Claude Fable 5.2 vs Step 5 Preview
Claude Fable 5.2 leads Step 5 Preview on coding, 87.8 to 57.4 on the Vibe Coding Index, and Step 5 Preview costs 14.8x less per output token ($2.70 vs $40.00 per million). Updated November 14, 2026; 33 benchmarks have a result for both.
Claude Fable 5.2 or Step 5 Preview: which to pick
Pick Claude Fable 5.2 for coding: it scores 87.8 on the Vibe Coding Index against 57.4 for Step 5 Preview.
Pick Step 5 Preview for output tokens 14.8x cheaper ($2.70 vs $40.00 per million) and work measured by Harvey's Legal Agent Benchmark (Vals AI) or Long context reasoning (AA-LCR), where it leads.
- Shared results
- 33
- Claude Fable 5.2 only
- 35
- Step 5 Preview only
- 42
- 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.
Coding
Vibe Coding Index, six public coding benchmarks
Claude Fable 5.2
Claude Fable 5.2 scores 87.8 against 57.4.
4 benchmarks behind each score
Intelligence
AA Intelligence Index
Claude Fable 5.2
Claude Fable 5.2 leads, 64.6 against 28.5.
Same board, both measured
Web design
Design Arena: websites
No call
Only Claude Fable 5.2 has a Design Arena: websites result, 1351.
Directional only
General
Vals Index
Claude Fable 5.2
Claude Fable 5.2 leads, 71.3% against 54.8%.
Same board, both measured
Long documents
Listed context window
No call
Both take 1M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Step 5 Preview
Claude Fable 5.2 $0.028, Step 5 Preview $0.0024 per turn.
List prices
At a glance
- Coding index
- Claude Fable 5.2 87.8 from 4 benchmarks, Step 5 Preview 57.4 from 4 benchmarks.
- Widest category
- Math, 58.0 points apart on average over 1 shared benchmark.
- Widest single gap
- LiveBench long agentic: Claude Fable 5.2 82.9% against Step 5 Preview 19.4%, 63.5 points apart on a 0 to 100 scale.
- Output price
- Claude Fable 5.2 $40.00 against Step 5 Preview $2.70 per million output tokens, 14.8x apart.
- Context window
- Both take 1M tokens.
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 5.2 | Bars | Step 5 Preview | Ties |
|---|---|---|---|---|
| Coding | 11 | 0 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 8 | 1 | ||
| Reasoning | 5 | 0 | ||
| Math | 1 | 0 | ||
| Knowledge | 1 | 0 | ||
| Web design | 1 | 0 | ||
| General | 3 | 1 | ||
| All shared boards | 31 | 2 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index110
| Benchmark | Claude Fable 5.2 | Step 5 Preview | Leader |
|---|---|---|---|
| LiveBench coding | 79.2% | 67.6% | Claude Fable 5.2 |
| LMArena WebDev | 1838 | 1573 | Claude Fable 5.2 |
| Terminal-Bench 4 (Vals AI) | 65.2% | 31.8% | Claude Fable 5.2 |
| Vibe Code Bench (Vals AI) | 93.8% | 70.4% | Claude Fable 5.2 |
| Code migration (Vals AI) | Not measured | 39.0% | Only Step 5 Preview measured |
| ProgramBench (Vals AI) | 19.0% | Not measured | Only Claude Fable 5.2 measured |
| IOI (Vals AI) | Not measured | 38.1% | Only Step 5 Preview measured |
| SWE-bench Multimodal (Vals AI) | 62.3% | 40.8% | Claude Fable 5.2 |
| SciCode | 67.7% | 58.9% | Claude Fable 5.2 |
| Terminal-Bench 4.0 (Artificial Analysis run) | 61.6% | 33.3% | Claude Fable 5.2 |
| FrontierCode 2.0 | 49.1% | 12.0% | Claude Fable 5.2 |
| FrontierSWE | 69.9% | Not measured | Only Claude Fable 5.2 measured |
| ALE-Bench | 2509.8 | Not measured | Only Claude Fable 5.2 measured |
| LMArena Text: coding | Not measured | 1482 | Only Step 5 Preview measured |
