claude Fable 5.1 measured
LMCA	65.5%	Not measured	Only Claude Fable 5.1 measured
Furniture assembly	70.0%	Not measured	Only Claude Fable 5.1 measured
LMArena Text	1512	1413	Claude Fable 5.1
LMArena Text: instruction following	1518	1399	Claude Fable 5.1
LMArena Text: creative writing	1509	1334	Claude Fable 5.1
LMArena Vision	1319	1237	Claude Fable 5.1
LMArena Text: English	1506	1421	Claude Fable 5.1
LMArena Text: non-English	1508	1401	Claude Fable 5.1
LMArena Text: Chinese	1584	1464	Claude Fable 5.1
LMArena Text: German	1499	1408	Claude Fable 5.1
LMArena Text: Japanese	1562	1401	Claude Fable 5.1
LMArena Text: Korean	1517	1367	Claude Fable 5.1
LMArena Text: French	1523	1435	Claude Fable 5.1
LMArena Text: Spanish	1520	1422	Claude Fable 5.1
LMArena Text: Russian	1520	1394	Claude Fable 5.1
LMArena Text: Polish	1525	1428	Claude Fable 5.1
LMArena Text: multi-turn	1493	1416	Claude Fable 5.1
LMArena Text: longer queries	1524	1402	Claude Fable 5.1
LMArena Text: writing and language	1510	1357	Claude Fable 5.1
LMArena Text: entertainment and media	1497	1352	Claude Fable 5.1
LMArena Vision: English	1313	1243	Claude Fable 5.1
LMArena Vision: Chinese	1391	1292	Claude Fable 5.1
LMArena Vision: reading text	1327	1243	Claude Fable 5.1
LMArena Vision: humor	1318	1207	Claude Fable 5.1
LMArena Vision: creative writing	1330	1205	Claude Fable 5.1
Neither model has a result on the other 13 boards here

Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared

Image generation benchmarks for Claude Fable 5.1 and Inkling Small
Benchmark	Claude Fable 5.1	Inkling Small	Leader
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 5.1$0.035Fits in one request

Inkling Small$0.0010Fits in one request

Inkling Small costs less

Repository review

50K input + 3K output tokens

Claude Fable 5.1$0.650Fits in one request

Inkling Small$0.026Fits in one request

Inkling Small costs less

Agent loop

200K input + 10K output tokens

Claude Fable 5.1$2.50Fits in one request

Inkling Small$0.102Fits in one request

Inkling Small 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 5.1 and Inkling Small
Specification	Anthropic Claude Fable 5.1	Thinking Machines Inkling Small
Maker	Anthropic	Thinking Machines
Weights	No public weights listed	Open weights
Released	September 1, 2026	July 30, 2026
Context window	1M	524K
Input $/Mtok	$10.00	$0.45
Output $/Mtok	$50.00	$1.20
Coding index	84.2	27.3
Independent measurements behind it	5	4
Cost per solved task	Not computable	$0.16
Source	OpenRouter listing	OpenRouter listing

Questions

Is Claude Fable 5.1 better than Inkling Small for coding?

Pick Claude Fable 5.1 for coding: it scores 84.2 on the Vibe Coding Index against 27.3 for Inkling Small. Pick Inkling Small for output tokens 41.7x cheaper ($1.20 vs $50.00 per million).

Which is cheaper, Claude Fable 5.1 or Inkling Small?

Claude Fable 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens; Inkling Small costs $0.45 and $1.20. Cost per solved task is known for Inkling Small only.

Which has the bigger context window, Claude Fable 5.1 or Inkling Small?

Claude Fable 5.1, with 1M tokens against 524K.

How many benchmarks is the Claude Fable 5.1 vs Inkling Small comparison based on?

78 benchmarks have a result for both models as of October 22, 2026. Claude Fable 5.1's coding index rests on 5 independent benchmarks and Inkling Small's on 4. Where only one model has a result, the page says so instead of naming a winner.

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<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/claude-fable-5-1-vs-thinkingmachines-inkling-small">LLMBenchmark.ai, Claude Fable 5.1 vs Inkling Small</a></p>

Claude Fable 5.1 or Inkling Small: which to pick

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Knowledge

Web design

General

Long documents

Everyday cost

Cost per solved task

At a glance

Benchmark by benchmark

What each workload costs

Chat turn

Repository review

Agent loop

Specification differences

Questions

Compare next