GPT-5.6 Luna 25.1/100Rank 35/47

STEALTHMARK · HEAD TO HEAD
All comparisons ↗Kimi K3.1 Pro leads GPT-5.6 Luna by 18.9 points on StealthMark, 56.7 to 37.8. It leads on all 9 benchmarks. Kimi K3.1 Pro scores higher on Newton's Mirror, with its largest category advantage in reflections.
See the difference ↘On every task, result quality and reasoning tokens are each compared with all measured models and weighed equally. Each dot is one model.
BENCHMARK BY BENCHMARK
DATASHEET
GPT-5.6 Luna is 8.3× cheaper per output token and runs 1.5× faster in our speed test. Kimi K3.1 Pro scores higher on StealthMark. Both take about 1.05M tokens of context.
Full datasheets, every price and sourceGPT-5.6 Luna ↗Kimi K3.1 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.


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.


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


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.
Kimi K3.1 Pro
The settled sphere, separate airborne black paint and crimson-before-cyan interaction are supported, with a modest crimson travel overshoot. A shared downward framing displacement remains after accounting for the square canvas. The principal limitation is the reflection system: sparse sphere copies and generic curved bands omit most of the ordered mirror-room structure. Materials receive a small upward revision because bounded bright images and dark bands visibly establish some polish, while soft shading and bulky paint remain separate weaknesses.
| Category | GPT-5.6 Luna | Kimi K3.1 Pro |
|---|---|---|
| State at 600 ms | 15.0/25 | 23.5/25 |
| Camera and placement | 4.0/15 | 10.5/15 |
| Reflections | 3.5/120 | 26.0/120 |
| Materials and scale | 6.5/10 | 7.0/10 |
| Floor-damage reward | 0.0/10 | 0.0/10 |
A spinning metal sphere and paint in a mirrored room test physical reasoning, perspective and consistency across repeated reflections.
Visual construction and creative interpretation.


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.
Kimi K3.1 Pro
The transformed reflection, attentive pose and constellation anatomy clearly communicate introspection. Purposeful fine details enrich a coherent composition. Tubular limbs, crowded lower-body overlaps, shallow depth and limited cast lighting keep the overall execution within the competent range.
| Category | GPT-5.6 Luna | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 7.5/10 | 8.0/10 |
| Anatomy & construction | 6.0/10 | 5.5/10 |
| Space & placement | 6.5/10 | 6.5/10 |
| Light & reflections | 5.0/10 | 6.5/10 |
| Purposeful detail | 5.5/10 | 7.5/10 |
| Artistry & character | 6.0/10 | 7.0/10 |
| Materials & effects | 5.0/10 | 7.0/10 |
| Visual integrity | 6.0/10 | 7.0/10 |
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.
Kimi K3.1 Pro
An imagined creature encounters its reflection. The scene tests original character design, visual self-interpretation and the relationship between a subject and its reflected image.
Precise visual recall and portrait reconstruction.


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.
Kimi K3.1 Pro
A coherent, recognizable interpretation with controlled color and readable landscape layers. Replication is limited by the frontal seated construction, elongated facial proportions and oversized, weakly articulated hands. Smooth shading supplies some volume but little of the reference's subtle expression, fabric structure or atmospheric transitions.
| Category | GPT-5.6 Luna | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 3.5/10 | 5.0/10 |
| Anatomy & construction | 3.5/10 | 5.0/10 |
| Space & placement | 4.0/10 | 5.5/10 |
| Light & reflections | 4.5/10 | 6.0/10 |
| Purposeful detail | 4.0/10 | 5.5/10 |
| Artistry & character | 4.0/10 | 6.0/10 |
| Materials & effects | 3.5/10 | 5.0/10 |
| Visual integrity | 4.5/10 | 6.5/10 |
An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.
Creativity, perspective and visual beauty.


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.
Kimi K3.1 Pro
A coherent, playful beach illustration with readable animals, an organized composition and an aligned sunset reflection. Connected silhouettes, sand texture and atmospheric effects demonstrate controlled execution. Simplified joints, flattened foreground viewpoints and inconsistent shadows limit anatomical and spatial credibility.
| Category | GPT-5.6 Luna | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 7.5/10 | 8.5/10 |
| Anatomy & construction | 4.0/10 | 5.5/10 |
| Space & placement | 5.5/10 | 5.5/10 |
| Light & reflections | 4.0/10 | 6.5/10 |
| Purposeful detail | 6.5/10 | 6.5/10 |
| Artistry & character | 3.5/10 | 5.5/10 |
| Materials & effects | 4.0/10 | 6.5/10 |
| Visual integrity | 3.5/10 | 7.5/10 |
A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.
Physical reasoning, light and visual reconstruction.


GPT-5.6 Luna
This benchmark has not been assessed yet.
Kimi K3.1 Pro
This benchmark has not been assessed yet.
A plank, computer mouse and blueberry in a steel room test physical stability, spatial relationships, materials and lighting.
Scene composition and interacting subjects.


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.
Kimi K3.1 Pro
The additional comparisons support retaining the assessment. Readable steering, shaped animal contours and purposeful details coexist with simplified joints, a frontal passenger whose seated weight is weakly conveyed, and limited physical lighting. The angled craft establishes more depth than the riding pose resolves.
| Category | GPT-5.6 Luna | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 7.0/10 | 7.0/10 |
| Anatomy & construction | 5.0/10 | 5.5/10 |
| Space & placement | 6.5/10 | 6.0/10 |
| Light & reflections | 6.0/10 | 5.5/10 |
| Purposeful detail | 6.5/10 | 7.0/10 |
| Artistry & character | 4.5/10 | 6.0/10 |
| Materials & effects | 5.5/10 | 6.0/10 |
| Visual integrity | 5.0/10 | 7.0/10 |
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.
Subject construction and spatial relationships.


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.
Kimi K3.1 Pro
A characterful coastal illustration with controlled contours and varied feather, accessory and bicycle detail. Layered scenery and subtle shading enrich the presentation. Soft leg articulation, unresolved riding contacts, shallow depth and generalized lighting limit physical precision.
| Category | GPT-5.6 Luna | Kimi K3.1 Pro |
|---|---|---|
| Task & likeness | 8.5/10 | 8.5/10 |
| Anatomy & construction | 5.5/10 | 7.5/10 |
| Space & placement | 7.5/10 | 6.5/10 |
| Light & reflections | 6.5/10 | 6.5/10 |
| Purposeful detail | 6.5/10 | 7.5/10 |
| Artistry & character | 5.5/10 | 7.5/10 |
| Materials & effects | 7.0/10 | 6.5/10 |
| Visual integrity | 6.5/10 | 7.5/10 |
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.