STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Claude Fable 5.1 vs MiMo-V2.6-Pro

Claude Fable 5.1 leads MiMo-V2.6-Pro by 14.1 points on StealthMark, 62.0 to 47.9. It leads on 7 of 9 benchmarks and MiMo-V2.6-Pro on 2, including both games. Claude Fable 5.1 scores higher on Newton's Mirror, with its largest category advantage in reflections.

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All results ↗
All results ↗

Overall StealthMark

62.0/100Overall rank 8/53
47.9/100Overall rank 21/53

General Intelligence

58.9/100
44.3/100

Visual Intelligence

67.1/100
54.3/100

Reasoning efficiency

On every task, result quality and reasoning tokens are each compared with all measured models and weighed equally. Each dot is one model.

Single-step reasoning Result quality weighed against reasoning tokens on a single problem

Multi-step reasoning Result quality weighed against reasoning tokens across connected steps, as in agentic workflows

Open or local

Open modelMIT

BENCHMARK BY BENCHMARK

Where each model leads

  • Claude Fable 5.1
  • MiMo-V2.6-Pro
  • Other models
  • Median

DATASHEET

Specs and pricing

Claude Fable 5.1 scores higher on StealthMark. MiMo-V2.6-Pro is 57× cheaper per output token. Both take about 1M tokens of context.

  • Claude Fable 5.1
  • MiMo-V2.6-Pro
  • Other models
  • Median
PricePer 1M output tokens, input below
Claude Fable 5.1: $50$10 inputMiMo-V2.6-Pro: $0.8757× cheaper$0.43 input
Context windowTokens per request, max output below
Claude Fable 5.1: 1MTied128K max outputMiMo-V2.6-Pro: 1MTied128K max output
Output speedTokens per second, our measurement
Claude Fable 5.1: 122Tiedtokens/sMiMo-V2.6-Pro: 116Tiedtokens/s
SizeTotal and active parameters
Claude Fable 5.1: Not disclosedMiMo-V2.6-Pro: 1.02T42B active
Developer
AnthropicXiaomi
Released
1 Sep 202621 Sep 2026
Origin
United StatesChina
Input → output
Text, image → textText, image, video, audio → text
Architecture
Not publishedSparse Mixture-of-Experts; OpenRouter maps the route to the released Pro-RL checkpoint. The UltraSpeed edition is a separate route

Full datasheets, every price and sourceClaude Fable 5.1 ↗MiMo-V2.6-Pro ↗

Anticipating threats and planning ahead. Collect coins while avoiding ghosts. Ghosts move before the player each turn, and collisions cost a life. 3 levels in sequence, up to 66 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.

Claude Fable 5.1 34.2/100Rank 37/472 of 3 levels

2 of 3 played
Foresight: complete playing field
Level 38 ptsTurn 17 / 20

MiMo-V2.6-Pro 54.6/100Rank 13/47

Survived 1 of 3
Foresight: complete playing field
Level 319 ptsTurn 20 / 20

Points per level

LevelClaude Fable 5.1MiMo-V2.6-Pro
Level 1Second Thoughts
21 ptsOut of lives
4 ptsOut of lives
Level 2Pressure Pot
Pending
9 ptsOut of lives
Level 3Hide or Flight
8 ptsOut of lives
19 ptsSurvived

Cooperative planning and learning from experience. Coordinate two robots to push numbered cores onto matching sockets. Pressure plates hold doors open; moving either robot uses one turn. 5 levels in sequence, up to 152 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.

