sifr-benchmark 0.1.32

Benchmark for evaluating LLM understanding of web UI: SiFR vs HTML vs AXTree vs Screenshots

SiFR Benchmark

How well do AI agents understand web UI?

Benchmark comparing SiFR vs HTML vs AXTree vs Screenshots across complex websites.

⚠️ This is an example run, not a definitive study. The benchmark is fully reproducible — run it yourself on your sites, your models, your use cases. We show our results; you verify on yours.

Results

Tested on 10 high-complexity sites: Amazon, YouTube, Reddit, eBay, Walmart, Airbnb, Yelp, IMDB, ESPN, GitHub.

All formats tested with equal 400KB token budget for fair comparison.

Format	Accuracy	Tokens (avg)
SiFR	71.7%	102K
Screenshot	27.0%	38K
Raw HTML	11.4%	122K
AXTree	1.5%	6K

SiFR is 2.7x more accurate than screenshots and 6.3x more accurate than raw HTML.

Per-Site Breakdown

Site	SiFR	Screenshot	HTML	AXTree
GitHub	🏆 100%	0%	—	0%
YouTube	🏆 100%	64%	0%	0%
Amazon	🏆 85.7%	22.9%	—	0%
Walmart	🏆 85.7%	13.3%	11.4%	0%
Reddit	🏆 83.3%	36%	—	0%
Yelp	🏆 62.5%	57.1%	—	0%
ESPN	🏆 57.1%	11.4%	22.9%	0%
IMDB	🏆 50%	16%	—	16.7%
eBay	🏆 28.6%	26.7%	11.4%	0%

SiFR wins on 9 out of 9 sites where it ran successfully.

What is SiFR?

Structured Interface Format for Representation — a compact format optimized for LLM understanding of web UI.

a015:
  tag: a
  text: "Add to Cart"
  box: [500, 300, 120, 40]
  attrs: {href: "/cart/add", class: "btn-primary"}
  salience: high

Key advantages:

• Actionable IDs: Every element gets a unique ID (a015, btn003)
• Salience scoring: High/medium/low importance ranking
• Structured for LLMs: Optimized for "find element → take action" tasks
• Model-agnostic: Works with any LLM that can read text

Installation

pip install sifr-benchmark

Prerequisites

1. Element-to-LLM Chrome Extension — captures pages in SiFR format

   • Load unpacked from element-to-llm-chrome/

2. API Keys

   export OPENAI_API_KEY=sk-...
   export ANTHROPIC_API_KEY=sk-ant-...  # optional
   

3. Playwright (for automated capture)

   playwright install chromium
   

Quick Start

Full Benchmark

Capture → Generate Ground Truth → Test — all in one command:

sifr-bench full-benchmark-e2llm https://www.amazon.com https://www.youtube.com \
  -e /path/to/element-to-llm-extension \
  -s 400

Options:

• -e, --extension — Path to E2LLM extension (required)
• -s, --target-size — Token budget in KB for ALL formats (default: 400)
• -m, --models — Models to test (default: gpt-4o-mini)
• -v, --verbose — Show detailed output

Other Commands

# List all benchmark runs
sifr-bench list-runs

# Compare multiple runs
sifr-bench compare benchmark_runs/run_1 benchmark_runs/run_2

# Validate SiFR files
sifr-bench validate examples/

# Show help
sifr-bench info

How It Works

1. Capture

The extension captures 4 formats simultaneously:

• SiFR — Structured format with salience scoring
• HTML — Raw rendered DOM (outerHTML)
• AXTree — Playwright accessibility tree
• Screenshot — Full-page PNG

2. Ground Truth Generation

GPT-4o Vision analyzes screenshot + SiFR to generate agent tasks:

• Click: "Click the Sign In button" → a003
• Input: "Enter search query" → input001
• Locate: "Find the main heading" → h1001

3. Benchmark

Each format tested with same token budget, same model, same prompts:

Task: "Click on the shopping cart icon"
Expected: a015

SiFR response: a015 ✓
HTML response: none ✗
Screenshot response: cart icon (no ID) ✗

Methodology Notes

Run it yourself. This benchmark exists so you can test on your own sites and models. Our results are one data point — your results on your use case matter more.

• Equal token budget: All formats truncated to same size (400KB default). Fair comparison.

• Ground truth is auto-generated: GPT-4o Vision creates tasks. For production, consider human verification.

• AXTree 0% is a real finding: Many agent frameworks use accessibility trees. This shows why that's problematic.

• 7 tasks per site: Practical, not academic. When did you last need 2000 clicks on one page?

Why Raw HTML Fails

Amazon HTML: 909KB original
After truncation: 400KB (loses 56% of content)
Result: 0% accuracy — critical elements gone

Amazon SiFR: 613KB original  
After truncation: 400KB (loses 35% of content)
Result: 85.7% accuracy — structure survives

HTML is verbose. When you truncate it, you lose random chunks. SiFR is pre-compressed with salience scoring — important elements survive truncation.

Output Format

        Benchmark Results: Combined (10 sites)
┏━━━━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━━┳━━━━━━━━━━┳━━━━━━━━┓
┃ Format     ┃ Accuracy ┃  Tokens ┃  Latency ┃ Status ┃
┡━━━━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━━╇━━━━━━━━━━╇━━━━━━━━┩
│ sifr       │    71.7% │ 101,683 │ 30,221ms │   ✅   │
│ screenshot │    27.0% │  38,074 │  7,942ms │   ⚠️   │
│ html_raw   │    11.4% │ 122,190 │ 35,901ms │   ⚠️   │
│ axtree     │     1.5% │   6,044 │  2,034ms │   ⚠️   │
└────────────┴──────────┴─────────┴──────────┴────────┘

Status:

• ✅ Success (accuracy ≥ 50%)
• ⚠️ Warning (accuracy < 50%)
• ❌ Failed (accuracy = 0%)

Run Directory Structure

Each benchmark creates an isolated run:

benchmark_runs/run_20251206_210357/
├── captures/
│   ├── sifr/*.sifr
│   ├── html/*.html
│   ├── axtree/*.json
│   └── screenshots/*.png
├── ground-truth/*.json
├── results/
│   ├── raw_results.json
│   └── summary.json
└── run_meta.json

Tested Models

Default: gpt-4o-mini

The benchmark supports any OpenAI or Anthropic model. Run with different models:

sifr-bench full-benchmark-e2llm ... -m gpt-4o
sifr-bench full-benchmark-e2llm ... -m claude-sonnet

Contributing

• Add test sites: Run benchmark on more URLs
• Improve ground truth: Manual verification of tasks
• New models: Add support in models.py
• Bug reports: Open an issue

Citation

@misc{sifr2025,
  title={SiFR: Structured Interface Format for AI Web Agents},
  author={SiFR Contributors},
  year={2025},
  url={https://github.com/Alechko375/sifr-benchmark}
}

License

MIT