Claude Fable 5.1 vs Inkling 2 Small
Claude Fable 5.1 leads Inkling 2 Small on coding, 82.8 to 48.9 on the Vibe Coding Index, and Inkling 2 Small costs 50.0x less per output token ($1.00 vs $50.00 per million). Updated November 14, 2026; 46 benchmarks have a result for both.
vs boards won of 46 shared
Claude Fable 5.1 or Inkling 2 Small: which to pick
Pick Claude Fable 5.1 for coding: it scores 82.8 on the Vibe Coding Index against 48.9 for Inkling 2 Small.
Pick Inkling 2 Small for output tokens 50.0x cheaper ($1.00 vs $50.00 per million) and a larger context window (1.05M against 1M tokens).
Model AClaude Fable 5.1Anthropic82.8/1005 independent benchmarksNo cost per solved taskModel BInkling 2 SmallThinking Machines48.9/1003 independent benchmarksNo cost per solved task
- Shared results
- 46
- Claude Fable 5.1 only
- 102
- Inkling 2 Small only
- 5
- 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 82.8 against 48.9.
5 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Fable 5.1
Claude Fable 5.1 leads, 50.0 against 30.6.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Claude Fable 5.1 has a AA Agentic Index result, 57.2.
Directional only
Reasoning
GPQA Diamond
No call
Only Claude Fable 5.1 has a GPQA Diamond result, 93.4%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Fable 5.1 has a MMLU Pro result, 92.4%.
Directional only
Web design
Design Arena: websites
No call
Only Claude Fable 5.1 has a Design Arena: websites result, 1305.
Directional only
General
Vals Index
No call
Only Inkling 2 Small has a Vals Index result, 56.1%.
Directional only
Long documents
Listed context window
Inkling 2 Small
Inkling 2 Small takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Inkling 2 Small
Claude Fable 5.1 $0.035, Inkling 2 Small $0.0008 per turn.
List prices
At a glance
- Coding index
- Claude Fable 5.1 82.8 from 5 benchmarks, Inkling 2 Small 48.9 from 3 benchmarks.
- Widest category
- Math, 31.1 points apart on average over 1 shared benchmark.
- Widest single gap
- Terminal-Bench 4 (Vals AI): Claude Fable 5.1 58.1% against Inkling 2 Small 12.6%, 60.6 points apart on a 0 to 100 scale.
- Output price
- Claude Fable 5.1 $50.00 against Inkling 2 Small $1.00 per million output tokens, 50.0x apart.
- Context window
- Claude Fable 5.1 takes 1M tokens, Inkling 2 Small 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.
| Category | Claude Fable 5.1 | Bars | Inkling 2 Small | Ties |
|---|---|---|---|---|
| Coding | 13 | 1 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 6 | 0 | ||
| Reasoning | 9 | 0 | ||
| Math | 1 | 0 | ||
| Knowledge | 3 | 0 | ||
| General | 12 | 0 | ||
| All shared boards | 45 | 1 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index131
| Benchmark | Claude Fable 5.1 | Inkling 2 Small | Leader |
|---|---|---|---|
| LiveBench coding | 89.7% | Not measured | Only Claude Fable 5.1 measured |
| LMArena WebDev | 1742 | 1647 | Claude Fable 5.1 |
| AA Coding Index | 80.7 | Not measured | Only Claude Fable 5.1 measured |
| LiveCodeBench (Vals AI) | 90.5% | Not measured | Only Claude Fable 5.1 measured |
| Terminal-Bench 4 (Vals AI) | 58.1% | 12.6% | Claude Fable 5.1 |
| Vibe Code Bench (Vals AI) | 90.3% | 81.5% | Claude Fable 5.1 |
| Code migration (Vals AI) | 54.6% | Not measured | Only Claude Fable 5.1 measured |
| ProgramBench (Vals AI) | 7.0% | 0.5% | Claude Fable 5.1 |
| IOI (Vals AI) | 90.8% | Not measured | Only Claude Fable 5.1 measured |
| Terminal-Bench 2.1 (Vals AI) | 85.0% | Not measured | Only Claude Fable 5.1 measured |
| SWE-bench Multimodal (Vals AI) | 61.3% | 43.1% | Claude Fable 5.1 |
| Vibe Code Bench 1-100 (Vals AI) | 28.0% | Not measured | Only Claude Fable 5.1 measured |
| SkillsBench (Vals AI) | 61.5% | Not measured | Only Claude Fable 5.1 measured |
| CyberBench (Vals AI) | 70.4% | 72.7% | Inkling 2 Small |
| SciCode | 63.1% | 52.3% | Claude Fable 5.1 |
| Terminal-Bench 4.0 (Artificial Analysis run) | 55.1% | 13.1% | Claude Fable 5.1 |
