[Feature]: Add Codex CLI version compatibility checks to surface unsupported versions clearly

[RichieCahill]

Before submitting

• I searched existing issues and did not find a duplicate.
• I am describing a concrete problem or use case, not just a vague idea.

Area

apps/desktop

Problem or use case

When updating from T3-Code-0.0.21-nightly.20260420.75-x86_64.AppImage to T3-Code-0.0.21-nightly.20260420.77-x86_64.AppImage on Linux (NixOS) with Codex CLI v0.114.0, Codex stops working.

Observed error:

Codex app-server provider probe failed: Invalid initialize payload: Missing key at ["codexHome"]

Proposed solution

T3 Code should validate the installed Codex CLI version against a supported compatibility range before using the Codex app-server.

For example:

define a minimum and maximum supported Codex version for each T3 Code release
surface a clear warning when the installed Codex version is outside that range
skip or guard incompatible app-server calls when compatibility is known to fail
document the tested Codex version range in release notes

This would make Codex/T3 Code compatibility problems much easier to diagnose and would prevent confusing runtime failures caused by protocol drift.

Why this matters

It would improve the user experience and reduce unnecessary bug reports by catching unsupported Codex versions early and surfacing a clear, actionable compatibility message.

Smallest useful scope

A minimal fix would be to add a Codex version compatibility check before app-server initialization and surface a clear error if the installed Codex version is outside the supported range.

Alternatives considered

No response

Risks or tradeoffs

No response

Examples or references

No response

Contribution

• I would be open to helping implement this.

[DommyMM]

@RichieCahill I'm on windows and rolling back from nightly to the latest stable fixed it for me. I'm not entirely sure what's wrong, as I reinstalled codex with npm i -g @openai/codex and codex itself told me:

      - codex-cli 0.124.0
      - T3 Code 0.0.22-nightly.20260423.108
      - native Windows, not WSL

if that matters. But so reverting from 0.22 nightly to the latest stable 0.21 seemed to fix the codex provider and [codexHome] issue without changing anything

[RichieCahill]

@RichieCahill I'm on windows and rolling back from nightly to the latest stable fixed it for me. I'm not entirely sure what's wrong, as I reinstalled codex with npm i -g @openai/codex and codex itself told me:

      - codex-cli 0.124.0
      - T3 Code 0.0.22-nightly.20260423.108
      - native Windows, not WSL

if that matters. But so reverting from 0.22 nightly to the latest stable 0.21 seemed to fix the codex provider and [codexHome] issue without changing anything

im running

• Codex v0.118.0
• T3 Code 0.0.22-nightly.20260423.108
• im on Linux
  Imo try down grading you codex version

[dukhevych]

same issue in stable 0.0.21

update:
not sure what exactly helped, but i have updated codex, switched t3code to nightly and then back to stable. all fine now.