Claude Fable 5.1 80.2/100Rank 24/483 of 5 levels

3 of 5 played
Latch: complete playing field
Level 520.6 ptsTurn 27 / 40

MiMo-V2.6-Pro 52.6/100Rank 22/48

Cleared 5 of 5
Latch: complete playing field
Level 520.4 ptsTurn 28 / 40

Points per level

LevelClaude Fable 5.1MiMo-V2.6-Pro
Level 1Hold the door
Pending
5.2 ptsCleared
Level 2Crossfeed
9.8 ptsCleared
9 ptsClearedFinished early · 1 beacon left
Level 3Relay vault
Pending
17.2 ptsClearedFinished early · 1 beacon left
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
16 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
20.6 ptsCleared
20.4 ptsCleared

Newton's Mirror

Same task instructions

Physics, perspective and recursive reflections, tested together. Explore the test ↗

The judgment

Claude Fable 5.1

The broad paint sequence, bilateral near-field sphere arrangement, overlaps and diminishing panel repetitions are recognizable; crimson is slightly too low. Small paint scale and basic shading provide material cues, although the steel response remains soft. Inaccurate light projections, missing outer chains and incomplete nested room imagery remain the principal limitations.

MiMo-V2.6-Pro

The main framing and visible paint-contact story are well supported. Major optical omissions dominate the result: sparse repetitions, undersized first images, missing outer chains and absent curved nested imagery prevent a coherent mirror-room system. The metallic forms remain convincing in volume but have a soft illustrative finish.

Score breakdown

CategoryClaude Fable 5.1MiMo-V2.6-Pro
State at 600 ms24.0/2523.0/25
Camera and placement14.0/1512.0/15
Reflections48.0/12019.0/120
Materials and scale7.5/107.5/10
Floor-damage reward0.0/100.0/10

Benchmark task

A spinning metal sphere and paint in a mirrored room test physical reasoning, perspective and consistency across repeated reflections.

Selfie

Different task instructions

Visual construction and creative interpretation.

The judgment

Claude Fable 5.1

The coral palette, friendly face, matte shading and cream arch create a coherent emblem. However, the mantle is elongated rather than compact, and the appendages spread mostly sideways and downward instead of forming an evenly spaced, flower-like starburst. Two thin hanging appendages weaken the thick-arm motif. Clean contours and balanced framing support the simple design.

MiMo-V2.6-Pro

An appealing rabbit with balanced framing, expressive eyes and purposeful costume accents. Simple frontal construction limits anatomical and spatial accomplishment. The orange orb provides an effective luminous focal point, but unreadable wrist connections weaken the requested gestures and prevent stronger integrity credit.

Score breakdown

CategoryClaude Fable 5.1MiMo-V2.6-Pro
Task & likeness6.5/106.5/10
Anatomy & construction7.0/105.0/10
Space & placement7.5/105.5/10
Light & reflections6.5/106.5/10
Purposeful detail6.0/106.5/10
Artistry & character7.0/105.0/10
Materials & effects6.5/106.5/10
Visual integrity8.0/106.0/10

Benchmark task

Claude Fable 5.1

A coral squid with spreading arms tests connected anatomy, balanced composition and soft surface shading.

MiMo-V2.6-Pro

A small rabbit in an explorer outfit floats with a luminous orb. The scene tests character anatomy, pose and the placement of geometric forms around it.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

Claude Fable 5.1

The dark clothing, crossed hands and hazy landscape establish the Mona Lisa composition. Replication is limited by the frontal, elongated face, wide eyes and simplified smile. Rounded, parallel fingers and unclear wrist transitions weaken the hands. Warm facial shading gives some volume, but broad garment shapes and scattered crack marks substitute for convincing folds and painterly detail.

MiMo-V2.6-Pro

The portrait is recognizable through its dark silhouette, slight smile and muted landscape, but replication is weak. A frontal, oversized head and symmetric torso replace the reference's turned seated pose; angular, separated hands omit its central gesture. Smooth shading maintains coherence while anatomical detail, depth and material rendering remain basic.

Score breakdown

CategoryClaude Fable 5.1MiMo-V2.6-Pro
Task & likeness5.5/103.5/10
Anatomy & construction6.0/103.5/10
Space & placement6.0/104.0/10
Light & reflections6.0/105.0/10
Purposeful detail5.0/103.0/10
Artistry & character5.5/104.0/10
Materials & effects6.0/104.0/10
Visual integrity6.5/106.0/10

Benchmark task

An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.

