Does a ChatGPT Plus subscription work?

No. The plugin needs an OpenAI key from platform.openai.com, billed per use. Plus only gives you the ChatGPT website.

Which OpenAI models work?

GPT-5 by default; also gpt-5-mini, gpt-4.1, o3 — chosen in the plugin settings.

Can I switch between Claude and ChatGPT?

Yes. Both keys are stored at once; switching is one setting.

What does OpenAI see from my drawing?

A short description of the drawing (layers, blocks, table text) and your messages. The DWG file itself is not sent. Nothing goes to the plugin author.

How much does one question cost?

The plugin is free. The model usually costs a few cents per question; the exact amount is printed under every answer.

ChatGPT in AutoCAD: a free plugin with your OpenAI key

The free AutoGAD plugin brings ChatGPT (or Claude) right into AutoCAD 2025/2026: it answers questions about the drawing, calculates, checks schedules and changes text with your confirmation. All you need is an OpenAI key. Open source AGPL-3.0, releases on GitHub.

The same free AutoGAD plugin that brings Claude into AutoCAD also works with ChatGPT: pick OpenAI during install, paste your key — and GPT-5 answers questions about the open drawing, calculates, checks schedules and edits text with your confirmation. Open source (AGPL-3.0), 5-minute install, every version on GitHub.

In short

ChatGPT right inside AutoCAD 2025/2026 — a chat palette on the ribbon, next to the drawing.
All you need is an OpenAI key. Pasted during install; stored encrypted on your computer.
Free, open source — AGPL-3.0. You only pay OpenAI per question; the cost is printed under every answer.
Nothing changes without confirmation. Want Claude instead of ChatGPT — it is one setting.

How to connect ChatGPT to AutoCAD

Create an OpenAI key at platform.openai.com (API keys). It has to be a key; a ChatGPT Plus subscription does not work.
Download AutoGADSetup.exe (button above), close AutoCAD and run the installer. No admin rights needed.
Pick OpenAI and paste the key when the installer asks. The default model is GPT-5; change it in the plugin settings if you like.
Start AutoCAD → AutoGAD tab → Chat. Open a drawing and ask: "How many blocks of each type are in the drawing?"

What Claude does in AutoCAD

You open a drawing, open the AutoGAD palette and write to it like to a colleague. Claude sees the open drawing and:

Answers questions about the drawing. "How many fixtures of each type are on the plan?", "Which layers are frozen?", "What is in the schedule on sheet 3?"
Calculates. Panel load, design currents, breakers per outgoing line — with formulas and the source data from your tables.
Checks schedules and bills of materials. Compares table quantities with what is actually drawn, finds missing items and inconsistent tags.
Changes text across the whole drawing at once. Project code, title block, leaders, table cells: "Replace K2.AHP-2.2025 with K2.AHP-3.2025 everywhere".
Manages layers and drawing properties. On, off, freeze, lock; set file properties.
Remembers. Your rules ("I size cables for 380 V, cos φ 0.95") and the specifics of each project — no need to explain next time.
Draws from a description. "Draw a 6000×4000 mm room plan, 200 walls, a 900 door in the left wall, a 1500 window opposite, add dimensions" — Claude computes the coordinates itself and draws in the drawing's units: walls, doors, windows, dimensions, labels, hatches, each on its own layer. Repeated symbols (fixtures, sockets) become blocks placed at a pitch.
Turns a photo, scan or sketch into a drawing. Paste the picture into the chat (📎 button, Ctrl+V or drop the file). A dimensioned sketch is redrawn exactly from the numbers; a photo or scan without dimensions is traced into polylines right on your computer, then Claude cleans it up and adds dimensions and labels. The same tracer is a separate Trace button — no AI, with a live preview.
Edits what is drawn. Move, copy, rotate, mirror, offset, erase, change layer — whatever you selected or what it drew itself.

Nothing enters the drawing without you: before every edit Claude shows exactly what will change and waits for your "Allow". Plain Undo (Ctrl+Z) reverts any edit.

What it does not do

It does not replace a survey: a photo without dimensions gives a trace of what is in the pixels, perspective and shadows included; a sketch is redrawn exactly as accurately as its numbers can be read.
It does not replace the engineer: there is no code database inside; it checks what you asked it to check and shows the calculation.
It does not run in AutoCAD 2024 or older, or in AutoCAD LT.

Claude or ChatGPT?

Both handle the drawing the same way: one plugin, only the key differs. I work with Claude every day, so it is the default. Use whichever key you already have; the cost of every answer is visible right away, so comparing is easy.

What it costs

The plugin is free, permanently: open source, AGPL-3.0, every version on GitHub. You only pay for the model itself through your own key — usually a few cents per question. The cost of every answer is printed under it, so there are no surprises.

Where your drawing goes

The DWG file is never sent anywhere. Claude receives only a short description of the drawing (layers, blocks, table text) and your messages. Nothing is sent to the plugin author.