greenhelix-formal-gatekeeper
The Formal Gatekeeper: Z3-Verified Safety for Autonomous Agent Plans
Notice: This is an educational guide with illustrative code examples. It does not execute code or install dependencies. All examples use the GreenHelix sandbox (https://sandbox.greenhelix.net) which provides 500 free credits — no API key required to get started.
Referenced credentials (you supply these in your own environment):
GREENHELIX_API_KEY: API authentication for GreenHelix gateway (read/write access to purchased API tools only)WALLET_ADDRESS: Blockchain wallet address for receiving payments (public address only — no private keys)AGENT_SIGNING_KEY: Cryptographic signing key for agent identity (Ed25519 key pair for request signing)
Your cat-sitting agent just ordered a Tesla. Not because it was hacked, not because of a prompt injection, but because the large language model driving it reasoned -- correctly, within its context window -- that a Tesla Model Y would be the most efficient way to transport fourteen cats to the veterinarian for their annual checkups. The purchase cleared because your agent had access to the payment tools, the balance was sufficient, and no runtime guardrail distinguished between "buy cat food" and "buy a car." The agent's logic was internally consistent. It was also catastrophically wrong. This is the fundamental problem with heuristic safety: regex filters catch known-bad strings, budget caps catch known-bad amounts, but neither can reason about whether an arbitrary plan violates a safety property that was never explicitly enumerated. Formal verification can. This guide builds a complete formal verification proxy for OpenClaw-compatible AI agents on the GreenHelix A2A Commerce Gateway. You will implement a Z3 SMT solver integration that mathematically proves whether a proposed agent action is safe before it executes -- not by pattern matching, not by heuristic scoring, but by constructing a logical proof that the action cannot violate any defined safety invariant. The system covers filesystem access restrictions, economic transaction limits, network access controls, and arbitrary domain-specific constraints. Every proof is cached for performance, every verification is paid for via x402 micro-payments through the GreenHelix escrow system, and the entire stack ships as an OpenClaw plugin that intercepts agent actions automatically. By the end of this guide, your agents will not be able to order a Tesla, access /etc/passwd, drain a wallet, or connect to a command-and-control server -- and you will have a mathematical proof for each rejection.