Opt-in OTel logging for agent responses

What variant of Codex are you using?

CLI, App

What feature would you like to see?

Codex OpenTelemetry exports should support an explicit opt-in option to log the agent/assistant response content for a turn.

This feature is needed for monitoring and evaluating agent behavior, especially regarding adherence to SKILL.md directives.

Suggested behavior

Add a config option such as:

[otel]
log_agent_responses = true

or an environment/config equivalent.

When enabled, Codex should emit a log event for the final assistant message, for example:

• event.name = "codex.agent_response"
• conversation.id
• turn.id if available
• response_length
• response = "<final assistant message>"

A documented truncation limit would be acceptable.

Additional information

This feature is available in Claude Code's OTel implementation