Introduction
We have contributed the following four pull requests to add Azure OpenAI support to Codex, letting you enjoy the same Codex experience as in ChatGPT while running securely on Azure:
We are collaborating with OpenAI on additional updates and integrations, so stay tuned. Meanwhile, follow the steps below to get Codex running on your Azure subscription.
Pending OpenAI's NPM release
Until OpenAI publishes a new release from main, please build from sourceAfter you are up and running, visit gitagu.com to configure your repository for Codex and to browse a growing catalog of other Azure-hosted coding agents, including GitHub Copilot Coding Agent, Cognition Devin, SRE Agent, and more.
Prerequisites
- An active Azure subscription with access to Azure OpenAI.
- Contributor permissions in Azure AI Foundry.
- macOS, Linux, or Windows 11 plus WSL 2 (Codex is trained on Unix-style shells).
- Node 18+ and
npmfor installing the CLI.
Step 1 – Deploy a Codex model in Azure AI Foundry
- Go to Azure AI Foundry @
ai.azure.comand create a new project. - Select a reasoning model such as
codex-mini,o4-mini, oro3. - Click Deploy, choose a name, and wait about two minutes.
- Copy the Endpoint URL and generate an API key.
Step 2 – Install the Codex CLI
npm install -g @openai/codex
export NODE_NO_WARNINGS=1 # Optional - to reduce verbosity
codex --version # verify installationStep 3 – Configure ~/.codex/config.json
{
"model": "codex-mini",
"provider": "azure",
"providers": {
"azure": {
"name": "AzureOpenAI",
"baseURL": "https://<your-resource>.cognitiveservices.azure.com/openai",
"envKey": "AZURE_OPENAI_API_KEY"
}
},
"history": {
"maxSize": 1000,
"saveHistory": true,
"sensitivePatterns": []
}
}# Linux, macOS, or WSL
export AZURE_OPENAI_API_KEY="<your-api-key>"
# Work-around for current Codex bug – also set:
export OPENAI_API_KEY="$AZURE_OPENAI_API_KEY"Step 4 – Explore with your coding agent
codex -p azure
# generate a unit test for src/utils/date.ts# convert this Java class to Python
Step 5 – Run Codex in GitHub Actions
Codex can execute as part of your CI pipeline. Store your API key in the
repository’s secret store as AZURE_OPENAI_API_KEY and add a job like:
jobs:
codex_refactor:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- name: Run Codex agent
run: |
npm install -g @openai/codex
export AZURE_OPENAI_API_KEY=${{ secrets.AZURE_OPENAI_API_KEY }}
export OPENAI_API_KEY=${{ secrets.AZURE_OPENAI_API_KEY }}
codex -p azure "# refactor the authentication module for clarity"Step 6 – Explore more agents with Gitagu
- Browse detailed docs and benchmarks for other Azure-hosted agents.
- Create repo-ready configuration guides with one click.
- Experiment with GitHub Copilot Coding Agent, Cognition Devin, SRE Agent, and others.
Troubleshooting
| Symptom | Fix |
|---|---|
401 Unauthorized or 403 Forbidden |
Export both AZURE_OPENAI_API_KEY and (until the bug is resolved) OPENAI_API_KEY with the same value.
Confirm that your key has project/deployment access. |
ENOTFOUND, DNS error, or 404 Not Found |
Verify baseURL in config.json uses your resource name and correct domain, e.g.
https://<resource>.openai.azure.com/openai.
Some tenants require the .cognitiveservices domain (example shared by a reader: https://ecano-project1rp-resource.cognitiveservices.azure.com/openai). |
| CLI says “no provider found” or ignores Azure settings | Open ~/.codex/config.json and ensure:
|
| In Codex, you get a warning that “codex-mini” is not in the list of available models for provider “azure” | This is a known issue, and we have a PR in progress to address this. Ignore this warning and proceed with codex-cli tasks. |
Conclusion
In just a few minutes you can connect an AI coding agent to your Azure tenant, keep intellectual property secure, and accelerate software delivery. Combine Codex CLI, GitHub Actions, and Gitagu’s agent catalog to build a flexible AI-powered engineering workflow. Give it a try and share what you create.
Questions or feedback? Drop a comment below
Hi Govind
Great article—thank you for sharing it!
I ran into an issue when executing codex -p azure and received an error message. Here are my current settings—do you happen to know what might be causing this? i am using WSL.
plee@plee:~$ codex --version
codex-cli 0.4.0
plee@plee:~$ cat .codex/config.json
{
"model": "codex-mini",
"provider": "azure",
"providers": {
"azure": {
"name": "AzureOpenAI",
"baseURL": "https://fine-tuning99.openai.azure.com/openai/",
"envKey": "AZURE_OPENAI_API_KEY"
}
},
...
I followed the tutorial, but I’m encountering an error when trying to use codex-mini:
“OpenAI rejected the request. Error details: Status: 400, Code: OperationNotSupported, Type: unknown, Message: 400 The chatCompletion operation does not work with the specified model, codex-mini. Please choose different model and try again. You can learn more about which models can be used with each operation here: https://go.microsoft.com/fwlink/?linkid=2197993.. Please verify your settings and try again.”
Additionally, I noticed that after deploying codex-mini on AI Foundry, the URI field appears to be empty.
Hi Andres, Thanks for giving it a shot. When you test again, please use o4-mini or o3 from Azure OpenAI.
I’ve updated the blog to list the new PRs – two were merged today, including the codex-mini update that adds response-API support. OpenAI is slated to publish a new npm release tomorrow. Once you update codex from the npm package, codex-mini should work as well.
In the meantime, o4-mini or o3 should let you proceed
Thanks for sharing, Govind. I am trying exact same steps from past few days but not able to successfully configure Azure Endpoint and key with the codex cli. I am getting “OpenAI rejected the request. Error details: Status: 404, Code: 404, Type: unknown, Message: 404 ╯
Resource not found. Please verify your settings and try again.”
I am trying to use o4-mini model. I couldn’t find the codex model in Azure foundry.
I was able to run codex cli using my openAI account but want to run it with Azure and it is not working. Thanks in advance.
Thanks for giving it a try, Anoop.
- Make sure your `~/.codex/config.json` matches the sample in the post, and that you are launching with `codex -p azure`.
- Confirm that the `AZURE_OPENAI_API_KEY` environment variable is set.
- If you’re on Windows, test inside WSL.
There’s a known bug on the main branch (PRs #1324 and #1321 are pending approval). Until those are merged, set OPENAI_API_KEY to the same value as AZURE_OPENAI_API_KEY. After the fix lands, this extra step won’t be necessary.
Thanks, Govind. I verified the config.json and other details but still it is not working getting same error of resource not found. Thanks anyway. Maybe will wait till the issue is merged in the main branch. Thanks.
Sorry to hear that. Please try using this URL pattern: https://.cognitiveservices.azure.com/openai – note the “cognitiveservices” segment. Depending on how you configured AI Foundry or your Azure OpenAI resource, the URI may vary. I’ve updated the troubleshooting section of the blog to reflect this. Let me know if it works. Meanwhile, the two PRs were just merged, so codex-mini should be functioning soon.
waiting for codex-mini to work. o4-mini is working perfectly. getting the following:
system
⚠️ OpenAI rejected the request. Error details: Status: 400, Code: OperationNotSupported, Type: unknown, Message: 400 The chatCompletion
operation does not work with the specified model, codex-mini. Please choose different model and try again. You can learn more about which
models can be used with each operation here: https://go.microsoft.com/fwlink/?linkid=2197993.. Please verify your settings and try again.