STEALTHMARK · HEAD TO HEAD
All comparisons ↗Fledge Alpha vs Muse Spark Open
Muse Spark Open leads Fledge Alpha by 8.3 points on StealthMark, 44.1 to 35.8. It leads on 4 of the 7 benchmarks with results for both and Fledge Alpha on 2, with 1 tied. Muse Spark Open scores higher on Ground Truth.
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
- Muse Spark Open
BENCHMARK BY BENCHMARK
Where each model leads
- Fledge Alpha
- Muse Spark Open
- Other models
- Median
Games
SVG
DATASHEET
Specs and pricing
Muse Spark Open scores higher on StealthMark and runs 5.8× faster in our speed test.
- Fledge Alpha
- Muse Spark Open
- Other models
- Median
- Developer
- Not publishedMeta
- Released
- Not published15 Oct 2026
- Origin
- Not publishedUnited States
- Input → output
- Not publishedText, image, audio, video → text
- Architecture
- Not publishedSparse mixture-of-experts Transformer with perception encoders; 62 decoder layers, 256 experts with 8 selected per token, grouped-query attention and sliding-window/full-attention layers.
Full datasheets, every price and sourceMuse Spark Open ↗
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.
Muse Spark Open 29.4/100Rank 34/47

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
Muse Spark Open 75.7/100Rank 12/48

Points per level
Newton's Mirror
Same task instructionsPhysics, perspective and recursive reflections, tested together. Explore the test ↗
Fledge Alpha 16.4/100 Rank 42/53

Muse Spark Open 19.6/100 Rank 39/53

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.
Muse Spark Open
The airborne black blob and deformed paint support the broad contact sequence, although cyan attachment and wheel-directed transport remain partial. The sphere and black blob have substantial framing errors. The dominant limitation is the largely absent mirror system: faint wall circles and isolated highlights provide little evidence of recursive room geometry or curved nested reflections. Oversized compact paint features and diffuse material treatment further limit credit.
Score breakdown
| Category | Fledge Alpha | Muse Spark Open |
|---|---|---|
| State at 600 ms | 9.0/25 | 14.0/25 |
| Camera and placement | 5.0/15 | 6.0/15 |
| Reflections | 7.5/120 | 8.0/120 |
| Materials and scale | 3.5/10 | 3.5/10 |
| 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 30/53

Muse Spark Open 52.1/100 Rank 40/53

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.
Muse Spark Open
The rounded silhouette and asymmetric expression make an appealing baby elephant, supported by a quiet background and grounding shadow. The protective action remains difficult to read: forefeet cannot be confidently traced into a grip, and seed contact is crowded by fine lines. Controlled simple shapes provide charm, but limited anatomical clarity, shading and surface detail leave the execution uneven.
Score breakdown
| Category | Fledge Alpha | Muse Spark Open |
|---|---|---|
| Task & likeness | 7.5/10 | 5.0/10 |
| Anatomy & construction | 6.5/10 | 4.5/10 |
| Space & placement | 7.0/10 | 6.0/10 |
| Light & reflections | 5.5/10 | 5.0/10 |
| Purposeful detail | 6.5/10 | 6.0/10 |
| Artistry & character | 4.0/10 | 5.0/10 |
| Materials & effects | 6.0/10 | 5.0/10 |
| Visual integrity | 6.5/10 | 6.5/10 |
Benchmark task
Fledge Alpha
An eager young seabird running toward the viewer tests expressive anatomy, balance and a convincing forward-moving pose.
Muse Spark Open
A small elephant protecting a delicate seed tests expressive anatomy, physical contact and contrasting organic materials.
Mona Lisa
Different task instructionsPrecise visual recall and portrait reconstruction.
Fledge Alpha 28.3/100 Rank 35/53

