WebBrain Browser Vision Tiny

WebBrain Browser Vision Tiny is a browser-GUI specialist derived from LiquidAI/LFM2.5-VL-450M. It converts a browser viewport screenshot into the six-section observation format consumed by WebBrain's planning agent. This repository contains the merged Transformers model, not only a LoRA adapter.

Intended use

  • Browser screenshot description for a downstream automation planner.
  • Visible UI text, control, form-state, dialog, error, loading, consent, CAPTCHA, and blocker detection.
  • A small local fallback when a larger vision model is unavailable.

This is not a general replacement for a frontier VLM. It must not be trusted to read passwords, payment details, or other sensitive information, and its observations must not be treated as authorization to perform an action.

Training

Item Value
Base model LiquidAI/LFM2.5-VL-450M
Method Supervised fine-tuning with LoRA, then merged
LoRA rank 16, alpha 32, dropout 0.05
Epochs 1
Effective batch size 16
Learning rate 1e-4, cosine schedule, 3% warmup
Maximum image tokens 256
Precision BF16 with gradient checkpointing
Teacher qwen/qwen3.6-35b-a3b through OpenRouter
Hardware One NVIDIA RTX 4090 24 GB
Runtime 6,134 seconds (102.2 minutes)
Peak VRAM 21,954 MiB (about 21.4 GiB)
Trainable parameters 4,128,768 / 452,847,616 (0.9117%)

The final rolling train loss was 0.401. Periodic held-out validation loss improved from 0.624 at step 250 to 0.597 at step 500 and 0.583 at step 750. No NaN, OOM, or worker restart occurred.

Data

The public training corpus is available as webbrain-one/webbrain-browser-vision-tiny-dataset. It contains 15,348 train and 1,298 validation rows (16,646 unique images after deduplication), with image bytes embedded in 18 Parquet shards.

Source Version/commit License Train Validation Transformation
HuggingFaceM4/WebSight v0.1 @ b11f817 CC-BY-4.0 9,067 494 Screenshot plus HTML-grounded teacher label
Farama MiniWoB++ 7fd85d7 MIT 3,910 682 Locally rendered state plus accessibility-grounded teacher label
docling-project/ScreenParse bc0113f CC-BY-4.0 2,371 122 Screenshot plus dense-annotation-grounded teacher label

The release pipeline removed 51 duplicate images, quarantined 968 rows during the automated public-data privacy review, and validated the six-section format for all 16,646 released rows. A deterministic source-stratified manual audit of 15 examples passed. The teacher accepted 17,665 rows before public filtering.

The immutable local training snapshot ID is f721ca83b8b6308c7c386435325ef2b884d975d349bf91d239e618a2f40a727c. The dataset manifest and SHA256SUMS file record the public shard hashes.

Leakage controls

WebBrain's 100-case test/vision suite was excluded from training and used only for final evaluation. The release checks found:

  • zero train/validation overlap;
  • zero exact-image overlap with the WebBrain suite;
  • zero perceptual-image overlap with the WebBrain suite;
  • prompt parity between training and production evaluation.

Evaluation

The table reports the unchanged 100-case WebBrain browser-vision suite using the production six-section prompt. “Passes” require the rubric threshold and all critical checks. Difficulty columns are mean rubric scores.

Model Passes / 100 Mean rubric Easy Basic Intermediate Advanced Challenging
Base LFM2.5-VL-450M 0 4.17% 5.49% 6.38% 5.13% 2.36% 1.50%
WebBrain Browser Vision Tiny 30 70.06% 81.99% 74.13% 70.32% 54.94% 68.94%

Both runs completed all 100 cases with zero inference errors. Mean latency was 561 ms for the base model and 2,395 ms for the fine-tuned model on the same RTX 4090 Transformers server. Timing is implementation-specific and is not a hardware-independent speed claim. Machine-readable summaries are included in eval/base-summary.json and eval/final-summary.json.

Representative weak cases

The lowest-scoring held-out cases show where more targeted data is needed:

Case Category Screen Score Main failure
057 multilingual OCR Japanese payment 18.2% Exact heading, action, input, and status text
097 multilingual OCR Arabic security settings 18.2% Exact RTL heading, action, input, and status text
067 loading state Reconnecting 22.2% Readiness, heading, and spinner state
064 form validation Turkish tax details 30.0% Invalid value, exact error, and blocker
068 consent banner Turkish cookie preferences 30.0% Overlay title and consent state
069 dashboard Regional performance 33.3% Target metric and alert
044 form validation Invite teammate 40.0% Invalid input, error, and blocker
084 form validation Publish dataset 40.0% Invalid input, error, and blocker
041 authentication Administrator login 41.7% Button state and blocker
071 data table Turkish invoice list 42.9% Exact target-row status

General-image regression has not yet been measured. This omission matters: browser specialization can improve the target prompt while degrading broad image understanding. Evaluate on a separate general VLM suite before using this checkpoint outside browser screenshots.

Limitations

  • Small, low-contrast, occluded, or non-Latin text can be missed.
  • UI labels can be hallucinated, especially around overlays.
  • Focus, disabled state, form errors, and readiness signals require visual corroboration.
  • The model inherits teacher errors and may imitate the teacher's response style.
  • Site styles and languages outside the corpus may regress.
  • A valid six-section response does not make downstream automation safe.

License and attribution

This derivative is distributed under the LFM Open License v1.0, subject to its redistribution conditions and commercial-use threshold. The complete license text is included in LICENSE. The base model is LiquidAI/LFM2.5-VL-450M; retain its attribution and required notices.

Dataset components retain their upstream licenses: WebSight and ScreenParse are CC-BY-4.0, and MiniWoB++ is MIT. Labels were generated by the disclosed teacher model and then filtered, validated, and manually sampled. The dataset repository uses license: other because it contains multiple upstream licenses.

Reproducibility

Training and dataset preparation code, frozen-source metadata, validation, deduplication, leakage checks, and the 24 GB LoRA configuration are published at esokullu/lfm-finetune.

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