STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Kimi K3.1 Pro vs Muse Spark Open

Kimi K3.1 Pro leads Muse Spark Open by 12.6 points on StealthMark, 56.7 to 44.1. It leads on 8 of 9 benchmarks, including both games, and Muse Spark Open on 1. Kimi K3.1 Pro scores higher on Newton's Mirror, with its largest category advantage in reflections.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

56.7/100Overall rank 11/53
44.1/100Overall rank 29/53

General Intelligence

53.9/100
42.6/100

Visual Intelligence

62.0/100
46.6/100

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

  • Muse Spark Open

BENCHMARK BY BENCHMARK

Where each model leads

  • Kimi K3.1 Pro
  • Muse Spark Open
  • Other models
  • Median

DATASHEET

Specs and pricing

Kimi K3.1 Pro scores higher on StealthMark. Muse Spark Open is 2.4× cheaper per output token and runs 3.1× faster in our speed test. Both take about 1M tokens of context.

  • Kimi K3.1 Pro
  • Muse Spark Open
  • Other models
  • Median
PricePer 1M output tokens, input below
Kimi K3.1 Pro: $10$2 inputMuse Spark Open: $4.252.4× cheaper$1.25 input
Context windowTokens per request, max output below
Kimi K3.1 Pro: 1MTied1M max outputMuse Spark Open: 1MTied1M max output
Output speedTokens per second, our measurement
Kimi K3.1 Pro: 117tokens/sMuse Spark Open: 3613.1× fastertokens/s
SizeTotal and active parameters
Kimi K3.1 Pro: 2.8T104B activeEstimatedMuse Spark Open: 816B42B active
Developer
Moonshot AIMeta
Released
23 Oct 202615 Oct 2026
Origin
ChinaUnited States
Input → output
Text, image, video → textText, image, audio, video → text
Architecture
Post-trained version of Kimi K3, a Mixture-of-Experts modelSparse mixture-of-experts Transformer with perception encoders; 62 decoder layers, 256 experts with 8 selected per token, grouped-query attention and sliding-window/full-attention layers.

Full datasheets, every price and sourceKimi K3.1 Pro ↗Muse Spark Open ↗

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.

Kimi K3.1 Pro 61.1/100Rank 10/47

Survived 1 of 3
Foresight: complete playing field
Level 315 ptsTurn 20 / 20

Muse Spark Open 29.4/100Rank 34/47

Survived 0 of 3
Foresight: complete playing field
Level 38 ptsTurn 15 / 20

Points per level

LevelKimi K3.1 ProMuse Spark Open
Level 1Second Thoughts
15 ptsOut of lives
4 ptsOut of lives
Level 2Pressure Pot
12 ptsOut of lives
9 ptsOut of lives
Level 3Hide or Flight
15 ptsSurvived
8 ptsOut of lives

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.

Kimi K3.1 Pro 81.8/100Rank 8/48

Cleared 5 of 5
Latch: complete playing field
Level 519.8 ptsTurn 31 / 40

Muse Spark Open 75.7/100Rank 12/48

Cleared 5 of 5
Latch: complete playing field
Level 519.6 ptsTurn 32 / 40

Points per level

LevelKimi K3.1 ProMuse Spark Open
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.8 ptsCleared
9.8 ptsCleared
Level 3Relay vault
19.2 ptsCleared
19.2 ptsCleared
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
17.8 ptsClearedFinished early · 1 beacon left
Level 5Second thoughts
19.8 ptsCleared
19.6 ptsCleared

Newton's Mirror

Same task instructions

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

The judgment

Kimi K3.1 Pro

The settled sphere, separate airborne black paint and crimson-before-cyan interaction are supported, with a modest crimson travel overshoot. A shared downward framing displacement remains after accounting for the square canvas. The principal limitation is the reflection system: sparse sphere copies and generic curved bands omit most of the ordered mirror-room structure. Materials receive a small upward revision because bounded bright images and dark bands visibly establish some polish, while soft shading and bulky paint remain separate weaknesses.

Muse Spark Open

The airborne black blob and deformed paint support the broad contact sequence, although cyan attachment and wheel-directed transport remain partial. The sphere and black blob have substantial framing errors. The dominant limitation is the largely absent mirror system: faint wall circles and isolated highlights provide little evidence of recursive room geometry or curved nested reflections. Oversized compact paint features and diffuse material treatment further limit credit.

Score breakdown

CategoryKimi K3.1 ProMuse Spark Open
State at 600 ms23.5/2514.0/25
Camera and placement10.5/156.0/15
Reflections26.0/1208.0/120
Materials and scale7.0/103.5/10
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

Kimi K3.1 Pro

The transformed reflection, attentive pose and constellation anatomy clearly communicate introspection. Purposeful fine details enrich a coherent composition. Tubular limbs, crowded lower-body overlaps, shallow depth and limited cast lighting keep the overall execution within the competent range.

Muse Spark Open

The rounded silhouette and asymmetric expression make an appealing baby elephant, supported by a quiet background and grounding shadow. The protective action remains difficult to read: forefeet cannot be confidently traced into a grip, and seed contact is crowded by fine lines. Controlled simple shapes provide charm, but limited anatomical clarity, shading and surface detail leave the execution uneven.