| FrontierCode 2.0 | 35.7% | 25.4% | 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 | 93.3% | Not measured | Only Claude Fable 5.1 measured |
| ALE-Bench | 2143.2 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: coding | 1527 | 1455 | Claude Fable 5.1 |
| LMArena Text: software and IT | 1525 | 1443 | Claude Fable 5.1 |
| LMArena WebDev: React | 1787 | 1660 | Claude Fable 5.1 |
| LMArena WebDev: HTML | 1681 | 1661 | Claude Fable 5.1 |
| LMArena WebDev: from an image | 1724 | Not measured | Only Claude Fable 5.1 measured |
| SWE-Bench Pro V2 | 99.1% | 97.7% | Claude Fable 5.1 |
| SWE Atlas: Codebase QnA | 60.0% | Not measured | Only Claude Fable 5.1 measured |
| SWE Atlas: Refactoring | 56.7% | Not measured | Only Claude Fable 5.1 measured |
| SWE Atlas: Test Writing | 67.0% | Not measured | Only Claude Fable 5.1 measured |
| GameBench 2 | 94.0 | Not measured | Only Claude Fable 5.1 measured |
| Terminal-Bench 4.0 | 57.9% | Not measured | Only Claude Fable 5.1 measured |
| CursorBench 4.0 | 51.8% | Not measured | Only Claude Fable 5.1 measured |
| ProgramBench | 9.0% | Not measured | Only Claude Fable 5.1 measured |
| Neither model has a result on the other 16 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Fable 5.1 | Inkling 2 Small | Leader |
|---|---|---|---|
| AA Intelligence Index | 50.0 | 30.6 | Claude Fable 5.1 |
| Epoch Capabilities Index | 167.0 | Not measured | Only Claude Fable 5.1 measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Fable 5.1 | Inkling 2 Small | Leader |
|---|---|---|---|
| AA Agentic Index | 57.2 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: agents building web apps | 1315 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: agents building full-stack apps | 1301 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: agents building mobile apps | 1253 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: agents building Godot games | 1304 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: HTML slides | 1390 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: PowerPoint slides | 1316 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: spreadsheets | 1346 | Not measured | Only Claude Fable 5.1 measured |
| LiveBench research | 88.5% | Not measured | Only Claude Fable 5.1 measured |
| LiveBench browser | 89.8% | Not measured | Only Claude Fable 5.1 measured |
| LiveBench long agentic | 74.2% | Not measured | Only Claude Fable 5.1 measured |
| SREBench (Vals AI) | 22.9% | 1.9% | Claude Fable 5.1 |
| Finance Agent (Vals AI) | 58.9% | Not measured | Only Claude Fable 5.1 measured |
| Tax Agent Bench (Vals AI) | 50.7% | 38.9% | Claude Fable 5.1 |
| Legal Research Bench (Vals AI) | 55.3% | 46.6% | Claude Fable 5.1 |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 21.7% | Only Inkling 2 Small measured |
| Excel Modeling Benchmark (Vals AI) | 76.7% | Not measured | Only Claude Fable 5.1 measured |
| BioMysteryBench (Vals AI) | Not measured | 70.0% | Only Inkling 2 Small measured |
| Terminal-Bench-Science (Vals AI) | 40.0% | 2.9% | Claude Fable 5.1 |
| Vals Science Index | Not measured | 32.7% | Only Inkling 2 Small 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% | 46.8% | Claude Fable 5.1 |
| Remote Labor Index | 17.9% | Not measured | Only Claude Fable 5.1 measured |
| PostTrainBench | 44.6% | 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 | 1237 | Not measured | Only Claude Fable 5.1 measured |
| MCP Atlas | 87.2% | 85.4% | Claude Fable 5.1 |
| Neither model has a result on the other 14 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index90
| Benchmark | Claude Fable 5.1 | Inkling 2 Small | Leader |
|---|---|---|---|
| GPQA Diamond | 93.4% | Not measured | Only Claude Fable 5.1 measured |
| LiveBench reasoning | 91.7% | Not measured | Only Claude Fable 5.1 measured |
| MysteryMechanism (Vals AI) | 47.8% | 25.2% | Claude Fable 5.1 |
| MMMU Pro (Vals AI) | 90.6% | Not measured | Only Claude Fable 5.1 measured |
| GPQA Diamond (Artificial Analysis run) | 93.7% | Not measured | Only Claude Fable 5.1 measured |
