Visual Explainer Marketplace

An agent skill that turns complex terminal output into styled HTML pages you actually want to read.

Ask your agent to explain a system architecture, review a diff, or compare requirements against a plan. Instead of ASCII art and box-drawing tables, it generates a self-contained HTML page and opens it in your browser.

> draw a diagram of our authentication flow
> /diff-review
> /plan-review ~/docs/refactor-plan.md

https://github.com/user-attachments/assets/55ebc81b-8732-40f6-a4b1-7c3781aa96ec

Why

Every coding agent defaults to ASCII art when you ask for a diagram. Box-drawing characters, monospace alignment hacks, text arrows. It works for trivial cases, but anything beyond a 3-box flowchart turns into an unreadable mess.

Tables are worse. Ask the agent to compare 15 requirements against a plan and you get a wall of pipes and dashes that wraps and breaks in the terminal. The data is there but it's painful to read.

This skill fixes that. Real typography, dark/light themes, interactive Mermaid diagrams with zoom and pan. Normal skill use has no build step and no dependency beyond a browser; optional MCP and PPTX utilities use small Node dependencies.

Install

Claude Code (marketplace):

/plugin marketplace add nicobailon/visual-explainer
/plugin install visual-explainer@visual-explainer-marketplace

Note: Claude Code plugins namespace commands as /visual-explainer:command-name.

Pi:

pi install git:github.com/nicobailon/visual-explainer

Or from a local checkout:

git clone --depth 1 https://github.com/nicobailon/visual-explainer.git
pi install ./visual-explainer

The package manifest advertises the canonical skill, command templates, and Pi tool:

"pi": {
  "extensions": ["./plugins/visual-explainer/extension.ts"],
  "skills": ["./plugins/visual-explainer"],
  "prompts": ["./plugins/visual-explainer/commands"],
  "image": "./banner.png"
}

The Pi extension registers one native visual_explainer tool. Use action: "prepare" to plan a visual explanation after generating or reviewing a substantial plan, architecture, diff, or implementation, and action: "render" to write complete HTML pages to ~/.agent/diagrams/. The opt-in action: "render_quick" validates a compact JSON spec and renders it with the bundled local renderer. Render actions can open with viewer: "browser" by default, viewer: "glimpse" when glimpseui is installed, or viewer: "auto" to try Glimpse and fall back to the browser. /generate-web-diagram remains the bundled prompt template command.

If you previously used the old curl/manual installer, remove those copied files before using pi install; otherwise Pi will report skill and prompt conflicts because the user-level copies shadow the package resources:

rm -rf ~/.pi/agent/skills/visual-explainer
rm -f ~/.pi/agent/prompts/{diff-review,fact-check,generate-slides,generate-visual-plan,generate-web-diagram,plan-review,project-recap}.md
rm -f ~/.pi/agent/prompts/s[h]are*.md

The legacy installer still works if you prefer copied skill and prompt files over package management, but it does not install the native Pi tool:

curl -fsSL https://raw.githubusercontent.com/nicobailon/visual-explainer/main/install-pi.sh | bash

MCP:

Use visual-explainer-mcp from a package install, or run npm install --no-package-lock before pointing your host at plugins/visual-explainer/mcp/server.mjs from a checkout. Some hosts need an absolute path to the binary. The MCP server is local stdio only. It does not call an LLM, start an HTTP listener, handle credentials, or write outside its configured output directory (default ~/.agent/diagrams/). Set VISUAL_EXPLAINER_OUTPUT_DIR to move that jail to another directory on the same machine; unset keeps the default path byte-identical. A configured jail must resolve to itself, so symlinked jail paths are rejected. Render targets reject existing symlinks and are written through a temporary file rename. Point the jail at a directory only your user can write; avoid world-writable or group-writable shared folders so another local user cannot replace render targets between validation and write.