Downcity
Core Concepts

Runtime Context

Explain what execution context is, what session is, and how plugins connect to them

Runtime Context

This page answers three questions:

  1. what execution context is
  2. what session is
  3. how plugins connect to them

Execution context

Execution context is the shared capability surface exposed during one run.

Plugins consume it to access stable runtime abilities without depending on every concrete host implementation.

Session

Session is the execution owner.

It is responsible for:

  • prompt execution
  • model/tool flow
  • run-local state
  • output production

Plugins do not replace session. They participate around it.

Plugin connection model

Plugins connect to runtime through:

  • actions
  • hooks
  • system text
  • lifecycle
  • HTTP

Managed plugins may also own long-lived runtime state, but session remains the execution core.

Practical reading rule

  • if you are tracing “who actually runs the turn”, look at session
  • if you are tracing “who exposes or augments capability”, look at plugin