STEALTHMARK · HEAD TO HEAD

All comparisons ↗

GPT-6 Luna vs GPT-6.1 Terra Low

GPT-6.1 Terra Low leads GPT-6 Luna by 2.2 points on StealthMark, 41.3 to 39.1. It leads on 5 of 9 benchmarks, including both games, and GPT-6 Luna on 4. GPT-6 Luna scores higher on Raccoon, with its largest category advantage in space & placement.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

39.1/100Overall rank 37/55
41.3/100Overall rank 35/55

General Intelligence

31.3/100
34.3/100

Visual Intelligence

52.0/100
53.1/100

BENCHMARK BY BENCHMARK

Where each model leads

  • GPT-6 Luna
  • GPT-6.1 Terra Low
  • Other models
  • Median

DATASHEET

Specs and pricing

  • GPT-6 Luna
  • GPT-6.1 Terra Low
  • Other models
  • Median
PricePer 1M output tokens, input below
GPT-6 Luna: $0.50$0.10 inputGPT-6.1 Terra Low: No list price
Context windowTokens per request, max output below
GPT-6 Luna: 1.05M128K max outputGPT-6.1 Terra Low: Not published
Output speedTokens per second, our measurement
GPT-6 Luna: 131tokens/sGPT-6.1 Terra Low: Not measured
Developer
OpenAINot published
Released
22 Sep 2026Not published
Origin
United StatesNot published
Input → output
Text, image → textNot published

Full datasheets, every price and sourceGPT-6 Luna ↗

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 34/51

Survived 0 of 3
Foresight: complete playing field
Level 36 ptsTurn 7 / 20

GPT-6.1 Terra Low 36.1/100Rank 26/51

Survived 1 of 3
Foresight: complete playing field
Level 39 ptsTurn 20 / 20

Points per level

LevelGPT-6 LunaGPT-6.1 Terra Low
Level 1Second Thoughts
15 ptsOut of lives
4 ptsOut of lives
Level 2Pressure Pot
5 ptsOut of lives
8 ptsOut of lives
Level 3Hide or Flight
6 ptsOut of lives
9 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 28/52

Cleared 4 of 5
Latch: complete playing field
Level 513 ptsTurn 15 / 40

GPT-6.1 Terra Low 62.4/100Rank 23/52

Cleared 4 of 5
Latch: complete playing field
Level 520.6 ptsTurn 27 / 40

Points per level

LevelGPT-6 LunaGPT-6.1 Terra Low
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
8.8 ptsClearedFinished early · 1 beacon left
9.2 ptsCleared
Level 3Relay vault
17 ptsCleared1 beacon left
18.8 ptsCleared
Level 4Passing bay
15.8 ptsClearedFinished early · 3 beacons left
10.2 ptsFinished early
Level 5Second thoughts
13 ptsFinished early
20.6 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.

GPT-6.1 Terra Low

Deformed colored paint and a separate airborne black body establish readable interaction history. Cyan has travelled too far, framing differs substantially, and the mirror system supplies only elementary bands and oval copies. Missing recursive geometry, nested spherical imagery and emitter mapping remain the dominant weaknesses.

Score breakdown

CategoryGPT-6 LunaGPT-6.1 Terra Low
State at 600 ms22.0/2522.0/25
Camera and placement3.5/154.0/15
Reflections5.0/12010.0/120
Materials and scale7.0/106.0/10
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

Same 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.

GPT-6.1 Terra Low

Six attached outward-facing heads, delicate scales and soft ivory shading establish an orderly decorative motif. Separate paddle-shaped bodies replace the required interlocking loops and leave no enclosed central hexagon. Surface detail provides interest, but repeated simple forms, schematic faces and limited anatomical modeling constrain the result.

Score breakdown

CategoryGPT-6 LunaGPT-6.1 Terra Low
Task & likeness4.5/104.0/10
Anatomy & construction3.5/103.5/10
Space & placement5.5/104.5/10
Light & reflections5.0/105.5/10
Purposeful detail5.0/105.5/10
Artistry & character5.0/105.0/10
Materials & effects5.0/105.5/10
Visual integrity4.5/104.0/10

Benchmark task

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.

Mona Lisa

Same 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.

GPT-6.1 Terra Low

A recognizable, coherent portrait with purposeful facial detail, warm local volume and layered scenery. The frontal pose, enlarged face, merged hands and shallow clothing construction substantially limit replication and drawing skill. The visible successes support retaining the current assessment.

Score breakdown

CategoryGPT-6 LunaGPT-6.1 Terra Low
Task & likeness4.5/105.0/10
Anatomy & construction4.0/104.5/10
Space & placement5.5/105.0/10
Light & reflections5.0/106.0/10
Purposeful detail5.0/105.0/10
Artistry & character4.5/105.5/10
Materials & effects5.0/105.0/10
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.

GPT-6.1 Terra Low

A coherent sunset scene demonstrates the beach, animals, birds and reflections. Flowing silhouettes, warm color transitions and intact attachments are its strongest properties. Simplified anatomy, the turtle's elevated viewing angle and symbolic surface effects constrain drawing complexity and physical depth.

Score breakdown

CategoryGPT-6 LunaGPT-6.1 Terra Low
Task & likeness7.5/108.0/10
Anatomy & construction5.0/105.5/10
Space & placement7.5/105.5/10
Light & reflections5.0/106.5/10
Purposeful detail7.0/106.0/10
Artistry & character5.0/105.0/10
Materials & effects6.5/105.5/10
Visual integrity6.0/107.5/10

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.

GPT-6.1 Terra Low

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.

GPT-6.1 Terra Low

Recognizable animals, a coherent craft and sweeping wake make an appealing cartoon. Basic limb construction, weakly demonstrated raccoon seating and limited shared perspective constrain the scene. Small identifying details work well, while lighting and materials remain broadly graphic.

Score breakdown

CategoryGPT-6 LunaGPT-6.1 Terra Low
Task & likeness8.0/106.5/10
Anatomy & construction5.5/105.0/10
Space & placement7.5/105.5/10
Light & reflections6.0/104.5/10
Purposeful detail7.0/106.0/10
Artistry & character5.5/105.0/10
Materials & effects6.5/105.0/10
Visual integrity5.0/106.0/10

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

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.

GPT-6.1 Terra Low

A coherent coastal illustration with a distinctive pelican, controlled contours and clearly organised bicycle wheels. Visible saddle support and shaped neck and wing contours earn credit beyond basic geometric construction. Rubbery legs, unresolved pedal contacts and absent steering contact limit the riding action. Lighting and materials remain restrained and spatially shallow.

Score breakdown

CategoryGPT-6 LunaGPT-6.1 Terra Low
Task & likeness8.0/107.0/10
Anatomy & construction5.0/105.5/10
Space & placement6.5/106.0/10
Light & reflections6.5/105.5/10
Purposeful detail7.5/106.5/10
Artistry & character6.5/106.0/10
Materials & effects6.5/106.0/10
Visual integrity7.0/106.0/10

Benchmark task

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