# Agentic Resource Discovery Specification (ARD) Agentic Resource Discovery (ARD) is an open specification ([[Apache 2.0 License]]) for publishing, discovering, and verifying AI capabilities across the web. Announced by Google, it answers the question an [[AI Agents|agent]] needs before it can act: where do capabilities exist, which one should I use, and is it safe to connect to. A client cannot use a capability it does not know exists, and today there is no standard way to answer that across organizations. ARD sits **before** invocation. It helps a client decide which capability to use; the actual call still happens through that resource's own mechanism ([[Model Context Protocol (MCP)|MCP]], an API, an agent framework, a workflow system). The discoverable "agentic resources" include tools, Skills, MCP servers, APIs, workflows, and other agents. ## How it works - **Catalogs**: an organization publishes an `ai-catalog.json` file at a well-known path on its domain, describing its capabilities. Domain ownership is the cryptographic basis for identity and trust. - **Registries**: search engines for the agentic web that crawl and index published catalogs, so agents can query for capabilities with verifiable trust metadata. - **Flow**: publish a catalog, discover via a registry or a direct fetch, cryptographically verify the publisher's identity, then connect directly using the resource's native protocol. ## Context - Builds on the Linux Foundation's AI Catalog data model; supports MCP servers, OpenAPI tools, A2A agents, and nested catalogs as discoverable resources - A spec, not a product: multiple discovery services can implement it (e.g. GitHub's Agent Finder, Hugging Face's Discover) - Google Cloud's Agent Registry (Gemini Enterprise Agent Platform) is adding native ARD support - Think of it as robots.txt / sitemaps for agent capabilities rather than web pages ## References - https://agenticresourcediscovery.org - https://agenticresourcediscovery.org/introduction/ - https://agenticresourcediscovery.org/ai_catalog_spec/ - https://agenticresourcediscovery.org/how_to_publish/ - https://developers.googleblog.com/en/announcing-the-agentic-resource-discovery-specification/ - https://github.com/ards-project/ard-spec - https://news.ycombinator.com/item?id=48573268 ## Related - [[AI Agents]] - [[Agentic Engineering]] - [[Model Context Protocol (MCP)]] - [[Large Language Models (LLMs)]] - [[Apache 2.0 License]]