Sovereign Execution Broker: A Runtime Gate for AI Agents on Blockchain

A new paper introduces the Sovereign Execution Broker (SEB), a runtime enforcement boundary designed to bridge the gap between AI agent autonomy and safe production mutation authority. The SEB architecture separates the lifecycle of an action into three phases—proposal, admission, and execution—transforming certified authority into a short-lived, revocable, auditable runtime capability.

The core insight is that existing access-control mechanisms either authorize identities or certify proposed actions, but neither provides a mandatory enforcement point at the moment of mutation. As the paper states, “production mutation authority should not reside inside non-deterministic reasoning processes” of autonomous agents. SEB fills this gap by consuming certificates issued by a Sovereign Assurance Boundary (SAB), verifying that the requested mutation matches the certified execution contract, and checking a set of dynamic conditions: validity windows, policy epochs, revocation epochs, and live-state drift. Only after these checks pass does SEB mint a scoped execution identity and invoke infrastructure APIs.

This design has direct parallels to blockchain-based smart contract execution, where transaction proposal, validation, and execution are separated. For crypto-AI systems, SEB provides a template for how on-chain or TEE-enforced AI agents could be granted scoped, revocable authority to mutate on-chain state. The broker acts as a mandatory gate that prevents an LLM’s non-deterministic output from directly calling production APIs or smart contract functions.

The SEB framework includes an execution model, certificate and replay-verification predicates, scoped identity semantics, bypass-prevention deployment patterns, and failure behavior. Crucially, it records signed decision and outcome records for every mutation, creating an auditable trail that can be verified on-chain. This enables disputable execution where any party can challenge a broker’s decision by verifying the signed record against on-chain policy.

The prototype was evaluated on AWS and Kubernetes clusters, measuring latency overheads, revocation propagation, drift detection, and security under fault injection. For crypto applications, the latency overhead of SEB-style enforcement is critical for determining whether such a broker could sit between an AI agent and a blockchain RPC endpoint without exceeding block times. If SEB’s overhead is sub-second, it could feasibly gate agent-to-contract calls in L2 environments where block times are 1–2 seconds.

The bypass-prevention deployment patterns ensure that production mutation APIs reject non-broker identities. In crypto terms, this is equivalent to requiring that smart contract functions be callable only through a specific proxy or relayer that enforces the SEB’s certified authority—analogous to how many DeFi protocols use access-controlled relayers or keeper networks. For on-chain AI agents, this means the agent’s wallet key would not directly sign transactions; instead, the SEB would hold the signing key and only use it after verifying the certified execution contract.