Show HN: APC Playground – Stop AI agents from modifying your API tool calls

APC is a proposed security layer that binds a governing security contract to the exact action an AI agent executes, validating security-relevant transitions and re-checking enforcement at the protected side-effect boundary. The public playground runs locally in the browser with synthetic inputs, letting users write policy expressions, mutate actions, test hostile conditions and export run records; it does not call external providers or execute real-world actions. The authors state that production deployment requires customer identity, policy, provider, egress, finality and reconciliation integrations to be implemented and verified for the action class.