VS Code quickstart
Install the extension, sign in, index your project and debug your first error.
You need VS Code 1.101 or later and a project folder. DebugAI reads Python, JavaScript and TypeScript best. Java and C# files are indexed and analysed too.
Using Cursor, Windsurf or VSCodium? Install from Open VSX instead (see how), then come back to step 2. Everything after the install is the same.
Install the extension
Open DebugAI on the Marketplace and press Install. Or in VS Code, open the Extensions view (Ctrl Shift X, or Cmd Shift X on a Mac), search for DebugAI and install it. From a terminal:
code --install-extension debugai.debugaiOnce it is installed, the status bar at the bottom right reads DebugAI: Get Free Key and a notice offers to sign you in.
Sign in
Open the Command Palette (Ctrl Shift P, or Cmd Shift P) and run DebugAI: Sign In. Or press Sign in on the notice.
Your browser opens on debugai.io with an eight-character code, and the same code is already on your clipboard. Sign in, or create a free account (no card), then check the code matches the one VS Code shows and press Connect it. You can close the tab.
Back in VS Code you will see DebugAI connected (free, 10/day).
The code expires after 10 minutes. On a machine with no browser, such as a remote server over SSH, the notice gives you the address instead: open it on any device and type the code.
Index your project
On the DebugAI connected message, press Index workspace. If the message is gone, run DebugAI: Index Entire Workspace from the Command Palette.
The status bar shows DebugAI indexing... with a percentage. When it finishes you get a count, for example Indexed 42 files. DebugAI can now trace an error across your codebase., and a panel listing the files it stored.
You only do this by hand once. From the next time VS Code starts, DebugAI indexes the project on its own, and sends each file again when you open or save it.
What indexing sends
The text of your source and config files, up to 50 KB each and up to 500 files per run. The free plan keeps 200 files per project. .env files, key files and folders like node_modules are never sent. To stop automatic indexing, turn off the debugai.autoIndex setting. More in Index your project.
Debug an error
Run the command that fails in VS Code's own terminal. Then right-click inside the terminal and pick DebugAI: Analyze Terminal Error. DebugAI shows the error it found, starting with Found in terminal:, and you press Analyze This.
If the error is in a file instead, select the error text and press Ctrl Alt D (Cmd Alt D on a Mac). That runs DebugAI: Analyze Error. With nothing selected, it offers the line under your cursor if that line reads as an error, and otherwise asks you to paste one.
The answer opens in a DebugAI panel beside your code.
You'll know it worked when
The panel shows a Root Cause that names a file and a line in your project, with one or more Ranked Fixes under it. The status bar now counts what is left today, for example DebugAI (9 left).
Review the fix and apply it
Each fix has a confidence figure and one of three labels: ✓ Verified (a mechanical check passed), ✗ Failed check (DebugAI disproved it and capped its confidence) or Not verified (the figure is the model's own estimate). Read a result explains every part of the panel.
Press Preview & Apply Fix. VS Code opens a diff titled DebugAI: Review Fix #1 with the file name. Read it like a pull request, then press Apply on the fix card, or Cancel.
After applying, the card offers Undo for 30 seconds. Ctrl Z in the file works too, because the change goes through the editor like your own typing. Run the failing command again to confirm the fix.
No error to try it on
- Run Your first debug: a three-file project with a planted bug, where the crash and the cause are in different files. It uses one of your 10 free debugs.
- Or run DebugAI: Try Demo Analysis. It opens a pre-made answer to a Celery worker crash, so you can see the panel without a project. It makes no request and does not count, and its fixes cannot be applied.
Next
- Read a result: confidence, the three labels, and the memory badges.
- Proactive Scan: DebugAI reads your recent changes and reports defects it can prove.
- VS Code agent mode: the extension already registers DebugAI as an MCP server for VS Code's agent mode.
- Something not working: Sign-in and keys, Indexing.