STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Muse Spark Open vs LongCat-2.0

Muse Spark Open leads LongCat-2.0 by 18.6 points on StealthMark, 44.1 to 25.5. It leads on 4 of the 7 benchmarks with results for both and LongCat-2.0 on 3. Muse Spark Open scores higher on Ground Truth.

See the difference ↘
All results ↗
Model guide ↗

Overall StealthMark

44.1/100Overall rank 29/53
25.5/100Overall rank 45/53

General Intelligence

42.6/100
17.2/100

Visual Intelligence

46.6/100
34.4/100

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
  • LongCat-2.0Multi-step reasoning not measured

Open or local

Open modelMIT

BENCHMARK BY BENCHMARK

Where each model leads

  • Muse Spark Open
  • LongCat-2.0
  • Other models
  • Median

DATASHEET

Specs and pricing

Muse Spark Open scores higher on StealthMark and runs 4.2× faster in our speed test. LongCat-2.0 is 3.5× cheaper per output token. Both take about 1M tokens of context.

  • Muse Spark Open
  • LongCat-2.0
  • Other models
  • Median
PricePer 1M output tokens, input below
Muse Spark Open: $4.25$1.25 inputLongCat-2.0: $1.203.5× cheaper$0.30 input
Context windowTokens per request, max output below
Muse Spark Open: 1MTied1M max outputLongCat-2.0: 1MTied
Output speedTokens per second, our measurement
Muse Spark Open: 3614.2× fastertokens/sLongCat-2.0: 86tokens/s
SizeTotal and active parameters
Muse Spark Open: 816B42B activeLongCat-2.0: Not disclosed
Developer
MetaMeituan
Released
15 Oct 2026Not published
Origin
United StatesChina
Input → output
Text, image, audio, video → textText → text
Architecture
Sparse 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.Mixture-of-Experts with LongCat Sparse Attention

Full datasheets, every price and sourceMuse Spark Open ↗LongCat-2.0 ↗

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.

Muse Spark Open 29.4/100Rank 34/47

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

Points per level

LevelMuse Spark OpenLongCat-2.0
Level 1Second Thoughts
4 ptsOut of lives
No run
Level 2Pressure Pot
9 ptsOut of lives
No run
Level 3Hide or Flight
8 ptsOut of lives
No run

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.

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

LevelMuse Spark OpenLongCat-2.0
Level 1Hold the door
5.2 ptsCleared
No run
Level 2Crossfeed
9.8 ptsCleared
No run
Level 3Relay vault
19.2 ptsCleared
No run
Level 4Passing bay
17.8 ptsClearedFinished early · 1 beacon left
No run
Level 5Second thoughts
19.6 ptsCleared
No run

Newton's Mirror

Same task instructions

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

The judgment

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.

LongCat-2.0

Cyan lies on the sphere's facing middle rather than showing its recent interaction near the apex. Separate airborne black and elongated crimson support part of the timing sequence. Small side images and an overlapping lower image provide limited reflection ordering, but recursive room structure, nested imagery and emitter mappings are largely absent. The main sphere is smaller and higher in the frame than prescribed, and the surfaces have a soft, matte appearance.

Score breakdown

CategoryMuse Spark OpenLongCat-2.0
State at 600 ms14.0/259.5/25
Camera and placement6.0/156.5/15
Reflections8.0/12012.5/120
Materials and scale3.5/105.5/10
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

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.

LongCat-2.0

Amber slit eyes, a pointed beak, cream feathers and gold-trimmed black clothing establish the secretive owl rogue. The head appears frontal rather than lowered, with much of the face exposed. The centered silhouette is effective, but stiff cloak geometry, shallow facial modeling and extremely dark clothing limit depth and finish. Sparse gold markings suggest the requested circuitry only loosely.

Score breakdown

CategoryMuse Spark OpenLongCat-2.0
Task & likeness5.0/107.0/10
Anatomy & construction4.5/106.0/10
Space & placement6.0/106.0/10
Light & reflections5.0/105.5/10
Purposeful detail6.0/106.0/10
Artistry & character5.0/106.5/10
Materials & effects5.0/105.5/10
Visual integrity6.5/106.5/10

Benchmark task

Muse Spark Open

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

LongCat-2.0

A cloaked owl with luminous eyes tests expression, fabric folds and the separation of dark forms.

Mona Lisa

Same task instructions

Precise visual recall and portrait reconstruction.

The judgment

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.

LongCat-2.0

The centered portrait, slight smile, overlapping hands and distant landscape suggest Mona Lisa, but replication is weak. The face has little volume, the shoulders and torso form a narrow wedge, and the hands are fingerless ovals with unresolved wrists. Broad gray background bands provide limited depth. A bright head rim and pale hands contrast with an almost featureless dark figure.

Score breakdown

CategoryMuse Spark OpenLongCat-2.0
Task & likeness3.0/100.5/10
Anatomy & construction3.0/100.5/10
Space & placement5.0/100.5/10
Light & reflections4.5/100.5/10
Purposeful detail4.0/100.0/10
Artistry & character3.0/100.5/10
Materials & effects4.0/100.0/10
Visual integrity6.0/100.5/10

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

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.

LongCat-2.0

The sunset, palms, birds and beach animals create a cheerful, readable scene. Clean silhouettes and a vivid sky establish the composition, but construction remains schematic. The right palm appears rooted in open water, shadows have limited connection to the sunset, and the sun’s reflection consists of rigid bands. Small creatures and beach equipment are recognizable but minimally developed.

Score breakdown

CategoryMuse Spark OpenLongCat-2.0
Task & likeness8.0/107.5/10
Anatomy & construction6.0/105.5/10
Space & placement6.5/105.5/10
Light & reflections5.5/106.0/10
Purposeful detail6.5/105.0/10
Artistry & character5.5/105.0/10
Materials & effects6.0/103.0/10
Visual integrity8.0/104.0/10

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

Muse Spark Open

This benchmark has not been assessed yet.

LongCat-2.0

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

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.

LongCat-2.0

The raccoon is recognizable and expressive, with a clear mask and striped tail. The dog's anatomy is poorly resolved, and the flattened craft lacks convincing steering and seating. Feet extend below the hull, weakening the sense of support. An appealing palette, clean shapes and decorative water effects give the illustration some polish.

Score breakdown

CategoryMuse Spark OpenLongCat-2.0
Task & likeness4.0/104.0/10
Anatomy & construction3.0/103.0/10
Space & placement6.0/104.5/10
Light & reflections4.5/105.5/10
Purposeful detail7.0/106.0/10
Artistry & character3.5/103.0/10
Materials & effects5.0/105.5/10
Visual integrity5.0/105.0/10

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

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.

LongCat-2.0

A clearly recognizable pelican cycles through a well-composed coastal sunset. Warm colors, flowing scarf, feather contours and bicycle details give the illustration character. The legs connect to the body, but the farther foot's pedal contact and the wing's handlebar grip remain ambiguous. Clean vector shapes provide polish, with limited material texture and directional shading.

Score breakdown

CategoryMuse Spark OpenLongCat-2.0
Task & likeness7.5/108.5/10
Anatomy & construction5.0/107.0/10
Space & placement6.0/108.0/10
Light & reflections5.0/107.5/10
Purposeful detail6.5/108.0/10
Artistry & character5.5/108.5/10
Materials & effects6.0/107.0/10
Visual integrity7.5/108.5/10

Benchmark task

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