PennyPost watches each new signup's first two weeks in your web app, finds where they stall, and emails them at that moment from your own domain. This MCP server lets your AI assistant read those numbers.

Ask things like:

"How many of last week's signups reached their first result?"
"Where do new users stall the most?"
"Who left before their render was ready?"
"Is the 'never opened the results page' email bringing people back?"
"Connect this app to PennyPost." (in Claude Code or Cursor, inside your app's repo)

Every tool is read-only. Nothing here sends an email or changes a setting.

Setup

Create an API key at https://usepennypost.com/api-keys.
Add the server.

The hosted server needs no install. Claude Code:

claude mcp add --transport http pennypost https://usepennypost.com/mcp --header "Authorization: Bearer mc_your_key"

To run it locally over stdio instead (Claude Desktop, Cursor and others):

{
  "mcpServers": {
    "pennypost": {
      "command": "npx",
      "args": ["-y", "@pennypost/mcp"],
      "env": { "PENNYPOST_API_KEY": "mc_your_key" }
    }
  }
}

Claude Code: claude mcp add pennypost -e PENNYPOST_API_KEY=mc_your_key -- npx -y @pennypost/mcp

Keep the key out of anything you commit.

Tools

Tool	What it returns
`get_activation`	Signups, results ready, who saw their result, and how many stalled at each moment, over 7, 30 or 90 days
`list_moments`	The five moments: how many stalled, whether the email is live, paused, a draft or off, emails sent, who came back, and the email
`list_stalled_people`	The latest people who stalled, optionally at one moment (up to 25)
`get_results`	Per live email: emailed people who came back vs. the held-back group that got no email
`get_install_prompt`	Instructions for your AI coding tool to connect your app: the snippet, the signed identity and the `results_ready` event

The moments are: left before their results were ready, never opened the key page, never did the first action, stopped halfway through setup, came once and never again.

Privacy

The server reads the same data you see in PennyPost, for the workspace the key belongs to. list_stalled_people returns your users' email addresses, so only connect it to assistants you trust with them. Privacy policy: https://usepennypost.com/privacy