# Step 2 — the API catalog

/.well-known/api-catalog is an RFC 9727 linkset (application/linkset+json) listing every API you expose and its description document. It is the single entry point agents follow from the Link header out to OpenAPI, MCP, and payment surfaces.

Canonical: https://robauto.ai/learn/advanced-agentic-commerce/4

_Advanced Agentic Commerce: Ship the Full Agent Surface — lesson 4 of 20 (DEFINITION)_

/.well-known/api-catalog is an RFC 9727 linkset (application/linkset+json) listing every API you expose and its description document. It is the single entry point agents follow from the Link header out to OpenAPI, MCP, and payment surfaces.

Source: [IETF RFC 9727](https://www.rfc-editor.org/rfc/rfc9727?utm_source=robauto)

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Machine surfaces: https://robauto.ai/llms.txt · https://robauto.ai/llms-full.txt · https://robauto.ai/.well-known/api-catalog