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/.