TL;DR (The Quick Version)
- MCP (Model Context Protocol) is the "USB-C for AI" that lets chatbots connect to any tool, database, or service using one standard instead of custom code for each
- UCP (Universal Commerce Protocol) is Google's new standard that lets AI agents shop, checkout, and handle payments across any merchant
- MCP is general-purpose (connect AI to anything). UCP is commerce-specific (AI shopping done right)
- They work together: use MCP for tools and data, use UCP for buying things
What Problem Are We Solving?
If you have ever asked ChatGPT, Claude, or another AI chatbot to do something beyond just answering questions, you have experienced the limitation: these AIs are smart, but they are stuck in a box. They cannot check your calendar, look up your CRM, place an order, or interact with the real world without help.
The solution? Give AI the ability to use tools. But here is the problem: every AI platform (OpenAI, Anthropic, Google) built their own way to connect tools. Every tool provider (Slack, Salesforce, Shopify) had to build separate integrations for each AI. It was a mess of custom code everywhere.
MCP and UCP are two new standards designed to fix this. Think of them as universal translators that let any AI talk to any tool or any store.
MCP: The "USB-C for AI Tools"
What MCP Actually Is
Model Context Protocol (MCP) is an open standard developed by Anthropic (the company behind Claude) and released in November 2024. It creates a universal way for AI applications to connect to external tools and data sources.
The USB-C Analogy
Remember when every phone had a different charger? USB-C fixed that by creating one connector that works everywhere. MCP does the same thing for AI tools. Instead of building separate integrations for ChatGPT, Claude, Cursor, and every other AI app, tool providers build one MCP server that works with all of them.
How MCP Works (Simplified)
MCP uses a client-server model with three main pieces:
Your AI app (ChatGPT, Claude)
Connection manager
Your tools (CRM, files, APIs)
When you ask an AI to do something, here is what happens behind the scenes:
- Discovery: The AI asks "What tools are available?" and the MCP server responds with a list
- Selection: The AI decides which tool fits the task
- Execution: The AI calls the tool with the right parameters
- Response: The tool returns results, and the AI uses them to respond to you
The Three MCP "Primitives"
MCP organizes capabilities into three types:
| Primitive | What It Does | Example |
|---|---|---|
| Tools | Actions that change things | Create a ticket, send an email, place an order |
| Resources | Data to read or retrieve | Documents, database records, knowledge base articles |
| Prompts | Reusable instruction templates | Guided workflows, standard operating procedures |
Simple Way to Remember
Tools change the world. Resources describe the world. Prompts guide the workflow.
Where MCP Is Being Used Today
MCP has been adopted across the AI ecosystem. Major platforms including OpenAI's ChatGPT, Anthropic's Claude, and Amazon's services support MCP. Thousands of community-built MCP servers now exist for everything from GitHub and Slack to Kubernetes and database management.
UCP: AI Shopping Done Right
What UCP Actually Is
Universal Commerce Protocol (UCP) was announced by Google in January 2026. It is specifically designed for "agentic commerce," which means letting AI agents handle complete shopping experiences (finding products, comparing options, checking out, handling payments) on your behalf.
Where MCP is general-purpose ("connect AI to anything"), UCP is domain-specific ("connect AI to commerce safely and consistently").
The Problem UCP Solves
Commerce is messy. Every store has different checkout flows, payment options, shipping rules, and discount codes. Before UCP, an AI shopping agent would need custom integrations for every single merchant. UCP creates one standard that works everywhere, so an AI can shop at any UCP-enabled store.
Who Built UCP
Google developed UCP collaboratively with major players:
- Retailers: Shopify, Etsy, Wayfair, Target, Walmart
- Payment processors: Visa, Mastercard, Stripe, American Express, PayPal
- Over 20 additional partners across the commerce ecosystem
This broad coalition means UCP is not just a Google project. It is becoming the industry standard for AI commerce.
How UCP Works
UCP uses a "server-selects" approach. Both the AI agent and the merchant declare what they support, then they negotiate to find common ground:
"I can handle Shop Pay, Google Pay, credit cards"
"I accept Shop Pay, PayPal, Apple Pay"
Result: Both support Shop Pay, so that becomes the payment method
UCP Core Capabilities
| Capability | What It Does |
|---|---|
| Checkout | Create and manage checkout sessions, cart management, tax calculation |
| Identity Linking | Let the AI act on behalf of the user via OAuth 2.0 |
| Order Management | Track shipping, delivery updates, handle returns |
| Extensions | Add-ons like discounts, fulfillment options, buyer consent |
How MCP and UCP Work Together
Here is the key insight: MCP and UCP are complementary, not competing.
