Installation

This guide covers setting up Nexus with various AI clients. Choose your preferred method below.

Prerequisites

• An MCP-compatible AI client (Claude Desktop, Cursor, VS Code, etc.)
• Node.js 18+ (for npx, only needed for local mode)

Step 1: Get Your API Key

Nexus requires an API key for all tool calls. Choose one of these methods:

Option A: CLI Login (Recommended)

The easiest way - opens your browser for GitHub/Google authentication:

Terminal

npx @nexus/cli auth loginOpening browser for authentication...Authenticated successfully!API key saved to ~/.nexus/config.json

View your API key anytime:

Terminal

npx @nexus/cli auth statusAPI Key: nxs_abc123...

Option B: Dashboard

1. Sign in at nexus.yogan.dev
2. Go to Dashboard → API Keys
3. Click Create API Key
4. Copy your key (starts with nxs_)

Save Your Key

API keys are only shown once. Store it securely - you'll need it for Step 2!

Step 2: Configure Your AI Client

OpenCode (Native Remote)

OpenCode supports native remote MCP - the simplest config:

Edit ~/.config/opencode/config.json:

{
  "mcp": {
    "nexus": {
      "type": "remote",
      "url": "https://api.nexus.yogan.dev/sse",
      "enabled": true,
      "headers": {
        "NEXUS_API_KEY": "nxs_your_api_key_here"
      }
    }
  }
}

That's it! No dependencies, no bridge packages.

Claude Code

Remote Mode (Recommended):

Terminal

claude mcp add nexus -e NEXUS_API_KEY=nxs_your_key_here -- npx -y mcp-remote https://api.nexus.yogan.dev/sse --header "NEXUS_API_KEY:\${NEXUS_API_KEY}"Added MCP server nexus

Local Mode (uses stored CLI credentials):

Terminal

claude mcp add nexus -- npx -y @nexus/cli serveAdded MCP server nexus

If you used npx @nexus/cli auth login, the CLI automatically uses your stored API key.

To verify:

Terminal

claude mcp listnexus npx -y mcp-remote https://api.nexus.yogan.dev/sse ...

Claude Desktop

Edit your Claude Desktop configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

Windows: %APPDATA%\Claude\claude_desktop_config.json

Linux: ~/.config/Claude/claude_desktop_config.json

Remote Mode (Recommended):

{
  "mcpServers": {
    "nexus": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://api.nexus.yogan.dev/sse",
        "--header",
        "NEXUS_API_KEY:${NEXUS_API_KEY}"
      ],
      "env": {
        "NEXUS_API_KEY": "nxs_your_api_key_here"
      }
    }
  }
}

Local Mode:

{
  "mcpServers": {
    "nexus": {
      "command": "npx",
      "args": ["-y", "@nexus/cli", "serve"],
      "env": {
        "NEXUS_API_KEY": "nxs_your_api_key_here"
      }
    }
  }
}

Local mode with CLI login

If you authenticated with `npx @nexus/cli auth login`, the CLI automatically uses your stored key. You can omit the `env` section in local mode.

Restart Claude Desktop after saving the file.

Cursor

Edit your Cursor MCP configuration:

macOS/Linux: ~/.cursor/mcp.json

Windows: %USERPROFILE%\.cursor\mcp.json

Remote Mode (Recommended):

{
  "mcpServers": {
    "nexus": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://api.nexus.yogan.dev/sse",
        "--header",
        "NEXUS_API_KEY:${NEXUS_API_KEY}"
      ],
      "env": {
        "NEXUS_API_KEY": "nxs_your_api_key_here"
      }
    }
  }
}

Local Mode:

{
  "mcpServers": {
    "nexus": {
      "command": "npx",
      "args": ["-y", "@nexus/cli", "serve"],
      "env": {
        "NEXUS_API_KEY": "nxs_your_api_key_here"
      }
    }
  }
}

Restart Cursor after saving the file.

VS Code (Copilot)

Edit your VS Code settings:

1. Open Settings (Cmd+, or Ctrl+,)
2. Search for "MCP"
3. Click "Edit in settings.json"

Remote Mode (Recommended):

{
  "github.copilot.chat.mcpServers": {
    "nexus": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://api.nexus.yogan.dev/sse",
        "--header",
        "NEXUS_API_KEY:${NEXUS_API_KEY}"
      ],
      "env": {
        "NEXUS_API_KEY": "nxs_your_api_key_here"
      }
    }
  }
}

Local Mode:

{
  "github.copilot.chat.mcpServers": {
    "nexus": {
      "command": "npx",
      "args": ["-y", "@nexus/cli", "serve"],
      "env": {
        "NEXUS_API_KEY": "nxs_your_api_key_here"
      }
    }
  }
}

Restart VS Code after saving.

Other MCP Clients

If your client supports native remote mode (like OpenCode), use:

Setting	Value
Type	remote
URL	https://api.nexus.yogan.dev/sse
Headers	{ "NEXUS_API_KEY": "nxs_your_key" }

Otherwise, use mcp-remote:

Setting	Value
Command	npx
Args	["-y", "mcp-remote", "https://api.nexus.yogan.dev/sse", "--header", "NEXUS_API_KEY:${NEXUS_API_KEY}"]
Environment	NEXUS_API_KEY=nxs_your_key

Example for Cline (~/.cline/mcp.json):

{
  "mcpServers": {
    "nexus": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://api.nexus.yogan.dev/sse",
        "--header",
        "NEXUS_API_KEY:${NEXUS_API_KEY}"
      ],
      "env": {
        "NEXUS_API_KEY": "nxs_your_api_key_here"
      }
    }
  }
}

Local Mode:

Setting	Value
Command	npx
Args	["-y", "@nexus/cli", "serve"]
Environment	NEXUS_API_KEY=nxs_your_key (or use CLI login)

Remote vs Local Mode

Feature	Native Remote	mcp-remote	Local Mode
Setup	Just config	Config + bridge	CLI install
Dependencies	None	mcp-remote	@nexus/cli
Client Support	OpenCode	Most clients	All clients
Offline	No	No	Yes (cached)
Best for	OpenCode users	Most users	Offline access

Using the CLI Auto-Config

The Nexus CLI can automatically configure your AI clients with local mode:

Terminal

npx @nexus/cli auth loginAuthenticated successfully!npx @nexus/cli initNexus SetupSelect clients to configure:> [x] Claude Desktop [x] CursorConfigured Claude DesktopConfigured Cursor

Verifying Installation

After installation, verify Nexus is working by asking your AI assistant:

"Use Nexus to search for React useEffect documentation"

The AI should use the query-docs tool to search the React documentation.

Authentication Error?

If you see "API key required" or "Authentication required": 1. Make sure you have your API key from Step 1 2. Verify your API key is set in `headers` (native remote) or `env` (mcp-remote/local) 3. Check the header name is `NEXUS_API_KEY`

Troubleshooting

If Nexus isn't working, check the [Troubleshooting Guide](/troubleshooting) for common issues and solutions.

Next Steps

• Quick Start - Learn the basics of using Nexus
• Authentication Guide - Learn more about API keys and scopes
• MCP Tools - Explore all available tools
• Memory Guide - Set up persistent project memory