One signed spending limit for every AI agent you run, across LLM calls and x402 payments.

TapVow puts one signed spending limit in front of every AI agent you run. It is a small local gateway. Your agents get virtual keys and the gateway holds the real ones. A call that would break the limit is refused with HTTP 402 before it reaches the provider. The same budget covers LLM calls and x402 stablecoin payments. Each charge and each refusal is a signed ledger entry, so you can check every cent later. TapVow never holds funds. It works with Claude Code, OpenCode and any OpenAI-compatible client. MIT licensed, Node 22.13 or newer. x402 payments have run on the Base Sepolia testnet only. Mainnet payments are 0 today.