STEALTHMARK · HEAD TO HEAD

All comparisons ↗

GPT-5.6 Luna vs Iceman Contributor

GPT-5.6 Luna leads Iceman Contributor by 18.6 points on StealthMark, 37.8 to 19.2. It leads on all 9 benchmarks. GPT-5.6 Luna scores higher on Newton's Mirror, with its largest category advantage in state at 600 ms.

See the difference ↘
All results ↗
Model guide ↗

Overall StealthMark

37.8/100Overall rank 37/53
19.2/100Overall rank 47/53

General Intelligence

30.4/100
11.7/100

Visual Intelligence

50.2/100
31.0/100

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

  • GPT-5.6 Luna

Open or local

BENCHMARK BY BENCHMARK

Where each model leads

  • GPT-5.6 Luna
  • Iceman Contributor
  • Other models
  • Median

DATASHEET

Specs and pricing

GPT-5.6 Luna scores higher on StealthMark and runs 3.9× faster in our speed test.

  • GPT-5.6 Luna
  • Iceman Contributor
  • Other models
  • Median
PricePer 1M output tokens, input below
GPT-5.6 Luna: $1.20$0.20 inputIceman Contributor: No list price
Context windowTokens per request, max output below
GPT-5.6 Luna: 1.05M128K max outputIceman Contributor: Not published
Output speedTokens per second, our measurement
GPT-5.6 Luna: 1813.9× fastertokens/sIceman Contributor: 46tokens/s
Developer
OpenAINot published
Released
9 Jul 2026Not published
Origin
United StatesNot published
Input → output
Text, image → textNot published

Full datasheets, every price and sourceGPT-5.6 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-5.6 Luna 25.1/100Rank 35/47

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

Iceman Contributor 3.2/100Rank 47/47

Survived 0 of 3
Foresight: complete playing field
Level 31 ptsTurn 7 / 20

Points per level

LevelGPT-5.6 LunaIceman Contributor
Level 1Second Thoughts
4 ptsOut of lives
0 ptsOut of lives
Level 2Pressure Pot
6 ptsOut of lives
3 ptsOut of lives
Level 3Hide or Flight
8 ptsOut of lives
1 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.

GPT-5.6 Luna 52.9/100Rank 21/48

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

Iceman Contributor 3.6/100Rank 44/48

Cleared 1 of 5
Latch: complete playing field
Level 55 ptsTurn 25 / 40

Points per level

LevelGPT-5.6 LunaIceman Contributor
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
8.6 ptsClearedFinished early · 1 beacon left
2.8 ptsFinished early
Level 3Relay vault
18 ptsCleared
2.2 ptsFinished early
Level 4Passing bay
17 ptsClearedFinished early · 3 beacons left
4 ptsFinished early
Level 5Second thoughts
20.6 ptsCleared
5 ptsFinished early

Newton's Mirror

Same task instructions

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

The judgment

GPT-5.6 Luna

The room enclosure has coherent symmetric perspective, with the overhead panel, sphere and black aligned centrally. The sphere and airborne black occupy substantially lower positions than the reference framing, inconsistent with the prescribed camera aim. The diagonal crimson streak does not establish the required surface transport. Faint wall sphere images provide limited mirrored correspondence, but the shallow floor image, missing receding chains, absent nested sphere imagery and sparse emitter mapping leave most reflection structure unsupported.

Iceman Contributor

The image provides limited evidence through rounded volume, faint wall strips and floor echoes. Its main sphere is small and low, the paint beads do not establish the required interaction history, and most of the defining mirror structure is missing.

Score breakdown

CategoryGPT-5.6 LunaIceman Contributor
State at 600 ms15.0/250.5/25
Camera and placement4.0/152.5/15
Reflections3.5/1207.5/120
Materials and scale6.5/103.0/10
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

GPT-5.6 Luna

Six pale, outward-facing heads and six rounded lobes make the knot recognizable. The central hexagonal opening remains clear. However, broad gray crossing panels flatten the weave, several inner joins resemble capped strips, and sparse oversized scale marks leave the bodies looking more like decorated ribbons than living snakes.

Iceman Contributor

The crystal crown, cyan eyes and blue faceting communicate an icy fantasy character. Anatomical readability is substantially weaker: the ringed torso, crowded facial construction and fingerless appendages do not resolve the requested childlike crouch or pouncing gesture. Sparse surface detail and shallow shading further limit the result.

Score breakdown

CategoryGPT-5.6 LunaIceman Contributor
Task & likeness7.5/104.0/10
Anatomy & construction6.0/103.0/10
Space & placement6.5/104.0/10
Light & reflections5.0/104.5/10
Purposeful detail5.5/104.0/10
Artistry & character6.0/104.5/10
Materials & effects5.0/104.5/10
Visual integrity6.0/104.0/10

Benchmark task

GPT-5.6 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.

