A2A protocol reality check: big-tech land grab in a tiny market

重新审视 A2A 协议：大厂的野心、极小的市场与被挤压的现实

Google's A2A protocol targets cross-company, long-running agent delegation—e.g., a Salesforce AI asking SAP's AI to check financial records while waiting for human approval. The use case is real but extremely niche, relevant only when giants like Salesforce, SAP, and ServiceNow need to chain their AIs across clouds. Inside a single system, local sub-agent mechanisms in Claude Code and Codex already handle multi-agent work with zero network overhead, eating A2A's lunch. Combined with prompt injection cascades, confused deputy attacks, and zombie tasks, A2A is destined to stay lukewarm among developers and quietly exist as enterprise B2B plumbing.

Why it matters: A sober, well-argued analysis of the A2A protocol's real niche (cross-company, long-running agent delegation) and its limited market versus MCP. Concrete enterprise examples ground the argument. Score stays at 78 rather than higher because this is commentary, not a breaking ne...