Paper Banana

PaperBanana: Academic Illustration Pipeline

Automates publication-ready academic illustrations via 5 specialized agents, each a separate call to the configured VLM or image model (Gemini by default): Retriever (categorize & select references) -> Planner (multimodal description) -> Stylist (polish) -> Visualizer (render) -> Critic (evaluate & refine).

Two output modes:

• DIAGRAM MODE: Each agent is a Python script calling the configured VLM / image model. Run scripts/orchestrate.py for end-to-end execution.
• PLOT MODE: Statistical plots generated as executable Python matplotlib/seaborn code (code-based to eliminate data hallucination).

Requirements: Python 3.10+ with google-genai>=2, matplotlib, seaborn, numpy, pillow, and an API key for the provider in use (default Gemini: GOOGLE_API_KEY or GEMINI_API_KEY). Optional: openai (for openai/... and openrouter/... models), anthropic, pypdf (PDF input).

Models: named provider/model; unprefixed names are inferred. Defaults are gemini-3.5-flash (Retriever/Planner/Stylist/Critic) and gemini-3-pro-image (Visualizer, "Nano Banana Pro"). Override with PAPERBANANA_VLM_MODEL / PAPERBANANA_IMAGE_MODEL or the orchestrator's --vlm-model / --image-model flags.

If the user names a provider or model, pass it via --vlm-model / --image-model. If a run fails with a missing-key or model error, run python scripts/validate_output.py --check-api and report which key or model is the problem.

Paper: PaperBanana: Automating Academic Illustration for AI Scientists (arXiv:2601.23265, Google/PKU). Official code: https://github.com/dwzhu-pku/PaperBanana

Step 1: Determine Output Mode

Decide which track to follow:

Critical rule: PLOT MODE always generates Python code (never image generation for data visualizations). Code-based generation eliminates data hallucination errors that corrupt numerical accuracy in image-based approaches.

Step 2: Execute Pipeline

DIAGRAM MODE — Automated Pipeline

Primary entry point: Run the end-to-end orchestrator:

python scripts/orchestrate.py \
  --methodology-file methodology.txt \
  --caption "Figure 1: Overview of proposed framework" \
  --mode diagram \
  --output output/diagram.png

Useful flags (combine as needed):

Or with inline text:

python scripts/orchestrate.py \
  --methodology "Our framework consists of three modules..." \
  --caption "Figure 1: System overview" \
  --mode diagram \
  --output output/diagram.png

The orchestrator chains all 5 agents automatically and handles the Critic's refinement loop (up to 3 iterations). Intermediate outputs, including every Visualizer attempt (diagram_iter{N}[_c{K}].png), are saved to output/work/; the best-scoring image is copied to --output. The run ends with a per-model token/image usage summary; relay it to the user.

Pipeline Details

Read references/DIAGRAM-PROMPTS.md for the actual Gemini prompt templates used by each agent.

Phase 1: RETRIEVER (scripts/retriever.py) — VLM call

• Classifies methodology into 1 of 4 categories from references/DIAGRAM-CATEGORIES.md
• Selects 2 most relevant reference diagrams from the 13 curated examples in assets/references/
• Identifies visual intent: Framework Overview, Pipeline/Flow, Detailed Module, Architecture Diagram

Phase 2: PLANNER (scripts/planner.py) — Multimodal VLM call

• Sends the 2 selected reference images + methodology text to Gemini as a multimodal prompt
• The VLM "sees" what good methodology diagrams look like (in-context learning from images)
• Generates an extremely detailed textual description of the target diagram
• With --input-image, the existing figure is attached too and the Planner must preserve its content while improving layout and legibility
• Critical: Natural language only for all visual attributes. NEVER hex codes or pixel dimensions

Phase 3: STYLIST (scripts/stylist.py) — VLM call

• Takes the Planner's description + full NeurIPS 2025 style guide + the target venue's typeset width and notes (--venue, --figure-width; data in assets/venues.json)
• Applies domain-specific styling based on the category from Phase 1
• Follows 5 critical rules: preserve aesthetics, intervene minimally, respect domain, enrich details, preserve content
• Outputs the polished description only

Phase 4: VISUALIZER (scripts/generate_image.py) — Image model call

• Renders the styled description with the configured image model: gemini-3-pro-image (Nano Banana Pro) by default; openai/gpt-image-2, gemini-3.1-flash-image, or an OpenRouter image model via --image-model
• With --input-image, the existing figure is passed as the edit source instead of generating from scratch
• With --num-candidates N, N images are rendered in parallel and all are scored by the Critic; the best is kept
• Prepends quality prefix (high-res, legible text, clean background, no watermarks)
• Aspect ratio selected based on visual intent (16:9 for pipelines, 3:2 for modules); output resolution 2K by default

Phase 5: CRITIC (scripts/critic.py) — Multimodal VLM call

• Sends the generated image + methodology text to Gemini for multimodal evaluation
• Scores on 4 dimensions (faithfulness, readability, conciseness, aesthetics)
• If faithfulness < 7 OR readability < 7: generates revised description → loops to Phase 4
• Maximum 3 refinement iterations

DIAGRAM MODE — Manual Execution

You can also run each agent individually for more control:

