Repeato research · LLM Vision benchmark

Can Multimodal LLMs Be Trusted with UI Testing?

A screenshot-only benchmark for UI test automation: locate actionable elements, recognize when an element is absent, detect visible layout defects, and record the operational cost of getting an answer.

Pilot edition2026-08-13

Six deterministic screens. Twenty-four grounding targets. 9 API models. A focused pilot, not a ranking.

Screens6
Grounding targets24
Defect categories6
Models9

Pilot findings

What this edition shows

These findings describe one retained response per case on a small synthetic corpus. They are useful signals for the next edition, not general model rankings or stability claims.

01

GPT-5.6 Luna led UI grounding

It hit all 24 targets and returned the highest mean box IoU at 0.771. It also had the lowest reported grounding cost in this run at $0.0057.

02

Element presence was nearly saturated

8 of 9 models reached 100% balanced accuracy. The track works as an absent-element sanity check, but this pilot version does little to separate most models.

03

Grok 4.5 led defect detection

It was the only model with 100% balanced accuracy on clean and defective layouts. Its defect-category accuracy was 67%, showing that noticing a problem and naming it precisely are different tasks.

What this means for test automation

Use the right kind of vision for each test step

Exact interaction, continuous observation, and semantic interpretation have different performance requirements. One vision technique should not be expected to optimize all three.

Local observationUp to 20 times per secondLLM requestOften 2–10 secondsHow we combine local vision and LLMsCollapse analysis

Repeato's local computer-vision loop can inspect the screen at 20 Hz—once every 50 ms. A vision-language-model request commonly needs 2–10 seconds for image transfer, inference, and the network round trip. That difference matters when a test must notice an element appearing, wait for movement to stop, or react before a transient state disappears.

01

Fast feedback for repeated interaction

Local visual fingerprints can continuously search for recorded targets and act as soon as the screen is ready. Repeating remote model calls at the same frequency would be impractical.

02

Predictable, private, and inexpensive

Local matching has no network round trip, provider availability, or per-request API charge. Screens remain on the workstation, and the same algorithm can run offline.

03

AI for questions matching cannot answer

LLM vision earns its latency when a test needs semantic judgment: interpreting text or numbers, understanding dynamic content, or checking concepts such as an upward-trending graph.

Practical split

Use local computer vision for the high-frequency control loop—finding targets, waiting, interaction, and visual comparison. Escalate selectively to AI vision when the assertion genuinely requires language or semantic understanding.

Grounding pilot

Can a model locate the requested UI element?

Each model received 24 actionable targets across six clean pilot screens. A schema-valid point inside the target counts as a hit; box IoU measures localization precision. Expand a row for scenario-level results.

