How to turn off Codex subagent tools with agents.enabled

Codex turns on its multi-agent tools (spawn_agent, send_input, resume_agent, wait_agent and close_agent) by default. To keep it working as a single agent, disable them under [agents] in config.toml.

[agents]
enabled = false

The older way was multi_agent = false under [features]. Since 0.168.0 (November 13), Codex warns when features.multi_agent is explicitly configured and points you to agents.enabled for disabling subagent tools. If an old config still has multi_agent, move it.

The same [agents] table also holds the default subagent model (default_subagent_model), the default reasoning effort (default_subagent_reasoning_effort), and the cap on concurrently open spawned-agent threads per session (max_concurrent_threads_per_session, excluding the primary).