| LMArena Text: software and IT | Not measured | 1471 | Only Step 5 Preview measured |
| LMArena WebDev: React | 1915 | 1589 | Claude Fable 5.2 |
| LMArena WebDev: HTML | 1738 | 1546 | Claude Fable 5.2 |
| LMArena WebDev: from an image | Not measured | 1551 | Only Step 5 Preview measured |
| GameBench 2 | 99.1 | 52.6 | Claude Fable 5.2 |
| CursorBench 4.0 | 60.0% | Not measured | Only Claude Fable 5.2 measured |
| Neither model has a result on the other 32 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Fable 5.2 | Step 5 Preview | Leader |
|---|---|---|---|
| AA Intelligence Index | 64.6 | 28.5 | Claude Fable 5.2 |
| Epoch Capabilities Index | 173.4 | Not measured | Only Claude Fable 5.2 measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index81
| Benchmark | Claude Fable 5.2 | Step 5 Preview | Leader |
|---|---|---|---|
| Design Arena: agents building full-stack apps | 1402 | Not measured | Only Claude Fable 5.2 measured |
| Design Arena: agents building mobile apps | 1325 | Not measured | Only Claude Fable 5.2 measured |
| Design Arena: spreadsheets | 1434 | Not measured | Only Claude Fable 5.2 measured |
| LiveBench research | 94.5% | 75.5% | Claude Fable 5.2 |
| LiveBench browser | 86.9% | 24.8% | Claude Fable 5.2 |
| LiveBench long agentic | 82.9% | 19.4% | Claude Fable 5.2 |
| SREBench (Vals AI) | Not measured | 0.4% | Only Step 5 Preview measured |
| Finance Agent (Vals AI) | Not measured | 50.7% | Only Step 5 Preview measured |
| Tax Agent Bench (Vals AI) | 32.1% | 27.3% | Claude Fable 5.2 |
| Legal Research Bench (Vals AI) | 46.1% | 40.4% | Claude Fable 5.2 |
| Harvey's Legal Agent Benchmark (Vals AI) | 5.0% | 12.9% | Step 5 Preview |
| Excel Modeling Benchmark (Vals AI) | Not measured | 57.1% | Only Step 5 Preview measured |
| BioMysteryBench (Vals AI) | 83.7% | 67.4% | Claude Fable 5.2 |
| Terminal-Bench-Science (Vals AI) | 55.7% | 2.9% | Claude Fable 5.2 |
| Vals Science Index | 63.7% | 29.6% | Claude Fable 5.2 |
| APEX-Agents | 80.1% | Not measured | Only Claude Fable 5.2 measured |
| Remote Labor Index | 41.3% | Not measured | Only Claude Fable 5.2 measured |
| SpireClimb | 15.5% | Not measured | Only Claude Fable 5.2 measured |
| Neither model has a result on the other 26 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Claude Fable 5.2 | Step 5 Preview | Leader |
|---|---|---|---|
| LiveBench reasoning | 88.8% | 83.8% | Claude Fable 5.2 |
| MysteryMechanism (Vals AI) | 51.8% | 18.5% | Claude Fable 5.2 |
| Humanity's Last Exam (Artificial Analysis run) | 74.3% | 46.5% | Claude Fable 5.2 |
| HLE-Diamond (Artificial Analysis run) | 80.2% | 24.3% | Claude Fable 5.2 |
| CritPt v2, hard subset (Artificial Analysis run) | 76.5% | 32.5% | Claude Fable 5.2 |
| GPQA Diamond (Epoch AI run) | 93.9% | Not measured | Only Claude Fable 5.2 measured |
| ARC-AGI | 98.5% | Not measured | Only Claude Fable 5.2 measured |
| ARC-AGI-2 | 93.8% | Not measured | Only Claude Fable 5.2 measured |
| SimpleBench | 94.9% | Not measured | Only Claude Fable 5.2 measured |
| Chess puzzles | 79.0% | Not measured | Only Claude Fable 5.2 measured |
| Mystery game puzzles | 90.0% | Not measured | Only Claude Fable 5.2 measured |
| EBR-bench | 90.5% | Not measured | Only Claude Fable 5.2 measured |
| LMArena Text: hard prompts | Not measured | 1463 | Only Step 5 Preview measured |
| LMArena Text: expert | Not measured | 1478 | Only Step 5 Preview measured |