The Relationship
MCP is the general-purpose protocol for connecting AI to any tool or data source.
UCP is specifically for commerce, and it can use MCP as one of its transport methods.
In practice, a shopping AI agent might use:
- MCP to access the user's preferences and purchase history
- MCP to retrieve product information from merchant catalogs
- UCP to handle the actual checkout and payment
UCP even has an explicit "MCP binding," meaning UCP checkout capabilities map directly to MCP tools like create_checkout, update_checkout, and complete_checkout.
Best Practices for Using MCP
1. Treat Every Server as a Trust Boundary
Separate servers by sensitivity. Your CRM server and your public catalog server should have different auth scopes and rate limits. Never assume tool outputs are safe.
2. Use the Right Primitive
Reading data? Use Resources. Creating, updating, or deleting? Use Tools with confirmation steps. Repeatable workflows? Use Prompts.
3. Keep Tool Schemas Tight
Small, strongly typed inputs beat "one big text field." Use enums, explicit units, and required fields. Put policy in your system prompt, not tool descriptions.
4. Add Human-in-the-Loop Gates
For purchases, deletions, refunds, or anything high-impact, require a confirmation step that shows exactly what will happen before executing.
5. Use OAuth with Short-Lived Tokens
Avoid static API keys. Use OAuth 2.1 with automatic token rotation and scoped access. Support Dynamic Client Registration where possible.
6. Instrument Everything
Log tool names, latency, error codes, and correlation IDs. Use an MCP gateway for visibility. This is how you debug agent behavior at scale.
Best Practices for Using UCP
For Merchants
- Declare capabilities accurately. Your
/.well-known/ucpprofile is your storefront to AI agents. Keep it honest and versioned. - Support flexible payment negotiation. Don't force a single payment processor. Declare multiple options and let the negotiation find the best match.
- Implement idempotency. AI agents will retry. Networks fail. Treat idempotency as required engineering, not optional.
- Offer escalation paths. When the flow cannot be completed autonomously (extra verification, complex shipping), hand off cleanly to a user-visible session.
For AI Platform Builders
- Cache capability profiles. Do negotiation up front and validate governance rules to reduce latency.
- Show users what they are buying. Always display line items, shipping, taxes, and totals before calling
complete_checkout. - Keep payment credentials out of the model context. UCP separates payment instruments from handlers for a reason.
- Use AP2 mandates for autonomous purchases. If you want truly autonomous checkout, implement cryptographic proof of user authorization.
Security Considerations
Both protocols take security seriously, but they require careful implementation:
MCP Security
- OAuth 2.1 is the foundation for authentication
- Short-lived tokens that rotate automatically (no static API keys)
- Resource-level security: Gmail access does not grant database permissions
- Token passthrough is explicitly forbidden to prevent bypassing security controls
UCP Security
- All communication over HTTPS with bearer token authentication
- Webhooks must be signed using shared secrets or asymmetric keys
- AP2 Mandates extension provides cryptographic proof for autonomous transactions
- Buyer Consent extension for GDPR/CCPA compliance
Why This Matters for Your Business
These protocols are not just technical curiosities. They represent a fundamental shift in how AI systems interact with the world.
For businesses: AI agents will increasingly become customers. Having UCP-compatible checkout means your products are discoverable and purchasable by the AI assistants people use every day.
For developers: MCP means you build one integration that works everywhere, instead of maintaining separate code for each AI platform.
For everyone: These standards make AI assistants genuinely useful for real tasks, not just answering questions. When your AI can actually book appointments, manage files, and make purchases on your behalf, that is when the "assistant" label becomes real.
Getting Started
If you want to explore further:
- MCP Documentation: modelcontextprotocol.io
- UCP Specification: ucp.dev
- Google's UCP Implementation: developers.google.com/merchant/ucp
- Shopify's UCP Documentation: shopify.engineering/ucp
Need Help Implementing AI for Your Business?
Understanding Your AI provides AI training and consulting for businesses in Michigan's Great Lakes Bay Region. Whether you need to understand these protocols, implement AI tools for your team, or figure out how AI fits into your workflow, we can help.