> ## Documentation Index
> Fetch the complete documentation index at: https://docs.asva-ai.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Core Concepts: UCP, ACP, Dark Traffic, and Readiness

> Understand the four pillars of agentic commerce — UCP, ACP, dark traffic attribution, and Readiness Score — and how they work together.

Agentic commerce is what happens when an AI assistant — ChatGPT, Google Gemini, Perplexity, or a brand's own copilot — can recommend *and complete* a purchase on behalf of a user. For your store to participate, four things need to be true: AI can find your products, you speak the right commerce protocol, AI can trigger a checkout, and you can see and measure what AI drove. Asva AI covers all four.

## The agentic commerce stack

1. **Discovery** — The AI can find your products via catalog feeds, AEO/GEO, and `.well-known/ucp`
2. **Protocol compliance** — You speak the right commerce language (UCP or ACP)
3. **Checkout** — The AI can trigger a payment on your behalf
4. **Attribution** — You can see and measure what AI drove

***

## Universal Commerce Protocol (UCP)

UCP is an open standard backed by Google that lets AI assistants discover, evaluate, and purchase from any merchant using a shared commerce language. When you implement UCP, Google AI Mode, Gemini, and any UCP-compatible agent can browse your catalog and complete purchases without the user leaving the AI experience.

**How it works:**

```
AI Agent
  │
  ├─ 1. Fetches /.well-known/ucp  →  discovers your capabilities
  ├─ 2. Calls /ucp/products       →  browses your catalog
  ├─ 3. Calls /ucp/checkout       →  initiates a cart/session
  ├─ 4. Triggers payment          →  your PSP processes it
  └─ 5. Gets order status         →  confirms purchase to user
```

**Where UCP surfaces:**

* Google AI Mode (Shopping)
* Google Gemini
* Any UCP-compatible AI agent

**Key files you need to host:**

* `/.well-known/ucp` — capability manifest (required; publicly accessible, no auth)
* Product catalog endpoint — your structured product feed
* Checkout endpoint — creates and completes orders

<Note>
  UCP builds on Google Merchant Center. If you already have a Merchant Center feed, you're halfway there. See the [Google Merchant Center guide](/ucp/google-merchant-center).
</Note>

***

## Agentic Commerce Protocol (ACP)

ACP is OpenAI's protocol for enabling ChatGPT and other OpenAI-powered agents to initiate and complete purchases via tool calls — without the user leaving the conversation.

**How it works:**

```
User: "Buy me those running shoes"
  │
ChatGPT
  ├─ Calls search_products tool   →  your catalog endpoint
  ├─ Presents options to user
  ├─ User confirms
  ├─ Calls initiate_checkout tool →  your checkout endpoint
  └─ Purchase completes in-conversation
```

**Where ACP surfaces:**

* ChatGPT (Instant Checkout)
* Any OpenAI-powered agent with function calling

**Key concepts:**

* **Tool definitions** — JSON schemas that describe your commerce tools to the agent
* **Checkout state machine** — create → update → complete flow
* **Idempotency** — safe retries with idempotency keys to prevent duplicate orders

<Note>
  ACP and UCP are complementary. Many brands implement both for maximum coverage across Google and OpenAI surfaces. See [UCP vs ACP](https://asva-ai.com/ucp-vs-acp) for guidance on which to prioritize.
</Note>

***

## Dark agentic traffic

When a user finds your product on ChatGPT or Gemini and then visits your site directly, that session typically arrives with no referrer — and lands in GA4 as "Direct" or "(not set)". This is dark agentic traffic: real, high-intent visits that your analytics can't see.

**Why this happens:**

* AI assistants use server-side requests that strip the browser referrer
* Referrer headers are removed by ChatGPT's click proxy
* UTM parameters are rarely appended by AI surfaces
* GA4's default channel grouping has no "AI" category

**What Asva does:**

Asva's attribution snippet analyzes session fingerprints, timing patterns, and UTM signals to identify AI-sourced sessions and surface them as a distinct channel in your analytics.

```
Without Asva:          With Asva:
Direct → 35%           Direct → 18%
Organic → 28%          Organic → 28%
Paid → 22%             Paid → 22%
                       AI Commerce → 17%  ← previously hidden
```

See [Dark traffic attribution](/attribution/dark-traffic) for implementation details.

***

## Readiness Score

The Readiness Score is Asva's 100-point audit of your site's agentic commerce readiness. Run it against any domain via the [Readiness API](/api-reference/readiness) or the [free browser tool](https://asva-ai.com/tools/readiness).

**What gets checked:**

| Category        | What we check                               | Weight |
| --------------- | ------------------------------------------- | ------ |
| Discoverability | `.well-known/ucp`, feeds, entity schema     | 30%    |
| Catalog         | Product data quality, variants, pricing     | 25%    |
| Checkout        | UCP/ACP endpoint health, payment support    | 25%    |
| Attribution     | Asva snippet, GA4 custom dims, dark traffic | 20%    |

**Score grades:**

| Score  | Grade | Meaning                                                                     |
| ------ | ----- | --------------------------------------------------------------------------- |
| 80–100 | A     | Agent-ready. Appearing on major AI surfaces.                                |
| 60–79  | B     | Mostly ready. A few gaps to close.                                          |
| 40–59  | C     | Partially implemented. Missing key endpoints or feeds.                      |
| 0–39   | D     | Not yet agent-ready. Start with the [quickstart](/introduction/quickstart). |

***

## AEO and GEO

**Answer Engine Optimization (AEO)** and **Generative Engine Optimization (GEO)** are the practices of making your brand and products easy for AI systems to find, cite, and transact with.

For commerce, that means:

* Structured product data (JSON-LD `Product` and `Offer` schema)
* Entity consistency — the same brand name, legal entity, and address everywhere
* UCP/ACP protocol compliance so agents can complete purchases
* Evidence blocks with official sources so AI cites you, not competitors

See the full [AEO/GEO guide](/attribution/aeo-geo) for implementation tactics.

***

## Glossary

| Term                  | Definition                                                                             |
| --------------------- | -------------------------------------------------------------------------------------- |
| **UCP**               | Universal Commerce Protocol — Google's open standard for agentic checkout              |
| **ACP**               | Agentic Commerce Protocol — OpenAI's protocol for ChatGPT Instant Checkout             |
| **`.well-known/ucp`** | Capability discovery manifest; must be hosted at your domain root with no auth         |
| **Dark traffic**      | AI-sourced sessions misattributed as Direct in analytics                               |
| **AEO**               | Answer Engine Optimization — structured data and entity clarity for AI discoverability |
| **GEO**               | Generative Engine Optimization — visibility in ChatGPT, Gemini, and Perplexity         |
| **Readiness Score**   | Asva's 100-point agentic commerce audit                                                |

Full definitions at [asva-ai.com/glossary](https://asva-ai.com/glossary).