Agentic AI Plumbing

In the rapidly evolving landscape of Agentic AI (systems where AI agents take autonomous actions), these five acronyms represent the "new plumbing" of the internet. They are open-source protocols that allow different AI agents, tools, and businesses to talk to each other, negotiate, and even spend money securely.

Here is the breakdown of the agentic AI stack:

1. MCP (Model Context Protocol)

• Role: The "USB-C" of AI.

• What it does: Developed by Anthropic (and adopted by Google, OpenAI, and Microsoft), MCP allows an AI model to safely "plug in" to your data and tools.

• Example: Instead of writing custom code to let an agent read your Google Drive or Slack, you use an MCP server. It provides the context (data) and tools (capabilities) the agent needs to work.

2. A2A (Agent-to-Agent Protocol)

• Role: The "Common Language" for agents.

• What it does: Launched by Google and now part of the Linux Foundation, A2A defines how one AI agent talks to another AI agent, even if they were built by different companies (e.g., a "Personal Assistant" agent talking to a "Travel Agency" agent).

• Example: Your personal shopping agent uses A2A to ask a merchant's agent, "Do you have this shirt in blue?" and receives a structured, machine-readable reply.

3. ACP (Agentic Commerce Protocol / Agent Communication Protocol)

• Role: The "Handshake" for transactions.

• What it does: This protocol (pioneered by OpenAI and Stripe) focuses on the workflow of commerce. it manages things like cart creation, price negotiation, and the handoff between the user and the merchant.

• Example: When you say "Buy this" in ChatGPT, ACP is the protocol managing the "checkout state" and ensuring the agent and merchant agree on the final price before paying.

4. AP2 (Agent Payments Protocol)

• Role: The "Secure Wallet" and Authorization.

• What it does: Another Google-led standard, AP2 is specifically for money. It uses "cryptographic mandates" (digital signatures) to prove that you actually authorized an agent to spend $50. It prevents an agent from "going rogue" and overspending.

• Example: You give your agent a mandate: "You can spend up to $100 on groceries this week." AP2 ensures the bank only clears the transaction if it fits those exact rules.

5. UCP (Universal Commerce Protocol)

• Role: The "Universal Bridge" for Retail.

• What it does: Developed by Google in collaboration with retailers like Shopify and Walmart, UCP is a high-level layer that unifies discovery and checkout. It allows a merchant to implement one standard and become instantly "shoppable" by any AI agent in the world.

• Example: A small boutique store implements UCP; suddenly, Gemini, Claude, and ChatGPT can all "see" their inventory and perform checkouts there without individual integrations.

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How they work together

Imagine you want to buy a pair of shoes:

1. MCP gives the agent access to your size and style preferences from your emails/files.

2. UCP allows the agent to find the shoes across different online stores.

3. A2A lets your agent talk to the store's agent to confirm they are in stock.

4. ACP handles the "Add to Cart" and checkout logistics.

5. AP2 securely processes the payment once you give the final "OK."

Try the simple demo https://github.com/dhirajpatra/Agentic-Commerce-Automation-Curve