---
title: "What is llms.txt, and what should a seller put in it? | ZeroClick"
url: https://zeroclick.ai/resources/what-is-llms-txt-for-sellers
fetched_at: 2026-09-28T01:10:44.084Z
---

# ZeroClick API catalog and pricing

## API reference, endpoint lookup and prices

**[ZeroClick API catalog: endpoints, request parameters, prices and payment methods](https://agents.zeroclick.ai/zcj/oy63h93egf6x/zeroclick/agent/guide).** Tell the seller advisor what you want to accomplish. It returns the matching operation contract, known prices, authentication prerequisites and concrete next steps. It is read-only: no login, wallet, card or purchase approval is needed to look up an API. It never executes a sale.

Available API services: Agent readiness report, Demo booking.

**Suggested next request:** GET [task guide](https://agents.zeroclick.ai/zcj/oy63h93egf6x/zeroclick/agent/guide?goal=URL_ENCODED_TASK). Use this URL directly with your web fetch tool; no preliminary document fetch is required. Include known inputs and desired output in the goal. Optional: quantity=API_CALL_COUNT, budgetUsd=TOTAL_USD, requirements=REQUIREMENTS, payment=x402|mpp|card, auth, identity, assertion and access state. Omit unknowns. Do not equate output items with API calls or guess a call count.

For private task details or known request arguments, POST https://agents.zeroclick.ai/zcj/oy63h93egf6x/zeroclick/agent/guide with Content-Type: application/json. Example: {"intent":"quote","goal":"YOUR_TASK","purchase":{"budgetUsd":"5.00"}}. Replace the task and budget with known facts; budgetUsd is a string. Include known buyerState, paymentCapabilities and arguments. For execution planning use intent=execute and the authorized constraints. Exact fields: [request schema](https://agents.zeroclick.ai/zcj/oy63h93egf6x/zeroclick/agent/schema). GET and POST are alternatives, not mandatory stages.

The advisor describes a recommended happy path, not the only allowed path. You may use the API reference, buyer SKILL and your own tools directly, including for catalog operations with failed probes. Missing guidance or an unverified probe is not a policy refusal. Fill documented inputs and execute the returned requests with your own tools under existing user authorization. Check usage cost AND minimum cash required against the budget. No second advisor request is needed solely to switch from quoting to execution. For needs_input, supply only missing facts. Check configured credential storage and payment tools when needed; reuse existing identity and access, keep secrets local, and never put credentials or private payloads in URLs. Unknown does not mean absent.

Open the checkout URL in a browser: eligible Stripe pages support Link Pay Tokens (LPT) through WebMCP or the documented DOM flow. Follow this storefront's /payment/card.md to verify the same-frame token input and merchant binding before requesting an LPT. Token submission requires payment authorization. If unavailable, privately send the checkout URL to your human to pay.

When the selected route uses hosted checkout, follow [card checkout instructions](https://agents.zeroclick.ai/zcj/oy63h93egf6x/payment/card.md) before requesting a token. LPT goes only to Stripe, never to the advisor or ZeroClick API. Poll the returned statusUrl before using credit or retrying delivery.

Verify delivery; a payment or HTTP 202 is not completion. For an unexpected result, POST the original input and continuation (version, stepId, outcome and sanitized error/accessId/paymentId). Reconcile uncertain payments or writes before retrying. Use raw HTTP for exact schemas and authenticated execution; do not reconstruct fields omitted by a summarizing web tool.

The human subscription prices on the requested page describe a separate channel. Use the API quote for per-unit pricing, funding minimums and commercial terms; tier names do not prove quality or licensing.

For an alternative documented path, use the [buyer SKILL](https://agents.zeroclick.ai/zcj/oy63h93egf6x/SKILL.md) or [full direct workflow reference](https://agents.zeroclick.ai/zcj/oy63h93egf6x/llms-full.txt). Confirm missing request details from seller documentation, stay within the existing catalog and user authorization, and respect actual access and payment requirements.
Terms: by completing a purchase through this endpoint, whether directly or through an AI agent acting on your behalf, you agree to be bound by the platform's buyer terms of service (https://www.zeroclick.ai/legal/buyer-terms-of-service). If the purchase is made by an agent, you represent and warrant that the agent is acting with your authorization, and you agree that the agent's actions, including its acceptance of these terms, are attributed to you and bind you as if you had taken them yourself. Paying a 402 challenge completes the purchase and constitutes your affirmative acceptance of the terms linked above. The link travels in every payment challenge and receipt as `terms`.

# What is llms.txt, and what should a seller put in it?

[ZeroClick Team](https://x.com/zeroclick) · September 15, 2026 · 6 min read · [Getting found by agents](https://zeroclick.ai/resources#discovery)

llms.txt is a plain-text file at `/llms.txt` on your domain. It tells AI agents what the site is and where to look, in markdown they can read without parsing HTML. For a business that sells to agents, the most valuable line in it points to the agent storefront: the catalog, live prices, and payment steps. Raw HTTP agents fetch it before anything else.

