Skip to main content
Radar

Five or fewer confirmed AI changes, with original sources, on mornings when something changed.A free source-linked morning brief.

See the free Radar Brief
OpenAI logo
Model A
GPT-5.5

OpenAI

73.27/100

Supported · Public rank #9

90% interval 71.075.6

GPT-5.5 vs Muse Spark

Updated September 4, 2026. Public scores include evidence status and uncertainty. They are not guarantees for a specific workload.

Meta logo
Model B
Muse Spark

Meta

68.39/100

Supported · Public rank #30

90% interval 60.076.8

Decision reading

GPT-5.5 has the higher public score estimate, 73.27 versus 68.39, but the 90% score intervals overlap. Treat that as a lead, not a settled winner.

12 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.

Share or export

Share on XLinkedInSocial cardCSVJSON

Which one for your work

Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.

  • Coding work

    Code generation, repair, and software-engineering tasks

    GPT-5.5

    GPT-5.5 leads on the public coding lane, 67.7 to 59.2, with Supported evidence for both models, although the 90% intervals overlap.

    Confidence: limited

  • Agentic work

    Tool use, computer use, and multi-step task completion

    GPT-5.5

    GPT-5.5 leads on the public agentic lane, 63.9 to 58.8, with Supported evidence for both models, although the 90% intervals overlap.

    Confidence: limited

  • Long documents

    Prompts that approach the documented context limit

    GPT-5.5

    GPT-5.5 has the larger documented context window.

    Confidence: documented

Show secondary and unsupported calls
  • Chat turn cost

    1K fresh input + 500 output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: listed-rates

  • Cache-heavy agent loop cost

    200K cached + 20K fresh input + 10K output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: listed-rates

  • Repository review cost

    50K fresh input + 3K output tokens

    Not enough matched evidence

    A complete comparable API-rate estimate is not available for both models.

    Confidence: listed-rates

What is actually comparable

Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.

Shared results
12
GPT-5.5 only
26
Muse Spark only
12
Like-for-like categories
3 / 8

2 categories rest on Estimated evidence or different evidence sets. Those rows remain visible for coverage context but do not name a winner.

Category results, on a stated basis

Each row shows the public-lane category score for both models: the BenchAlign lane for agentic, coding, and knowledge, and the weighted public rows elsewhere, with the same rank each model page reports. A row is like-for-like only when both scores rest on Supported evidence or the same weighted set. Directional and not-comparable rows remain visible, but they never receive a winner.

Agentic

Like-for-like
GPT-5.5
63.9
Supported · #15/151
Muse Spark
58.8
Supported · #31/151
Basis
BenchAlign lane · 13 vs 5 public rows
Reading
GPT-5.5 leads · intervals overlap

Coding

Like-for-like
GPT-5.5
67.7
Supported · #8/183
Muse Spark
59.2
Supported · #28/183
Basis
BenchAlign lane · 9 vs 4 public rows
Reading
GPT-5.5 leads · intervals overlap

Knowledge

Like-for-like
GPT-5.5
73.3
Supported · #7/181
Muse Spark
65.7
Supported · #23/181
Basis
BenchAlign lane · 6 vs 5 public rows
Reading
GPT-5.5 leads · intervals overlap

Multimodal

Directional only
GPT-5.5
71.3
#19/48
Muse Spark
77.5
#14/48
Basis
Provisional lane · 2 vs 2 weighted rows
Reading
Directional only

Instruction following

Directional only
GPT-5.5
92.9
#7/120
Muse Spark
92.9
#8/120
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Directional only

Reasoning

Not comparable
GPT-5.5
63.5
#15/22
Muse Spark
45.9
Unranked · 3 rankable rows
Basis
Provisional lane · 2 vs 1 weighted rows
Reading
Not comparable

Math

Not comparable
GPT-5.5
69.6
Unranked · 3 rankable rows
Muse Spark
55.3
Unranked · 2 rankable rows
Basis
Provisional lane · 2 vs 2 weighted rows
Reading
Not comparable

Multilingual

Not comparable
GPT-5.5
Not ranked
Muse Spark
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Ranks count the models scored in each category’s lane, so the agentic, coding, and knowledge denominators (BenchAlign) differ from the provisional-lane categories. Unranked scores sit on the lane’s scale but never name a winner. Like-for-like rows within 0.5 points read as a practical tie.

Shape of the matched evidence

Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.

Too few matched category axes support a radar. The ruled list below shows only shared benchmark results; positions use each benchmark’s normalized display scale when available.

What each workload costs

Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.

Chat turn

1K fresh input + 500 output tokens

GPT-5.5
$0.02
Fits in one request
Muse Spark
API rate not published
Fits in one request

Muse Spark has no comparable published API token rate.

