MCP resume_path for Codex sessions

[rabsef-bicrym]

I would like to propose adding resume_path support to the Codex MCP tool so MCP clients can resume prior sessions across desktop and mobile. A tested implementation is available in #10117.

Motivation

• Cross-device continuity: start a session on desktop and resume on mobile (or the other way around)
• Better MCP UX: treats Codex as stateful when used through MCP, instead of stateless
• Parity with other CLI workflows: keeps Codex competitive in Happy-style multi-surface use

This matters for MCP clients like Happy CLI that provide a mobile surface on top of a local Codex process.

Implementation

#10117 includes:

• Optional resume_path in the MCP tool schema
• MCP runner logic that resumes from the rollout path when provided
• Backward compatibility for existing callers
• Tests covering schema updates and legacy payload compatibility

This simply exposes existing Codex resume behavior through MCP.

Contribution policy

I’ve read the invitation-only contribution update and understand the shift toward high‑signal discussion and prioritization. Sharing this here in case it aligns with the roadmap or a known need (in addition to the use case of Happy CLI resume).

Companion work

Happy CLI side: slopus/happy-cli#151 uses the MCP resume-path to provide a clean resume picker and consistent mobile/desktop experience.

Request

If this is aligned, I’d appreciate feedback on the approach in #10117. If there’s a preferred shape for MCP resume or a different path the team wants, I’m happy to adjust or drop the change.

[etraut-openai]

@rabsef-bicrym, thanks for starting the conversation. I'm going to convert this to a feature request so it gets more visibility and upvotes. We use upvotes on feature requests to gauge interest and inform priorities for Codex development.

[rabsef-bicrym]

Sorry - I'm trying to comport w/ the new guidelines. Thank you for the conversion.

[etraut-openai]

Here's a link to the feature request.

[etraut-openai]

I'm trying to comport w/ the new guidelines

Thanks! Much appreciated.