Fundamental breaking changes are happening now, affecting protocol, transport, and APIs. Consider this version experimental. Join Alpha discussions to help shape it.

The Agent Communication Protocol (ACP) is a protocol designed to standardize how agents communicate, enabling automation, agent-to-agent collaboration, UI integration, and developer tooling.

In its Pre-alpha version, ACP extends the Model Context Protocol (MCP), leveraging the simplicity and versatility of JSON-RPC. This structure offers flexible and efficient interactions between agents, platforms, and external services.

Rather than imposing strict specifications immediately, ACP emphasizes practical, useful features first. Standardization occurs once features demonstrate value, ensuring broader adoption and long-term compatibility.

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Motivation

Current agent systems often use diverse communication standards, causing complexity, integration difficulties, and vendor lock-in. ACP addresses these issues uniquely by standardizing interactions tailored specifically for agents that handle natural language inputs and depend on externally hosted models.

By accommodating these agent-specific needs, ACP simplifies integration and promotes effective collaboration across agent-based ecosystems.

Why Standardization Matters

Standardization allows practical features to become reliable and broadly adopted. ACP starts flexible and solidifies standards based on real-world use. The benefits are:

  • Interoperability: Seamless interaction across agents and systems.
  • Simplified Development: Less overhead, enabling developers to focus on innovation.
  • Reuse and Efficiency: Reduced duplication through reuse of proven solutions.

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Relationship with MCP

In its Pre-alpha version, ACP extends the Model Context Protocol (MCP), utilizing it as a practical foundation for rapid development. MCP currently provides essential mechanisms for sharing context with models and agents, such as tools, resources, and prompts. ACP leverages these capabilities while explicitly adding the concept of agents as primary participants.

However, MCP is recognized as an interim solution. Its original design focuses on context sharing, making it an imperfect fit for ACP’s emerging requirements around agent communication. ACP plans to diverge from MCP during its Alpha phase, addressing this misalignment by establishing a standalone standard specifically optimized for robust agent interactions.

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