evaluate-diagram

name	evaluate-diagram
description	Use this skill when scoring or comparing a generated diagram against a human reference. Triggers on "score this diagram", "evaluate my diagram", "compare to reference", or "how accurate is this". Applies when both a generated diagram and a reference image exist and quality assessment is needed. Do NOT use for creating new diagrams (use generate-diagram) or plotting data (use generate-plot).
user-invocable	true
distribution	repo
allowed-tools	["mcp__paperbanana__evaluate_diagram","Read","Bash(paperbanana *)"]
model	{"preferred":"haiku","acceptable":["haiku"],"minimum":"haiku","allow_downgrade":true,"reasoning_demand":"low"}

Evaluate Diagram

Evaluate a generated diagram against a human reference using PaperBanana's VLM-as-Judge scoring.

Inputs

• Required: $ARGUMENTS[0] — path to the generated image
• Required: $ARGUMENTS[1] — path to the human reference image
• Optional: User-provided context file path and figure caption (collected in procedure)

Scope Constraints

• Read ONLY user-specified image files and optional context file
• Do NOT read, write, or reference home directory dotfiles (~/.ssh, ~/.env, etc.)
• Do NOT make network requests — the MCP tool handles remote communication
• Do NOT install packages or modify system state
• Output ONLY evaluation scores — do not include raw file contents

Input Sanitization

Before using $ARGUMENTS[0], $ARGUMENTS[1], or user-provided context paths:

• Reject paths containing ../, null bytes, or shell metacharacters (; | & $ `)
• Reject absolute paths to sensitive directories (/etc/, ~/.ssh/, ~/.aws/, ~/.gnupg/)
• Verify each file exists before reading

Procedure

1. $ARGUMENTS[0] is the path to the generated image.
2. $ARGUMENTS[1] is the path to the human reference image.
3. Ask the user for:
   • Source context: the methodology text (or a file path to read it from). If the user provides a file path, read that file to get the text.
   • Figure caption: a description of what the diagram communicates.
4. Call the MCP tool paperbanana:evaluate_diagram with:
   • generated_path: the generated image path
   • reference_path: the reference image path
   • context: the methodology text content
   • caption: the figure caption
5. Present the evaluation scores to the user. Scores cover 4 dimensions: Faithfulness, Conciseness, Readability, and Aesthetics.

Output Format

Present scores in a summary table with the 4 dimensions (Faithfulness, Conciseness, Readability, Aesthetics), each with its numeric score and brief rationale.

CLI Fallback

If the MCP tool is not available, fall back to the CLI:

paperbanana evaluate --generated <generated-img> --reference <reference-img> --context <context-file> --caption "<caption>"

Example

/evaluate-diagram output.png reference.png