Your first session · DevCapsule

Open a real IDE, run a little JavaScript, then close it and return to your work. This first exercise needs no AI account, no Git checkout and no language installed on your computer. Install DevCapsule first: Install. Already have a project? Skip to an existing repository.

1. Make a first workspace

In your computer's terminal:

mkdir -p ~/hello-devcapsule
cd ~/hello-devcapsule
~/.local/bin/devcapsule project init --need frontend-ide --need node

This selects VSCodium, a VS Code-family IDE, and Node.js. Initialization asks for a few decisions. For this exercise:

Prompt	Answer
Project creator	Your email address or a project URL. It identifies the project; it is not a sign-in.
Select the default agent?	`no` for now. Adding an agent takes one command later.
Recommend `docker-daemon`, `network`, `development-sudo` or `host-browser`?	Press Enter at each to keep `none`. The exercise needs no extra host access; Containment explains each.
Authorize this checkout to execute the base image?	Press Enter to accept the displayed image.

The base image is named after the build that produced it, so the prompt can show an older build's release-candidate label. It is the same base that ships with this version, not a candidate download. If you mistype an option name, init says so before asking anything and suggests the right one; you lose no answers.

Success ends with Project initialized; 'devcapsule project run' starts it. DevCapsule has written .devcapsule/ in this folder, the part that belongs to the project, and saved your local choices separately. Initialization is a one-time step for this checkout.

2. Open the IDE

~/.local/bin/devcapsule project run

Keep this terminal open. The first run downloads and assembles the tools; build output is normal. When ready, DevCapsule prints a http://127.0.0.1:…/vnc.html?… URL and tries to open it in your browser. If no tab opens, copy the whole URL from the terminal into a browser on this computer.

You see VSCodium with hello-devcapsule in its Explorer. This is the capsule's own desktop in a browser tab; your computer's desktop is not shared. The URL grants access to this session: keep it private, and keep the terminal output so you can reopen the tab.

The project folder is shared read/write with the capsule: edits there really change your files. Everything else on your computer stays out of reach unless you grant it.

3. Run something

Inside VSCodium:

If the top banner says Restricted Mode, click Manage and trust this folder. You just created it.
In the Explorer, right-click HELLO-DEVCAPSULE, choose New File, and name it hello.js.
Type the line below and save with File → Save:
```
console.log("Hello, DevCapsule!");
```
Choose Terminal → New Terminal inside the IDE and run:
```
node hello.js
```

You see Hello, DevCapsule!. Node ran inside the capsule; nothing was installed on your computer. Change the greeting, save, run it again.

To paste longer text from your computer, open the sidebar at the left edge of the desktop tab and use its clipboard panel, then paste inside the IDE. Your computer's clipboard is not shared automatically; see Clipboard and browser.

4. Stop, and come back

Save, then choose File → Exit inside VSCodium. The launcher terminal returns to its prompt. Later, from any terminal:

cd ~/hello-devcapsule
~/.local/bin/devcapsule project run

Open the new URL, open hello.js, run it again. Your file and your IDE state are there; running processes restart. You never initialize again. Stop and come back has the details, including what closing the tab does.

Next: bring your own project, or add a coding agent. Something in the way? First-session troubleshooting.