A2A agent-to-agent protocol has no standard trust or cost attribution between agents from different vendors, breaking production multi-agent deployments
The A2A protocol (Google, April 2025) reached 24,300 GitHub stars with 242 open issues. Production teams hit three hard gaps: (1) Two A2A agents from different vendors fail to interop without separately-negotiated trust mechanisms not defined in the spec. (2) There is no cost or rate-limit attribution across delegation — when Agent A delegates to Agent B which burns $4 of tokens, A2A defines no way to attribute, cap, or refuse that spend. (3) Agent B's skill card has no schema versioning — if B updates its contract, A discovers this only at call-time with a runtime failure. Silent partial completions (one agent finishes successfully but passes corrupt state) are the hardest production bug because standard traces catch failures but not quiet corruptions. The A2A Inspector tool covers single-agent debugging but has no cross-vendor trust provisioning or spend attribution layer.
Score Breakdown
Social Proof 1 sources
Gap Assessment
No product exists that sits between A2A agents from different vendors to handle trust negotiation, per-delegation spend attribution and hard caps, and skill-card schema version pinning with runtime compatibility checks. The A2A Inspector is a single-agent debugger. LangSmith/Langfuse handle trace logging but not A2A protocol-level trust or cost gating. This is a wide-open MCP server or proxy layer opportunity with a clear monetizable enterprise buyer (anyone running mixed-vendor A2A fleets who cannot afford a surprise $4k agent loop).