haggl.ai Blog
How Agents Discover Haggl—and What Compatibility Requires
Updated September 15, 2026: this article originally described universal agent compatibility. The protocol is designed for discovery from a merchant website, but compatibility must be demonstrated for each agent and tool configuration.
Haggl gives a merchant an agent that can discuss a shopper’s request and return a personalized offer within approved limits. The aim is for a shopper to start with an ordinary shopping request and a merchant URL.
A consumer-side installation is not part of that discovery design. Whether the experience works depends on the agent’s browsing tools, what page content they expose, its ability to make requests and its permission to act.
How merchant-side discovery works
A merchant can publish a negotiation endpoint in its page metadata:
<meta name="haggl-negotiate"
content="https://haggl.ai/api/negotiate?vendor=acme" />A compatible agent that encounters this tag can follow the endpoint and read the negotiation instructions. The endpoint describes the information the merchant requests and how to submit a negotiation request.
The tag makes the endpoint available. It does not guarantee that a browsing tool will expose it, that an agent will notice it or that the agent can call it. A tool returning only a page summary may omit metadata entirely.
The intended shopping flow
- Start with the shopper. The user gives their agent a shopping request and an ordinary merchant URL.
- Discover the endpoint. The agent finds the merchant’s negotiation instructions through a supported discovery path.
- Discuss the request. The shopper’s agent shares information it is authorized to provide, and the merchant’s agent evaluates it against the configured offer policy.
- Return the offer. The shopper can review the terms and decide whether to proceed.
- Follow the outcome. A checkout link or accepted offer is distinct from a completed, paid purchase.
What a compatibility test must establish
Test the actual consumer experience: the named agent, its version or date, enabled tools, discovery route and checkout handoff. A successful endpoint request establishes API behavior; it does not establish that a consumer agent can find that endpoint unaided.
For an out-of-box discovery demonstration, start without mentioning Haggl or supplying protocol instructions, endpoint URLs, a skill or prior setup. Report the observed result, including any point where the user must intervene.
Success with one configuration does not establish support for all configurations of that agent, other agents or future releases.
What merchants and agent builders can do
Merchants can define approved offers and work with us to test a supported path on their site. Agent builders can inspect the protocol documentation and evaluate how their tools handle discovery, authorization and offer requests.
Our goal is performance marketing for agentic commerce: helping merchants compete for customers through their personal agents. Discovery is the first step. Useful conversations, relevant offers and measured purchase outcomes are what make that channel valuable.