Getting started
Use your ChatGPT or Codex subscription in BloxBot
September 8, 2026
If you already pay for ChatGPT Plus or Pro, you do not need to buy API credits to use OpenAI models in BloxBot. Open Settings, go to Providers, pick OpenAI, and choose Sign in with OpenAI. Your browser opens, you log in with the ChatGPT account you already have, and the models your plan covers appear in the model picker.
This works because BloxBot is a desktop shell around OpenCode, and OpenCode supports the subscription sign-in path for the OpenAI provider alongside the usual API key. BloxBot surfaces whichever auth methods the provider offers, so the option is there without any extra setup.
Step by step
- Install BloxBot and connect Roblox Studio first. The setup guide covers that part.
- Open Settings, then the Providers tab.
- Find OpenAI in the provider list and click it.
- Choose Sign in with OpenAI rather than Use an API key.
- Complete the login in the browser window that opens. If BloxBot shows a code field, paste the code the browser gives you back into it.
- The dialog closes on its own once the provider connects. Open the Models tab and pick an OpenAI model.
BloxBot shows the sign-in button only for providers that advertise an OAuth method, so if you see only the API key field, OpenCode is not offering the subscription flow for that provider on your machine. Updating to the latest BloxBot release is the first thing to try, since it ships a newer OpenCode.
What you get, and what you do not
The model picker lists the models your account grants. OpenCode's documentation says OpenAI models should be available after the sign-in, but the real boundary is whatever OpenAI attaches to your plan, and that has changed before. If you specifically want GPT-6 Astra and it does not appear in the list, an API key is the reliable route.
You also inherit the plan's usage allowance. That is the real trade-off. With an API key you pay per token and keep going; with a subscription you pay nothing extra and stop when the allowance runs out. For Roblox work that distinction bites harder than it does for ordinary coding, because an agent operating Studio through MCP spends tokens on every scene inspection, not just on the code it writes.
Making the allowance last
The same discipline that improves results also cuts consumption. Roblox OpenGameEval found the largest model gains on bounded tasks with a named target and a checkable outcome, which we broke down in writing better Roblox AI tasks. Three habits do most of the work:
- Name the target. “Inspect ServerScriptService.Checkpoints” costs one tool call. “Fix the checkpoints” costs a scene-tree crawl first.
- State the check. Tell the agent how you will know it worked, so it tests the result instead of guessing at one.
- Start fresh sessions. A long thread resends its whole history on every turn. When you move to an unrelated system, open a new session.
Mixing providers helps too. BloxBot connects several at once, so you can keep a subscription model for the heavy reasoning and switch to a cheaper API model for routine edits.
Where the credentials live
BloxBot runs OpenCode with its own sandboxed config, cache, state, and data directories inside the BloxBot workspace folder in your home directory. Your login is stored in that data directory, not in a system-wide OpenCode install, so connecting OpenAI here does not touch a separate OpenCode setup you may already use in a terminal.
The generated OpenCode config file is rewritten from scratch every time BloxBot starts, so hand-editing it will not stick. Credentials are not in that file and survive restarts. To remove them, use Disconnect on the provider in Settings.
The rules to respect
OpenAI intends subscription sign-in for personal coding assistance. That means one person using their own plan. It is not a way to resell model access, run a shared service, or put one account behind a team of developers. If you are building something commercial with more than one seat, use API keys.
BloxBot itself stays free and open source either way. It never brokers model access, so nothing about the app changes based on how you pay OpenAI. That independence is the point, and it is the argument in why BloxBot still matters.
Frequently asked questions
Can I use a ChatGPT Plus subscription in BloxBot instead of an API key?
Yes. BloxBot runs OpenCode, and OpenCode's documentation recommends a ChatGPT Plus or Pro plan for its OpenAI sign-in. Open Settings, go to Providers, choose OpenAI, and pick Sign in with OpenAI instead of Use an API key.
Does using my ChatGPT subscription in BloxBot cost extra?
No extra charge, but it draws on the same Codex usage allowance as your plan. Heavy agentic sessions in Roblox Studio consume that allowance quickly, and you hit a rate limit rather than a bill.
Which models can I use with a ChatGPT subscription?
Whatever your plan grants. OpenCode's documentation says OpenAI models should be available after signing in, and the BloxBot model picker lists what your account actually returns. If a specific model is missing, an API key is the reliable route.
Where does BloxBot store the OpenAI login?
In the sandboxed OpenCode data directory inside your BloxBot workspace folder, not in your system-wide OpenCode install. Disconnecting the provider in Settings removes it.
Is signing in with a ChatGPT plan allowed?
OpenAI's subscription sign-in is intended for personal coding assistance. It is not a license to resell access, run a multi-user service, or share one account across a team.