Capy

MCP server that gives AI coding agents the context they need to build and update UI — preview pages, design-system artifacts, and incremental diffs.

Website · npm · Docs

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What it does

Capy inspects your React / Next.js repo and returns structured briefs so AI agents can implement UI changes with precision — no hallucinated components, no guessed tokens.

Three tools:

Tool	Purpose
get_preview_brief	Returns repo map, inspection plan, constraints, and a /preview spec for the agent to follow
get_design_system	Writes a machine-readable design-system JSON artifact (.capy/design-system.json)
update_preview	Diffs against last snapshot, refreshes the design system, returns an incremental update brief

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Quick start

npx capy-mcp@latest

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Setup

Pick your client. One command or one config change — you're set.

Agents

Claude Code

claude mcp add --scope user capy -- npx -y capy-mcp@latest

Or add to ~/.claude/mcp.json:

{
  "mcpServers": {
    "capy": {
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"]
    }
  }
}

Claude Desktop

Add to your config file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "capy": {
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"]
    }
  }
}

Codex

codex mcp add capy -- npx -y capy-mcp@latest

Or add to ~/.codex/config.toml:

[mcp_servers.capy]
command = "npx"
args = ["-y", "capy-mcp@latest"]

Gemini CLI

Add to ~/.gemini/settings.json:

{
  "mcpServers": {
    "capy": {
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"]
    }
  }
}

Copilot CLI

Add to ~/.vscode-server/data/User/mcp.json:

{
  "servers": {
    "capy": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"]
    }
  }
}

Make sure Copilot Chat is in Agent mode — MCP tools only work there.

Mistral Vibe

Add to ~/.vibe/config.toml:

[[mcp_servers]]
name = "capy"
transport = "stdio"
command = "npx"
args = ["-y", "capy-mcp@latest"]

Kimi Code

kimi mcp add --transport stdio capy -- npx -y capy-mcp@latest

Or add to ~/.kimi/mcp.json:

{
  "mcpServers": {
    "capy": {
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"]
    }
  }
}

OpenCode

Add to ~/.config/opencode/opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "capy": {
      "type": "local",
      "command": ["npx", "-y", "capy-mcp@latest"],
      "enabled": true
    }
  }
}

QwenCode

Add to settings.json:

{
  "mcpServers": {
    "capy": {
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"]
    }
  }
}

IDEs

Cursor

Add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "capy": {
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"]
    }
  }
}

VS Code

Add to ~/.vscode-server/data/User/mcp.json:

{
  "servers": {
    "capy": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"]
    }
  }
}

Or via Command Palette: MCP: Open User Configuration

Windsurf

Add to ~/.codeium/windsurf/mcp.json:

{
  "mcpServers": {
    "capy": {
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"]
    }
  }
}

Zed

Add to your settings file:

• macOS: ~/.zed/settings.json
• Linux: ~/.config/zed/settings.json
• Windows: %USERPROFILE%\AppData\Roaming\Zed\settings.json

{
  "context_servers": {
    "capy": {
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"],
      "env": {}
    }
  }
}

Antigravity

Add to your config file:

• macOS: ~/.gemini/antigravity/mcp_config.json
• Windows: %USERPROFILE%\.gemini\antigravity\mcp_config.json

{
  "mcpServers": {
    "capy": {
      "command": "npx",
      "args": ["-y", "capy-mcp@latest"]
    }
  }
}

Or via UI: Agent session → … dropdown → MCP Servers → Manage MCP Servers → View raw config.

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Library usage

import {
  buildPreviewBrief,
  buildDesignSystemArtifact,
  runPreviewUpdate,
  detectFramework,
} from "capy-mcp";

const brief = await buildPreviewBrief(process.cwd(), { task: "build_preview" });
const designSystem = await buildDesignSystemArtifact(process.cwd());
const update = await runPreviewUpdate(process.cwd());

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Local development

cd capy-mcp
npm install
npm test
npx capy-mcp

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Built by Anant Singhal

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