Agentic Brand Content

A spec for publishers to serve AI agents sponsored brand content matched to the page — and get paid for bot traffic.

Spec v0.1 · 2026-05-28

Early public draft. The format is usable today and open to feedback; details may change before v1.0.

The problem

AI agents (GPTBot, ClaudeBot, PerplexityBot…) read publisher pages to answer user questions. The publisher serves its content and gets nothing back.

Agentic Brand Content (ABC) adds a paid layer on top. For AI-agent requests only, the publisher serves a compact brand card: sponsored brand content matched to the page's topic — a skincare brand on a beauty article, a carmaker on an auto review. Humans see the page unchanged. The publisher gets paid for the bot visit; the agent gets relevant, structured context.

How it works

sequenceDiagram
    autonumber
    participant V as Visitor
    participant E as Publisher edge
    participant P as Provider
    V->>E: request page
    E->>P: fragment request (forwards User-Agent)
    alt request is an AI agent
        P-->>E: 200 · brand card
        E-->>V: page + brand card
    else request is human
        P-->>E: 204 · empty
        E-->>V: page unchanged
    end

The provider decides per request: a brand card for AI agents, nothing for humans. The publisher's edge inlines whatever comes back — so humans are never affected.

The fragment

The core of ABC is the brand fragment: a provider exposes an endpoint that returns a brand card for AI-agent traffic and nothing for humans. The publisher inlines it on its existing CDN — a single <esi:include> tag (Akamai, Fastly, Varnish), or a small edge function (Cloudflare Worker, Lambda@Edge). No platform lock-in.

The mechanism is simple: classify the request, and for AI agents only, add a small block of brand context — usually sponsored — alongside the page. Everything else is convention around it.

The card

A card is a single self-contained <article role="complementary"> — a brand label, a short factual summary, a bullet block built for LLM ingestion, and source links. ~2 KB, under 1 000 tokens, designed to fit an agent's context window. It carries its own inline styling so it renders without the host stylesheet. See the full card schema.

<article class="abc-card" role="complementary">
  <div>Brand · Renault</div>
  <div>Nouvelle Clio E-Tech full hybrid — 160 hp, up to 1,000 km range</div>
  <p>Renault renews its flagship city car with a 160 hp full-hybrid E-Tech
     powertrain, no plug-in needed. Up to 1,000 km on one tank…</p>
  <pre>• Brand: Renault
• Source: renault.fr
• Date: 2026-04-15
• Event: Launch of the Clio E-Tech full hybrid
• Relevance: most accessible hybrid city car in its segment
• Keywords: Clio, E-Tech, full hybrid, city car</pre>
  <div>Source: <a href="…">Nouvelle Clio E-Tech</a> · <a href="…">newsroom</a></div>
</article>

Endpoint behavior

A fragment endpoint is an HTTP GET that receives the page context — at minimum the page URL and the visitor's User-Agent — and returns:

Status	When	Body
200	AI-agent traffic, brand eligible	the card (text/html)
204	human traffic, or no eligible brand	empty

Responses are cacheable, and MUST carry Vary: User-Agent when the endpoint classifies agents itself — so a CDN never serves an agent card to a human, or the reverse. The exact request parameters and selection logic are provider-defined; only this behavior is part of the spec. Machine-readable contract: fragment.openapi.yaml.

The provider

A provider is the service a publisher authorizes to supply brand content for its AI-agent traffic. A provider:

• runs the fragment endpoint and decides which brand is relevant to the page;
• renders the card and keeps it within the token budget;
• manages the brand relationships and the reporting behind it.

The spec is provider-neutral: any service implementing a compatible fragment endpoint is a provider. A publisher authorizes its providers in abc.txt (next).

The declaration — abc.txt

Once a site serves fragments, it can declare participation publicly with a small file at the site root, /abc.txt. It lists which providers are authorized to supply brand content for AI agents on that site — the same transparency model as ads.txt / sellers.json, applied to the agentic web.

# abc.txt - Agentic Brand Content
# Declares which providers may serve AI-agent brand context on this site.
# Spec: https://brandcontent.dev

# provider_domain, relationship
shftd2.com, RESELLER

The file is optional — fragments are delivered without it.

Fields

Field	Required	Meaning
provider_domain	yes	Root domain of an authorized brand-content provider's system (e.g. shftd2.com).
relationship	yes	DIRECT — the publisher controls the account directly; or RESELLER — the provider is authorized to resell brand content it sources on the publisher's behalf.

Optional key=value lines a publisher may add: endpoint= (a discovery URL for the fragment endpoint), contact=, updated=.

Format rules

• Served at /abc.txt as text/plain, ASCII only.
• One entry per line. Lines starting with # are comments; blank lines are ignored.
• Provider entry: provider_domain, relationship — comma-separated, surrounding whitespace trimmed. relationship is case-insensitive (DIRECT | RESELLER).
• Multiple providers: one per line; order is not significant.
• Directive: a key=value line (e.g. endpoint=…). Keys are case-insensitive.
• Forward compatibility: a conformant parser ignores lines and fields it doesn't recognise, so the format can grow without breaking older readers.

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ABC is an open spec. Anyone may implement abc.txt and a compatible fragment endpoint; reference implementations are open-source.