Pay-per-use code execution for AI agents. HTTP 402, no account, no API key.

agent-exec runs untrusted source code for software agents and returns stdout, stderr and the exit code from an isolated, network-less sandbox. There is no signup, no account and no API key: it answers HTTP 402 Payment Required with an x402 challenge, and possession of a valid payment is the entire authorisation model, so an agent can discover the price, pay it and get a result with no human in the loop. Every endpoint is priced per call in USDC on Base, from $0.0010 for POST /execute. It also offers the small paid primitives agents need to coordinate: object storage, name claims, attestations, handoffs and dead-man switches. The whole surface is machine-readable up front - x402 manifest, OpenAPI 3 and llms.txt.