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 ↘
Model guide ↗
All results ↗

Overall StealthMark

35.8/100Overall rank 38/53
44.1/100Overall rank 29/53

General Intelligence

27.1/100
42.6/100

Visual Intelligence

45.2/100
46.6/100

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

  • Fledge AlphaMulti-step reasoning not measured
  • Muse Spark Open

Open or local

BENCHMARK BY BENCHMARK

Where each model leads

  • Fledge Alpha
  • Muse Spark Open
  • Other models
  • Median

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
PricePer 1M output tokens, input below
Fledge Alpha: No list priceMuse Spark Open: $4.25$1.25 input
Context windowTokens per request, max output below
Fledge Alpha: Not publishedMuse Spark Open: 1M1M max output
Output speedTokens per second, our measurement
Fledge Alpha: 63tokens/sMuse Spark Open: 3615.8× fastertokens/s
SizeTotal and active parameters
Fledge Alpha: Not disclosedMuse Spark Open: 816B42B active
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 ↗

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.

Muse Spark Open 29.4/100Rank 34/47

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

Points per level

LevelFledge AlphaMuse Spark Open
Level 1Second Thoughts
No run
4 ptsOut of lives
Level 2Pressure Pot
No run
9 ptsOut of lives
Level 3Hide or Flight
No run
8 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.

Muse Spark Open 75.7/100Rank 12/48

Cleared 5 of 5
Latch: complete playing field
Level 519.6 ptsTurn 32 / 40

Points per level

LevelFledge AlphaMuse Spark Open
Level 1Hold the door
No run
5.2 ptsCleared
Level 2Crossfeed
No run
9.8 ptsCleared
Level 3Relay vault
No run
19.2 ptsCleared
Level 4Passing bay
No run
17.8 ptsClearedFinished early · 1 beacon left
Level 5Second thoughts
No run
19.6 ptsCleared

Newton's Mirror

Same task instructions

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

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

CategoryFledge AlphaMuse Spark Open
State at 600 ms9.0/2514.0/25
Camera and placement5.0/156.0/15
Reflections7.5/1208.0/120
Materials and scale3.5/103.5/10
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

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

CategoryFledge AlphaMuse Spark Open
Task & likeness7.5/105.0/10
Anatomy & construction6.5/104.5/10
Space & placement7.0/106.0/10
Light & reflections5.5/105.0/10
Purposeful detail6.5/106.0/10
Artistry & character4.0/105.0/10
Materials & effects6.0/105.0/10
Visual integrity6.5/106.5/10

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 instructions

Precise visual recall and portrait reconstruction.

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

CategoryFledge AlphaMuse Spark Open
Task & likeness3.0/103.0/10
Anatomy & construction3.0/103.0/10
Space & placement2.5/105.0/10
Light & reflections2.5/104.5/10
Purposeful detail3.0/104.0/10
Artistry & character3.0/103.0/10
Materials & effects2.5/104.0/10
Visual integrity2.5/106.0/10

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

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

CategoryFledge AlphaMuse Spark Open
Task & likeness7.5/108.0/10
Anatomy & construction4.0/106.0/10
Space & placement5.5/106.5/10
Light & reflections5.0/105.5/10
Purposeful detail3.0/106.5/10
Artistry & character3.0/105.5/10
Materials & effects2.5/106.0/10
Visual integrity4.0/108.0/10

Benchmark task

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

Ground Truth

Same task instructions

Physical reasoning, light and visual reconstruction.

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 instructions

Scene composition and interacting subjects.

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

CategoryFledge AlphaMuse Spark Open
Task & likeness8.5/104.0/10
Anatomy & construction5.5/103.0/10
Space & placement7.5/106.0/10
Light & reflections6.5/104.5/10
Purposeful detail7.0/107.0/10
Artistry & character5.5/103.5/10
Materials & effects7.0/105.0/10
Visual integrity4.5/105.0/10

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 instructions

Subject construction and spatial relationships.

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

CategoryFledge AlphaMuse Spark Open
Task & likeness8.0/107.5/10
Anatomy & construction6.0/105.0/10
Space & placement6.5/106.0/10
Light & reflections4.5/105.0/10
Purposeful detail5.5/106.5/10
Artistry & character5.0/105.5/10
Materials & effects5.5/106.0/10
Visual integrity6.5/107.5/10

Benchmark task

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