Claude Fable 5.2 vs Ember-1
Claude Fable 5.2 leads Ember-1 on coding, 87.8 to 52.6 on the Vibe Coding Index, and Ember-1 costs 2.7x less per output token ($15.00 vs $40.00 per million). Updated November 14, 2026; 9 benchmarks have a result for both.
Claude Fable 5.2 or Ember-1: which to pick
Pick Claude Fable 5.2 for coding: it scores 87.8 on the Vibe Coding Index against 52.6 for Ember-1.
Pick Ember-1 for output tokens 2.7x cheaper ($15.00 vs $40.00 per million) and a larger context window (1.05M against 1M tokens).
- Shared results
- 9
- Claude Fable 5.2 only
- 59
- Ember-1 only
- 7
- Like-for-like categories
- 3 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 52.6.
4 and 2 benchmarks behind the scores
Intelligence
AA Intelligence Index
No call
Only Claude Fable 5.2 has a AA Intelligence Index result, 64.6.
Directional only
Web design
Design Arena: websites
No call
Only Claude Fable 5.2 has a Design Arena: websites result, 1351.
Directional only
General
Vals Index
No call
Only Claude Fable 5.2 has a Vals Index result, 71.3%.
Directional only
Long documents
Listed context window
Ember-1
Ember-1 takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Ember-1
Claude Fable 5.2 $0.028, Ember-1 $0.011 per turn.
List prices
At a glance
- Coding index
- Claude Fable 5.2 87.8 from 4 benchmarks, Ember-1 52.6 from 2 benchmarks.
- Widest category
- Coding, 35.1 points apart on average over 3 shared benchmarks.
- Widest single gap
- Terminal-Bench 4 (Vals AI): Claude Fable 5.2 65.2% against Ember-1 20.7%, 59.3 points apart on a 0 to 100 scale.
- Output price
- Claude Fable 5.2 $40.00 against Ember-1 $15.00 per million output tokens, 2.7x apart.
- Context window
- Claude Fable 5.2 takes 1M tokens, Ember-1 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 5.2 | Bars | Ember-1 | Ties |
|---|---|---|---|---|
| Coding | 3 | 0 | ||
| Agentic work | 5 | 0 | ||
| Reasoning | 1 | 0 | ||
| All shared boards | 9 | 0 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index30
| Benchmark | Claude Fable 5.2 | Ember-1 | Leader |
|---|---|---|---|
| LiveBench coding | 79.2% | Not measured | Only Claude Fable 5.2 measured |
| LMArena WebDev | 1838 | Not measured | Only Claude Fable 5.2 measured |
| Terminal-Bench 4 (Vals AI) | 65.2% | 20.7% | Claude Fable 5.2 |
| Vibe Code Bench (Vals AI) | 93.8% | 83.9% | Claude Fable 5.2 |
| Code migration (Vals AI) | Not measured | 32.5% | Only Ember-1 measured |
| ProgramBench (Vals AI) | 19.0% | Not measured | Only Claude Fable 5.2 measured |
| IOI (Vals AI) | Not measured | 46.3% | Only Ember-1 measured |
| SWE-bench Multimodal (Vals AI) | 62.3% | Not measured | Only Claude Fable 5.2 measured |
| CyberBench (Vals AI) | Not measured | 69.5% | Only Ember-1 measured |
| SciCode | 67.7% | Not measured | Only Claude Fable 5.2 measured |
| Terminal-Bench 4.0 (Artificial Analysis run) | 61.6% | Not measured | Only Claude Fable 5.2 measured |
| FrontierCode 2.0 | 49.1% | Not measured | Only Claude Fable 5.2 measured |
| FrontierSWE | 69.9% | Not measured | Only Claude Fable 5.2 measured |
| ALE-Bench | 2509.8 | Not measured | Only Claude Fable 5.2 measured |
| LMArena WebDev: React | 1915 | Not measured | Only Claude Fable 5.2 measured |
| LMArena WebDev: HTML | 1738 | Not measured | Only Claude Fable 5.2 measured |
| GameBench 2 | 99.1 | 63.1 | 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 34 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Claude Fable 5.2 | Ember-1 | Leader |
|---|---|---|---|
| AA Intelligence Index | 64.6 | Not measured | Only Claude Fable 5.2 measured |
| 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 index50
| Benchmark | Claude Fable 5.2 | Ember-1 | 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% | Not measured | Only Claude Fable 5.2 measured |
| LiveBench browser | 86.9% | Not measured | Only Claude Fable 5.2 measured |
| LiveBench long agentic | 82.9% | Not measured | Only Claude Fable 5.2 measured |
| Finance Agent (Vals AI) | Not measured | 51.8% | Only Ember-1 measured |
| Tax Agent Bench (Vals AI) | 32.1% | 31.1% | Claude Fable 5.2 |
| Legal Research Bench (Vals AI) | 46.1% | 44.7% | Claude Fable 5.2 |
