Claude Desktop

Claude Desktop supports remote MCP servers as custom connectors.

Add it

Connectors UI

Settings → Connectors → Add custom connector
Name: Vulnetix
URL: https://mcp.vulnetix.com/mcp
Add a header called Authorization with the value ApiKey <orgId>:<hex>
Save, then quit Claude Desktop entirely and reopen it

Warning Closing the window is not quitting. On macOS use ⌘Q or Claude → Quit; on Windows, exit from the system-tray icon. A connector added without a full restart appears in Settings but never connects, which reads as a broken server.

Config file

Edit the config directly:

OS	Path
macOS	`~/Library/Application Support/Claude/claude_desktop_config.json`
Windows	`%APPDATA%\Claude\claude_desktop_config.json`
Linux	`~/.config/Claude/claude_desktop_config.json`

{
  "mcpServers": {
    "vulnetix": {
      "type": "http",
      "url": "https://mcp.vulnetix.com/mcp",
      "headers": {
        "Authorization": "ApiKey <orgId>:<hex>"
      }
    }
  }
}

Quit and reopen.

Confirm it works

The tools icon (🔨) in the message box should show Vulnetix tools. Then:

Look up CVE-2021-44228 and tell me whether it is in the CISA KEV catalogue.

Claude asks permission before the first tool call. You can allow once or for the chat.

Using the prompts

Claude Desktop surfaces MCP prompts through the + button in the message box, listed under the server name. Pick one and it is inserted with its arguments.

The 33 Vulnetix prompts include the full Pix workflow library. Sixteen of them drive a local CLI, which is less useful in Claude Desktop than in a terminal-based agent, and each says so at the top.

Worth knowing

Config is read at launch only. Every change needs a full quit.

Extended thinking helps. For multi-step questions (“triage this CVE for a public-facing Java service”), extended thinking gives the model room to chain several tools rather than answering off one.

No filesystem access. Claude Desktop has no repository context, so the local-execution prompts have nothing to run against. Use Claude Code or another terminal agent for those.

Troubleshooting

Connector saved but never connects. You did not fully quit. This accounts for most reports.

“Could not attach to MCP server”. Check the URL ends in /mcp and that a corporate proxy is not intercepting TLS.

Every tool returns 401. The header needs both halves of the key.

Tools icon missing entirely. No server is connected. Open Settings → Connectors and check the state there first.