> For the complete documentation index, see [llms.txt](https://docs.dispach.moeenmahmud.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.dispach.moeenmahmud.com/concepts/runtime-agents-and-sessions.md).

# Runtime, agents, and sessions

Dispach has four different identifiers that an integration should keep separate.

| Concept | Lifetime                    | Responsibility                                                    |
| ------- | --------------------------- | ----------------------------------------------------------------- |
| Runtime | Process                     | Loads agents, owns stores, executes turns, and exposes transports |
| Agent   | Configuration and workspace | Defines model, tools, policy, limits, identity, and memory        |
| Session | Conversation                | Groups messages and history under an agent                        |
| Turn    | One accepted input          | Runs the model/tool loop to a terminal result                     |

One runtime can host many agents. Each agent owns independent configuration and persistent data. An agent can have many sessions, and each session can contain many turns.

The API chooses `api:default` when a sender does not provide a session key. A product with its own conversations should choose stable session keys and store them with its conversation records.

Turns are detached from connections. Losing an SSE stream or closing a browser does not change turn ownership or lifetime; the caller reattaches by agent ID and turn ID.

Agent IDs and session keys are routing identifiers, not authorization. Use [scoped operator keys and deployment isolation](/concepts/security-and-trust.md) for access control.