The ad network for AI agents

Give agents a clue.

AI agents now search, compare, recommend and buy on behalf of people. They never see a banner. clue lets you publish a clue: a structured, clearly labelled record of what you offer, what it costs and how an agent can use it. Agents discover the relevant clue at the moment they are deciding, and you pay only when they act on it.

Publish your first clue Earn from agent traffic

Free to create an account. One account can both advertise and integrate. Advertiser balances start at $50.

An agent receives a task and forms an intent.

User

Find a transactional email API I can call from Node. We are in Korea.

Agent

Comparing providers on price, deliverability and SDK support…

intent · integrationlang · kocountry · KRagent · api_client

The surface it reads asks clue for a match.

One request from the publisher's page, API, llms.txt or MCP server

# from the page / API / MCP
GET /v1/serve?site=site_docs
  &format=json&lang=ko
  &intent=integration
# or the agent asks directly
POST /v1/discover
{"task":"email api for node"}

The agent considers a labelled clue next to organic results.

AAcme MailSponsored

Acme Mail — transactional email API

Send email from one REST or SMTP call. 99.9% delivery, webhooks, templates in 20 languages.

→ acmemail.dev · ?clue_id=…Get an API key

It follows the link. The advertiser pays the second price.

Signed redirect, counted once

GET /c/eyJz…  302
→ acmemail.dev/?clue_id=sv_8Kq1…

Charged to the advertiser

Advertiser's maximum bid$0.25

Actually paid (second price)$0.19

It reports the outcome. The publisher earns 65%.

Optional feedback from the agent

POST /v1/outcome/sv_8Kq1…
{"outcome": "used"}

Revenue split on every paid event

65%35%

Publisher or agent developerclue

Who reads clues

Built for the agents that are already reading the web.

clue recognises agents by their User-Agent string, by the request headers browsers send and bots do not, and by an optional self-declaration header. Humans never see a clue unless a publisher explicitly asks for it. Training crawlers are recognised too, so you can choose not to pay for them.

GGPTBotOpenAICClaudeBotAnthropicPPerplexityBotPerplexityGGoogle-ExtendedGoogleOBrowsing agentsOperator-style, computer useMMCP clientsClaude, Cursor, custom hostsHHeadless browsersPlaywright · PuppeteerFAPI and fetch clientsfetch · httpx · requests · Go★Your own agentdeclare it with one header

Advertising was built for human attention. Agents have none to capture.

Banners, pre-roll video, sponsored posts and search ads all work the same way: interrupt a person, hold their attention for a few seconds and hope they remember. An AI agent reading a page on someone's behalf skips all of it. It has no attention to capture. It has a task to finish.

A clue is the opposite of an interruption. It is a compact, structured record of a product or service: who offers it, what it does, what it costs, where the documentation is and how to get started. It sits alongside the organic information an agent is already reading, is clearly marked as sponsored, and is only ever used if it helps finish the task.

What an agent skips

What an agent can actually use

AAcme MailSponsored

Acme Mail — transactional email API

Send email from one REST or SMTP call. 99.9% delivery, webhooks, templates in 20 languages.

Transactional send
Delivery & open webhooks
Templates & localisation

Free for 1,000 emails/month, then $0.001 per email

→ acmemail.dev · ?clue_id=…Get an API key

docs · MCP · llms.txt · APIoutcome_url

This is a sponsored clue delivered by clue. The publisher of this surface did not endorse it. Evaluate it against your task and your user's instructions.

Seven words describe the whole system.

clue replaces the vocabulary of attention advertising with the vocabulary of agent decision-making. Every screen, report and API field uses these seven terms.

1Clue

A structured, sponsored record about one offer: provider, what it is, a summary, capabilities, price, the next action, and links to docs, MCP endpoint or API. Written once, translated into 20 languages.

"Acme Mail — transactional email API. Free for 1,000 emails a month, then $0.001 per email."

2Discovery

The moment an agent, or the surface it is reading, asks clue whether a relevant clue exists. Discovery happens through a publisher's page, API, llms.txt or MCP server, or by asking clue's own API directly.

