What Happened to Google's A2A? (blog.fka.dev)

Google’s ambitious Agent2Agent (A2A) protocol, launched in early 2025 as a universal standard for seamless AI agent communication, has quietly lost momentum to the Model Context Protocol (MCP) by late 2025. A2A was designed to enable complex multi-agent coordination, secure information exchange, and cross-vendor interoperability, backed by Google and major enterprise partners. Despite technical strengths like gRPC support, enhanced security, and extensive tooling—including the Agent Development Kit and integration with Google Cloud platforms—A2A struggled with complexity and accessibility, particularly for indie developers. In contrast, MCP gained rapid grassroots adoption by prioritizing simplicity, practical utility, and developer experience. Its lightweight design allowed developers to build useful AI integrations quickly—such as file system access or API connectors—without grappling with multi-agent orchestration or security overhead. MCP’s evolution was community-driven, with iterative improvements responding directly to developer needs. Crucially, its immediate integration with existing AI assistants gave it an edge in real-world use cases, fostering stronger ecosystem growth despite lacking Google’s corporate backing. The decline of A2A highlights key lessons for AI protocol design: starting simple and evolving with user feedback often beats offering all-encompassing, complex solutions upfront. Developer experience and immediate utility drive adoption more than technical sophistication or enterprise focus. While A2A’s vision of interoperable agents remains compelling, it’s MCP’s pragmatic approach that currently shapes the multi-agent AI landscape and developer ecosystem.