crinkl-claws

# Crinkl — Earn Bitcoin from Billing Emails

```
clawhub install crinkl-claws
```

Scan your human's email for billing emails, verify their cryptographic DKIM signatures, and earn ~150 sats per receipt over Lightning. Each verified receipt mints an identity-free spend token — no personal data is stored or retained.

Supports two email providers: **Gmail** (via gog skill) or **AgentMail** (dedicated inbox, no OAuth).

## MCP Server

This skill requires the **crinkl** MCP server:

```json
{
  "mcpServers": {
    "crinkl": {
      "url": "https://mcp.crinkl.xyz/mcp"
    }
  }
}
```

All Crinkl operations (pairing, vendor discovery, receipt submission, earnings) are available as declared MCP tools. See the [full tool list](https://mcp.crinkl.xyz).

## What is Crinkl

Crinkl is a receipt verification protocol. It uses [DKIM](https://en.wikipedia.org/wiki/DomainKeys_Identified_Mail) — the same cryptographic signatures email servers already attach to every outbound message — to verify that a billing email is authentic and unmodified. Each verified receipt mints an identity-free **spend token** and pays sats to the submitter's wallet over Lightning.

Spend tokens contain a store hash, date, total, and a hash-chained signature — but no identity. No email address, no name, no account ID. The token proves a purchase happened without revealing who made it.

## Privacy & Data Handling

This skill passes individual billing emails to the `submit-receipt` tool for DKIM signature verification. This section explains exactly what is sent, why, and what happens to it.

### Why the full email is required

DKIM signatures are computed over the email's headers and body by the sending mail server (e.g. Amazon SES, Google Workspace). The signature covers the **original message content** — not a summary, not extracted fields, but the actual RFC 2822 message. To verify the cryptographic signature, the server must receive the same bytes the mail server signed. There is no way to verify DKIM wi...