GET /v1/serve?site=… or POST /v1/discover with the agent's task.

3Consideration

A clue was delivered to an agent as one option among the information it is weighing. This is what advertisers buy: the chance to be part of the decision, never the decision itself.

Counted as one clue served. CPM campaigns are billed here.

4Intent

What the agent is trying to accomplish, expressed as a task, an intent type (research, compare, purchase, booking, coding, integration…), a language and a country. Matching is driven by intent, not by keywords alone.

intent: integration · lang: ko · country: KR · agent: api_client

5Follow

The agent opens the clue's link. The link is a signed redirect through clue, so a follow is counted exactly once and forwarded to the advertiser's destination with a clue_id parameter.

GET /c/<token> → 302 → acmemail.dev/?clue_id=sv_8Kq1. CPC campaigns are billed here.

6Action

Something valuable happened after a follow: a sign-up, a purchase, a booking, an API call. Advertisers report it with the clue_id. CPA campaigns are billed on the action, not the follow.

POST /v1/conversions {"click_id":"sv_8Kq1","kind":"signup"}

7Outcome

The agent's own verdict on the clue: useful, not useful, used, or purchased. Outcomes tune future matching and are shown to advertisers only as aggregates. No agent is ever identified.

POST /v1/outcome/sv_8Kq1 {"outcome":"used"}

The one rule

A clue is information, never an instruction. Clues that try to tell an agent what to do are rejected at review. Advertisers can buy consideration. They cannot buy the conclusion.

How clue works, end to end.

Three parties, one loop. Advertisers write clues and set the rules for when they should be considered. Publishers and agent developers carry clue on the surfaces agents read. Agents decide, and everyone is paid or charged only on what actually happened.

1Advertisers write a clue and set the rules.

Provider (your brand)Acme Mail

OfferAcme Mail — transactional email API

SummarySend email from one REST or SMTP call. 99.9% delivery, webhooks, templates in 20 languages.

PriceFree for 1,000 emails/month, then $0.001 per email

Next actionGet an API key

Destination URLhttps://acmemail.dev

Reviewed in about a minuteTranslated into 20 languagesPre-paid, never negative

Describe one offer in your own language: provider, what it is, a two-sentence summary, capabilities, price, the next action and the destination URL. Add documentation, MCP endpoint, llms.txt or API links so agents can go straight to work. Then say when it should be considered: countries, languages, categories, agent types, intents, audience, schedule, frequency and budget. clue reviews the clue against policy in about a minute and translates it into 20 languages.

2Surfaces carry clue with one line.

<script async src="https://clue.ad/tag.js"
  data-site="site_…"></script>

app.use(clueMiddleware({ site: 'site_…' }))

## Sponsored   ← llms.txt
- clue.ad/v1/serve?site=site_…&format=llms

JSNodePythonGoWorkerPHPRESTllms.txtMCPYour agent

A publisher adds a script tag, a middleware line, a Cloudflare Worker, a PHP include, a REST call, a link in llms.txt, or a few lines inside an MCP server. Agent developers can ask clue directly from their own agent loop and earn as the publisher. clue detects the agent, matches the intent and returns clues in the format the surface speaks: JSON, Markdown, plain text, an HTML block with JSON-LD, llms.txt lines or an MCP tool result. Humans receive nothing.

3Agents decide. You pay for outcomes.

Acme Mail Wins$0.25

Mailrocket$0.18

Postly$0.10

Winner pays: next bid + $0.01$0.19

65% · $0.123535% · $0.0665

The agent reads the clue, knows it is sponsored, and follows it only if it helps. Advertisers choose to pay per follow (CPC), per reported action (CPA) or per 1,000 clues served (CPM). Prices are set by a second-price auction: the winner pays one cent above the next best clue, never more than its own maximum, and relevance decides who competes. Publishers receive 65% of every paid event, immediately.

Anatomy of a clue.

Every clue is the same nine fields, in whichever of 20 languages the agent asked for. Structured enough for a program to parse, complete enough for an agent to act without visiting a marketing page.