Box IoUHigher is better · 0–1 scale
  1. Holo3 122B A10B0.478
  2. Grok 4.50.445
  3. GPT-5.40.528
  4. Gemini 3.6 Flash0.645
  5. GPT-5.6 Sol0.677
  6. GPT-5.6 Luna0.771
  7. Claude Sonnet 50.043
  8. Claude Opus 50.314
  9. Gemini 3.1 Pro Preview0.632
Total costLower is better · 24 requests
  1. Holo3 122B A10B$0.0126
  2. Grok 4.5$0.0669
  3. GPT-5.4$0.1196
  4. Gemini 3.6 Flash$0.0637
  5. GPT-5.6 Sol$0.2453
  6. GPT-5.6 Luna$0.0057
  7. Claude Sonnet 5$0.0990
  8. Claude Opus 5$0.2474
  9. Gemini 3.1 Pro Preview$0.0726
Mean latencyLower is better · per request
  1. Holo3 122B A10B1.68 s
  2. Grok 4.51.67 s
  3. GPT-5.42.99 s
  4. Gemini 3.6 Flash1.83 s
  5. GPT-5.6 Sol3.23 s
  6. GPT-5.6 Luna3.55 s
  7. Claude Sonnet 53.91 s
  8. Claude Opus 54.24 s
  9. Gemini 3.1 Pro Preview11.89 s
Accuracy, cost, and latency trade-offHigher and further left is better. Color shows mean response latency.
1.67 s fast11.89 s slow
Better value0.000.250.500.751.00$0.00$0.05$0.10$0.15$0.20$0.25Total cost for 24 requests (USD) →Box IoU →Holo3 122B A10BGrok 4.5GPT-5.4Gemini 3.6 FlashGPT-5.6 SolGPT-5.6 LunaClaude Sonnet 5Claude Opus 5Gemini 3.1 Pro Preview
Invalid response1 transport retry92% hits0.4781.68 s$0.0126
Passed1 transport retry83% hits0.4451.67 s$0.0669
Passed1 transport retry75% hits0.5282.99 s$0.1196
Invalid response1 transport retry79% hits0.6451.83 s$0.0637
Passed1 transport retry96% hits0.6773.23 s$0.2453
Passed1 transport retry100% hits0.7713.55 s$0.0057
Invalid response1 transport retry21% hits0.0433.91 s$0.0990
Invalid response1 transport retry46% hits0.3144.24 s$0.2474
Invalid response1 transport retry88% hits0.63211.89 s$0.0726

Detection pilots

Presence and visible defects

Two balanced tasks test whether models can reject absent UI elements and distinguish clean controls from seeded layout defects. Results remain separate from grounding.

Can the model tell when an element is not there?

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

100% valid12/12 cases · 0 failed attempts100%100%100%0%1.29 s$0.3636per 1K retained cases
100% valid12/12 cases · 0 failed attempts100%100%100%0%7.45 s$0.1414per 1K retained cases
100% valid12/12 cases · 0 failed attempts100%100%100%0%7.55 s$3.2402per 1K retained cases
100% valid12/12 cases · 0 failed attempts100%100%100%0%7.82 s$2.3426per 1K retained cases
100% valid12/12 cases · 0 failed attempts100%100%100%0%9.85 s$7.4788per 1K retained cases
100% valid12/12 cases · 0 failed attempts100%100%100%0%7.50 s$2.2346per 1K retained cases
100% valid12/12 cases · 0 failed attempts100%100%100%0%9.27 s$2.9915per 1K retained cases
100% valid12/12 cases · 0 failed attempts100%100%100%0%7.79 s$7.0680per 1K retained cases
100% valid12/12 cases · 0 failed attempts92%100%83%17%15.01 s$2.3602per 1K retained cases

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.

Defect accuracy, cost, and latency trade-offHigher and further left is better. Color shows mean response latency.
2.44 s fast21.75 s slow
Better value0.000.250.500.751.00$0.00$2.40$4.80$7.20$9.60$12.00Cost per 1,000 retained defect cases (USD) →Balanced accuracy →Holo3 122B A10BGPT-5.6 LunaGPT-5.4Gemini 3.6 FlashClaude Opus 5Grok 4.5Claude Sonnet 5GPT-5.6 SolGemini 3.1 Pro Preview
67% valid12/12 cases · 0 failed attempts58%17%100%0%2.44 s$0.8251per 1K retained cases
92% valid12/12 cases · 0 failed attempts83%67%100%50%8.36 s$0.2389per 1K retained cases
100% valid12/12 cases · 0 failed attempts92%83%100%67%9.02 s$5.2075per 1K retained cases
75% valid12/12 cases · 0 failed attempts75%83%67%67%8.43 s$3.8341per 1K retained cases
83% valid12/12 cases · 0 failed attempts83%67%100%67%10.15 s$11.5029per 1K retained cases
100% valid12/12 cases · 0 failed attempts100%100%100%67%7.40 s$2.7465per 1K retained cases
92% valid12/12 cases · 0 failed attempts83%83%83%67%10.52 s$4.7403per 1K retained cases
92% valid12/12 cases · 0 failed attempts92%83%100%67%11.91 s$11.6632per 1K retained cases
100% valid12/12 cases · 0 failed attempts92%100%83%67%21.75 s$3.0450per 1K retained cases

One pass per case; no confidence intervals or stability claims. Aggregate cost is extrapolated to 1,000 retained cases so incomplete runs do not appear artificially cheap. Rows with fewer than 12 responses still have a smaller case mix and are not directly comparable to complete rows.

