There is a real, live protocol called x402 that lets an AI agent pay for web content automatically. No login, no card entry, no human approval. A site says payment required, the agent signs a small crypto payment, gets the content. This already exists and is already being used.
Two things worried me once I understood how it works. First, there is no memory built into the protocol. A vendor can scam an agent, return nothing useful, and the agent has no way to know not to pay that same vendor again. Second, if an agent reads regular web pages as part of its job, a malicious page can hide fake payment instructions in the page text itself, hoping the model mistakes it for something real.
Built GateKeep402 to address both. It checks a vendor's history before paying and blocks vendors that have proven unreliable. It also makes it structurally impossible for a payment to be built from anything except a genuine protocol response, so hidden page text can never trigger a real payment no matter how convincing it looks.
Verified against a real transaction on Solana's public devnet, not a simulation, with 45 automated tests. Open source, MIT license, installable via pip. Link in the comments.
Would like to hear how others are thinking about the risks of giving agents real spending power. This feels like an early and mostly unsolved part of the space.
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