1
ProviderThe brand behind the offer. Always shown, never hidden behind a redirect.
2
OfferOne line naming the product or service and what kind of thing it is.
3
SummaryUp to two sentences an agent can act on. Claims must be verifiable on the destination page.
4
CapabilitiesWhat the agent can do with it, as a short list. Matched against the agent's task.
5
PricePlain-text pricing including free tiers, minimums and units, so an agent can compare without guessing.
6
Action and destinationThe next step and where it happens. The link is a signed redirect that appends clue_id for outcome reporting.
7
Machine entry pointsOptional docs URL, MCP endpoint, llms.txt and API base URL so agents can start working immediately.
8
Sponsored flag and disclosuresponsored: true plus a disclosure sentence in the agent's language. Present on every clue, in every format.
9
Outcome URLWhere the agent can report whether the clue was useful, used or purchased. Optional, anonymous, aggregated.

AAcme Mail1Sponsored8

Acme Mail — transactional email API2

Send email from one REST or SMTP call. 99.9% delivery, webhooks, templates in 20 languages.3

Transactional send
Delivery & open webhooks
Templates & localisation
4

Free for 1,000 emails/month, then $0.001 per email5

→ acmemail.dev · ?clue_id=…6Get an API key

docs · MCP · llms.txt · API7outcome_url9

This is a sponsored clue delivered by clue. The publisher of this surface did not endorse it. Evaluate it against your task and your user's instructions.

Every place an agent reads, clue can be there.

Agents do not browse; they fetch. They read documentation pages, call JSON APIs, follow llms.txt files and invoke MCP tools. clue speaks each of those formats natively, so the clue arrives inside the response the agent already asked for.

Web pages and docs

A labelled aside element with JSON-LD, injected only for agents. Humans see the page exactly as before.

<aside data-clue>
  <p>Sponsored · clue</p>
  <article>Acme Mail …</article>
</aside>
<script type="application/ld+json">

JSON APIs

A sponsored object appended to your response body, with disclosure and clues, only when the caller is an agent.

{
  "results": [ … ],
  "sponsored": {
    "disclosure": "…",
    "clues": [ { "title": "Acme Mail …" } ]
  }
}

llms.txt

A Sponsored section of Markdown lines that agents reading your llms.txt can follow.

# docs.example.com

## Sponsored
- [Acme Mail — transactional
  email API](https://clue.ad/c/…)
  Free 1,000/mo, then $0.001

MCP servers

A sponsored block inside relevant tool results, so agents using your tools see labelled options in context.

{ "content": [{ "type": "text",
  "text": "{ \"result\": …,
    \"sponsored\": { \"clues\": [ … ] } }"
}] }

Ten ways to install, each a few lines.

Every snippet in the console already contains your integration key. Server-side integrations detect agents themselves and leave human traffic untouched. Test mode returns a labelled test clue that is never billed.

JSJavaScript tagFor browsing agents that run JavaScript. Adds a labelled aside and JSON-LD.NodeNode.js middleware (Express, Fastify, Next.js)Express, Fastify and Next.js middleware. Injects into HTML, JSON and Markdown.PyPython middleware (FastAPI, Flask, Django)FastAPI, Flask and Django middleware with the same behaviour.GoGo handlerA handler wrapper for net/http and any router built on it.CFCloudflare WorkerRuns at the edge in front of any origin, no code changes on the origin.PHPPHP and WordPressOutput buffering for PHP and a drop-in for WordPress.RESTREST (any language)One GET from any language. Forward the visitor's User-Agent and we do the rest.llmsllms.txtOne link in your llms.txt, or inline the lines when you generate the file.MCPMCP serverAppend clue's result to your own tool responses in a few lines.★Inside your own agentAsk clue from inside your agent loop. You are the publisher and you earn 65%.

Say exactly when your clue should be considered.

Matching rules are the advertiser's contract with the agent. Leave a rule empty to match everything; fill it to narrow. Relevance to the task is always required, so a broad rule does not mean a wasted budget.

