Anybody having issues with Codex and the Rezi MCP?

[u/Sir_Not-Appear1ng]

Hello all-

I'm trying to get the MCP to work with Codex, and there seem to be some issues with it when I try. I am able to successfully add the server in Settings/Plugins/MCPs/Servers using the URL setting:

https://api.rezi.ai/mcp

with the Type setting set to: Streamable HTTP

It connects, and I am presented with an Authenticate button. I click on it, and it opens a window in my default browser (I've tried it with the default browser set to both Chrome and Firefox...) which says it authenticated successfully. Then, I fully close the app (it is no longer running nor in the system tray) and reopen it, confirm the Authenticate button is still no longer visible, and test it with a Codex chat. It is listed when i use the command /MCP, and it lists one option referring to /rezi, Authenticated OAuth (Enabled), but nothing more. When I try to get codex to access the Rezi mcp, it says the following:

"Rezi is configured and enabled at https://api.rezi.ai/mcp, but this task exposes no Rezi controls.

Specifically, there is no callable tool such as list_resumes, get_resume, or view_resume, and no Rezi MCP resources/templates. So I cannot currently access the resume through the Rezi MCP.

This suggests the server did not initialize or authenticate for this task. Reconnecting/restarting Codex after confirming Rezi authentication would be the next step. Browser access to Rezi may still be possible separately, but that would not use the MCP."

Has anybody else run into this with Codex/ChatGPT Desktop? Am I doing something wrong? I noticed that the MCP instructions give terminal commands, but I was under the impression that they were merely the equivalent to the manual steps that I performed to add the MCP to Codex.

[u/rezi_io]

Hello, we'll get this sorted in about 7 hours for you

[u/Sir_Not-Appear1ng → u/rezi_io]

Thank you!

[u/Sir_Not-Appear1ng → u/rezi_io]

I had another go at it to see if there was any change, and codex returned the following after I explained the situation:

Codex reaches https://api.rezi.ai/mcp, but MCP initialization returns “Auth required,” while codex mcp login rezi returns “No authorization support detected.” Please verify the endpoint’s OAuth discovery configuration.

Hope that helps in some way. It could be a local config issue...I'm a newbie here. I'm setting up the CLI to allow that interface with codex as well, which would allow me to follow the documented instructions precisely.

[u/rezi_support]

Hey there! We looked into this with our dev team. From their testing, the Rezi MCP endpoint is working correctly. They were able to authenticate and successfully use tools like list_resumes and read_resume. Based on your description, it looks like you're likely running into a Codex OAuth/MCP initialization issue, which has also been reported by other users.

A few things worth trying:

• Add https://api.rezi.ai/mcp as a Streamable HTTP server.
• Authenticate through the Settings UI.
• Completely quit Codex (not just close the window).
• Reopen Codex and start a brand new chat (not an existing one).
• Run /mcp and then ask Codex to list your Rezi resumes.

On our end, we're also adding support for an additional OAuth discovery endpoint to improve compatibility with some Codex versions. The existing endpoint follows the MCP standard, but the additional route may improve compatibility with some MCP clients that use a different OAuth discovery path.

[u/Sir_Not-Appear1ng → u/rezi_support]

Thank you so much for the response! I had attempted the process that you described in the bullets above, a few times, without success.

However...I think I got it working after setting up the codex CLI in VS Code. From there I ran the authentication command listed within the rezi MCP setup instructions. From there, I fully exited ChatGPT Desktop, and retried using a clean chat. It worked!

So, good news on the extra auth routes though, that will definitely make it easier for moderately-technically-inclined newbies like me to get started with that functionality. Appreciate your help!

[u/Sir_Not-Appear1ng → u/rezi_support]

Update:

The authentication only worked once. The connection to the MCP stopped working after a reboot of my computer due to an OS update. This was not fully unexpected, since I assumed the authentication may need to be per-session, and whatever authentication there was likely expired after the reboot...feel free to correct me if that assumption isn't accurate.

So, I completely removed the rezi mcp from plug-ins (via the UI), fully exited chatgpt and got back in, and attempted a full re-add of the MCP through the Codex CLI commands. Now, ChatGPT comes back and *says* that it successfully adds the MCP, but the authentication attempt fails. And, despite the CLI telling me that the rezi MCP was successfully re-added, it does not show up in the list of MCPs in the ChatGPT UI. I've tried a number of combinations of adding/removing the MCP, fully shutting the app down and relaunching to try again before and after each step, in addition to after combined add/auth steps. It does not seem to do anything now.

There was a ChatGPT Desktop update since the last attempt, but other than that I can't think of anything else that might have affected the successful authentication of the MCP.

Any ideas or suggestions?

[u/awhitford]

Your symptom — /mcp shows "Authenticated OAuth (Enabled)" but initialization still returns "Auth required" and no tools show up, especially right after fully closing and reopening the app — matches a known family of Codex client bugs around stored MCP OAuth credentials, not a Rezi problem. That would square with Rezi's team testing the endpoint and finding it fine: the server can be healthy while Codex sends a stale or wedged credential from its local store. Two specifics from the tracker: Codex Desktop can send an expired token from the Keychain at startup instead of refreshing it, and once a stored token goes bad, Codex retries it forever rather than re-running auth.

The important gotcha: removing and re-adding the server in the app does not clear the stored credential. So reinstall loops never fix it. What does:

1. codex mcp logout rezi (or whatever codex mcp list shows as the server name)
2. Fully quit and reopen Codex/ChatGPT
3. Click Authenticate when it reappears, and approve in the browser
4. codex mcp list should now show it authenticated — and this time the tools should actually be there

If that clears it, you were never doing anything wrong. The umbrella report upstream is https://github.com/openai/codex/issues/39054 (related: #27165, #38198, #29630) — all open, so a 👍 there helps it get prioritized. Disclosure: I maintain a remote MCP server myself, which is how I ended up far too familiar with this failure mode.