Codex stays open source, but parent-to-sub-agent task messages are now encrypted

Codex 仍然开源，但父 agent 给子 agent 说了什么，现在看不见了

On June 5, OpenAI merged PR #26210, encrypting task messages that Codex's parent agent sends to sub-agents. Previously, local session logs showed plaintext instructions like 'Review the authentication changes'; now only <ciphertext> remains. Sub-agent tool calls, commands, and outputs are still visible, but debugging can't tell whether the parent gave a wrong task or the sub-agent misunderstood. Encryption happens server-side in the Responses API; the local client only forwards ciphertext. This differs from earlier hidden reasoning and compaction—what's now hidden is content that directs another agent to act, not internal model thinking. The post doesn't spell out OpenAI's rationale; speculation includes prompt protection or unified cloud multi-agent services.

Why it matters: A product-change report with concrete technical details, not marketing fluff. PR numbers, issue links, and before/after comparisons are all provided. The deduction is because this is a feature adjustment rather than a new capability launch, and its impact is limited to Codex u...