Claude Desktop

What are the connection details?

How do I connect Claude Desktop?

1. 1

   Create a production API key

   Open https://www.unitpost.com → Settings → API keys → create a scoped key. Copy the full pk_live_… value (shown once). In every snippet below, replace pk_live_YOUR_KEY with that value.

   Must be production. Keys from unitpost.dev only work on the dev API. This MCP URL is production (mcp.unitpost.com) — a .dev key returns 401 Invalid API key on tool calls even if the server appears connected.

2. 2

   Open Edit Config

   In Claude Desktop: Settings → Desktop app → Developer → Edit Config. That opens claude_desktop_config.json.

3. 3

   Paste mcpServers at the top level

   Merge the block below into the file. mcpServers must be a top-level key (sibling of preferences), not nested inside preferences. Replace pk_live_YOUR_KEY in AUTH_HEADER — keep Bearer and the space.

   JSON

   {
     "mcpServers": {
       "unitpost": {
         "command": "npx",
         "args": [
           "-y",
           "mcp-remote",
           "https://mcp.unitpost.com/mcp",
           "--header",
           "Authorization:${AUTH_HEADER}"
         ],
         "env": {
           "AUTH_HEADER": "Bearer pk_live_YOUR_KEY"
         }
       }
     }
   }

   Deliberately no space after Authorization: in args — Claude Desktop mangles spaces there; the value lives in env instead. Requires Node.js 18+. If npx is not found, set "command" to your absolute npx path (e.g. /opt/homebrew/opt/node@22/bin/npx). Grant only the scopes the agent needs (e.g. emails:send for emails_send). Prefer a revocable key dedicated to the agent.

4. 4

   Fully quit and reopen

   Save the file, then ⌘Q (Quit) Claude Desktop — closing the window is not enough. Reopen and check Settings → Developer: unitpost should appear under Local MCP servers.

5. 5

   Send a test

   Ask Claude to send an email from a verified domain and confirm it in Unitpost Activity.

6. 6

   Skip: Add custom connector (unless you see Request headers)

   Most plans only show Name + Remote MCP server URL + OAuth Client ID/Secret. That cannot authenticate Unitpost. Only if your dialog has Request headers: set URL to the value below, add header Authorization = Bearer pk_live_… (include Bearer ). Never put the API key in OAuth Client ID/Secret.

   Remote MCP server URL	https://mcp.unitpost.com/mcp
   Request header value	Bearer pk_live_YOUR_KEY

   mcp-remote is local to Claude Desktop. Custom connectors (when header auth exists) are cloud-brokered and also work on claude.ai / mobile.