OpenAI’s own Developer Mode documentation says multiple apps can be combined, but actual custom MCP + OpenAI Apps behavior does not match

Ah, I think I understand what you’re going for. To be honest, I’d recommend using Codex for this right now, which can use all of the apps you have set up in ChatGPT. This is very much an intentional behavior in ChatGPT built for safety over capability. A lot of this is getting revisited as we merge ChatGPT and Codex, so I would hang tight for a bit and see how things develop.