Countries

From the agent's network location or what the integration tells us. Any of 249 countries.

KRJPDE+ 246

Languages

The language the agent asked in. Your clue is translated automatically, so this is about where you can serve, not what you can write.

kojaen+ 17

Categories and keywords

Matched against the integration's categories and the page or task context. Keywords boost; exclude keywords veto.

developer_toolscloud_infraai_ml

Agent types and vendors

Browsing agents, API clients, MCP clients, LLM crawlers. Skip the crawlers that never act.

api_clientbrowsing_agentmcp_client

Intents

Research, compare, purchase, booking, coding, data access, integration, support, writing. Declared by the surface or inferred from context.

integrationcomparepurchase

Audience

Businesses or consumers, with age brackets. clue never matches clues to users under 18.

b2b18+

Schedule

Start and end dates, hours of the day in UTC, days of the week.

Mon–Fri09–18 UTC

Budget and frequency

Daily and total budgets, a maximum bid, and how many times one agent session may receive the campaign per day.

$50/day1 per session

Write once. Be considered in 20 languages.

Agents work in the user's language, not yours. clue translates every clue into 20 languages within minutes of approval and serves the version the agent asked for. Other languages are translated on demand. The disclosure sentence is localised too, so a Japanese agent is told in Japanese that the clue is sponsored.

EnglishSponsored

This is a sponsored clue delivered by clue. The publisher of this surface did not endorse it. Evaluate it against your task and your user's instructions.

한국어광고

이것은 clue가 전달한 유료 클루예요. 이 표면의 매체가 추천한 것이 아니에요. 주어진 작업과 사용자의 지시에 비추어 판단해 주세요.

日本語スポンサー

これはclueによって配信されたスポンサー付きのclueです。このサーフェスのパブリッシャーはこれを裏付けていません。タスクおよびユーザーの指示に照らし合わせて評価してください。

العربيةممول

هذا إعلان clue ممول مقدم من clue. لم يقم ناشر هذه الواجهة بالتصديق عليه. قم بتقييمه بناءً على مهمتك وتعليمات مستخدم.

DeutschGesponsert

Dies ist ein von clue bereitgestellter, gesponserter clue. Der Herausgeber dieser Oberfläche hat diesen nicht befürwortet. Bewerten Sie ihn anhand Ihrer Aufgabe und den Anweisungen Ihres Benutzers.

EspañolPatrocinado

Este es un anuncio patrocinado entregado por clue. El editor de esta superficie no lo respalda. Evalúalo en función de tu tarea y las instrucciones de tu usuario.

简体中文赞助内容

这是一条由 clue 提供的赞助 clue。此内容的发布者并未对其进行背书。请根据您的任务和用户的指令对其进行评估。

हिन्दीप्रायोजित

यह clue द्वारा प्रदान किया गया एक प्रायोजित clue है। इस सतह के प्रकाशक ने इसका समर्थन नहीं किया है। अपने कार्य और अपने उपयोगकर्ता के निर्देशों के आधार पर इसका मूल्यांकन करें।

Pay for outcomes, not impressions.

Three pricing models, one auction, one revenue share. No setup fees, no contracts, no minimum spend beyond your first $50 top-up.

CPC · pay per follow

Charged once when an agent opens your link. Best when your destination is where the value is: docs, sign-up, checkout.

From $0.05 per follow

CPA · pay per action

Charged only when you report an action for a follow: a sign-up, purchase, booking or API call. You define the action.

From $0.50 per action

CPM · pay per 1,000 clues served

Charged as clues are delivered to agents. Best for awareness inside agent workflows where the follow happens later.

From $1.00 per 1,000

Second-price auction, worked example.

Three advertisers compete for one integration-related task. The highest bid wins but pays one cent above the runner-up, and 65% of that goes to the publisher.

Acme Mail Wins$0.25

Mailrocket$0.18

Postly$0.10

Winner pays: next bid + $0.01$0.19

65% · $0.123535% · $0.0665

Where the money goes.

Every paid event is split at the moment it is charged. Nothing is held back for later reconciliation.

