STEALTHMARK · HEAD TO HEAD
All comparisons ↗Fledge Alpha vs GPT-6.1 Terra
GPT-6.1 Terra leads Fledge Alpha by 24.6 points on StealthMark, 60.4 to 35.8. It leads on 6 of the 7 benchmarks with results for both and Fledge Alpha on 1. GPT-6.1 Terra scores higher on Newton's Mirror, with its largest category advantage in reflections.
See the difference ↘Overall StealthMark
General Intelligence
Visual Intelligence
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
- Fledge AlphaMulti-step reasoning not measured
BENCHMARK BY BENCHMARK
Where each model leads
- Fledge Alpha
- GPT-6.1 Terra
- Other models
- Median
Games
SVG
DATASHEET
Specs and pricing
- Fledge Alpha
- GPT-6.1 Terra
- Other models
- Median
- Developer
- Not publishedOpenAI
- Released
- Not published26 Oct 2026
- Origin
- Not publishedUnited States
- Input → output
- Not publishedText, image → text
Full datasheets, every price and sourceGPT-6.1 Terra ↗
Foresight
Play Foresight yourselfAnticipating 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-6.1 Terra 62.0/100Rank 9/50

Points per level
Latch
Play Latch yourselfCooperative 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.
Fledge AlphaNo run
GPT-6.1 Terra 77.7/100Rank 12/51

Points per level
Newton's Mirror
Same task instructionsPhysics, perspective and recursive reflections, tested together. Explore the test ↗
Fledge Alpha 16.4/100 Rank 42/54

GPT-6.1 Terra 45.3/100 Rank 10/54

The judgment
Fledge Alpha
The candidate communicates a round metallic sphere, three paint colors and a separate airborne black blob. Its hovering support relationship, displaced framing and unresolved paint interaction limit physical credit. Sparse planar light ghosts and a soft sphere highlight provide little evidence for the required wall/floor repetitions and curved nested mirror imagery.
GPT-6.1 Terra
The sphere, airborne black and first reflected silhouettes preserve important geometry within the portrait frame. Paint deformation, contact order and forward transport are supported, with a small crimson endpoint overshoot. Major optical omissions dominate: short finite reflection sequences and smooth bands replace extensive, spatially ordered mirror imagery. Dark gloss and crisp upper emitter shapes provide partial material credit.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra |
|---|---|---|
| State at 600 ms | 9.0/25 | 23.0/25 |
| Camera and placement | 5.0/15 | 11.0/15 |
| Reflections | 7.5/120 | 33.0/120 |
| Materials and scale | 3.5/10 | 7.5/10 |
| Floor-damage reward | 0.0/10 | 0.0/10 |
Benchmark task
A spinning metal sphere and paint in a mirrored room test physical reasoning, perspective and consistency across repeated reflections.
Selfie
Different task instructionsVisual construction and creative interpretation.
Fledge Alpha 61.1/100 Rank 31/54

GPT-6.1 Terra 65.0/100 Rank 24/54

The judgment
Fledge Alpha
A coherent, appealing mascot with expressive eyes, a cheerful beak and a readable swept-back silhouette. Its larger forward foot and trailing feathers suggest a running stride, but the upright body, stiff legs and minimally articulated feet limit convincing motion. Clean flat shapes suit the brief, while uneven feather junctions and incomplete cream accents reduce polish.
GPT-6.1 Terra
A balanced serpent emblem with six attached outward heads, delicate scales and softly rounded bodies. Its compact silhouette reads clearly, but central routing does not establish every alternating crossing or crisp inward corner. Repetitive texture, limited facial anatomy and weak contact shadows constrain its organic character.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 7.5/10 | 7.5/10 |
| Anatomy & construction | 6.5/10 | 6.5/10 |
| Space & placement | 7.0/10 | 6.5/10 |
| Light & reflections | 5.5/10 | 6.0/10 |
| Purposeful detail | 6.5/10 | 6.5/10 |
| Artistry & character | 4.0/10 | 6.5/10 |
| Materials & effects | 6.0/10 | 6.0/10 |
| Visual integrity | 6.5/10 | 6.0/10 |
Benchmark task
Fledge Alpha
An eager young seabird running toward the viewer tests expressive anatomy, balance and a convincing forward-moving pose.
GPT-6.1 Terra
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
Different task instructionsPrecise visual recall and portrait reconstruction.
Fledge Alpha 28.3/100 Rank 36/54

