STEALTHMARK · HEAD TO HEAD

All comparisons ↗

GPT-6 Luna vs MiMo-V2.6-Pro

MiMo-V2.6-Pro leads GPT-6 Luna by 8.8 points on StealthMark, 47.9 to 39.1. It leads on 6 of 9 benchmarks, including both games, and GPT-6 Luna on 3. MiMo-V2.6-Pro scores higher on Newton's Mirror, with its largest category advantage in reflections.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

39.1/100Overall rank 35/53
47.9/100Overall rank 21/53

General Intelligence

31.3/100
44.3/100

Visual Intelligence

52.0/100
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

  • GPT-6 Luna
  • MiMo-V2.6-Pro
  • Other models
  • Median

DATASHEET

Specs and pricing

GPT-6 Luna is 1.7× cheaper per output token and runs 14% faster in our speed test. MiMo-V2.6-Pro scores higher on StealthMark. Both take about 1.05M tokens of context.

  • GPT-6 Luna
  • MiMo-V2.6-Pro
  • Other models
  • Median
PricePer 1M output tokens, input below
GPT-6 Luna: $0.501.7× cheaper$0.10 inputMiMo-V2.6-Pro: $0.87$0.43 input
Context windowTokens per request, max output below
GPT-6 Luna: 1.05MTied128K max outputMiMo-V2.6-Pro: 1MTied128K max output
Output speedTokens per second, our measurement
GPT-6 Luna: 13114% fastertokens/sMiMo-V2.6-Pro: 116tokens/s
SizeTotal and active parameters
GPT-6 Luna: Not disclosedMiMo-V2.6-Pro: 1.02T42B active
Developer
OpenAIXiaomi
Released
22 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 sourceGPT-6 Luna ↗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.

GPT-6 Luna 29.8/100Rank 32/47

Survived 0 of 3
Foresight: complete playing field
Level 36 ptsTurn 7 / 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

LevelGPT-6 LunaMiMo-V2.6-Pro
Level 1Second Thoughts
15 ptsOut of lives
4 ptsOut of lives
Level 2Pressure Pot
5 ptsOut of lives
9 ptsOut of lives
Level 3Hide or Flight
6 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.

GPT-6 Luna 44.0/100Rank 25/48

Cleared 4 of 5
Latch: complete playing field
Level 513 ptsTurn 15 / 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

LevelGPT-6 LunaMiMo-V2.6-Pro
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
8.8 ptsClearedFinished early · 1 beacon left
9 ptsClearedFinished early · 1 beacon left
Level 3Relay vault
17 ptsCleared1 beacon left
17.2 ptsClearedFinished early · 1 beacon left
Level 4Passing bay
15.8 ptsClearedFinished early · 3 beacons left
16 ptsClearedFinished early · 3 beacons left
Level 5Second thoughts
13 ptsFinished early
20.4 ptsCleared

Newton's Mirror

Same task instructions

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

The judgment

GPT-6 Luna

The schematic scene supports the paint contact order and compact paint scale. Its low, undersized main sphere and incorrectly placed wall images depart from the reference geometry. A few shrinking wall images provide limited optical organization, while absent lateral recursion and outer chains, broad sphere ribbons and isolated panel highlights leave most nested room and emitter mapping undeveloped.

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

CategoryGPT-6 LunaMiMo-V2.6-Pro
State at 600 ms22.0/2523.0/25
Camera and placement3.5/1512.0/15
Reflections5.0/12019.0/120
Materials and scale7.0/107.5/10
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

GPT-6 Luna

Sixfold symmetry, pale coloring and six outward-facing heads establish the motif. However, every neck floats clear of the knot. Squared outer sections replace the required semicircular lobes, and the large stepped opening lacks a regular hexagonal contour. Repeated scales and soft shading suggest skin, but translucent crossings and doubled edges weaken the living, interwoven construction.

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

CategoryGPT-6 LunaMiMo-V2.6-Pro
Task & likeness4.5/106.5/10
Anatomy & construction3.5/105.0/10
Space & placement5.5/105.5/10
Light & reflections5.0/106.5/10
Purposeful detail5.0/106.5/10
Artistry & character5.0/105.0/10
Materials & effects5.0/106.5/10
Visual integrity4.5/106.0/10

Benchmark task

GPT-6 Luna

A pale serpent woven into an interlocking knot tests connected anatomy, repeated structure and readable overlaps. Organic surface detail must work with the overall geometry.

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

GPT-6 Luna

The dark veil, crossed arms, restrained smile and layered landscape clearly evoke Mona Lisa. Clean contours and muted colors create a coherent illustration. Replication is limited by enlarged, outlined eyes, simplified facial volume, broad shoulders and indistinct overlapping hands. Gradients suggest depth, but lack the original's subtle painterly transitions.

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

CategoryGPT-6 LunaMiMo-V2.6-Pro
Task & likeness4.5/103.5/10
Anatomy & construction4.0/103.5/10
Space & placement5.5/104.0/10
Light & reflections5.0/105.0/10
Purposeful detail5.0/103.0/10
Artistry & character4.5/104.0/10
Materials & effects5.0/104.0/10
Visual integrity6.0/106.0/10

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

GPT-6 Luna

The warm sky, layered sea and framing palms create an appealing beach composition. Animals, birds, toys and reflected sunlight fulfill the brief. Human anatomy remains schematic, and simplified figures offer limited expression. Missing shadows and the dolphin's splashless jump weaken physical grounding, while clean silhouettes and readable small details support the illustration.

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

CategoryGPT-6 LunaMiMo-V2.6-Pro
Task & likeness7.5/108.5/10
Anatomy & construction5.0/105.0/10
Space & placement7.5/106.0/10
Light & reflections5.0/106.5/10
Purposeful detail7.0/106.5/10
Artistry & character5.0/105.0/10
Materials & effects6.5/106.0/10
Visual integrity6.0/106.0/10

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

GPT-6 Luna

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

GPT-6 Luna

Expressive faces, warm sunset colors and clean silhouettes create an appealing illustration. The raccoon sits on the dog's back, but the dog's grip and steering linkage remain unclear. The broad hull resembles a speedboat, and flat shading, absent sun reflections and modest water displacement limit depth and motion.

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

CategoryGPT-6 LunaMiMo-V2.6-Pro
Task & likeness8.0/107.0/10
Anatomy & construction5.5/105.0/10
Space & placement7.5/105.5/10
Light & reflections6.0/105.5/10
Purposeful detail7.0/106.0/10
Artistry & character5.5/104.0/10
Materials & effects6.5/105.5/10
Visual integrity5.0/104.5/10

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

GPT-6 Luna

The pelican’s distinctive bill and the coordinated vintage poster palette make an appealing illustration. Circular wheels, orderly spokes and clean lettering strengthen the design. Riding mechanics are less convincing: neither wing reaches the handlebars, pedal contact is ambiguous, and the drivetrain is incomplete. The wheels sit against water without a clear supporting surface. Flat lighting limits volume.

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

CategoryGPT-6 LunaMiMo-V2.6-Pro
Task & likeness8.0/106.5/10
Anatomy & construction5.0/105.0/10
Space & placement6.5/106.0/10
Light & reflections6.5/105.5/10
Purposeful detail7.5/106.0/10
Artistry & character6.5/106.0/10
Materials & effects6.5/105.5/10
Visual integrity7.0/106.0/10

Benchmark task

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