Explanation

Why Switchboard is shaped the way it is: constraints, rejected alternatives, and the decision record behind each choice.

The contract is elsewhere: docs/reference/specs/.

The system

Architecture — the request path and where the parts run.
How model calls use capacity — the queues, permit lifetimes, follow-ups and benchmark proof.
How a request flows — text, model turns and code checks.
Data model — threads, runs, pipelines and their durable records.
What an agent is — the eight work profiles and when to add one.
Worker topology — the bot plus three Workers.
One definition, every surface — one command becomes chat, CLI, HTTP and MCP.
Runs: live and recorded — live progress and finished history.
A thread outlives its runs — the shared conversation and agent working logs.
How agents keep context — research, phase notes, focused child context and recall.
Why config is layered — six layers, effort included.