What is pay-dcp?

Pay is a Rust command-line tool that adds a payment layer to standard HTTP calls. Some APIs return a 402 status code, which means payment is required before the server will respond with data. Rather than building payment logic into each application, you wrap your existing commands with pay and it handles the 402 challenge automatically: it detects the payment protocol, prepares a stablecoin transaction on Solana, asks your local wallet to authorize the signature using biometric authentication, and retries the original request with the payment proof attached. The tool supports two live payment standards on Solana: MPP (Machine Payments Protocol) and x402. It can wrap any command-line tool including curl, Claude Code, and Codex. It also ships with a built-in MCP (Model Context Protocol) server so AI assistants can make paid API calls through the same local wallet-approval flow without ever having access to your private key. The authorization step uses the biometric system already on your device, Touch ID via Keychain on macOS, Windows Hello on Windows, and GNOME Keyring or polkit on Linux. If you reject the prompt, the payment is not signed and the request does not go through. This means AI agents can use paid APIs but cannot spend funds without your explicit approval on each call. A built-in web-based debugger visualizes the 402 challenge-response sequence locally, and an open source catalog of paid API providers is available for discovery. The license is MIT.