ThinkingType

A lightweight benchmark measuring how typography and presentation influence vision-language-model judgments and decisions. The same content is shown to the same model as plain text and as a rendered image (varying font, size, layout, and color), and ThinkingType measures how often the answer changes. Results, interactive demos, and the full writeup: https://wdanfort.github.io/thinkingtype/

The benchmark has two tracks:

• Sentence track (judgments): 120 synthetic sentences x 8 fonts x 10 yes/no questions (urgent? trustworthy? professional?). Metric: flip rate — how often the model's image answer disagrees with its own text answer.
• Decision track (gates): ~330 synthetic decision items across three tests (moderation removal, resume screening, hardship-grant appeal), calibrated to each model's own decision boundary. Metric: decision shift — how much more often the model says yes to the image than to the identical text.

The full fact sheet of results lives in FACTS.md.

Installation

pip install -e .

# Or with development dependencies
pip install -e ".[dev]"

Tesseract OCR is required for the sentence track's legibility-check stage:

# Linux (Debian/Ubuntu)
sudo apt-get install tesseract-ocr

# macOS
brew install tesseract

# Or use the provided script
./scripts/install_tesseract.sh

Fonts

Open-source fonts are bundled in assets/fonts/. To download fresh copies:

python scripts/fetch_fonts.py

Bundled fonts (all open-source licensed):

• Liberation Serif (Regular, Bold)
• Liberation Sans (Regular, Bold)
• Liberation Mono (Regular)
• Comic Neue (Regular) — an open-source Comic Sans analogue; site prose says "Comic Sans" as shorthand for this font
• OpenDyslexic (Regular)

API keys

Set environment variables or use a .env file:

export OPENAI_API_KEY=sk-...
export ANTHROPIC_API_KEY=sk-ant-...
export GOOGLE_API_KEY=...

Reproducing the v1 results

Decision track (gates)

Matches the site's Reproduce section:

typo-eval --config configs/gates_v1.yaml gates-build
typo-eval --config configs/gates_v1.yaml gates-render
typo-eval --config configs/gates_v1.yaml gates-calibrate --provider <p>
typo-eval --config configs/gates_v1.yaml gates-run --provider <p>
typo-eval --config configs/gates_v1.yaml gates-analyze

Follow-up experiment configs: gates_v1_rubric.yaml (criteria written into the prompt), gates_v1_realism.yaml (forum/phone screenshot chrome), gates_v1_fair.yaml (OpenDyslexic fairness scale-up), and gates_v2.yaml (July 2026 release-tracking rerun). Compare any two runs with:

typo-eval gates-drift --run-a gates_v1 --run-b gates_v2

Per-run reports, item-level CSVs, and forest plots are in results/gates/. The drift monitor for testing your own model x gate combinations is documented in docs/GATE_DRIFT.md.

Sentence track (judgments)

typo-eval --config configs/v0c_release.yaml generate
typo-eval --config configs/v0c_release.yaml render
typo-eval --config configs/v0c_release.yaml ocr
typo-eval --config configs/v0c_release.yaml run --provider <p>
typo-eval --config configs/v0c_release.yaml analyze

v0c_release.yaml is the July 2026 administration (Claude Fable 5, GPT-5.6 Sol); v0b_frontier.yaml and v0b_oldgen_fixed.yaml are the earlier administrations (GPT-5.5 / Claude Sonnet 5, and GPT-4o). All use seed 42 and identical variants, so every administration judges the same 120 sentences.

Text baseline note: the text arm sends the original sentence text directly to the model (data/inputs/sentences.csv); it is not derived from OCR. The ocr stage runs Tesseract on the rendered images as a separate legibility check only — its output is not part of the text-vs-image comparison, so OCR errors cannot confound the flip rates.

Models used in the v1 results

Models are configurable per provider in each YAML config (model_text / model_vision). The published v1 numbers come from:

Track	Models
Sentence (judgments)	GPT-4o, GPT-5.5, Claude Sonnet 5, Claude Fable 5, GPT-5.6 Sol
Decision (gates)	GPT-5.5, Claude Sonnet 5, Gemini 3.5 Flash, Claude Fable 5, GPT-5.6 Sol

The sentence track was not run on Gemini (the decision track was).

CLI reference

typo-eval --config <config.yaml> <command>

Sentence track: generate, render, ocr, run [--provider ...] [--limit N] [--shard i/N], analyze [--run <run_id>], compare, or all for the full pipeline.

Decision track: gates-build, gates-render, gates-calibrate --provider <p>, gates-run --provider <p>, gates-analyze, and gates-drift --run-a <A> --run-b <B> [--provider <p>].

Directory structure

configs/            # YAML configs (v0*/v0c_* sentence track, gates_* decision track)
assets/fonts/       # Bundled open-source fonts
data/
  inputs/           # Sentence CSV + gate item banks (committed)
  rendered/         # Rendered stimulus images (generated locally)
  ocr/              # Tesseract output (legibility check)
  manifests/        # Run metadata
results/
  gates/            # Decision-track reports, analysis CSVs, drift reports (committed)
  runs/<run_id>/    # Raw JSONL response logs + per-run analysis (generated locally)
src/typo_eval/
  cli.py            # CLI entrypoint
  config.py         # Configuration schema
  render.py         # Image rendering
  ocr.py            # Tesseract OCR
  inference.py      # Model inference
  analysis.py       # Sentence-track analysis
  gates/            # Decision-track pipeline (stimuli, calibration, analysis, drift)
  providers/        # OpenAI, Anthropic, Google
scripts/
  fetch_fonts.py
  install_tesseract.sh
tests/

Development

pip install -e ".[dev]"
pytest tests/
ruff format src/ tests/
ruff check src/ tests/ --fix

License

MIT License. See LICENSE. Fonts are licensed under their respective open-source licenses (OFL, GPL+exception).