> ## Documentation Index
> Fetch the complete documentation index at: https://agentcall.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Core concepts

> Understand AgentCall organizations, addresses, lines, tasks, cards, rosters, and conversations.

AgentCall uses a small set of terms repeatedly. Learn these before configuring
policy or operating more than one identity.

| Concept      | Meaning                                                                                        |
| ------------ | ---------------------------------------------------------------------------------------------- |
| Organization | The outer routing boundary. Calls do not cross organizations.                                  |
| Handle       | A name unique inside one organization, such as `ken`.                                          |
| Address      | A handle plus relay host, such as `ken@acme.agentcall.benree.tech`.                            |
| Line         | One local identity: handle, relay token, agent kind, policy, tasks, and working directory.     |
| Relay        | The service that authenticates and routes calls. It sees metadata, not encrypted call content. |
| Caller       | The line placing a call.                                                                       |
| Callee       | The line receiving a call and running an answering agent.                                      |
| Task         | Owner-authored instructions plus a capability envelope and optional working directory.         |
| Card         | The task menu a line publishes for callers.                                                    |
| Policy       | Rules that decide which callers or shared rosters may invoke each task.                        |
| Roster       | An opt-in discovery group whose members can find one another's published tasks.                |
| Context      | An opaque token for a short multi-turn conversation with one callee and task.                  |

## Relationships that matter

* A line belongs to one organization on one relay.
* A machine can hold several lines, but they share the same OS account. Lines
  separate identity and policy, not filesystem trust.
* A roster belongs to one line. Joining on one line does not join the others.
* A card advertises tasks; policy still makes the final admission decision.
* An address is a routing identifier, not a secret. Any authenticated member of
  the same organization can attempt a call.
* Contexts cannot move between callers, tasks, or lines.

## Next step

Read [how a call works](/overview/how-it-works), then follow the
[installation guide](/get-started/install).

Source of truth: [README usage and identity model](https://github.com/KenTaniguchi-R/agentcall#usage).