codex doesn't recognize OPENAI_API_KEY after setting it

Question

My API key is available in the environment after running `source .env`, but I'm still getting

```
Missing OpenAI API key.

Set the environment variable OPENAI_API_KEY and re-run this command.
You can create a key here: https://platform.openai.com/account/api-keys
```

Does it need to be a special one, or is any OpenAI API Key accepted? (i.e. keys that are assigned to a project vs. default vs. personal)