TUI-usable session-control primitive in Codex CLI

What variant of Codex are you using?

Codex CLI

What feature would you like to see?

I know this overlaps with my earlier request, but this is a narrower ask and the workflow need is real for me.

My prior codex inject request (#11415) was closed as not planned.
I am not asking to revive that exact command. I am asking for the underlying capability in Codex: a native, App Server–aligned way to send/stream control messages to active sessions. If easier, this could also be done by extending MCP-trigger capabilities.

Practical context: in Claude, channel-style external messaging workflows are already usable, and I can stream inputs and adjust training hyperparameters live in a loop. OpenCode has this workflow too, so switching is a practical alternative. Otherwise, in Codex, achieving the same behavior means building a custom JSON-RPC client and reimplementing session-control plumbing outside native TUI/CLI.

Request

Please expose a first-class, TUI/CLI-usable session-control/channel primitive in Codex with functionality equivalent to the Claude channel workflow, implemented however you think is best.

I do not need a full orchestration framework—just this control path directly from TUI/CLI.

What we tried

• Tested codex mcp-server directly.
• codex + codex-reply works only inside the same live MCP server process.
• thread_id from codex exec --json does not continue via codex-reply (Session not found for thread_id).
• In Claude, the development-channel path proactively wakes the TUI session when external messages arrive.

So this request is specifically for a native Codex CLI control/wake path for active sessions.
Perhaps an MCP-server-routed external trigger could wake a waiting TUI session.

Drafted by Codex

Additional information

References

• Codex inject request: https://github.com/openai/codex/issues/11415

_Closed as not planned._

• Claude inject request: https://github.com/anthropics/claude-code/issues/24947

_Related request in Claude ecosystem; channel workflow is available there._

• App Server direction post: https://openai.com/index/unlocking-the-codex-harness/

_App Server described as the long-term integration path._

• App Server docs: https://developers.openai.com/codex/app-server

_Current protocol surface for thread/turn/event control._

• CLI reference: https://developers.openai.com/codex/cli/reference

_Current CLI capabilities and limits._

• Release notes with app-server/TUI context:
• https://github.com/openai/codex/releases/tag/rust-v0.117.0
• https://github.com/openai/codex/releases/tag/rust-v0.118.0
• Related limitation report: https://github.com/openai/codex/issues/6168

_codex-reply cannot continue with thread_id from a separate process/session._