Research Finding

TrustBench (arXiv:2603.09157, Mar 10, 2026) intercepts agent actions after formulation but before execution using domain-specific plugins. Reports 87% reduction in harmful actions at sub-200ms latency. MIT license.

Applicability

Zeph's CompositeExecutor pipeline already passes tool calls through ExfiltrationGuard and shell sandbox. TrustBench's pre-execution plugin architecture extends this:

• Add a PreExecutionVerifier trait to zeph-tools
• CompositeExecutor calls verifier(s) before dispatching to the actual executor
• Domain-specific rule sets (e.g., disallow destructive shell commands outside allowed_paths, disallow tool URLs matching injection patterns)

The sub-200ms latency is compatible with interactive sessions.

Design Sketch

trait PreExecutionVerifier: Send + Sync {
    fn verify(&self, tool_name: &str, args: &serde_json::Value) -> VerificationResult;
}

enum VerificationResult {
    Allow,
    Block { reason: String },
    Warn { message: String },
}

Integrate after ExfiltrationGuard in CompositeExecutor::execute.

Source

Research session 2026-03-13. arXiv:2603.09157 (TrustBench). MIT license.