# Phase 1: Retriever
python scripts/retriever.py --methodology-file text.txt --output work/retriever.json

# Phase 2: Planner (add --input-image old.png to improve an existing figure)
python scripts/planner.py --methodology-file text.txt --caption "Figure 1: ..." \
  --references work/retriever.json --output work/planner.json

# Phase 3: Stylist (venue defaults to neurips)
python scripts/stylist.py --description work/planner.json --venue icml --figure-width single \
  --output work/stylist.json

# Phase 4: Visualizer (extract styled_description from JSON, pass to generate_image.py;
# add --reference-image old.png to edit an existing figure, --model openai/gpt-image-2 to switch renderer)
python scripts/generate_image.py --prompt-file work/styled_desc.txt --aspect-ratio 16:9 \
  --image-size 2K --output output/diagram.png

# Phase 5: Critic
python scripts/critic.py --image output/diagram.png --methodology-file text.txt \
  --description work/stylist.json --output work/critic.json

PLOT MODE

Read references/PLOT-PROMPTS.md for detailed agent prompts. Read references/PLOT-STYLE-GUIDE.md for aesthetic rules.

Plot mode uses the host agent for reasoning and code generation — no image-model API calls are needed for plot generation itself.

Phase 1: CATEGORIZE (Retriever)

Match data characteristics and visual intent:

Phase 2: PLAN (Planner)

Create a detailed specification that explicitly enumerates:

• Every raw data point with exact coordinates/values
• Axis ranges, labels, tick marks, scales (linear/log)
• Color assignments for each series/category
• Font sizes for title, axis labels, tick labels, legend
• Line widths, marker sizes, marker shapes
• Legend placement and formatting
• Grid style (major/minor, dashed/solid)
• Figure dimensions and DPI

Phase 3: STYLE (Stylist)

Read references/PLOT-STYLE-GUIDE.md for NeurIPS 2025 plot aesthetics.

Key styling rules:

• White backgrounds only
• Colorblind-friendly palettes (see assets/palettes/colorblind_safe.json)
• Sans-serif fonts (Helvetica, Arial, or DejaVu Sans)
• Markers on line charts for print readability
• Inward-facing tick marks
• Subtle grid lines (light gray, dashed)

Phase 4: VISUALIZE (Visualizer — Code Generation)

Generate complete, self-contained Python matplotlib/seaborn code. Use scripts/plot_generator.py as a reference implementation or run it directly with a JSON config:

python scripts/plot_generator.py --config plot_config.json --venue icml --width single --output figure.pdf

--venue and --width size the figure to the venue's column (single) or text (double) width from assets/venues.json; use the same widths for figsize when writing custom code.

Code requirements:

• Self-contained: all data defined inline, no external file dependencies
• Apply .mplstyle from assets/matplotlib_styles/academic_default.mplstyle
• Set OUTPUT_PATH variable for output file location
• 300 DPI, bbox_inches='tight'
• No plt.show() — save only
• Support both PDF and PNG output

After generating the code, execute it to produce the plot image.

Phase 5: CRITIQUE (Critic)

Same rubric as diagram mode, plus plot-specific checks:

• Data fidelity: Every data point correctly plotted
• Axis accuracy: Ranges, labels, scales match specification
• Layout: No overlapping labels, legends, or data points
• Code correctness: Syntax valid, imports available, output saved

If code execution failed, analyze the error, simplify the approach, and regenerate.

Quick Start Examples

Diagram (automated): Run scripts/orchestrate.py with your methodology text file and caption.

Diagram (via agent): "Generate a methodology diagram for my transformer architecture. Here is the methodology section: [paste text]. Caption: Overview of our proposed multi-head attention framework."

Plot: "Create a bar chart comparing model performance. Data: {BERT: 92.3, GPT-4: 88.1, Claude: 95.7, Gemini: 91.2}. Intent: F1 score comparison across language models."

Improve: "Improve this figure: [attach image] using this methodology: [paste text]" → run scripts/orchestrate.py --input-image figure.png --methodology-file text.txt.

From a paper: "Make the method figure for paper.pdf" → scripts/orchestrate.py --methodology-file paper.pdf --pages 3-5 (ask for or infer the method-section pages).

Other provider: "Use GPT Image for rendering" → add --image-model openai/gpt-image-2 (needs OPENAI_API_KEY).

File Reference

Environment Setup

# Default provider (Gemini) for all agents
export GOOGLE_API_KEY="your-api-key-here"   # GEMINI_API_KEY also works

# Optional: other providers (install with: pip install openai anthropic)
export OPENAI_API_KEY="..."        # openai/gpt-5.5, openai/gpt-image-2, and openrouter/... via OPENROUTER_API_KEY
export ANTHROPIC_API_KEY="..."     # anthropic/claude-opus-5 (reasoning agents only)

# Optional: swap models (defaults shown). Cheaper: gemini-3.1-flash-lite / gemini-3.1-flash-image
export PAPERBANANA_VLM_MODEL="gemini-3.5-flash"
export PAPERBANANA_IMAGE_MODEL="gemini-3-pro-image"

# Install dependencies (add pypdf for PDF input)
pip install "google-genai>=2" matplotlib seaborn numpy pillow

Verify setup: python scripts/validate_output.py --check-deps --check-api (checks packages, the API keys, and that both configured models are reachable).