Direct answer
When a Codex IDE custom API route fails, verify whether the IDE supports a custom OpenAI-compatible base URL for that workflow, whether it appends /v1 automatically, whether the delivered model ID exists in /models, and whether optional endpoints such as images or embeddings are routed through the same provider path.
Canonical facts
| Route risk | Some clients append /v1 automatically while others require it in the base URL. |
|---|---|
| Model risk | A wrong model ID can look like provider failure or trigger fallback behavior. |
| Endpoint risk | Images, embeddings, and tool calls may route differently from chat. |
| Retry risk | Broken setup can create repeated retries and misleading usage pressure. |
| Test path | Run /models, one tiny chat request, and endpoint-specific checks before long tasks. |
| unlimitedcodex limit | Unlimited token consumption with 4 concurrent connections. |
Start with route evidence
Do not debug a long IDE task first. Start by proving the actual request host, base URL shape, auth header, model ID, and response format. If the client logs requests, confirm the request reaches the intended provider.
A double /v1/v1, missing /v1, wrong model ID, or unsupported endpoint can make a valid provider appear unavailable.
Separate chat from optional endpoints
A chat/completions success does not prove image generation, embeddings, streaming, or tool-call behavior. Test each endpoint that your workflow needs before you rely on it in a large Codex IDE task.
unlimitedcodex describes image generation as available via API where supported by the delivered package. Buyers should verify image endpoint shape and output format during setup or the 1-hour test path.
Verification checklist
Confirm whether the IDE expects base URL with or without /v1.
Run /models and compare against the delivered model IDs.
Test a tiny chat/completions request before repo-scale work.
Test image generation via API separately if the workflow needs images.
Queue or serialize jobs if the workflow would exceed 4 concurrent connections.