Salt

An MCP server and Agent Skills for building applications with the Salt Design System — JP Morgan Chase's open-source React component library.

What it does

This project gives AI agents access to Salt DS knowledge so they can help you build Salt applications accurately, using the right components, props, patterns, and best practices — instead of guessing.

MCP Tools let agents look things up on the fly:

• Component APIs, props, and examples
• Usage guidelines and accessibility rules
• Design patterns (forms, navigation, search, etc.)
• Foundations (density, spacing, color, typography)

Agent Skills give agents step-by-step instructions for common tasks:

• Scaffolding a new Salt app
• Building page layouts
• Creating forms
• Implementing UI patterns
• Converting Figma designs to Salt code

Prerequisites

• Node.js (v18+)
• An MCP-compatible client or an agent that supports the Agent Skills standard (e.g. VS Code with GitHub Copilot, Claude Code, Cursor, Gemini CLI, Windsurf)
• A local clone of the Salt DS repository:

  git clone --depth 1 https://github.com/jpmorganchase/salt-ds.git ~/Code/salt-ds
  

Setup

# Clone this repo
git clone https://github.com/feesch/salt-mcp.git
cd salt-mcp

# Install dependencies
npm install

# Build
npm run build

Register the MCP server

The repo includes a .mcp.json file that Claude Code and some other clients auto-discover. For other clients, configure the server manually:

{
  "servers": {
    "salt-mcp": {
      "type": "stdio",
      "command": "node",
      "args": ["/absolute/path/to/salt-mcp/build/index.js"]
    }
  }
}

{
  "mcpServers": {
    "salt-mcp": {
      "command": "node",
      "args": ["./build/index.js"]
    }
  }
}

{
  "mcpServers": {
    "salt-mcp": {
      "command": "node",
      "args": ["/absolute/path/to/salt-mcp/build/index.js"]
    }
  }
}

Install the skills

Copy the skills/ directory into the location your agent expects:

• Claude Code: Copy into .claude/skills/ in your project or home directory
• Cursor: Copy into .cursor/skills/
• VS Code / GitHub Copilot: Skills are not yet natively supported — use the MCP tools directly, or paste skill content into your Copilot Chat prompt as instructions
• Other agents: See your agent's documentation for the skills directory

Skills follow the open Agent Skills standard and work with any compatible agent.

MCP Tools

Skills

Skills are portable instruction sets that guide agents through multi-step tasks. They follow the Agent Skills standard.

Keeping Salt DS up to date

The MCP tools read from your local Salt DS clone at runtime, so they automatically reflect any updates. Skills contain some static mapping tables but always instruct agents to verify via the tools.

To pull the latest Salt DS changes:

git -C ~/Code/salt-ds pull

No rebuild of salt-mcp is needed — the tools will return updated data immediately.

Development

npm run build        # Compile TypeScript
npm test             # Run unit tests (37 tests via Vitest)
npm run test:watch   # Run tests in watch mode

Project structure

salt-mcp/
  src/
    index.ts            # MCP server with tools
    helpers.ts          # Shared helpers and security functions
    helpers.test.ts     # Unit tests (Vitest)
  skills/               # Agent Skills (agentskills.io standard)
    salt-app/SKILL.md
    salt-page/SKILL.md
    salt-form/SKILL.md
    salt-pattern/SKILL.md
    salt-figma/SKILL.md
  .mcp.json             # Shareable MCP server config
  package.json
  tsconfig.json

References

• Salt Design System — official site
• Salt DS GitHub — source code
• Model Context Protocol — MCP specification
• Agent Skills — open standard for portable agent skills