| Harvey's Legal Agent Benchmark (Vals AI) | 5.0% | Not measured | Only Claude Fable 5.2 measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 63.4% | Only Ember-1 measured |
| BioMysteryBench (Vals AI) | 83.7% | 67.0% | Claude Fable 5.2 |
| Terminal-Bench-Science (Vals AI) | 55.7% | 5.7% | Claude Fable 5.2 |
| Vals Science Index | 63.7% | 31.8% | 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 27 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Fable 5.2 | Ember-1 | Leader |
|---|---|---|---|
| LiveBench reasoning | 88.8% | Not measured | Only Claude Fable 5.2 measured |
| MysteryMechanism (Vals AI) | 51.8% | 22.5% | Claude Fable 5.2 |
| Humanity's Last Exam (Artificial Analysis run) | 74.3% | Not measured | Only Claude Fable 5.2 measured |
| HLE-Diamond (Artificial Analysis run) | 80.2% | Not measured | Only Claude Fable 5.2 measured |
| CritPt v2, hard subset (Artificial Analysis run) | 76.5% | Not measured | Only Claude Fable 5.2 measured |
| 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 |
| 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 12 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index5 boards, none shared
| Benchmark | Claude Fable 5.2 | Ember-1 | 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% | Not measured | Only Claude Fable 5.2 measured |
| MathArena | 82.8% | Not measured | Only Claude Fable 5.2 measured |
| Neither model has a result on the other 9 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
| Benchmark | Claude Fable 5.2 | Ember-1 | Leader |
|---|---|---|---|
| AA-Omniscience | 66.8 | Not measured | Only Claude Fable 5.2 measured |
| SimpleQA Verified | 94.0% | Not measured | Only Claude Fable 5.2 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 17 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index6 boards, none shared
| Benchmark | Claude Fable 5.2 | Ember-1 | 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% | Not measured | Only Claude Fable 5.2 measured |
| Neither model has a result on the other 3 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index9 boards, none shared
| Benchmark | Claude Fable 5.2 | Ember-1 | Leader |
|---|---|---|---|
| Vals Index | 71.3% | Not measured | Only Claude Fable 5.2 measured |
| LiveBench data analysis | 81.5% | Not measured | Only Claude Fable 5.2 measured |
| Public Benefits Bench (Vals AI) | Not measured | 66.2% | Only Ember-1 measured |
| SAGE (Vals AI) | Not measured | 86.4% | Only Ember-1 measured |
| Long context reasoning (AA-LCR) | 83.3% | Not measured | Only Claude Fable 5.2 measured |
| GDPval-AA | 1831 | Not measured | Only Claude Fable 5.2 measured |
| 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 |
| Neither model has a result on the other 40 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Fable 5.2 | Ember-1 | 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
Ember-1 costs less
Repository review
50K input + 3K output tokens
Ember-1 costs less
Agent loop
200K input + 10K output tokens
Ember-1 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 | Fireworks Ember-1 |
|---|---|---|
| Maker | Anthropic | Fireworks |
| Weights | No public weights listed | No public weights listed |
| Released | November 9, 2026 | September 24, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $8.00 | $3.00 |
| Output $/Mtok | $40.00 | $15.00 |
| Coding index | 87.8 | 52.6 |
| Independent measurements behind it | 4 | 2 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Fable 5.2 better than Ember-1 for coding?
Pick Claude Fable 5.2 for coding: it scores 87.8 on the Vibe Coding Index against 52.6 for Ember-1. Pick Ember-1 for output tokens 2.7x cheaper ($15.00 vs $40.00 per million) and a larger context window (1.05M against 1M tokens).
Which is cheaper, Claude Fable 5.2 or Ember-1?
Claude Fable 5.2 costs $8.00 per million input tokens and $40.00 per million output tokens; Ember-1 costs $3.00 and $15.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Fable 5.2 or Ember-1?
Ember-1, with 1.05M tokens against 1M.
How many benchmarks is the Claude Fable 5.2 vs Ember-1 comparison based on?
9 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 Ember-1's on 2. Where only one model has a result, the page says so instead of naming a winner.