| Humanity's Last Exam (Artificial Analysis run) | 59.1% | 44.1% | Claude Fable 5.1 |
| HLE-Diamond (Artificial Analysis run) | 60.1% | 28.7% | Claude Fable 5.1 |
| CritPt v2, hard subset (Artificial Analysis run) | 62.0% | 35.0% | Claude Fable 5.1 |
| ARC-AGI | 97.5% | 96.5% | Claude Fable 5.1 |
| ARC-AGI-2 | 90.0% | 81.7% | Claude Fable 5.1 |
| SimpleBench | 86.6% | Not measured | Only Claude Fable 5.1 measured |
| Chess puzzles | 48.0% | Not measured | Only Claude Fable 5.1 measured |
| Mystery game puzzles | 58.0% | Not measured | Only Claude Fable 5.1 measured |
| EBR-bench | 57.1% | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: hard prompts | 1527 | 1421 | Claude Fable 5.1 |
| LMArena Text: expert | 1546 | 1478 | Claude Fable 5.1 |
| LMArena Text: hard prompts in English | 1522 | 1424 | Claude Fable 5.1 |
| LMArena Vision: diagrams | 1346 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: homework | 1339 | Not measured | Only Claude Fable 5.1 measured |
| Humanity's Last Exam (Scale run) | 51.3% | Not measured | Only Claude Fable 5.1 measured |
| GoBench | 2268 | Not measured | Only Claude Fable 5.1 measured |
| Neither model has a result on the other 5 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Fable 5.1 | Inkling 2 Small | Leader |
|---|---|---|---|
| OTIS Mock AIME | 100.0% | Not measured | Only Claude Fable 5.1 measured |
| FrontierMath, tiers 1 to 3 | 90.2% | Not measured | Only Claude Fable 5.1 measured |
| FrontierMath, tier 4 | 87.8% | Not measured | Only Claude Fable 5.1 measured |
| ProofBench | 100.0% | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: math | 1530 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: mathematical work | 1542 | Not measured | Only Claude Fable 5.1 measured |
| MathArena | 73.6% | 42.4% | 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 index30
| Benchmark | Claude Fable 5.1 | Inkling 2 Small | Leader |
|---|---|---|---|
| MMLU Pro | 92.4% | Not measured | Only Claude Fable 5.1 measured |
| LegalBench (Vals AI) | 88.5% | Not measured | Only Claude Fable 5.1 measured |
| TaxEval (Vals AI) | 76.0% | Not measured | Only Claude Fable 5.1 measured |
| MortgageTax (Vals AI) | 70.8% | Not measured | Only Claude Fable 5.1 measured |
| MedCode (Vals AI) | 53.5% | Not measured | Only Claude Fable 5.1 measured |
| AA-Omniscience | 46.3 | 16.1 | Claude Fable 5.1 |
| SimpleQA Verified | 70.8% | Not measured | Only Claude Fable 5.1 measured |
| GeoBench | 84.0% | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: science | 1535 | 1409 | Claude Fable 5.1 |
| LMArena Text: medicine and healthcare | 1529 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: legal and government | 1516 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: business and finance | 1494 | 1415 | Claude Fable 5.1 |
| PRBench Finance | 50.8% | Not measured | Only Claude Fable 5.1 measured |
| PRBench Legal | 51.6% | Not measured | Only Claude Fable 5.1 measured |
| 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
| Benchmark | Claude Fable 5.1 | Inkling 2 Small | Leader |
|---|---|---|---|
| Design Arena: websites | 1305 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: UI components | 1332 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: game dev | 1364 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: data viz | 1345 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: 3D | 1387 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: all code categories | 1330 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: SVG | 1292 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: ASCII art | 1318 | Not measured | Only Claude Fable 5.1 measured |
| LiveBench design | 81.6% | Not measured | Only Claude Fable 5.1 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index120
| Benchmark | Claude Fable 5.1 | Inkling 2 Small | Leader |
|---|---|---|---|
| Vals Index | Not measured | 56.1% | Only Inkling 2 Small measured |
| LiveBench data analysis | 80.3% | Not measured | Only Claude Fable 5.1 measured |
