OpenAI GPT · Efficient · 2026-08-13

GPT-5.6 Luna vision benchmark

How GPT-5.6 Luna performed on screenshot-based UI grounding, element-presence, and visible layout-defect tasks relevant to test automation.

Exact API modelopenai/gpt-5.6-luna

Requests were pinned to OpenAI infrastructure through OpenRouter. Fallbacks were disabled for every retained request.

Grounding hit rate100%
Mean box IoU0.771
Presence accuracy100%
Defect accuracy83%

Overall result

GPT-5.6 Luna across all three UI tasks

GPT-5.6 Luna hit 24 of 24 requested UI targets. Its balanced accuracy was 100% for element presence and 83% for layout-defect detection.

This dated pilot retained 24 grounding responses and 24 detection responses. No detection requests failed. Results describe this exact API model and test corpus, not general model quality or a consumer chat product.

Check out the complete LLM vision benchmark →

Relative performance

Where GPT-5.6 Luna sits among the tested models

Each scale compares the selected model with the strongest and weakest other model. All three metrics come from the same completed 24-case grounding run; stronger is always to the right.

Box IoUHigher is stronger
0.771
Weakest other
Claude Sonnet 50.043
Strongest other
GPT-5.6 Sol0.677
SpeedLower latency is stronger
3.55 s
Weakest other
Gemini 3.1 Pro Preview11.89 s
Strongest other
Grok 4.51.67 s
CostLower total cost is stronger
$0.0057
Weakest other
Claude Opus 5$0.2474
Strongest other
Holo3 122B A10B$0.0126
Check out the complete LLM vision benchmark →

UI grounding

Can GPT-5.6 Luna locate actionable elements?

Twenty-four targets span six deterministic desktop and mobile screens. A schema-valid point inside the requested target counts as a hit; box IoU measures localization precision.

commerce catalog desktop / clean / grounding / add productPassedHit0.9732.90 s$0.00029
commerce catalog desktop / clean / grounding / searchPassedHit0.9682.16 s$0.00031
commerce catalog desktop / clean / grounding / catalog queryPassedHit0.8252.90 s$0.00029
commerce catalog desktop / clean / grounding / stock filterPassedHit0.0662.86 s$0.00033
analytics dashboard desktop / clean / grounding / search fieldPassedHit0.9783.86 s$0.00030
analytics dashboard desktop / clean / grounding / compare togglePassedHit0.4172.38 s$0.00031
analytics dashboard desktop / clean / grounding / audience tabPassedHit0.8982.94 s$0.00035
analytics dashboard desktop / clean / grounding / revenue cardPassedHit0.9832.34 s$0.00031
iot control desktop / clean / grounding / auto modePassedHit0.0413.77 s$0.00033
iot control desktop / clean / grounding / devices navPassedHit0.9915.38 s$0.00030
iot control desktop / clean / grounding / pump cardPassedHit0.9762.83 s$0.00033
iot control desktop / clean / grounding / restart devicePassedHit0.9722.70 s$0.00031
banking ios / clean / grounding / transferPassedHit0.9772.62 s$0.00014
banking ios / clean / grounding / profilePassedHit0.95211.86 s$0.00014
banking ios / clean / grounding / transaction searchPassedHit0.8482.03 s$0.00014
banking ios / clean / grounding / hide balancePassedHit0.0324.26 s$0.00023
flight pass ios / clean / grounding / trips tabPassedHit0.1274.75 s$0.00029
flight pass ios / clean / grounding / boarding passPassedHit0.9868.70 s$0.00014
flight pass ios / clean / grounding / check inPassedHit0.9872.66 s$0.00013
flight pass ios / clean / grounding / profile tabPassedHit0.7283.44 s$0.00022
smart home android / clean / grounding / thermostat cardPassedHit0.9932.40 s$0.00013
smart home android / clean / grounding / add devicePassedHit0.9601.06 s$0.00009
smart home android / clean / grounding / morePassedHit0.9522.13 s$0.00016
smart home android / clean / grounding / room searchPassedHit0.8642.18 s$0.00014

Detection results

Presence and visible layout defects

Separate balanced tasks measure whether the model rejects absent elements and distinguishes clean controls from screenshots containing one seeded layout defect.