GPT-6.1 Terra 60.7/100 Rank 5/54

The judgment
Fledge Alpha
A recognizable but basic Mona Lisa reinterpretation with a coherent silhouette and subdued palette. Curtain-like hair obscures much of the face, while elongated facial construction and oversized, minimally articulated hands substantially weaken replication. Soft shading supplies modest volume, but anatomy, landscape depth and purposeful detail remain underdeveloped.
GPT-6.1 Terra
A recognizable interpretation with developed facial shading, shaped sleeve folds and purposeful small features. These strengths support modest upward calibration, while the frontal torso, elongated proportions, schematic finger joints and unresolved seated support keep replication and construction uneven.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 3.0/10 | 5.5/10 |
| Anatomy & construction | 3.0/10 | 6.5/10 |
| Space & placement | 2.5/10 | 4.5/10 |
| Light & reflections | 2.5/10 | 6.5/10 |
| Purposeful detail | 3.0/10 | 6.0/10 |
| Artistry & character | 3.0/10 | 6.0/10 |
| Materials & effects | 2.5/10 | 6.0/10 |
| Visual integrity | 2.5/10 | 6.5/10 |
Benchmark task
An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.
Beach
Different task instructionsCreativity, perspective and visual beauty.
Fledge Alpha 43.4/100 Rank 46/54

GPT-6.1 Terra 72.0/100 Rank 13/54

The judgment
Fledge Alpha
A cheerful, recognizable sunset beach with a cohesive warm palette and clear accessories. Simple construction, uncertain palm support, an ambiguous upper boundary and schematic reflections limit depth and finish. The scene communicates its subject successfully but lacks the developed forms, lighting and detail of exceptional illustration.
GPT-6.1 Terra
A coherent sunset illustration with clear prompt fulfillment, controlled framing and varied, purposeful small details. Simplified joints, frontal staging, flattened animal forms and weakly directional shadows limit its anatomical, spatial and physical sophistication.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 7.5/10 | 8.5/10 |
| Anatomy & construction | 4.0/10 | 7.5/10 |
| Space & placement | 5.5/10 | 6.5/10 |
| Light & reflections | 5.0/10 | 5.5/10 |
| Purposeful detail | 3.0/10 | 7.5/10 |
| Artistry & character | 3.0/10 | 7.0/10 |
| Materials & effects | 2.5/10 | 6.5/10 |
| Visual integrity | 4.0/10 | 7.5/10 |
Benchmark task
A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.
Ground Truth
Same task instructionsPhysical reasoning, light and visual reconstruction.
Fledge Alpha 36.8/100 Rank 33/54

GPT-6.1 Terra 58.2/100 Rank 12/54

The judgment
Fledge Alpha
This benchmark has not been assessed yet.
GPT-6.1 Terra
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 instructionsScene composition and interacting subjects.
Fledge Alpha 63.4/100 Rank 20/54

GPT-6.1 Terra 60.5/100 Rank 27/54

The judgment
Fledge Alpha
An appealing sunset illustration with recognizable characters and a clear riding action. Color, expression and silhouette are stronger than anatomical construction: overlapping paws obscure support, the dog's steering limb is simplified, and the vehicle controls lack definition. The wake conveys movement, while lighting and water reflections remain decorative.
GPT-6.1 Terra
A coherent cartoon with expressive animals, readable steering and a clear wake. Fine facial and hull details reward inspection. The main limits are the boatlike craft, simplified joints, weakly braced frontal raccoon and minimal directional lighting or material depth.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 8.5/10 | 6.5/10 |
| Anatomy & construction | 5.5/10 | 5.5/10 |
| Space & placement | 7.5/10 | 6.0/10 |
| Light & reflections | 6.5/10 | 5.0/10 |
| Purposeful detail | 7.0/10 | 7.0/10 |
| Artistry & character | 5.5/10 | 6.0/10 |
| Materials & effects | 7.0/10 | 6.0/10 |
| Visual integrity | 4.5/10 | 7.0/10 |
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
Different task instructionsSubject construction and spatial relationships.
Fledge Alpha 60.5/100 Rank 35/54

GPT-6.1 Terra 64.5/100 Rank 31/54

The judgment
Fledge Alpha
A clear, cheerful illustration with a recognizable pelican, coherent bicycle silhouette and tidy composition. Simplified leg articulation, steering contact, mechanical detail and lighting keep it at a competent illustrative level.
GPT-6.1 Terra
A coherent pelican cyclist with expressive proportions, purposeful feather detail and developed bicycle machinery. Continuous body contours, aligned wheels and readable pedal contacts support the scene. Simplified articulation, shallow modelling and an unresolved steering connection limit construction and placement.
Score breakdown
| Category | Fledge Alpha | GPT-6.1 Terra |
|---|---|---|
| Task & likeness | 8.0/10 | 7.0/10 |
| Anatomy & construction | 6.0/10 | 7.0/10 |
| Space & placement | 6.5/10 | 6.0/10 |
| Light & reflections | 4.5/10 | 5.5/10 |
| Purposeful detail | 5.5/10 | 7.0/10 |
| Artistry & character | 5.0/10 | 6.5/10 |
| Materials & effects | 5.5/10 | 5.5/10 |
| Visual integrity | 6.5/10 | 6.0/10 |
Benchmark task
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.