According to CoinMeta, Lightning Labs has released an open-source extension, pi402, which enables AI programming agents to use Bitcoin to pay for inference fees over the Lightning Network. This tool is specifically built for pi programming agents and does not require registration of an account, API keys, or a credit card; the agent can start working immediately after paying for the invoice. pi402 is based on the L402 protocol and combines HTTP 402 responses with Lightning Network invoices to achieve token billing and instant settlement. Sellers can accept payments through Aperture and Lightmeter tools, and neither buyers nor sellers need to operate Lightning nodes; the payments are processed by Wavelength wallets that are based on Ark.