Flowbook

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Storybook for flowcharts. Auto-discovers Mermaid diagram files from your codebase, organizes them by category, and renders them in a browsable viewer.

Quick Start

# Initialize — adds scripts + example file
npx flowbook@latest init

# Start dev server
npm run flowbook
# → http://localhost:6200

# Build static site
npm run build-flowbook
# → flowbook-static/

CLI

flowbook init                Set up Flowbook in your project
flowbook dev  [--port 6200]  Start the dev server
flowbook build [--out-dir d] Build a static site
flowbook skill <agent> [-g]  Install AI agent skill & /flowbook command

flowbook init

• Adds "flowbook" and "build-flowbook" scripts to your package.json

flowbook dev

Starts a Vite dev server at http://localhost:6200 with HMR. Any .flow.md or .flowchart.md file changes are picked up instantly.

flowbook build

Builds a static site to flowbook-static/ (configurable via --out-dir). Deploy it anywhere.

Writing Flow Files

Create a .flow.md (or .flowchart.md) file anywhere in your project:

---
title: Login Flow
category: Authentication
tags: [auth, login, oauth]
order: 1
description: User authentication flow with OAuth2
---

```mermaid
flowchart TD
    A[User] --> B{Authenticated?}
    B -->|Yes| C[Dashboard]
    B -->|No| D[Login Page]
```

Flowbook automatically discovers the file and adds it to the viewer.

Frontmatter Schema

| Field | Type | Required | Description | |---------------|------------|----------|------------------------------------| | title | string | No | Display title (defaults to filename) | | category | string | No | Sidebar category (defaults to "Uncategorized") | | tags | string[] | No | Filterable tags | | order | number | No | Sort order within category (default: 999) | | description | string | No | Description shown in detail view |

File Discovery

Flowbook scans for these patterns by default:

**/*.flow.md
**/*.flowchart.md

Ignores node_modules/, .git/, and dist/.

AI Agent Skill

Use flowbook skill to install AI agent skills and /flowbook slash commands for your coding agents. When a coding agent (Claude Code, OpenAI Codex, VS Code Copilot, Cursor, Gemini CLI, etc.) detects the keyword "flowbook" in your prompt, it will:

1. Analyze your codebase for logical flows (API routes, auth, state management, business logic, etc.)
2. Set up Flowbook if not already initialized
3. Generate .flow.md files with Mermaid diagrams for every significant flow
4. Verify the build

flowbook skill

Install skills and /flowbook slash commands for specific agents:

# Install for a specific agent (project-level)
flowbook skill opencode
flowbook skill claude
flowbook skill cursor

# Install for all agents
flowbook skill all

# Install globally (available across all projects)
flowbook skill opencode -g
flowbook skill all --global

What gets installed:

| Component | Description | |-----------|-------------| | Skill (SKILL.md) | Auto-triggers when you mention "flowbook" in prompts | | Slash command (/flowbook) | Explicit trigger — type /flowbook to generate flowcharts |

Slash commands are installed for agents that support them: Claude Code, Cursor, Windsurf, OpenCode.

Install via skills.sh

You can also install the skill standalone using skills.sh:

# Project-level
npx skills add Epsilondelta-ai/flowbook

# Global
npx skills add -g Epsilondelta-ai/flowbook

Note: npx skills add installs skills only (SKILL.md). Use flowbook skill to also install /flowbook slash commands.

Supported Agents

| Agent | Skill | Slash Command | |-------|-------|---------------| | Claude Code | .claude/skills/flowbook/SKILL.md | .claude/commands/flowbook.md | | OpenAI Codex | .agents/skills/flowbook/SKILL.md | — | | VS Code / GitHub Copilot | .github/skills/flowbook/SKILL.md | — | | Google Antigravity | .agent/skills/flowbook/SKILL.md | — | | Gemini CLI | .gemini/skills/flowbook/SKILL.md | — | | Cursor | .cursor/skills/flowbook/SKILL.md | .cursor/commands/flowbook.md | | Windsurf (Codeium) | .windsurf/skills/flowbook/SKILL.md | .windsurf/workflows/flowbook.md | | AmpCode | .amp/skills/flowbook/SKILL.md | — | | OpenCode / oh-my-opencode | .opencode/skills/flowbook/SKILL.md | .opencode/command/flowbook.md |

If you didn't use flowbook skill or npx skills add, copy files manually:

# Skill
mkdir -p .claude/skills/flowbook
cp node_modules/flowbook/src/skills/flowbook/SKILL.md .claude/skills/flowbook/

# Slash command (Claude Code)
mkdir -p .claude/commands
cp node_modules/flowbook/src/commands/flowbook.md .claude/commands/

Replace directories with the appropriate paths from the table above.

.flow.md files ──→ Vite Plugin ──→ Virtual Module ──→ React Viewer
                    │                   │
                    ├─ fast-glob scan   ├─ export default { flows: [...] }
                    ├─ gray-matter      │
                    │  parse            └─ HMR on file change
                    └─ mermaid block
                       extraction

1. Discovery — fast-glob scans the project for *.flow.md / *.flowchart.md
2. Parsing — gray-matter extracts YAML frontmatter; regex extracts ```mermaid blocks
3. Virtual Module — Vite plugin serves parsed data as virtual:flowbook-data
4. Rendering — React app renders Mermaid diagrams via mermaid.render()
5. HMR — File changes invalidate the virtual module, triggering a reload

Project Structure

src/
├── types.ts                    # Shared types (FlowEntry, FlowbookData)
├── node/
│   ├── cli.ts                  # CLI entry point (init, dev, build, skill)
│   ├── server.ts               # Programmatic Vite server & build
│   ├── init.ts                 # Project initialization logic
│   ├── skill.ts                # AI agent skill & command installer
│   ├── discovery.ts            # File scanner (fast-glob)
│   ├── parser.ts               # Frontmatter + mermaid extraction
│   └── plugin.ts               # Vite virtual module plugin
├── skills/
│   └── flowbook/
│       └── SKILL.md            # AI agent skill definition
├── commands/
│   ├── flowbook.md             # Slash command (frontmatter format)
│   └── flowbook.plain.md       # Slash command (plain markdown format)
└── client/
    ├── index.html              # Entry HTML
    ├── main.tsx                # React entry
    ├── App.tsx                 # Layout with search + sidebar + viewer
    ├── vite-env.d.ts           # Virtual module type declarations
    ├── styles/globals.css      # Tailwind v4 + custom styles
    └── components/
        ├── Header.tsx          # Logo, search bar, flow count
        ├── Sidebar.tsx         # Collapsible category tree
        ├── MermaidRenderer.tsx # Mermaid diagram rendering
        ├── FlowView.tsx        # Single flow detail view
        └── EmptyState.tsx      # Empty state with guide

## Development (Contributing)

```bash
git clone https://github.com/Epsilondelta-ai/flowbook.git
cd flowbook
npm install

# Local dev (uses root vite.config.ts)
npm run dev

# Build CLI
npm run build

# Test CLI locally
node dist/cli.js dev
node dist/cli.js build

Tech Stack

• Vite — Dev server with HMR
• React 19 — UI
• Mermaid 11 — Diagram rendering
• Tailwind CSS v4 — Styling
• gray-matter — YAML frontmatter parsing
• fast-glob — File discovery
• tsup — CLI bundler
• TypeScript — Type safety

License

MIT