STEALTHMARK · HEAD TO HEAD

All comparisons ↗

GPT-5.6 Terra vs GPT-6.1 Terra Low

GPT-5.6 Terra leads GPT-6.1 Terra Low by 4.5 points on StealthMark, 45.8 to 41.3. It leads on 5 of 9 benchmarks, including Latch, and GPT-6.1 Terra Low on 4, including Foresight. GPT-5.6 Terra scores higher on Selfie, with its largest category advantage in prompt & likeness.

See the difference ↘
All results ↗
All results ↗

Overall StealthMark

45.8/100Overall rank 26/55
41.3/100Overall rank 35/55

General Intelligence

41.9/100
34.3/100

Visual Intelligence

52.7/100
53.1/100

BENCHMARK BY BENCHMARK

Where each model leads

  • GPT-5.6 Terra
  • GPT-6.1 Terra Low
  • Other models
  • Median

DATASHEET

Specs and pricing

  • GPT-5.6 Terra
  • GPT-6.1 Terra Low
  • Other models
  • Median
PricePer 1M output tokens, input below
GPT-5.6 Terra: $12$2 inputGPT-6.1 Terra Low: No list price
Context windowTokens per request, max output below
GPT-5.6 Terra: 1.05M128K max outputGPT-6.1 Terra Low: Not published
Output speedTokens per second, our measurement
GPT-5.6 Terra: 102tokens/sGPT-6.1 Terra Low: Not measured
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 Terra ↗

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 Terra 30.1/100Rank 33/51

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-5.6 TerraGPT-6.1 Terra Low
Level 1Second Thoughts
5 ptsOut of lives
4 ptsOut of lives
Level 2Pressure Pot
9 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-5.6 Terra 80.0/100Rank 10/52

Cleared 5 of 5
Latch: complete playing field
Level 520.6 ptsTurn 27 / 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-5.6 TerraGPT-6.1 Terra Low
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.6 ptsCleared
9.2 ptsCleared
Level 3Relay vault
19.2 ptsCleared
18.8 ptsCleared
Level 4Passing bay
18.2 ptsClearedFinished early · 3 beacons left
10.2 ptsFinished early
Level 5Second thoughts
20.6 ptsCleared
20.6 ptsCleared

Newton's Mirror

Same task instructions

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

The judgment

GPT-5.6 Terra

The real sphere and airborne black blob are substantially too low in the complete frame after accounting for aspect ratio. The first wall and floor reflections have incompatible placement, relative size or silhouette. Both lateral regions lack the references' receding lane-and-chain organization. The few recognizable mirror images provide limited optical structure. The main, side and floor spheres replace nested mirror imagery with smooth bands, while sparse planar light patches and broad spherical highlights fail to establish coherent repeated emitter mapping.

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-5.6 TerraGPT-6.1 Terra Low
State at 600 ms24.0/2522.0/25
Camera and placement6.0/154.0/15
Reflections7.0/12010.0/120
Materials and scale5.5/106.0/10
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-5.6 Terra

Six ivory heads and rounded lobes create a striking radial emblem around a clear hexagonal opening. Soft shading gives the bodies volume, but abrupt rectangular and diagonal band endings make the continuous alternating weave ambiguous. Repetitive scale lines and simplified faces convey an ornamental serpent more convincingly than living anatomy.

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-5.6 TerraGPT-6.1 Terra Low
Task & likeness7.5/104.0/10
Anatomy & construction5.5/103.5/10
Space & placement7.0/104.5/10
Light & reflections7.5/105.5/10
Purposeful detail6.5/105.5/10
Artistry & character5.5/105.0/10
Materials & effects6.5/105.5/10
Visual integrity5.0/104.0/10

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-5.6 Terra

The dark clothing, central portrait and restrained smile evoke the Mona Lisa, but replication is limited by the broad face, elongated neck, nearly frontal pose and indistinct landscape. Soft gradients give the face some volume. Crossed arms become rounded masses without readable fingers or wrists, and the expression lacks the original's subtlety. Clean framing and curves support an otherwise basic, uneven portrait.

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-5.6 TerraGPT-6.1 Terra Low
Task & likeness4.0/105.0/10
Anatomy & construction3.0/104.5/10
Space & placement4.5/105.0/10
Light & reflections5.0/106.0/10
Purposeful detail4.0/105.0/10
Artistry & character4.0/105.5/10
Materials & effects4.0/105.0/10
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-5.6 Terra

Warm sunset gradients, framing palms and colorful beach activities create an appealing scene. Animals, birds and a sun reflection fulfill the brief. The dog and turtle remain schematic, foreground depth is shallow, and the reflection forms rigid bands. Clean silhouettes and readable accessories support a competent illustration, but limited anatomy, material variation and lighting keep it below exceptional.

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-5.6 TerraGPT-6.1 Terra Low
Task & likeness7.5/108.0/10
Anatomy & construction5.0/105.5/10
Space & placement6.0/105.5/10
Light & reflections5.0/106.5/10
Purposeful detail6.5/106.0/10
Artistry & character5.0/105.0/10
Materials & effects5.5/105.5/10
Visual integrity5.0/107.5/10

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-5.6 Terra

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-5.6 Terra

Expressive faces, a recognizable raccoon perched on the dog, and a sweeping wake make an appealing cartoon. The principal weakness is the steering interaction: the dog's paw sits beside the control assembly without a convincing handlebar grip. Bold outlines and coherent layering provide polish, while simplified shading, compressed seating geometry and angular splashes limit depth and physical credibility.

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-5.6 TerraGPT-6.1 Terra Low
Task & likeness7.5/106.5/10
Anatomy & construction5.0/105.0/10
Space & placement7.0/105.5/10
Light & reflections6.0/104.5/10
Purposeful detail7.0/106.0/10
Artistry & character5.0/105.0/10
Materials & effects7.0/105.0/10
Visual integrity7.5/106.0/10

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-5.6 Terra

The oversized bill, expressive eye and balanced twilight palette make the cyclist immediately readable. Clean contours and wheel details support the illustration, but the rabbit-like head tufts weaken pelican likeness. The wing does not clearly grip the handlebar, pedal contact is uneven, and the drivetrain is incomplete. Lighting remains mostly decorative.

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-5.6 TerraGPT-6.1 Terra Low
Task & likeness6.0/107.0/10
Anatomy & construction6.0/105.5/10
Space & placement7.0/106.0/10
Light & reflections6.5/105.5/10
Purposeful detail7.0/106.5/10
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.