Architecture

Internal architecture notes for major runtime mechanisms and subsystem design.

Steering: injecting messages into a running agent loop between tool calls.
SubTurn Mechanism: sub-agent coordination, concurrency control, and lifecycle handling.
Session System: session scope allocation, JSONL persistence, alias compatibility, and migration. (ZH)
Routing System: agent dispatch, session policy selection, and light/heavy model routing. (ZH)
Hook System Guide: current hook architecture and protocol details.
Agent Refactor: notes and checkpoints for the agent refactor work.

For proposal-style or exploratory docs, also see ../design/.