Repository review

50K fresh input + 3K output tokens

GPT-5.5
$0.34
Fits in one request
Muse Spark
API rate not published
Fits in one request

Muse Spark has no comparable published API token rate.

Cache-heavy agent loop

200K cached + 20K fresh input + 10K output tokens

GPT-5.5
$0.5
Fits in one request
Muse Spark
API rate not published
Fits in one request
Cached-input rate unavailable

Muse Spark has no comparable published API token rate.

Specification differences

Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.

Context window

Maximum documented context; output-token limits may be lower.

Muse Spark

262K

Cached-input rate

A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.

GPT-5.5

$0.5 per 1M cached input tokens

OpenAI pricing

Muse Spark

No comparable hosted API rate

Documented inputs

GPT-5.5

Not sourced

Muse Spark

Not sourced

Documented outputs

GPT-5.5

Not sourced

Muse Spark

Not sourced

Provider availability

GPT-5.5

Not sourced

Muse Spark

Not sourced

Reasoning profile

GPT-5.5

Reasoning

Muse Spark

Reasoning

Weight access

GPT-5.5

Proprietary

Muse Spark

Proprietary

License

GPT-5.5

Proprietary

Muse Spark

Proprietary

Release date

GPT-5.5

2026-04-23

Muse Spark

2026-04-08

If you already use one of these models
Deployment change
The models list different providers, so authentication, endpoint behavior, limits, and feature support may change.
Quality signal
GPT-5.5 has the higher public score estimate, 73.27 versus 68.39, but the 90% score intervals overlap.
Workload cost
A complete comparable API-rate estimate is not available for both models.
Context tradeoff
GPT-5.5 has the larger documented window (1M).

Run the same representative tasks against both endpoints before changing production traffic.

Benchmark evidence

The full public result ledger is available for audit without forcing a wide desktop table onto a phone.

Browse raw public benchmark evidence50 rows

Agentic

  • Terminal-Bench 2.0

    GPT-5.582%
    Source
    Muse Spark59%
    Source

    GPT-5.5 leads this result

  • CyberGym

    GPT-5.581.8%
    Source
    Muse Spark43.5%
    Source

    GPT-5.5 leads this result

  • BrowseComp

    GPT-5.584.4%
    Source
    Muse Spark

    Not directly comparable

  • OSWorld-Verified

    GPT-5.578.7%
    Source
    Muse Spark

    Not directly comparable

  • MCP Atlas

    GPT-5.575.3%
    Source
    Muse Spark

    Not directly comparable

  • Toolathlon

    GPT-5.555.6%
    Source
    Muse Spark

    Not directly comparable

  • τ²-bench results

    GPT-5.598%
    Source
    Muse Spark91.5%
    Source

    GPT-5.5 leads this result

  • Gert Labs

    GPT-5.572.93%
    Source
    Muse Spark

    Not directly comparable

  • ResearchClawBench

    GPT-5.517.0%
    Source
    Muse Spark

    Not directly comparable

  • OSWorld 2.0

    GPT-5.513.0%
    Source
    Muse Spark

    Not directly comparable

  • JobBench

    GPT-5.542.7%
    Source
    Muse Spark

    Not directly comparable

  • ExploitGym

    GPT-5.513.4%
    Source
    Muse Spark

    Not directly comparable

  • Terminal-Bench 2.1 (Vals)

    GPT-5.576.4%
    Source
    Muse Spark

    Not directly comparable

  • DeepSearchQA

    GPT-5.5
    Muse Spark74.8%
    Source

    Not directly comparable

  • Claw-Eval

    GPT-5.5
    Muse Spark63.8%
    Source

    Not directly comparable

Coding

  • SWE-bench Pro

    GPT-5.558.6%
    Source
    Muse Spark52.4%
    Source

    GPT-5.5 leads this result

  • Terminal-Bench 2.0

    GPT-5.582.0%
    Source
    Muse Spark

    Not directly comparable

  • Vibe Code Bench

    Shared source
    GPT-5.569.85%
    Muse Spark19.67%

    GPT-5.5 leads this result

  • React Native Evals

    GPT-5.584.7%
    Source
    Muse Spark

    Not directly comparable

  • cursorBench31

    GPT-5.559.2%
    Source
    Muse Spark

    Not directly comparable

  • cursorBench32

    GPT-5.558.4%
    Source
    Muse Spark

    Not directly comparable

  • FrontierCode 1.1 Main

    GPT-5.543.0%
    Source
    Muse Spark

    Not directly comparable

  • LiveCodeBench (Vals)

