Codex app: global Custom instructions / ~/.codex/AGENTS.md not injected into project chat context

Summary

Global Custom instructions configured in the Codex app appear to be saved correctly to ~/.codex/AGENTS.md, but they were not included in the visible/contextual instructions for a project chat. The assistant only received the project-level AGENTS.md, so the global personalization rules were silently not applied until the user showed a screenshot and the assistant manually inspected ~/.codex/AGENTS.md.

Expected behavior

Global personal/custom instructions should be loaded and applied in every Codex chat, including project chats with their own AGENTS.md files. Project-level instructions can still have documented precedence, but the global file should not disappear entirely.

If this behavior is intentional, the UI/docs should clearly say that Settings > Personalization writes to a file that may not be injected into project chat context automatically.

Observed behavior

• Settings > Personalization contained several global rules.
• ~/.codex/AGENTS.md also contained those rules.
• The project had its own shorter AGENTS.md at /Users/sergey/Documents/Codex/Projects/Машины/AGENTS.md.
• In the chat's initial context, only the project AGENTS.md instruction was visible/applied.
• The assistant did not see or apply the global rules until the user explicitly pointed out the mismatch and the assistant manually checked the global file.

This made the configured personalization feel unreliable, especially for workflow rules that the user expected to apply to every new request.

Repro steps

1. In Codex app Settings > Personalization, add multiple global custom instructions.
2. Confirm they are written to ~/.codex/AGENTS.md.
3. Open a project that has a project-level AGENTS.md with a smaller/different set of instructions.
4. Start or continue a project chat.
5. Ask whether the assistant sees the global personalization rules.
6. Observe that only project-level instructions are visible/applied unless the assistant manually reads ~/.codex/AGENTS.md.

Impact

Users can configure global personalization and assume it is active, while the model may silently operate without it. This is particularly confusing because the documented behavior suggests personal instructions should shape communication globally, while project AGENTS.md files should handle project/team-specific guidance.

Documentation context

The Codex manual indicates that Settings > Personalization custom instructions update personal instructions in AGENTS.md, and the customization guidance describes global ~/.codex/AGENTS.md as a place for communication preferences/personal rules. In this case, those global instructions existed on disk but were not injected into the project chat context.

Suggested fixes

• Load and merge global ~/.codex/AGENTS.md into project chat context with documented precedence.
• Add a diagnostic view or startup note showing which instruction files were loaded for the current chat.
• If global instructions are intentionally not loaded in some project-chat cases, clarify this in Settings > Personalization and the docs.