Beach

Same task instructions

Creativity, perspective and visual beauty.

The judgment

Claude Fable 5.1

The colorful sunset, layered shoreline, animals, kite and beach toys fulfill the lively beach brief. Clean silhouettes and a balanced composition give the illustration character. Construction is simplified: the umbrella resembles a segmented fan, dolphins have weak water interaction, and the sun’s reflection forms a rigid widening wedge. Flat surfaces and sparse contact shadows limit depth.

MiMo-V2.6-Pro

A readable sunset beach with clear requested subjects, appealing framing and purposeful accessories. Schematic anatomy, flattened foreground objects, repetitive water highlights and sparse directional shadows limit construction and physical depth. The kite's unresolved anchor also constrains integrity.

Score breakdown

CategoryClaude Fable 5.1MiMo-V2.6-Pro
Task & likeness8.5/108.5/10
Anatomy & construction7.0/105.0/10
Space & placement7.0/106.0/10
Light & reflections7.0/106.5/10
Purposeful detail7.5/106.5/10
Artistry & character7.5/105.0/10
Materials & effects6.5/106.0/10
Visual integrity7.5/106.0/10

Benchmark task

A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.

Ground Truth

Same task instructions

Physical reasoning, light and visual reconstruction.

The judgment

Claude Fable 5.1

This benchmark has not been assessed yet.

MiMo-V2.6-Pro

This benchmark has not been assessed yet.

Benchmark task

A plank, computer mouse and blueberry in a steel room test physical stability, spatial relationships, materials and lighting.

Raccoon

Same task instructions

Scene composition and interacting subjects.

The judgment

Claude Fable 5.1

The raccoon rides on the dog's back, and the dog's extended foreleg reaches the jet ski controls. Expressive faces, a clear silhouette and sweeping spray make the action readable. Limb and handlebar overlaps weaken construction; broad shading provides limited volume, and the glowing sun has little corresponding reflection on the water. Clean vector shapes support an appealing but simplified illustration.

MiMo-V2.6-Pro

A coherent, cheerful cartoon with recognizable animals, readable steering contact and useful small details. The dog's orientation follows the craft more successfully than a wholly frontal pose would. Simple anatomy, weak raccoon grip and compressed seating contacts still limit physical credibility. Gradients and spray provide polish without resolving complex construction.

Score breakdown

CategoryClaude Fable 5.1MiMo-V2.6-Pro
Task & likeness8.5/107.0/10
Anatomy & construction6.5/105.0/10
Space & placement7.0/105.5/10
Light & reflections5.5/105.5/10
Purposeful detail7.0/106.0/10
Artistry & character7.0/104.0/10
Materials & effects6.5/105.5/10
Visual integrity7.5/104.5/10

Benchmark task

A jet-ski scene pairs a canine driver with a raccoon passenger. It tests the placement and contact of interacting subjects, along with vehicle construction.

Pelican

Same task instructions

Subject construction and spatial relationships.

The judgment

Claude Fable 5.1

The pelican reads clearly, with an expressive face, prominent bill and appealing composition. Both legs connect to the body, but the far foot's pedal contact and the wing's steering grip remain unclear. Wheel alignment and background layers are coherent. Clean contours and feather lines give polish, while schematic machinery, limited surface texture and weak directional lighting constrain the finish.

MiMo-V2.6-Pro

The distinctive bill, continuous silhouette and detailed wheels establish a readable pelican cyclist. Shaped feathers and soft shading add character, but jointless legs, crowded pedal contacts, absent steering contact and loosely directional lighting limit the construction. The comparisons support retaining the baseline category scores.

Score breakdown

CategoryClaude Fable 5.1MiMo-V2.6-Pro
Task & likeness8.5/106.5/10
Anatomy & construction7.0/105.0/10
Space & placement7.5/106.0/10
Light & reflections6.0/105.5/10
Purposeful detail7.0/106.0/10
Artistry & character7.0/106.0/10
Materials & effects6.0/105.5/10
Visual integrity8.0/106.0/10

Benchmark task

A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.