| LMArena Text: hard prompts in English | Not measured | 1463 | Only Step 5 Preview measured |
| LMArena Vision: diagrams | Not measured | 1295 | Only Step 5 Preview measured |
| LMArena Vision: homework | Not measured | 1274 | Only Step 5 Preview measured |
| Humanity's Last Exam (Scale run) | 72.4% | Not measured | Only Claude Fable 5.2 measured |
| GoBench | 2566 | Not measured | Only Claude Fable 5.2 measured |
| Neither model has a result on the other 7 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Fable 5.2 | Step 5 Preview | Leader |
|---|---|---|---|
| OTIS Mock AIME | 99.7% | Not measured | Only Claude Fable 5.2 measured |
| FrontierMath, tiers 1 to 3 | 95.1% | Not measured | Only Claude Fable 5.2 measured |
| FrontierMath, tier 4 | 100.0% | Not measured | Only Claude Fable 5.2 measured |
| ProofBench | 100.0% | 42.0% | Claude Fable 5.2 |
| LMArena Text: math | Not measured | 1462 | Only Step 5 Preview measured |
| LMArena Text: mathematical work | Not measured | 1465 | Only Step 5 Preview measured |
| MathArena | 82.8% | Not measured | Only Claude Fable 5.2 measured |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Fable 5.2 | Step 5 Preview | Leader |
|---|---|---|---|
| AA-Omniscience | 66.8 | 16.4 | Claude Fable 5.2 |
| SimpleQA Verified | 94.0% | Not measured | Only Claude Fable 5.2 measured |
| LMArena Text: science | Not measured | 1462 | Only Step 5 Preview measured |
| LMArena Text: medicine and healthcare | Not measured | 1441 | Only Step 5 Preview measured |
| LMArena Text: legal and government | Not measured | 1441 | Only Step 5 Preview measured |
| LMArena Text: business and finance | Not measured | 1444 | Only Step 5 Preview measured |
| PRBench Finance | 47.1% | Not measured | Only Claude Fable 5.2 measured |
| PRBench Legal | 49.0% | Not measured | Only Claude Fable 5.2 measured |
| Neither model has a result on the other 13 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Fable 5.2 | Step 5 Preview | Leader |
|---|---|---|---|
| Design Arena: websites | 1351 | Not measured | Only Claude Fable 5.2 measured |
| Design Arena: UI components | 1371 | Not measured | Only Claude Fable 5.2 measured |
| Design Arena: game dev | 1396 | Not measured | Only Claude Fable 5.2 measured |
| Design Arena: 3D | 1517 | Not measured | Only Claude Fable 5.2 measured |
| Design Arena: all code categories | 1373 | Not measured | Only Claude Fable 5.2 measured |
| LiveBench design | 85.1% | 70.8% | Claude Fable 5.2 |
| Neither model has a result on the other 3 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index31
| Benchmark | Claude Fable 5.2 | Step 5 Preview | Leader |
|---|---|---|---|
| Vals Index | 71.3% | 54.8% | Claude Fable 5.2 |
| LiveBench data analysis | 81.5% | 63.5% | Claude Fable 5.2 |
| Public Benefits Bench (Vals AI) | Not measured | 58.1% | Only Step 5 Preview measured |
| Long context reasoning (AA-LCR) | 83.3% | 88.3% | Step 5 Preview |
| GDPval-AA | 1831 | 1591 | Claude Fable 5.2 |
| DTBench | 99.2% | Not measured | Only Claude Fable 5.2 measured |
| LMCA | 70.6% | Not measured | Only Claude Fable 5.2 measured |
| Furniture assembly | 90.0% | Not measured | Only Claude Fable 5.2 measured |
| LMArena Text | Not measured | 1443 | Only Step 5 Preview measured |
| LMArena Text: instruction following | Not measured | 1445 | Only Step 5 Preview measured |
