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Model A
GPT-5.6 Luna

OpenAI

64.65/100

Estimated · Public rank #40

90% interval 58.970.4

GPT-5.6 Luna vs Inkling-Small

Updated September 10, 2026. Public scores include evidence status and uncertainty. They are not guarantees for a specific workload.

Thinking Machines Lab logo
Model B
Inkling-Small

Thinking Machines Lab

59.25/100

Supported · Public rank #69

90% interval 52.466.1

Decision reading

GPT-5.6 Luna has the higher public score estimate, 64.65 versus 59.25, 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.

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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-5.6 Luna

    GPT-5.6 Luna leads on the public coding lane, 66.8 to 43.8, with Supported evidence for both models and non-overlapping 90% intervals.

    Confidence: stronger

  • Agentic work

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

    GPT-5.6 Luna

    GPT-5.6 Luna leads on the public agentic lane, 56.8 to 36.9, with Supported evidence for both models and non-overlapping 90% intervals.

    Confidence: stronger

  • Long documents

    Prompts that approach the documented context limit

    GPT-5.6 Luna

    GPT-5.6 Luna has the larger documented context window.

    Confidence: documented

Show secondary and unsupported calls
  • Chat turn cost

    1K fresh input + 500 output tokens

    GPT-5.6 Luna

    GPT-5.6 Luna has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates

  • Cache-heavy agent loop cost

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

    GPT-5.6 Luna

    GPT-5.6 Luna has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates

  • Repository review cost

    50K fresh input + 3K output tokens

    GPT-5.6 Luna

    GPT-5.6 Luna has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    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-5.6 Luna only
18
Inkling-Small only
13
Like-for-like categories
3 / 8

1 category rests 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-5.6 Luna
56.8
Supported · #32/152
Inkling-Small
36.9
Supported · #128/152
Basis
BenchAlign lane · 9 vs 5 public rows
Reading
GPT-5.6 Luna leads

Coding

Like-for-like
GPT-5.6 Luna
66.8
Supported · #9/151
Inkling-Small
43.8
Supported · #97/151
Basis
BenchAlign lane · 8 vs 6 public rows
Reading
GPT-5.6 Luna leads

Knowledge

Like-for-like
GPT-5.6 Luna
64.1
Supported · #27/183
Inkling-Small
56.5
Supported · #46/183
Basis
BenchAlign lane · 6 vs 6 public rows
Reading
GPT-5.6 Luna leads · intervals overlap

Multimodal

Directional only
GPT-5.6 Luna
67.1
#21/48
Inkling-Small
48.8
#39/48
Basis
Provisional lane · 1 vs 2 weighted rows
Reading
Directional only

Reasoning

Not comparable
GPT-5.6 Luna
51.2
#19/20
Inkling-Small
42.7
Unranked · 3 rankable rows
Basis
Provisional lane · 2 vs 1 weighted rows
Reading
Not comparable

Math

Not comparable
GPT-5.6 Luna
94.4
Unranked · 3 rankable rows
Inkling-Small
76.9
Unranked · 2 rankable rows
Basis
Provisional lane · 2 vs 2 weighted rows
Reading
Not comparable

Multilingual

Not comparable
GPT-5.6 Luna
Not ranked
Inkling-Small
Not ranked
Basis
Provisional lane · 0 vs 0 weighted rows
Reading
Not comparable

Instruction following

Not comparable
GPT-5.6 Luna
Not ranked
Inkling-Small
89.6
#25/123
Basis
Provisional lane · 0 vs 1 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-5.6 Luna
$0.0008
Fits in one request
Inkling-Small
$0.0013
Fits in one request

GPT-5.6 Luna has the lower modeled cost

Costs use the listed standard API rates.

Repository review

50K fresh input + 3K output tokens

GPT-5.6 Luna
$0.0136
Fits in one request
Inkling-Small
$0.03332
Fits in one request

GPT-5.6 Luna has the lower modeled cost

Costs use the listed standard API rates.

Cache-heavy agent loop

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

GPT-5.6 Luna
$0.02
Fits in one request
Inkling-Small
$0.0492
Fits in one request

GPT-5.6 Luna has the lower modeled cost

Costs use the listed standard API rates.

