Runs one isolated, bounded Sagents execution per admitted request.
Install optional sagents == 0.17.1. Configure :agent as a function receiving
a BackendRequest and returning {:ok, agent, state}, :result as a function
mapping a successful terminal tool result to %{status: ..., facts: ..., summary: ...},
and :completion_tool as its name. :max_runs defaults to 8 (maximum 100).
The application constructs the model, credentials and synchronous tools. Build
the agent with replace_default_middleware: true and empty middleware; default
filesystem/subagent tools, custom modes, fallbacks and asynchronous tools are
deliberately unsupported. This makes execution ownership and authority explicit.
Cancellation is advisory: it stops local execution and reports an uncertain external outcome. It never confirms reversal of an already executed tool. Updates, model token streams, progress and clarification are not advertised.