MCP via npx (@postoid/mcp)

The official @postoid/mcp package connects AI apps that can only run local (stdio) MCP servers, such as older Claude Desktop versions or some IDEs, to Posto. The package simply forwards messages to Posto's MCP server, so you get the same tools as a direct connection. Does your app already support Streamable HTTP (latest Claude Desktop, Cursor, Claude Code)? Then you don't need this package; use the configuration in API and MCP.

Before you start

1. Install Node.js 18 or newer (npx comes with it). Check with node -v in a terminal.
2. Create an API key in Brand & social accounts → API & MCP (/app/settings/api). API keys need the Agency plan or the API & MCP add-on.

Check whether the package is available

In Brand & social accounts → API & MCP, under Connect an AI assistant (MCP), open the npx @postoid/mcp tab:

• If the tab shows a configuration and a Copy button, the package is published. Follow the steps below.
• If it says Available once published., the package isn't on npm yet and the npx command will fail. For now, use the Other apps tab as described in API and MCP.

Set it up in Claude Desktop

1. In Claude Desktop, open Settings → Developer → Edit Config. The claude_desktop_config.json file opens (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\).
2. In the npx @postoid/mcp tab, click Copy, then paste into that file. If the file already lists other servers, add the "posto" block inside the existing mcpServers. Replace pk_live_XXXXXXXXXXXXXXXX with your API key if it isn't filled in.
3. Save the file, quit Claude Desktop completely (not just the window), then open it again.
4. Try asking, for example: "Check my Posto AI credit balance."

What you copy from the tab looks roughly like this:

{
  "mcpServers": {
    "posto": {
      "command": "npx",
      "args": ["-y", "@postoid/mcp"],
      "env": {
        "POSTO_API_KEY": "pk_live_XXXXXXXXXXXXXXXX"
      }
    }
  }
}

Other apps that use stdio servers (e.g. Cursor in .cursor/mcp.json) use the same block.

Extra settings (optional)

Add these inside env in the configuration if needed:

• POSTO_WORKSPACE_ID: for agency keys, the id of the target client workspace (you can find it with the list_brands tool).
• POSTO_MCP_URL: the MCP server address, https://posto.id/mcp by default. Leave it unless support asks you to change it.
• POSTO_MCP_DEBUG: set to 1 for short logs on stderr, without message contents and without the key.

Troubleshooting

• "POSTO_API_KEY is not set": POSTO_API_KEY in env is empty. Fill in your API key, then restart the app.
• 401 or "Invalid or revoked API key": the key has a typo or was revoked. Create a new key, replace POSTO_API_KEY, then restart the app.
• The Posto server doesn't show up or npx fails: make sure you have Node.js 18 or newer and that the npx @postoid/mcp tab shows a configuration. After installing Node.js, quit and reopen your AI app.
• Session ended after 30 minutes of inactivity: the package opens a new session automatically.
• AI credits are charged the same as in the web app (including AI text actions), and actions that use many AI credits (large carousels, AI images, batches) ask for your approval first.

Still stuck? Contact [email protected].