Regression: encrypted MultiAgentV2 messages remove readable task audit trail

What version of Codex CLI is running? Upstream main after #26210 (Encrypt multi-agent v2 message payloads, merged 2026-06-05). This appears to affect versions that include that change and enable MultiAgentV2 (post-0.137.0). What subscription do you have? Not subscription-specific. Which model were you using? Not model-specific. This concerns MultiAgentV2 spawn_agent, send_message, and followup_task message handling. What platform is your computer? Not platform-specific. What terminal emulator and version are you using (if applicable)? Not terminal-specific. Codex doctor report Not applicable. The regression is visible from the merged code behavior in #26210 rather than from local environment state. What issue are you seeing? #26210 makes MultiAgentV2 agent task/message payloads opaque to Codex by marking the model-facing message parameter as encrypted, storing only InterAgentCommunication.encrypted_content, and leaving InterAgentCommunication.content empty. The encrypted delivery path is understandable as privacy hardening, but it also removes the human-readable task/message text from local rollout history, trace reduction, and parent-side audit/debug surfaces. That makes it difficult to answer basic questions such as:

What task did this spawn_agent call give the child agent? What message was sent to a subagent? Why did a child thread exist when reviewing a rollout after the fact?

This is different from #26753, which reports request validation failures for encrypted tool schemas. This issue is about auditability and debuggability after the encrypted schema is accepted. What steps can reproduce the bug?

Use a build containing Encrypt multi-agent v2 message payloads #26210 with MultiAgentV2 enabled. Have the model call spawn_agent, send_message, or followup_task. Inspect the parent rollout/history/trace for the subagent task. The task/message content is hidden behind ciphertext rather than being available as human-readable audit text.

What is the expected behavior? Codex should preserve a human-readable, structured audit copy of the subagent task/message while still allowing encrypted delivery to the recipient model. A possible shape is to keep the encrypted message field for model delivery, but add a separate non-encrypted audit field for the readable task text.

The audit field should be persisted in rollout/history/trace metadata so users and maintainers can inspect what was delegated without needing to decrypt model-delivery ciphertext. Additional information Related PR/issues:

Encryption change: Encrypt multi-agent v2 message payloads #26210 Related but distinct schema-validation issue: MultiAgentV2 encrypted spawn_agent schema returns 400: model not configured for encrypted tool use #26753

The goal is not necessarily to revert encrypted delivery. The concern is that encrypted delivery should not fully remove local human auditability for subagent delegation.