tutorial-guide-agent-runtime

A valid init.json plus the lingtai-agent run command is sufficient to start an agent. The TUI is only a Go frontend that writes init.json, launches the Python process, and monitors heartbeat files.

The agent reads init.json, loads the env file, resolves the venv, builds the Agent object, cleans stale signals, installs signal handlers, starts in ASLEEP state, and blocks on shutdown. It is a long-running Python process that does not exit after one task.

Signal files (.interrupt, .suspend, .sleep, .prompt) are filesystem-based controls placed in the agent's home directory. External tools like the TUI write them to control the running agent, while .agent.heartbeat tracks liveness with updating timestamps.

Only editable sections like identity/lingtai and pad can be changed by the agent; protected sections such as principle, covenant, rules, and procedures are host-written. The brief is externally maintained by the secretary.

Character is durable state the agent authors for itself in system/lingtai.md via the psyche, not a seed field in init.json. This identity section is how agents develop unique personalities through experience.