What is ARD? Agentic Resource Discovery

At 6:40 on a Tuesday morning, a homeowner in St. Paul finds water pooling under her kitchen sink. She doesn't open a search page. She tells her AI assistant to find a plumber who can come today and book the first free slot. Whether it can do that depends on something most business owners have never heard of: Agentic Resource Discovery.

What Agentic Resource Discovery is

ARD, short for Agentic Resource Discovery, is a shared way for a business to list what its AI tools can do so that agents can find them. An agent is an AI assistant that can take steps for you, such as booking a visit or filling in a form.

The rules live in one open specification, the ARD spec, which anyone can use for free. It's still young. The current version is 0.91, dated August 26, 2026, and it's marked as a proposal that is still changing. Its authors want agents to find tools "similar to how search engines discover web pages," instead of setting up each tool by hand.

Where search engines helped people find pages, ARD aims to help agents find the jobs a business can do for them.

A plumber's day, the way the spec pictures it

The spec comes with a sample business, and it happens to be a plumber: Bob's Plumbing & Drain, a family company in Minneapolis. Bob is not real, but his sample file is a working example that anyone can read. Here is how his Tuesday could go.

Long before that morning, Bob put one file on his website at /.well-known/ard.json. It lists what his business can do for an agent. Each item names a tool, says where it lives and gives a few sample requests, such as "find an emergency plumber in Minneapolis." The spec asks for two to five per item. Search uses them to match a need to a tool.

At 6:40, the homeowner's agent sends her request to a registry. A registry is a search engine for agent tools. It visits websites, reads files like Bob's and keeps an index of what it finds. Her request about a leaking sink matches Bob's sample requests well, so his listing comes back near the top.

At 7:00, Bob's shop opens. The agent now talks to Bob's business directly, not through the registry. Bob lists an assistant of his own, which other agents can chat with to ask questions, check which technicians are free and book an appointment. It books the homeowner for 9:30.

Later that morning, a property manager's agent asks Bob for a price on a water heater swap. That request goes to a different part of Bob's listing: three small tools that check open times, request a quote and share his business hours. They sit behind an MCP server. MCP, or Model Context Protocol, is a common standard that lets an agent use a tool without custom setup for each one.

Bob's file could also list skills. A skill is a folder of instructions and scripts that an agent loads when a task calls for it, such as reading an old spreadsheet. Bob doesn't need any, so his list stops at the assistant and the three tools.

What Bob had to do

The ARD file was the small part. Bob's booking assistant and quote tools had to exist first, built by him or by a software vendor. The file only makes them findable. He posted it on his own site and keeps it up to date. Any registry that visits can now list his tools. The official publishing guide is clear that this does not guarantee every service will find him.

The file also ties each tool to Bob's web address. Every tool's name includes his domain, like urn:air:bobs-plumbing.example:mcp:storefront. A registry can check that name against the site where it found the file, which makes it harder for someone else to list fake tools under Bob's name.

The spec says registries make tools findable "the moment they are published." For a small business, that means no separate deal with each AI company. You describe your services once, in one place you control.

Most AI assistants can't search ARD on their own yet, so for now someone has to plug a registry in by hand. Our setup guide walks through it for Claude, Cursor and other tools.

Who is behind ARD

ARD went public on June 17, 2026. The official ARD site says a working group builds it, with people from Microsoft, Google, Hugging Face, GoDaddy and others. Google's launch post calls ARD "the missing layer of the agentic web."

StealthStack is not part of that group. We are an independent team that implements the spec: we read ARD files from across the web and build a search index from them. The spec belongs to its authors, and nothing here speaks for them. Our own story is in what StealthStack is and why we built it.

Should your business do anything yet?

It depends on what you offer.

Maybe customers can already book, order or get a quote from you online. If so, ask the company behind that system whether it publishes an ARD file for you. We expect many small businesses to get ARD this way, through a vendor, without touching a file.

If you have a web developer and your booking or quoting already runs online, send them the publishing guide linked above. The ARD part is one file and a few lines of setup. If nothing runs online yet, the tools come first and the file comes after.

If nothing you offer can be done by an agent yet, such as a shop that only sells in person, there is nothing to publish today. Your website and your search ranking still matter for the people who find you.

Next steps

1. Read the official introduction to ARD. It is short and written in plain prose.
2. Search our index for a service like yours and see who already lists one.
3. Read AI agents for small business: a sea of tools to see what this means for buying and selling, then browse what agents can find today.

Frequently asked questions

What does ARD stand for?

Agentic Resource Discovery. It is an open specification for publishing agent tools, services and other agents on the web so that agents can find them.

Do I need ARD if I already have a website?

Only if agents can already do something with you online, such as book or request a quote. The section above, "Should your business do anything yet?", covers each case.

Is ARD the same as MCP?

No. MCP is how an agent talks to a tool. ARD is how the agent finds that tool in the first place, so the two work together.

Who owns ARD?

No single company. It is an open specification developed by a working group and published under the Apache 2.0 license.