STEALTHMARK · HEAD TO HEAD

All comparisons ↗

LongCat-2.0 vs Step 5 Preview

Step 5 Preview leads LongCat-2.0 by 13.5 points on StealthMark, 39.0 to 25.5. LongCat-2.0 leads on 4 of the 7 benchmarks with results for both and Step 5 Preview on 3. Step 5 Preview scores higher on Newton's Mirror, with its largest category advantage in state at 600 ms.

See the difference ↘
Model guide ↗
All results ↗

Overall StealthMark

25.5/100Overall rank 45/53
39.0/100Overall rank 36/53

General Intelligence

17.2/100
37.1/100

Visual Intelligence

34.4/100
41.9/100

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

  • LongCat-2.0Multi-step reasoning not measured

Open or local

Open modelMIT

BENCHMARK BY BENCHMARK

Where each model leads

  • LongCat-2.0
  • Step 5 Preview
  • Other models
  • Median

DATASHEET

Specs and pricing

Both take about 1M tokens of context.

  • LongCat-2.0
  • Step 5 Preview
  • Other models
  • Median
PricePer 1M output tokens, input below
LongCat-2.0: $1.20$0.30 inputStep 5 Preview: No list price
Context windowTokens per request, max output below
LongCat-2.0: 1MTiedStep 5 Preview: 1MTied
Output speedTokens per second, our measurement
LongCat-2.0: 86tokens/sStep 5 Preview: Not measured
SizeTotal and active parameters
LongCat-2.0: Not disclosedStep 5 Preview: 600B27B active
Developer
MeituanStepFun
Origin
ChinaNot published
Input → output
Text → textText, image, video → text
Architecture
Mixture-of-Experts with LongCat Sparse AttentionSparse mixture-of-experts; 92 layers (88 MoE), 352 routed experts with 8 selected per token plus a shared expert; grouped-query attention with 512-token sliding windows and full attention every fourth layer; 3 multi-token-prediction layers; vision tower for image and video input

Full datasheets, every price and sourceLongCat-2.0 ↗Step 5 Preview ↗

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.

Step 5 Preview 59.9/100Rank 42/491 of 3 levels

1 of 3 played
Foresight: complete playing field
Level 122 ptsTurn 28 / 28

Points per level

LevelLongCat-2.0Step 5 Preview
Level 1Second Thoughts
No run
22 ptsSurvived
Level 2Pressure Pot
No run
Pending
Level 3Hide or Flight
No run
Pending

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.

Step 5 Preview 40.7/100Rank 28/50

Cleared 4 of 5
Latch: complete playing field
Level 515 ptsTurn 35 / 40

Points per level

LevelLongCat-2.0Step 5 Preview
Level 1Hold the door
No run
5.2 ptsCleared
Level 2Crossfeed
No run
9 ptsCleared
Level 3Relay vault
No run
18.6 ptsCleared
Level 4Passing bay
No run
15.6 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
No run
15 ptsFinished early

Newton's Mirror

Same task instructions

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

The judgment

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.

Step 5 Preview

The main sphere, airborne black and small colored features occupy broadly appropriate positions. Most of the defining mirror system is absent, and paint interaction remains only partially supported. The small paint features do not visibly establish a separate volume-scale violation.

Score breakdown

CategoryLongCat-2.0Step 5 Preview
State at 600 ms9.5/2520.0/25
Camera and placement6.5/1513.5/15
Reflections12.5/12020.0/120
Materials and scale5.5/107.0/10
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

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.

Step 5 Preview

A charming diagonal climber and warm palette communicate the central idea. Simple rounded construction, crowded limb counting, uncertain footholds and an unattached upper shelf limit its physical coherence. Growth bands and the yarn trail add specificity, but the requested material distinctions and unravelled bootie remain underdeveloped.

Score breakdown

CategoryLongCat-2.0Step 5 Preview
Task & likeness7.0/106.0/10
Anatomy & construction6.0/104.5/10
Space & placement6.0/105.0/10
Light & reflections5.5/105.5/10
Purposeful detail6.0/105.5/10
Artistry & character6.5/105.0/10
Materials & effects5.5/106.0/10
Visual integrity6.5/105.0/10

Benchmark task

LongCat-2.0

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

Step 5 Preview

Character scenes test expression, anatomy, materials and coherent visual construction.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

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.

Step 5 Preview

A recognizable, coherent simplification with purposeful facial contours and differentiated fingers. These provide more construction and detail than the broad silhouette alone suggests. The oversized face, frontal seated pose, unresolved wrists and sparse landscape still substantially limit likeness, depth and finish.

Score breakdown

CategoryLongCat-2.0Step 5 Preview
Task & likeness0.5/104.0/10
Anatomy & construction0.5/104.0/10
Space & placement0.5/104.0/10
Light & reflections0.5/103.5/10
Purposeful detail0.0/104.0/10
Artistry & character0.5/104.0/10
Materials & effects0.0/103.0/10
Visual integrity0.5/103.5/10

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

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.

Step 5 Preview

A recognizable sunset beach with clear warm-cool contrast and playful accessories. Basic animal construction, shallow foreground placement and schematic reflections limit spatial and physical credibility. Sparse descriptive detail and abruptly ended sky bands constrain the finish.

Score breakdown

CategoryLongCat-2.0Step 5 Preview
Task & likeness7.5/104.0/10
Anatomy & construction5.5/103.0/10
Space & placement5.5/103.5/10
Light & reflections6.0/103.5/10
Purposeful detail5.0/103.0/10
Artistry & character5.0/103.0/10
Materials & effects3.0/103.5/10
Visual integrity4.0/104.0/10

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

LongCat-2.0

This benchmark has not been assessed yet.

Step 5 Preview

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

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.

Step 5 Preview

Recognizable animals, a bright palette and identifying accessories support a basic cartoon. Primitive anatomy, partial seated support, unresolved steering and weak hull-water contact limit the central action. Lighting and spray provide atmosphere without establishing convincing physical depth.

Score breakdown

CategoryLongCat-2.0Step 5 Preview
Task & likeness4.0/104.0/10
Anatomy & construction3.0/104.5/10
Space & placement4.5/103.0/10
Light & reflections5.5/103.5/10
Purposeful detail6.0/104.0/10
Artistry & character3.0/103.5/10
Materials & effects5.5/103.0/10
Visual integrity5.0/103.0/10

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

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.

Step 5 Preview

The pelican and bicycle are recognizable, with a pleasant palette and basic diffuse shading. The riding relationship fails physically: the bird is unsupported, the front wheel is unmounted, and pedalling is unresolved. Simple geometric construction and sparse material treatment further limit the drawing.

Score breakdown

CategoryLongCat-2.0Step 5 Preview
Task & likeness8.5/103.0/10
Anatomy & construction7.0/103.0/10
Space & placement8.0/103.0/10
Light & reflections7.5/103.0/10
Purposeful detail8.0/104.0/10
Artistry & character8.5/103.0/10
Materials & effects7.0/103.0/10
Visual integrity8.5/102.0/10

Benchmark task

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