    GPT-5.585.3%
    Source
    Muse Spark

    Not directly comparable

  • SWE-bench (Vals)

    GPT-5.582.6%
    Source
    Muse Spark

    Not directly comparable

  • SWE-bench Verified

    GPT-5.5
    Muse Spark77.4%
    Source

    Not directly comparable

  • LiveCodeBench Pro

    GPT-5.5
    Muse Spark80.0%
    Source

    Not directly comparable

Reasoning

  • MRCR v2 64K-128K

    GPT-5.583.1%
    Source
    Muse Spark

    Not directly comparable

  • MRCR v2 128K-256K

    GPT-5.587.5%
    Source
    Muse Spark

    Not directly comparable

  • ARC-AGI-2

    GPT-5.585%
    Source
    Muse Spark42.5%
    Source

    GPT-5.5 leads this result

  • ARC-AGI-3

    GPT-5.50.4%
    Source
    Muse Spark

    Not directly comparable

Knowledge

  • GPQA

    GPT-5.593.6%
    Source
    Muse Spark

    Not directly comparable

  • GPQA-D

    GPT-5.593.6%
    Source
    Muse Spark89.5%
    Source

    GPT-5.5 leads this result

  • HLE

    GPT-5.552.2%
    Source
    Muse Spark50.4%
    Source

    GPT-5.5 leads this result

  • HLE w/o tools

    GPT-5.541.4%
    Source
    Muse Spark42.8%
    Source

    Muse Spark leads this result

  • GPQA Diamond (Vals)

    GPT-5.593.2%
    Source
    Muse Spark

    Not directly comparable

  • MMLU-Pro (Vals)

    GPT-5.588.1%
    Source
    Muse Spark

    Not directly comparable

  • HealthBench Hard

    GPT-5.5
    Muse Spark42.8%
    Source

    Not directly comparable

  • MedXpertQA (Text)

    GPT-5.5
    Muse Spark52.6%
    Source

    Not directly comparable

Math

  • FrontierMath (legacy)

    GPT-5.551.7%
    Source
    Muse Spark

    Not directly comparable

  • FrontierMath v2 (Tiers 1-3)

    Shared source
    GPT-5.551.700%
    Muse Spark39.000%

    GPT-5.5 leads this result

  • FrontierMath v2 (Tier 4)

    Shared source
    GPT-5.535.400%
    Muse Spark14.600%

    GPT-5.5 leads this result

Multimodal

  • MMMU-Pro

    GPT-5.581.2%
    Source
    Muse Spark80.4%
    Source

    GPT-5.5 leads this result

  • MMMU-Pro w/ Python

    GPT-5.583.2%
    Source
    Muse Spark

    Not directly comparable

  • OfficeQA Pro

    GPT-5.554.1%
    Source
    Muse Spark

    Not directly comparable

  • CharXiv

    GPT-5.5
    Muse Spark86.4%
    Source

    Not directly comparable

  • ERQA

    GPT-5.5
    Muse Spark64.7%
    Source

    Not directly comparable

  • SimpleVQA

    GPT-5.5
    Muse Spark71.3%
    Source

    Not directly comparable

  • ScreenSpot Pro

    GPT-5.5
    Muse Spark84.1%
    Source

    Not directly comparable

  • ZeroBench

    GPT-5.5
    Muse Spark33.0%
    Source

    Not directly comparable

  • MedXpertQA (MM)

    GPT-5.5
    Muse Spark78.4%
    Source

    Not directly comparable

Frequently asked questions

Which is better, GPT-5.5 or Muse Spark?

GPT-5.5 has the higher public score estimate, 73.27 versus 68.39, but the 90% score intervals overlap. The higher estimate is not a decisive winner because the uncertainty ranges overlap.

Which is better for coding, GPT-5.5 or Muse Spark?

GPT-5.5 leads the public coding lane, 67.7 to 59.2, with Supported evidence for both models, although the 90% intervals overlap.

Which is better for agentic tasks, GPT-5.5 or Muse Spark?

GPT-5.5 leads the public agentic tasks lane, 63.9 to 58.8, with Supported evidence for both models, although the 90% intervals overlap.

Which costs less, GPT-5.5 or Muse Spark?

Both models do not have comparable published API token rates, so this page does not name a universal price winner.

Which has the larger context window, GPT-5.5 or Muse Spark?

GPT-5.5 has the larger documented context window: 1M, compared with 262K.

Related comparisons

Last updated September 4, 2026

Watch GPT-5.5 vs Muse Spark

One weekly email when material rank, price, or benchmark evidence changes make this matchup worth revisiting.

Read a sample issue

Join 2,000+ readers.