| Public Benefits Bench (Vals AI) | 74.9% | Not measured | Only Claude Fable 5.1 measured |
| SAGE (Vals AI) | Not measured | 88.6% | Only Inkling 2 Small measured |
| MedScribe (Vals AI) | 91.3% | Not measured | Only Claude Fable 5.1 measured |
| Long context reasoning (AA-LCR) | 85.3% | 83.3% | Claude Fable 5.1 |
| GDPval-AA | 1765 | 1630 | 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 | 1403 | Claude Fable 5.1 |
| LMArena Text: instruction following | 1520 | 1408 | Claude Fable 5.1 |
| LMArena Text: creative writing | 1514 | 1348 | Claude Fable 5.1 |
| LMArena Vision | 1322 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: English | 1507 | 1418 | Claude Fable 5.1 |
| LMArena Text: non-English | 1507 | 1390 | Claude Fable 5.1 |
| LMArena Text: Chinese | 1582 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: German | 1503 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: Japanese | 1560 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: Korean | 1505 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: French | 1515 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: Spanish | 1510 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: Russian | 1518 | 1377 | Claude Fable 5.1 |
| LMArena Text: Polish | 1537 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: multi-turn | 1492 | 1408 | Claude Fable 5.1 |
| LMArena Text: longer queries | 1523 | 1403 | Claude Fable 5.1 |
| LMArena Text: writing and language | 1515 | 1381 | Claude Fable 5.1 |
| LMArena Text: entertainment and media | 1498 | 1359 | Claude Fable 5.1 |
| LMArena Vision: English | 1316 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: Chinese | 1397 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: reading text | 1329 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: humor | 1326 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: creative writing | 1325 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Document | 1515 | Not measured | Only Claude Fable 5.1 measured |
| Neither model has a result on the other 15 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Fable 5.1 | Inkling 2 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 2 Small$0.0008Fits in one request
Inkling 2 Small costs less
Repository review
50K input + 3K output tokens
Claude Fable 5.1$0.650Fits in one request
Inkling 2 Small$0.018Fits in one request
Inkling 2 Small costs less
Agent loop
200K input + 10K output tokens
Claude Fable 5.1$2.50Fits in one request
Inkling 2 Small$0.070Fits in one request
Inkling 2 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.
| Specification | Anthropic Claude Fable 5.1 | Thinking Machines Inkling 2 Small |
|---|---|---|
| Maker | Anthropic | Thinking Machines |
| Weights | No public weights listed | Open weights |
| Released | September 1, 2026 | November 9, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $10.00 | $0.30 |
| Output $/Mtok | $50.00 | $1.00 |
| Coding index | 82.8 | 48.9 |
| Independent measurements behind it | 5 | 3 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Fable 5.1 better than Inkling 2 Small for coding?
Pick Claude Fable 5.1 for coding: it scores 82.8 on the Vibe Coding Index against 48.9 for Inkling 2 Small. Pick Inkling 2 Small for output tokens 50.0x cheaper ($1.00 vs $50.00 per million) and a larger context window (1.05M against 1M tokens).
Which is cheaper, Claude Fable 5.1 or Inkling 2 Small?
Claude Fable 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens; Inkling 2 Small costs $0.30 and $1.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Fable 5.1 or Inkling 2 Small?
Inkling 2 Small, with 1.05M tokens against 1M.
How many benchmarks is the Claude Fable 5.1 vs Inkling 2 Small comparison based on?
46 benchmarks have a result for both models as of November 14, 2026. Claude Fable 5.1's coding index rests on 5 independent benchmarks and Inkling 2 Small's on 3. Where only one model has a result, the page says so instead of naming a winner.