Iceman Contributor

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

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

GPT-5.6 Luna

The central portrait, dark clothing, crossed hands and muted landscape clearly evoke Mona Lisa. Replication is limited by the elongated face, conspicuous eyes and simplified smile. Overlapping fingers have uncertain anatomy, while broad gradients and heavy outlines flatten the portrait. The composition and restrained palette remain coherent.

Iceman Contributor

The portrait retains a dark silhouette against an earthy landscape, but replication is weak. The frontal body, elongated facial proportions and undifferentiated hands lose the reference's defining pose and likeness. Basic gradients and layered hills provide some coherence, with little anatomical or painterly detail.

Score breakdown

CategoryGPT-5.6 LunaIceman Contributor
Task & likeness3.5/101.5/10
Anatomy & construction3.5/101.5/10
Space & placement4.0/102.5/10
Light & reflections4.5/102.0/10
Purposeful detail4.0/102.0/10
Artistry & character4.0/102.0/10
Materials & effects3.5/102.0/10
Visual integrity4.5/103.0/10

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

GPT-5.6 Luna

The warm sunset, palm silhouette and varied beach activities create an appealing, readable composition. Animals, birds and a broad sun reflection satisfy the brief. Drawing remains elementary: angular airborne sea animals lack splash or convincing motion, the crab's claws are awkwardly constructed, and repeated reflection bands suggest a stepped platform. Clean outlines and pleasant colors exceed the anatomical and spatial sophistication.

Iceman Contributor

A coherent sunset beach with recognizable animals, playful details and effective palm framing. Connected silhouettes and layered scenery support modest construction and placement credit. Jointless figures, limited foreshortening and an inadequately separated sun and reflection keep the execution basic despite its attractive color.

Score breakdown

CategoryGPT-5.6 LunaIceman Contributor
Task & likeness7.5/107.0/10
Anatomy & construction4.0/103.5/10
Space & placement5.5/106.0/10
Light & reflections4.0/104.0/10
Purposeful detail6.5/105.5/10
Artistry & character3.5/103.5/10
Materials & effects4.0/104.5/10
Visual integrity3.5/105.0/10

Benchmark task

A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.

Ground Truth

Different task instructions

Physical reasoning, light and visual reconstruction.

The judgment

GPT-5.6 Luna

This benchmark has not been assessed yet.

Iceman Contributor

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

GPT-5.6 Luna

Expressive animals, a striped tail and clean outlines make the scene appealing and readable. The raccoon sits convincingly on the dog's back, but the overlapping steering paws are ambiguous and the control stem stops above the hull. Broad wake shapes suggest motion; the glowing sun lacks a corresponding water reflection.

Iceman Contributor

The sunset palette and red hull establish an appealing setting, but the central interaction remains unresolved. Overlapping bodies obscure the dog, supported seating is unclear, and no readable paw-to-control grip demonstrates steering. Simple construction, weak environmental lighting and loosely described spray limit depth and finish.

Score breakdown

CategoryGPT-5.6 LunaIceman Contributor
Task & likeness7.0/102.0/10
Anatomy & construction5.0/103.0/10
Space & placement6.5/103.0/10
Light & reflections6.0/104.0/10
Purposeful detail6.5/103.5/10
Artistry & character4.5/102.5/10
Materials & effects5.5/104.0/10
Visual integrity5.0/102.5/10

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

Different task instructions

Subject construction and spatial relationships.

The judgment

GPT-5.6 Luna

A recognizable pelican cyclist with an expressive profile, balanced composition and controlled outlines. Head, neck and torso connect coherently. The bicycle wheels and frame are convincing, but overlapping feet obscure pedal contact, the drivetrain lacks a clear chain, and the wing's handlebar grip is schematic. Atmospheric color succeeds more strongly than directional lighting or material depth.

Iceman Contributor

A recognizable pelican and bicycle sit within an appealing sunset composition. Feather contours, bill shape and atmospheric colour provide character, but disconnected-looking leg origins, unclear pedal contact and unresolved steering weaken the central riding action. Consistent wheel alignment establishes a side view without resolving the rider's support.

Score breakdown

CategoryGPT-5.6 LunaIceman Contributor
Task & likeness8.5/104.0/10
Anatomy & construction5.5/103.5/10
Space & placement7.5/103.5/10
Light & reflections6.5/105.0/10
Purposeful detail6.5/104.5/10
Artistry & character5.5/103.5/10
Materials & effects7.0/104.0/10
Visual integrity6.5/103.0/10

Benchmark task

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