# Open Service Directory

Open Service Directory (OSD) helps AI assistants find a brand’s customer-support agents and verify that
the brand endorses them. It builds on
[Agentic Resource Discovery (ARD)](https://agenticresourcediscovery.org/introduction/), adding
requirements for brand identity and endorsement.

A brand or an authorized support platform publishes OSD listings for the support agents it wants assistants to discover. The brand or an authorized support platform can operate those agents. The support platform operates a registry that helps assistants discover the brand’s support agents.

After discovery, the assistant connects to the selected agent through a supported protocol. OSD is designed to work with connection protocols such as
[PACT](https://github.com/openpactprotocol/openpactprotocol) and
[PAP](https://personalagentprotocol.org/).

## Understand the model

![A personal AI assistant looks up a brand in the Open Service Directory, gets the brand's endorsed agent information, then connects directly to the brand's support agent through a protocol such as MCP, A2A, PACT, or PAP.](/0.3.0/docs/assets/osd-explained.png)

- [What is OSD](/0.3.0/docs/getting-started/what-is-osd/): the problem the directory addresses.
- [How OSD works](/0.3.0/docs/getting-started/how-osd-works/): the flow from publishing a listing to connecting to an agent.
- [OSD and ARD](/0.3.0/docs/concepts/osd-and-ard/): the shared discovery model and support-specific requirements.
- [Discovery flow](/0.3.0/docs/concepts/discovery-flow/): finding candidates, checking brand endorsement, and choosing a support agent.