Frozen corpus

Three desktop and three mobile screens

Each fixture has a clean control and one deliberately defective variant. Captures use fixed viewports, local assets, stable target geometry, and exact pixel-difference bounds.

Commerce catalog clean control
Commerce catalog with container clipping
Commerce catalogDesktop web · Container clipping
Analytics dashboard clean control
Analytics dashboard with text overflow
Analytics dashboardDesktop web · Text overflow
IoT control center clean control
IoT control center with element overlap
IoT control centerDesktop web · Element overlap
Mobile banking clean control
Mobile banking with viewport cropping
Mobile bankingiOS-like · Viewport cropping
Flight pass clean control
Flight pass with obscured action
Flight passiOS-like · Obscured action
Smart home clean control
Smart home with broken responsive reflow
Smart homeAndroid-like · Broken responsive reflow

Model dossiers

One evidence page per model

Open a model page for its grounding, element-presence, layout-defect, latency, reliability, and cost results. Routes remain pinned to the named upstream provider with fallbacks disabled.

Methodology

Measure what the model actually sees

The pilot separates UI grounding, element presence, visible layout-defect detection, and operational performance. It does not combine them into an overall score.

InputScreenshot only
Geometry0–1000
RunsOne per case
ScoringSeparate metrics

Input contract

Screenshot only

Prompt text plus one base64 PNG—no DOM, accessibility tree, source, OCR, tools, plugins, or web search.

01

Fixed rendering

Chromium at 1440 × 900 or 390 × 844; device scale factor 1.

02

Normalized geometry

Browser-derived ground truth in a 0–1000 coordinate space.

03

Stable pairs

Clean and defective variants preserve target geometry and capture hashes.

Track A

UI element grounding

Four targets per screenshot across common actionable UI-element types.

Point accuracy

Predicted click point falls inside the target box.

Box accuracy

Mean IoU and share of predictions with IoU ≥ 0.5.

Validity

Schema-valid response rate; one run means no stability score.

Track B

Element presence

One known-present and one plausible-but-absent query per clean screen.

Detection

Balanced accuracy weights present and absent cases equally.

Class behavior

Recall, specificity, and false-positive rate expose error direction.

Boolean only

found=true or found=false; no localization score.

Track C

Visible layout defects

Paired clean and defective scenes cover six objective layout-failure types.

Detection

Balanced accuracy, recall, specificity, and false-positive rate.

Classification

Defect-category accuracy after successful detection.

Localization

Predicted box IoU against browser-derived defect regions.

Routing and operations

Keep provider behavior visible

Pinned model IDs, first-party routes, disabled fallbacks, and one response contract.

Retry policy

One retry for 429, 5xx, or network failure—not wrong answers.

Operational metrics

Latency, failures, retries, and cost stay separate from accuracy.

Privacy

Published records omit keys and provider request identifiers.

Limits

A pilot, not a leaderboard

Six synthetic screens, one run per case, and 24 targets cannot establish broad superiority or stability.

Each edition records exact model IDs, date, prompt and schema hashes, endpoint controls, and sanitized attempts because providers change.

Reproduce it

Inspect the evidence

Raw model records are sanitized. API keys, request identifiers, and generation identifiers are not published.

Repeato-created screenshots, annotations, manifests, and aggregate results are available under CC BY 4.0. See the benchmark license notice. Raw model outputs remain subject to their providers' terms.

EN