HandoffProbe

HandoffProbe is an open-source CLI for adversarial security testing of AI agent handoffs. It checks whether security properties such as delegated authority, principal identity, tenant continuity, approval and consent, credential audience, replay protection, cancellation, retry identity and audit lineage survive the transition from A2A 1.0 to MCP 2026-07-28.

The current v0.2.0 release includes 22 deterministic security tests, secure and intentionally vulnerable fixtures, terminal, JSON and Markdown reporters, deterministic CI exit codes and a reusable GitHub Action. HandoffProbe is local-first, uses synthetic fixtures, requires no paid AI service, collects no telemetry and requires no signup.