| LMArena Text: creative writing | Not measured | 1415 | Only Step 5 Preview measured |
| LMArena Vision | Not measured | 1263 | Only Step 5 Preview measured |
| LMArena Text: English | Not measured | 1455 | Only Step 5 Preview measured |
| LMArena Text: non-English | Not measured | 1429 | Only Step 5 Preview measured |
| LMArena Text: Chinese | Not measured | 1495 | Only Step 5 Preview measured |
| LMArena Text: German | Not measured | 1454 | Only Step 5 Preview measured |
| LMArena Text: Japanese | Not measured | 1397 | Only Step 5 Preview measured |
| LMArena Text: Korean | Not measured | 1404 | Only Step 5 Preview measured |
| LMArena Text: French | Not measured | 1446 | Only Step 5 Preview measured |
| LMArena Text: Spanish | Not measured | 1442 | Only Step 5 Preview measured |
| LMArena Text: Russian | Not measured | 1433 | Only Step 5 Preview measured |
| LMArena Text: Polish | Not measured | 1405 | Only Step 5 Preview measured |
| LMArena Text: multi-turn | Not measured | 1440 | Only Step 5 Preview measured |
| LMArena Text: longer queries | Not measured | 1453 | Only Step 5 Preview measured |
| LMArena Text: writing and language | Not measured | 1429 | Only Step 5 Preview measured |
| LMArena Text: entertainment and media | Not measured | 1413 | Only Step 5 Preview measured |
| LMArena Vision: English | Not measured | 1279 | Only Step 5 Preview measured |
| LMArena Vision: Chinese | Not measured | 1315 | Only Step 5 Preview measured |
| LMArena Vision: reading text | Not measured | 1278 | Only Step 5 Preview measured |
| LMArena Vision: creative writing | Not measured | 1251 | Only Step 5 Preview measured |
| Neither model has a result on the other 19 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Fable 5.2 | Step 5 Preview | 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
Step 5 Preview costs less
Repository review
50K input + 3K output tokens
Step 5 Preview costs less
Agent loop
200K input + 10K output tokens
Step 5 Preview 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 5.2 | StepFun Step 5 Preview |
|---|---|---|
| Maker | Anthropic | StepFun |
| Weights | No public weights listed | Open weights |
| Released | November 9, 2026 | October 8, 2026 |
| Context window | 1M | 1M |
| Input $/Mtok | $8.00 | $1.00 |
| Output $/Mtok | $40.00 | $2.70 |
| Coding index | 87.8 | 57.4 |
| Independent measurements behind it | 4 | 4 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Fable 5.2 better than Step 5 Preview for coding?
Pick Claude Fable 5.2 for coding: it scores 87.8 on the Vibe Coding Index against 57.4 for Step 5 Preview. Pick Step 5 Preview for output tokens 14.8x cheaper ($2.70 vs $40.00 per million) and work measured by Harvey's Legal Agent Benchmark (Vals AI) or Long context reasoning (AA-LCR), where it leads.
Which is cheaper, Claude Fable 5.2 or Step 5 Preview?
Claude Fable 5.2 costs $8.00 per million input tokens and $40.00 per million output tokens; Step 5 Preview costs $1.00 and $2.70. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Fable 5.2 or Step 5 Preview?
Neither: both take 1M tokens.
How many benchmarks is the Claude Fable 5.2 vs Step 5 Preview comparison based on?
33 benchmarks have a result for both models as of November 14, 2026. Claude Fable 5.2's coding index rests on 4 independent benchmarks and Step 5 Preview's on 4. Where only one model has a result, the page says so instead of naming a winner.