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.

GPT-5.6 Luna

Inkling-Small

1M

Cached-input rate

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

GPT-5.6 Luna

$0.02 per 1M cached input tokens

OpenAI pricing

Inkling-Small

$0.116 per 1M cached input tokens

Provider availability

GPT-5.6 Luna

Generally Available · OpenAI Responses API

OpenAI model catalog

Inkling-Small

Not sourced

Reasoning profile

GPT-5.6 Luna

Reasoning

Inkling-Small

Hybrid

Weight access

GPT-5.6 Luna

Proprietary

Inkling-Small

Open Weight

License

GPT-5.6 Luna

Proprietary

Inkling-Small

Open Weight

Release date

GPT-5.6 Luna

2026-07-09

Inkling-Small

2026-07-30

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-5.6 Luna has the higher public score estimate, 64.65 versus 59.25, but the 90% score intervals overlap.
Workload cost
Repository review: $0.0136 vs $0.03332. Cache-heavy agent loop: $0.02 vs $0.0492.
Context tradeoff
GPT-5.6 Luna has the larger documented window (1.05M).

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 evidence43 rows

Agentic

  • Terminal-Bench 3.0

    GPT-5.6 Luna14.3%
    Source
    Inkling-Small

    Not directly comparable

  • Terminal-Bench 2.0

    GPT-5.6 Luna84.7%
    Source
    Inkling-Small64.7%
    Source

    GPT-5.6 Luna leads this result

  • BrowseComp

    GPT-5.6 Luna83.3%
    Source
    Inkling-Small77.4%
    Source

    GPT-5.6 Luna leads this result

  • OSWorld 2.0

    GPT-5.6 Luna45.6%
    Source
    Inkling-Small

    Not directly comparable

  • CyberGym

    GPT-5.6 Luna77.9%
    Source
    Inkling-Small

    Not directly comparable

  • ExploitGym

    GPT-5.6 Luna12.4%
    Source
    Inkling-Small

    Not directly comparable

  • Toolathlon

    GPT-5.6 Luna53.4%
    Source
    Inkling-Small

    Not directly comparable

  • Terminal-Bench 2.1 (Vals)

    GPT-5.6 Luna79.0%
    Source
    Inkling-Small55.1%
    Source

    GPT-5.6 Luna leads this result

  • ApprenticeBench

    GPT-5.6 Luna7%
    Source
    Inkling-Small

    Not directly comparable

  • MCP Atlas

    GPT-5.6 Luna
    Inkling-Small79.6%
    Source

    Not directly comparable

  • Toolathlon-Verified

    GPT-5.6 Luna
    Inkling-Small54.4%
    Source

    Not directly comparable

Coding

  • SWE-bench Pro

    GPT-5.6 Luna62.7%
    Source
    Inkling-Small55.9%
    Source

    GPT-5.6 Luna leads this result

  • Terminal-Bench 2.0

    GPT-5.6 Luna84.7%
    Source
    Inkling-Small64.7%
    Source

    GPT-5.6 Luna leads this result

  • DeepSWE

    GPT-5.6 Luna67.2%
    Source
    Inkling-Small

    Not directly comparable

  • FrontierCode 1.1 Extended

    GPT-5.6 Luna55.1%
    Source
    Inkling-Small

    Not directly comparable

  • cursorBench32

    GPT-5.6 Luna61.1%
    Source
    Inkling-Small

    Not directly comparable

  • VulcanBench v3

    GPT-5.6 Luna85.5%
    Source
    Inkling-Small

    Not directly comparable

  • SWE-bench (Vals)

    GPT-5.6 Luna93.0%
    Source
    Inkling-Small82.2%
    Source

    GPT-5.6 Luna leads this result

  • cursorBench40

    GPT-5.6 Luna35.9%
    Source
    Inkling-Small

    Not directly comparable

  • SWE-bench Verified

    GPT-5.6 Luna
    Inkling-Small80.2%
    Source

    Not directly comparable

  • SciCode

    GPT-5.6 Luna
    Inkling-Small48.7%
    Source

    Not directly comparable

  • LiveCodeBench (Vals)