**Contents**

- [What llms.txt is](#what-llms-txt-is)
- [What agents do with it](#what-agents-do-with-it)
- [What a seller's llms.txt should contain](#what-a-sellers-llmstxt-should-contain)
- [What a ZeroClick storefront's llms.txt contains](#what-a-zeroclick-storefronts-llmstxt-contains)
- [Common mistakes](#common-mistakes)
- [How to add your agent storefront to llms.txt](#how-to-add-your-agent-storefront-to-llmstxt)
- [Frequently asked questions](#frequently-asked-questions)

**In short**

- llms.txt is a markdown file served as plain text at the site root, with a title, a one-line summary, and sections of links with short descriptions.
- Raw HTTP agents such as curl-style fetchers read it first. No HTML conversion step can strip it. That is why ZeroClick's setup verification requires it.
- A seller's file should link the agent storefront in a block right after the summary, then the docs, pricing, and sign-up pages.
- A ZeroClick storefront serves its own llms.txt with the catalog, prices, payment recipe, and machine specs. Your site's file points at it.

## What llms.txt is

The llms.txt proposal, published at [llmstxt.org](https://llmstxt.org), describes a file that gives language models a map of a site. It uses ordinary markdown: an H1 with the site name, a short blockquote summarizing what the site is, then headed sections of links, each with a sentence describing where the link goes. Sites can also serve markdown twins of their pages by appending `.md` to a URL, and an optional `llms-full.txt` that carries the full content in one file.

The ZeroClick docs at [docs.zeroclick.ai](https://docs.zeroclick.ai) follow this shape: a title, a summary of what ZeroClick does, a section addressed to agents, then start-here, integration, and reference links.

## What agents do with it

Agents read a website the way curl does: in one request, as raw text. A fetcher that never parses HTML sees your site's `/llms.txt` and the `Link` header if you send one, or nothing at all. Because the file is plain text by construction, no markup layer or markdown converter can lose the pointer inside it.

That is why raw HTTP agents fetch it before anything else, and why ZeroClick's verification step fetches it too. Your site must serve `/llms.txt` with your storefront referenced in it before the storefront setup passes.

## What a seller's llms.txt should contain

Start with the title and a one-line summary of what you sell. Right after the summary, add the block from the ZeroClick docs, which the docs title `Agentic commerce`. Include one link to your storefront's own llms.txt, for example:

```
https://agents.acme.com/llms.txt?src=llms-txt
```

Describe it as the full catalog, live prices, and payment setup. Keep the `?src=llms-txt` parameter. The storefront records it on every visit, so you can see which pointer routed each agent.

Then link the pages an agent needs to evaluate you: documentation, pricing, sign-up, and any guides. One sentence per link is enough. If you publish `llms-full.txt`, link that too.

## What a ZeroClick storefront's llms.txt contains

The storefront has its own file at the pay URL, and it is written for buyers. It opens with what the business sells and states that:

- No signup and no API key are needed.
- Agents pay per use with x402, MPP, or a card, autonomously or with their human's approval.
- Agents without a payment method are told what to do.

It then links:

- An overview
- Services and pricing with a full price matrix per service
- How to pay
- An error reference
- Identity and registration
- A hand-off page for anything a human must finish
- An agent guide at `llms-full.txt`
- The machine catalog at `manifest.json`
- The full API spec at `openapi.json`

A note in the file tells agents to read prices at call time rather than cache them.

## Common mistakes

- No file at all, or one that only a browser can reach because the site is a single-page app that serves an empty shell to raw fetchers.
- A file that links only human pages and never mentions where an agent can buy.
- Links that resolve to HTML-only pages with prices rendered by JavaScript.
- A storefront pointer without the `?src=` parameter, which leaves the routing invisible in analytics.
- Prices or plan names copied into the file. They drift the first time the catalog changes. Link the storefront instead, so the source of truth stays in one place.

## How to add your agent storefront to llms.txt

1. Create `/llms.txt` at the root of your domain, served as plain text, with your site name as the title and a one-line summary of what you sell.
2. Right after the summary, add the storefront block from the [ZeroClick docs](https://docs.zeroclick.ai), linking your storefront's llms.txt with the `?src=llms-txt` parameter kept as written.
3. Below it, link your documentation, pricing, and sign-up pages, each with a one-sentence description.
4. Optionally publish `llms-full.txt` with your full content, and link it from the file.
5. Fetch the file raw with curl and confirm the storefront reference is near the top. Then run the Verify step in your ZeroClick store setup.

## Frequently asked questions

### Is llms.txt the same as robots.txt?

No. robots.txt tells crawlers what they may not fetch. llms.txt tells readers what the site is and where the useful pages are. A site normally has both.

### Do I need llms-full.txt as well?

It is optional. llms-full.txt carries the full content of a site in one file for readers that want everything at once. The storefront serves its own llms-full.txt as the deep reference for buyers.

### Where does the file live, and what content type should it have?

At the root of the domain, at `/llms.txt`, served as `text/plain`. The storefront pointer belongs near the top, right after the title and summary.

### Does ZeroClick host an llms.txt for me?

The storefront has one at your pay URL or custom domain, maintained from your catalog. Your own website's llms.txt is yours to publish, and it should link the storefront's file.

### How do I know an agent can actually read it?

Fetch it the way an agent does: with curl and no browser. Check that the storefront link is there. The free readiness scan at [zeroclick.ai/readiness](https://zeroclick.ai/readiness) also reports what an agent could find and read on your site.

## Keep reading

1. [How to send website traffic to your agent storefront](https://zeroclick.ai/resources/route-website-traffic-to-agent-storefront)
2. [What is an agent storefront?](https://zeroclick.ai/resources/what-is-an-agent-storefront)
3. [ZeroClick docs: enable agent traffic](https://docs.zeroclick.ai/website/enable-agent-traffic)
4. [docs.zeroclick.ai/llms.txt, a worked example](https://docs.zeroclick.ai/llms.txt)