Why free model tiers look dead when they aren't

I keep a small probe script that walks a list of OpenAI-compatible endpoints and asks each one the same two questions: what do you have, and will you answer a chat right now. For months I only looked at the first answer. That was the mistake.

On 09.10.2026 I finally logged both. Groq answered 200 on openai/gpt-oss-20b and qwen/qwen3.8-27b — catalog and chat both clean. Google Gemini returned 62 models from the catalog and then 429 on the chat call. Mistral returned 46 models and 429 on chat. NVIDIA NIM returned 80 models, and the IDs I tried came back 410 Gone. SambaNova returned 402 with balance_units: 0 . Four failures that look identical in a dashboard and are four completely different things.

A 200 from the catalog only means your key parsed

The /v1/models endpoint is an authentication check with a list stapled to it. It confirms the header parsed, the key resolved to an account, and maybe that the account is allowed to see the catalog.…