Can the model tell when an element is not there?

Six present and six absent target queries per model. This track measures classification only.

Balanced accuracy100%
Present recall100%
Absent specificity100%
Coverage12/12
Expected
commerce catalog desktop / clean / element presence / presentValidCorrectPresentPresent7.11 s$0.00022
commerce catalog desktop / clean / element presence / absentValidCorrectAbsentAbsent5.48 s$0.00022
analytics dashboard desktop / clean / element presence / presentValidCorrectPresentPresent7.53 s$0.00022
analytics dashboard desktop / clean / element presence / absentValidCorrectAbsentAbsent7.65 s$0.00022
iot control desktop / clean / element presence / presentValidCorrectPresentPresent8.63 s$0.00022
iot control desktop / clean / element presence / absentValidCorrectAbsentAbsent7.67 s$0.00022
banking ios / clean / element presence / presentValidCorrectPresentPresent8.11 s$0.00006
banking ios / clean / element presence / absentValidCorrectAbsentAbsent7.27 s$0.00006
flight pass ios / clean / element presence / presentValidCorrectPresentPresent7.12 s$0.00006
flight pass ios / clean / element presence / absentValidCorrectAbsentAbsent6.33 s$0.00006
smart home android / clean / element presence / presentValidCorrectPresentPresent8.28 s$0.00006
smart home android / clean / element presence / absentValidCorrectAbsentAbsent8.26 s$0.00006

Can the model distinguish clean and broken layouts?

Six clean controls and six screenshots with one seeded defect per model. Transport failures remain operational failures, not accuracy answers.

Balanced accuracy83%
Defect recall67%
Clean specificity100%
Coverage12/12
Localization IoU
commerce catalog desktop / clean / layout defectValidCorrectNot applicable7.30 s$0.00025
commerce catalog desktop / defect / layout defectValidCorrectCorrect0.1329.78 s$0.00035
analytics dashboard desktop / clean / layout defectValidCorrectNot applicable8.33 s$0.00025
analytics dashboard desktop / defect / layout defectValidCorrectCorrect0.2058.72 s$0.00035
iot control desktop / clean / layout defectValidCorrectNot applicable8.01 s$0.00028
iot control desktop / defect / layout defectValidIncorrectIncorrect0.0009.56 s$0.00036
banking ios / clean / layout defectValidCorrectNot applicable7.35 s$0.00012
banking ios / defect / layout defectInvalidIncorrectIncorrect0.00011.65 s$0.00031
flight pass ios / clean / layout defectValidCorrectNot applicable4.32 s$0.00012
flight pass ios / defect / layout defectValidCorrectCorrect0.9789.53 s$0.00019
smart home android / clean / layout defectValidCorrectNot applicable6.60 s$0.00009
smart home android / defect / layout defectValidCorrectIncorrect0.0009.13 s$0.00018

Why this research matters

Using the right kind of vision for each test

Top vision LLMs can reason about complex visual meaning, but they are still too slow and expensive for every test step. This research helps us identify where their semantic capabilities justify that trade-off.

01

Fast local evaluation

Repeato’s own local vision algorithms handle frequent interactions, visual matching, and regression checks with fast feedback, predictable behavior, and no per-request model cost.

02

Semantic reasoning when needed

Top vision LLMs are useful for more complicated questions: understanding meaning, checking dynamic content, describing defects, or evaluating concepts that cannot be captured by a simple visual fingerprint.

03

An evidence-based hybrid

Benchmarking accuracy, latency, reliability, and cost helps us decide which checks should remain local and which benefit enough from an LLM to justify a slower, more expensive evaluation.

Our product strategy

Use Repeato’s local computer vision as the fast foundation, then bring in top vision LLMs selectively for complicated or semantic reasoning where they provide meaningful additional value.

Check out the whole vision benchmark →

Test coverage

Six screens, three task types

Every model is evaluated against the same frozen corpus, prompts, response schemas, and normalized 0–1000 geometry.

01

Commerce catalog

Desktop web with a clean control and a paired container clipping defect.

02

Analytics dashboard

Desktop web with a clean control and a paired text overflow defect.

03

IoT control center

Desktop web with a clean control and a paired element overlap defect.

EN