    GPT-5.6 Luna
    Inkling-Small85.9%
    Source

    Not directly comparable

Reasoning

  • ARC-AGI-2

    GPT-5.6 Luna59.5%
    Source
    Inkling-Small40.1%
    Source

    GPT-5.6 Luna leads this result

  • ARC-AGI-3

    GPT-5.6 Luna0.2%
    Source
    Inkling-Small

    Not directly comparable

  • CritPt

    GPT-5.6 Luna
    Inkling-Small8.3%
    Source

    Not directly comparable

Knowledge

  • GPQA

    GPT-5.6 Luna92.3%
    Source
    Inkling-Small89.5%
    Source

    GPT-5.6 Luna leads this result

  • GPQA-D

    GPT-5.6 Luna92.3%
    Source
    Inkling-Small89.5%
    Source

    GPT-5.6 Luna leads this result

  • HealthBench Professional

    GPT-5.6 Luna55.7%
    Source
    Inkling-Small

    Not directly comparable

  • HealthBench Hard

    GPT-5.6 Luna32.0%
    Source
    Inkling-Small

    Not directly comparable

  • GPQA Diamond (Vals)

    GPT-5.6 Luna91.7%
    Source
    Inkling-Small83.6%
    Source

    GPT-5.6 Luna leads this result

  • MMLU-Pro (Vals)

    GPT-5.6 Luna86.0%
    Source
    Inkling-Small85.6%
    Source

    GPT-5.6 Luna leads this result

  • HLE

    GPT-5.6 Luna
    Inkling-Small47.8%
    Source

    Not directly comparable

  • HLE w/o tools

    GPT-5.6 Luna
    Inkling-Small31.6%
    Source

    Not directly comparable

Math

  • FrontierMath (legacy)

    GPT-5.6 Luna78.6%
    Source
    Inkling-Small

    Not directly comparable

  • FrontierMath v2 (Tiers 1-3)

    GPT-5.6 Luna78.600%
    Source
    Inkling-Small

    Not directly comparable

  • FrontierMath v2 (Tier 4)

    GPT-5.6 Luna58.500%
    Source
    Inkling-Small

    Not directly comparable

  • AIME26

    GPT-5.6 Luna
    Inkling-Small95.5%
    Source

    Not directly comparable

  • HMMT Feb 2026

    GPT-5.6 Luna
    Inkling-Small90.2%
    Source

    Not directly comparable

Multimodal

  • MMMU-Pro

    GPT-5.6 Luna78.4%
    Source
    Inkling-Small74%
    Source

    GPT-5.6 Luna leads this result

  • MMMU-Pro w/ Python

    GPT-5.6 Luna79.5%
    Source
    Inkling-Small

    Not directly comparable

  • CharXiv

    GPT-5.6 Luna
    Inkling-Small81.3%
    Source

    Not directly comparable

  • CharXiv w/o tools

    GPT-5.6 Luna
    Inkling-Small77.4%
    Source

    Not directly comparable

Instruction following

  • IFBench

    GPT-5.6 Luna
    Inkling-Small82.2%
    Source

    Not directly comparable

Frequently asked questions

Which is better, GPT-5.6 Luna or Inkling-Small?

GPT-5.6 Luna has the higher public score estimate, 64.65 versus 59.25, 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-5.6 Luna or Inkling-Small?

GPT-5.6 Luna leads the public coding lane, 66.8 to 43.8, with Supported evidence for both models and non-overlapping 90% intervals.

Which is better for agentic tasks, GPT-5.6 Luna or Inkling-Small?

GPT-5.6 Luna leads the public agentic tasks lane, 56.8 to 36.9, with Supported evidence for both models and non-overlapping 90% intervals.

Which costs less, GPT-5.6 Luna or Inkling-Small?

For the stated presets, chat costs $0.0008 on GPT-5.6 Luna and $0.0013 on Inkling-Small; repository review costs $0.0136 and $0.03332; the cache-heavy agent loop costs $0.02 and $0.0492. Costs use the listed standard API rates.

Which has the larger context window, GPT-5.6 Luna or Inkling-Small?

GPT-5.6 Luna has the larger documented context window: 1.05M, compared with 1M.

Related comparisons

Last updated September 10, 2026

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