Muse Spark Open 37.8/100 Rank 27/53

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.
Muse Spark Open
A recognizable, orderly interpretation with clean major contours, connected body forms and modest facial shading. Wide eyes, frontal symmetry and schematic hands limit likeness and expression. Layered scenery establishes basic depth, but shallow arm overlaps, flat clothing and sparse fine detail keep the execution basic and uneven.
Score breakdown
| Category | Fledge Alpha | Muse Spark Open |
|---|---|---|
| Task & likeness | 3.0/10 | 3.0/10 |
| Anatomy & construction | 3.0/10 | 3.0/10 |
| Space & placement | 2.5/10 | 5.0/10 |
| Light & reflections | 2.5/10 | 4.5/10 |
| Purposeful detail | 3.0/10 | 4.0/10 |
| Artistry & character | 3.0/10 | 3.0/10 |
| Materials & effects | 2.5/10 | 4.0/10 |
| Visual integrity | 2.5/10 | 6.0/10 |
Benchmark task
An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.
Beach
Different task instructionsCreativity, perspective and visual beauty.
Fledge Alpha 43.4/100 Rank 47/53

Muse Spark Open 64.2/100 Rank 25/53

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.
Muse Spark Open
A coherent sunset beach with readable activities, balanced framing and controlled colour transitions. Small accessories add interest, but schematic anatomy, limited surface detail, weak directional shadows and a geometric reflection constrain its finish. Most shapes and overlaps remain clean.
Score breakdown
| Category | Fledge Alpha | Muse Spark Open |
|---|---|---|
| Task & likeness | 7.5/10 | 8.0/10 |
| Anatomy & construction | 4.0/10 | 6.0/10 |
| Space & placement | 5.5/10 | 6.5/10 |
| Light & reflections | 5.0/10 | 5.5/10 |
| Purposeful detail | 3.0/10 | 6.5/10 |
| Artistry & character | 3.0/10 | 5.5/10 |
| Materials & effects | 2.5/10 | 6.0/10 |
| Visual integrity | 4.0/10 | 8.0/10 |
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 33/53

Muse Spark Open 51.9/100 Rank 12/53

The judgment
Fledge Alpha
This benchmark has not been assessed yet.
Muse Spark Open
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 instructionsScene composition and interacting subjects.
Fledge Alpha 63.4/100 Rank 20/53

Muse Spark Open 43.9/100 Rank 40/53

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.
Muse Spark Open
Expressive faces, distinct accessories and clean color separation make the scene appealing and recognizable. Character detail is stronger than the functional construction: steering contact, limb overlaps and seating remain ambiguous. The readable hull and lively spray establish motion, while limited directional shading and simplified surfaces constrain depth and physical coherence.
Score breakdown
| Category | Fledge Alpha | Muse Spark Open |
|---|---|---|
| Task & likeness | 8.5/10 | 4.0/10 |
| Anatomy & construction | 5.5/10 | 3.0/10 |
| Space & placement | 7.5/10 | 6.0/10 |
| Light & reflections | 6.5/10 | 4.5/10 |
| Purposeful detail | 7.0/10 | 7.0/10 |
| Artistry & character | 5.5/10 | 3.5/10 |
| Materials & effects | 7.0/10 | 5.0/10 |
| Visual integrity | 4.5/10 | 5.0/10 |
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 34/53

Muse Spark Open 60.5/100 Rank 34/53

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.
Muse Spark Open
A controlled, appealing cartoon with a recognizable pelican, expressive face and clean curved forms. Feather lines, spokes and bill shading provide useful complexity. Aligned wheels and a ground shadow establish placement, but uncertain pedal contacts and obscured mechanical connections weaken support and riding action. Lighting remains loosely coordinated with the sun.
Score breakdown
| Category | Fledge Alpha | Muse Spark Open |
|---|---|---|
| Task & likeness | 8.0/10 | 7.5/10 |
| Anatomy & construction | 6.0/10 | 5.0/10 |
| Space & placement | 6.5/10 | 6.0/10 |
| Light & reflections | 4.5/10 | 5.0/10 |
| Purposeful detail | 5.5/10 | 6.5/10 |
| Artistry & character | 5.0/10 | 5.5/10 |
| Materials & effects | 5.5/10 | 6.0/10 |
| Visual integrity | 6.5/10 | 7.5/10 |
Benchmark task
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.