Score breakdown

CategoryKimi K3.1 ProMuse Spark Open
Task & likeness8.0/105.0/10
Anatomy & construction5.5/104.5/10
Space & placement6.5/106.0/10
Light & reflections6.5/105.0/10
Purposeful detail7.5/106.0/10
Artistry & character7.0/105.0/10
Materials & effects7.0/105.0/10
Visual integrity7.0/106.5/10

Benchmark task

Kimi K3.1 Pro

An imagined creature encounters its reflection. The scene tests original character design, visual self-interpretation and the relationship between a subject and its reflected image.

Muse Spark Open

A small elephant protecting a delicate seed tests expressive anatomy, physical contact and contrasting organic materials.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

Kimi K3.1 Pro

A coherent, recognizable interpretation with controlled color and readable landscape layers. Replication is limited by the frontal seated construction, elongated facial proportions and oversized, weakly articulated hands. Smooth shading supplies some volume but little of the reference's subtle expression, fabric structure or atmospheric transitions.

Muse Spark Open

A recognizable, orderly interpretation with clean major contours, connected body forms and modest facial shading. Wide eyes, frontal symmetry and schematic hands limit likeness and expression. Layered scenery establishes basic depth, but shallow arm overlaps, flat clothing and sparse fine detail keep the execution basic and uneven.

Score breakdown

CategoryKimi K3.1 ProMuse Spark Open
Task & likeness5.0/103.0/10
Anatomy & construction5.0/103.0/10
Space & placement5.5/105.0/10
Light & reflections6.0/104.5/10
Purposeful detail5.5/104.0/10
Artistry & character6.0/103.0/10
Materials & effects5.0/104.0/10
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

Different task instructions

Creativity, perspective and visual beauty.

The judgment

Kimi K3.1 Pro

A coherent, playful beach illustration with readable animals, an organized composition and an aligned sunset reflection. Connected silhouettes, sand texture and atmospheric effects demonstrate controlled execution. Simplified joints, flattened foreground viewpoints and inconsistent shadows limit anatomical and spatial credibility.

Muse Spark Open

A coherent sunset beach with readable activities, balanced framing and controlled colour transitions. Small accessories add interest, but schematic anatomy, limited surface detail, weak directional shadows and a geometric reflection constrain its finish. Most shapes and overlaps remain clean.

Score breakdown

CategoryKimi K3.1 ProMuse Spark Open
Task & likeness8.5/108.0/10
Anatomy & construction5.5/106.0/10
Space & placement5.5/106.5/10
Light & reflections6.5/105.5/10
Purposeful detail6.5/106.5/10
Artistry & character5.5/105.5/10
Materials & effects6.5/106.0/10
Visual integrity7.5/108.0/10

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

Kimi K3.1 Pro

This benchmark has not been assessed yet.

Muse Spark Open

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

Different task instructions

Scene composition and interacting subjects.

The judgment

Kimi K3.1 Pro

The additional comparisons support retaining the assessment. Readable steering, shaped animal contours and purposeful details coexist with simplified joints, a frontal passenger whose seated weight is weakly conveyed, and limited physical lighting. The angled craft establishes more depth than the riding pose resolves.

Muse Spark Open

Expressive faces, distinct accessories and clean color separation make the scene appealing and recognizable. Character detail is stronger than the functional construction: steering contact, limb overlaps and seating remain ambiguous. The readable hull and lively spray establish motion, while limited directional shading and simplified surfaces constrain depth and physical coherence.

Score breakdown

CategoryKimi K3.1 ProMuse Spark Open
Task & likeness7.0/104.0/10
Anatomy & construction5.5/103.0/10
Space & placement6.0/106.0/10
Light & reflections5.5/104.5/10
Purposeful detail7.0/107.0/10
Artistry & character6.0/103.5/10
Materials & effects6.0/105.0/10
Visual integrity7.0/105.0/10

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

Different task instructions

Subject construction and spatial relationships.

The judgment

Kimi K3.1 Pro

A characterful coastal illustration with controlled contours and varied feather, accessory and bicycle detail. Layered scenery and subtle shading enrich the presentation. Soft leg articulation, unresolved riding contacts, shallow depth and generalized lighting limit physical precision.

Muse Spark Open

A controlled, appealing cartoon with a recognizable pelican, expressive face and clean curved forms. Feather lines, spokes and bill shading provide useful complexity. Aligned wheels and a ground shadow establish placement, but uncertain pedal contacts and obscured mechanical connections weaken support and riding action. Lighting remains loosely coordinated with the sun.

Score breakdown

CategoryKimi K3.1 ProMuse Spark Open
Task & likeness8.5/107.5/10
Anatomy & construction7.5/105.0/10
Space & placement6.5/106.0/10
Light & reflections6.5/105.0/10
Purposeful detail7.5/106.5/10
Artistry & character7.5/105.5/10
Materials & effects6.5/106.0/10
Visual integrity7.5/107.5/10

Benchmark task

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