Dev Server

Every thread can run its own live development server, letting you preview the application as the AI agent makes changes. The dev server runs in isolation within the thread’s directory — different threads can run servers on different ports simultaneously.

Setting Up the Run Command

Before you can use the Run/Stop button, the project needs a Run Command configured. This is the shell command that starts your dev server.

1. Open Project Settings (gear icon in the sidebar next to the project name).
2. Enter the Run Command — for example:
   • bun dev
   • npm run dev
   • python manage.py runserver
   • rails server
   • cargo watch -x run
3. Click Save.

The run command is shared across all threads of the project but runs independently in each thread’s own directory.

Starting and Stopping the Server

The Run/Stop button is in the top toolbar of the thread view. It is visible once a Run Command is configured.

• Click Run (▶) — Tarsk executes the Run Command in the thread’s working directory. The button changes to a stop icon while the server is running.
• Click Stop (■) — Tarsk terminates the process.

The server starts in the background; you can continue chatting with the agent while it runs.

Tip

Start the dev server before asking the agent to make UI changes. That way you can immediately see the results in the browser without a separate step.

Viewing Server Output

When the dev server is running, the Output panel appears below the chat area. It shows a live stream of the server’s stdout and stderr — useful for:

• Confirming the server started successfully and which port it’s on
• Seeing compile errors or build warnings
• Watching hot-reload events as the agent makes file changes

The output panel is scrollable. Click the X to hide it without stopping the server.

The Terminal Panel

In addition to the Output panel, every thread has a Terminal panel — a general-purpose interactive terminal scoped to that thread’s directory. Access it via the Terminal button in the toolbar.

	Output Panel	Terminal Panel
Purpose	View dev server stdout/stderr	Run ad-hoc shell commands
Interactive	No (read-only log)	Yes (full shell)
Auto-starts	When Run is clicked	Manual
Persists	While server is running	Until you close it

Use the Terminal panel to:

• Inspect files: ls, cat, head
• Run migrations: bun run migrate
• Check git state: git status, git log
• Install a package the agent referenced: bun add some-package

Port Configuration

Tarsk does not assign ports automatically — your Run Command determines the port. If you run multiple threads simultaneously, ensure they use different ports. Common approaches:

• Pass a PORT environment variable in the command: PORT=3001 bun dev
• Configure different ports per-thread via .env files the agent can create

Workflow Example

1. Configure Run Command: bun dev (starts on port 3000)
2. Click Run — see “ready on http://localhost:3000” in the Output panel
3. Open http://localhost:3000 in your browser
4. Ask the agent: “Change the hero section background to a gradient from indigo to purple”
5. The agent edits the CSS; hot-reload updates your browser instantly
6. Review the change, then ask for the next one