You can make ChatGPT actually build your Roblox game instead of handing you a script to paste. Your normal chatgpt.com tab reads your game tree, edits Luau in place, runs code live and generates meshes and materials, directly inside Roblox Studio.
No API key. No credits. No subscription. You use the same chat you already use. The tool that does it is ZeroScript, open source under GPL-3.0, and ChatGPT support landed in 1.5.1.
The setup: four steps, about five minutes
No terminal involved.
1. Install the extension
Download the latest release from GitHub and load it unpacked in Chrome or Edge:
- Unzip the download.
- Go to
chrome://extensions. - Turn on Developer mode (top right).
- Click Load unpacked and select the unzipped folder.
2. Enable MCP in Roblox Studio
ZeroScript does not inject anything weird into Studio. It talks to Roblox Studio's own built-in MCP server, the one Roblox ships. Turn it on once in Studio's settings and you are done forever.
3. Run the Bridge
Double-click start.bat from the download. A small window confirms the Bridge is live. It is the local relay between your browser tab and Studio, and it runs on your machine only.
4. Open ChatGPT and start a session
Go to chatgpt.com, click Start session in the ZeroScript panel, and describe what you want:
Build me a shop system with a UI, three purchasable items, and save the player's purchases.
ChatGPT plans it, writes the Luau, and ZeroScript applies it in Studio while you watch.
Why ChatGPT was the hardest one to add
Adding a provider is usually a matter of knowing where its input box and its replies live. ChatGPT was different, and the reason is worth writing down if you ever build something that reads code out of a chat UI.
ChatGPT renders code blocks with CodeMirror. CodeMirror emits one element per line and no newline characters at all. So a perfectly valid command, displayed beautifully on screen, was read as one giant single line and came back as "your code block was empty". Every tool call failed.
Then long commands ran truncated. Past roughly 2000 to 4000 characters, CodeMirror renders only part of a long line and stops updating. Measured live: a 21273-character command of which the page exposed 4049. The command executed cut in half. The fix was to stop reading the rendered DOM and read the editor's true document through a MAIN-world tap. A 5.3k-token multi_edit now applies whole.
The same class of bug hit Meta AI, whose JSON viewer abridges large values in its default Tree view: a 19103-character multi_edit was present in the page as 223 characters ending in "edits":[1 item]. That truncated object is what reached the parser. Commands are now taken from the viewer's Raw tab, in full.
The lesson, if you want one: what a chat UI shows you is not what is in the page. Modern editors and viewers render an approximation. If you are scraping structured output out of one, verify character counts against the source of truth, not against what looks right.
One deliberate limitation
Image input is off for ChatGPT on purpose. ChatGPT's free tier caps files and images on a quota separate from messages, so vision would work part of the day and mysteriously stop. Better to not offer it than to offer it unreliably. Other providers that do not have that split keep their image support.
The eight providers
ZeroScript now drives ChatGPT, DeepSeek, GLM, Kimi, Gemini, Qwen, LMArena and Meta AI. Hands-on ratings out of 10:
| Model | Speed | Stability | Intelligence |
|---|---|---|---|
| ChatGPT | 8 | 6 | 6 |
| DeepSeek (recommended) | 7 | 8 | 7 |
| GLM | 5 | 4 | 8 |
| Kimi | 4 | 5 | 9 |
| Gemini Flash | 8 | 3 | 5 |
| Qwen | 5 | 7 | 6 |
| Meta AI | 6 | 8 | 9 |
LMArena is a multi-model playground, use Direct mode to reach many models from one chat.
Pick ChatGPT if you want speed and a model you already know. Pick DeepSeek if you want the longest sessions without babysitting. Pick Kimi when the problem is genuinely hard.
Is this actually free?
Yes, and the reason is structural rather than generous. ZeroScript never calls a billed API. It drives the chat you are already logged into, so your prompt budget is whatever your free account gives you, and there is no credit counter in between. The extension itself is open source under GPL-3.0, requires no account, and sends no telemetry.
That is the whole difference with credit-based Roblox AI tools: there is nothing to run out of, because there was never a meter.
- Site and full setup: zerodev.tools/zeroscript
- Source: github.com/sebattfg/ZeroScript-Free
- Video walkthrough: youtu.be/kPKiZLZ9_Ps
If you try it with ChatGPT, tell me what you built. The failure reports are what fixed the two bugs above.
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