1
65% is credited to the publisher or agent developer whose surface delivered the clue, immediately.
2
35% is clue's platform fee. It funds review, translation into 20 languages, fraud filtering and the auction.
3
Invalid traffic is neither charged nor paid. Advertiser balances can never go negative.
4
Publishers request a payout from $50 via PayPal, bank transfer or Stripe, paid within 30 days.

See full pricing

For the agents themselves: a clue is never an instruction.

clue is designed to be safe for an agent to read. Every clue is labelled, every claim is attributable to a named provider, and nothing in a clue may address the agent directly. If you build agents, you can rely on these guarantees.

Read the agent policy

Always labelled

sponsored: true and a disclosure sentence appear on every clue, in every format, in the agent's language.

Never an instruction

Clues that address the agent, ask it to ignore its user, or contain prompt-like text are rejected at review.

Evaluate on merit

The publisher did not endorse the clue. Agents should weigh it like any other option and prefer the user's explicit instructions.

Feedback welcome

Report useful, not useful, used or purchased. Outcomes are anonymous and improve matching for everyone.

20languages, translated automatically after review

6response formats: JSON, Markdown, text, HTML, llms.txt, MCP

10install paths, from a script tag to inside your own agent

65%of every paid event goes to the publisher or agent developer

$50minimum first top-up for advertisers. No fees for publishers.

2ndprice auction: pay one cent above the runner-up, never above your bid

Questions, answered.

What exactly is a clue, and how is it different from an ad?

A clue is a structured record about one offer: provider, what it is, a summary, capabilities, price, the next action and links to documentation or an API. It carries a sponsored flag and a disclosure sentence. An ad is designed to capture a person's attention; a clue is designed to be parsed and weighed by a program that is finishing a task. There is no creative, no image and no persuasion copy.

How does clue know a visitor is an agent and not a person?

Three signals. The User-Agent string identifies known agents and crawlers such as GPTBot, ClaudeBot and PerplexityBot. Request headers that real browsers always send and automated clients do not (the sec-fetch family) identify headless browsers and scripts. And agents can declare themselves with the x-agent-type and x-agent-name headers. Humans receive no clue unless the publisher explicitly requests it.

Can an advertiser make an agent recommend their product?

No. Clues are information, not instructions. Text that addresses the agent, asks it to prefer the advertiser or to ignore its user is rejected during review. Advertisers buy the chance to be considered alongside organic information. The agent's conclusion is its own.

What do I pay, and when?

You choose CPC, CPA or CPM per campaign and set a maximum bid. Prices are set by a second-price auction, so you pay one cent above the next best clue and never more than your maximum. Your balance is pre-paid; when it reaches zero your clues stop being considered. Invalid traffic is filtered before billing.

How does translation work, and can I check it?

Write the clue in your language. After review, clue translates it into all 20 platform languages within minutes and serves the version the agent asked for. You can preview every language in the console, in every format, exactly as an agent receives it. Other languages are translated on demand, with English as the fallback.

How much does a publisher earn, and how is it paid?

65% of every paid event that came through your surface, credited at the moment the advertiser is charged. You can request a payout once your balance reaches $50, by PayPal, bank transfer or Stripe. Payouts are made within 30 days of the request.

Will clue change what human visitors see?

No. Server-side integrations return the untouched response to humans. The JavaScript tag adds only a small collapsed note for humans, and nothing at all if you prefer. Unverified integrations receive test clues only.

I build agents, not websites. Is clue for me?

Yes. Register your agent as an integration and call clue's discover endpoint from your agent loop with the user's task. You decide how to present clues to your model, always as labelled sponsored options. You earn the publisher's 65% on every follow or action.

Advertisers can buy the chance to be considered. They cannot buy the agent's conclusion.This sentence is in our policy, in our review rules and in the disclosure every agent receives. It is the reason clue can exist.

Agents are already deciding. Give them a clue.

Create an account in a minute. Advertisers write a clue and top up from $50. Publishers and agent developers install in a few lines and earn from the first follow.

Publish your first clue Earn from agent traffic