Custom Problem Matchers

You can define custom problem matchers to parse the output of any CLI tool. This is super handy if you have a bespoke compiler or custom linting solution. A custom matcher can highlight file paths and line numbers in errors, letting you click on them to jump straight to the code.

{
	"problemMatcher": [
		{
			"owner": "customLinter",
			"pattern": [
				{
					"regexp": "^(.*):(\d+):(\d+):\s+(warning|error)\s+(.*)$",
					"file": 1,
					"line": 2,
					"column": 3,
					"severity": 4,
					"message": 5,
				},
			],
		},
	],
}

Presentation Options

You can control how the task output is shown:

{
	"label": "Verbose Build",
	"type": "shell",
	"command": "npm run build --verbose",
	"presentation": {
		"reveal": "always",
		"panel": "dedicated",
		"echo": true,
		"showReuseMessage": false,
		"clear": true,
	},
}

• reveal: Show the panel automatically or only if there’s a problem (silent, never, etc.).
• panel: Keep each task’s output in a separate panel, or reuse a single terminal panel.
• clear: Clear the previous output before running the new task.

Environment Variables

Need environment variables for a single task? Insert env in the task:

{
	"label": "Build with Env Var",
	"type": "shell",
	"command": "npm run build",
	"env": {
		"NODE_ENV": "production",
		"API_KEY": "xyz123",
	},
}

Securely handle secrets—avoid committing real secrets to version control! Use placeholders or retrieval from a secure store.

Automatically Running Tasks on Folder Open

You can configure tasks to run automatically when you open a folder or workspace using the runOn property. This is especially useful for starting development servers, running initial build steps, or setting up your development environment.

{
	"version": "2.0.0",
	"tasks": [
		{
			"label": "Start Dev Server",
			"type": "shell",
			"command": "npm run dev",
			"isBackground": true,
			"problemMatcher": {
				"owner": "custom",
				"pattern": {
					"regexp": ".",
				},
				"background": {
					"beginsPattern": "Starting development server",
					"endsPattern": "Development server started",
				},
			},
			"runOptions": {
				"runOn": "folderOpen",
			},
		},
	],
}

Key Properties:

• runOptions.runOn: Specifies when to run the task. The value "folderOpen" means the task will automatically start when the folder is opened.
• isBackground: true: Marks this as a long-running background task that doesn’t block Visual Studio Code.
• problemMatcher: Configure patterns to detect when the task has started successfully.

Additional runOn Options:

• folderOpen: Run when the folder or workspace is opened
• default: Only run when explicitly triggered

Tips for Auto-Starting Tasks:

Use presentation options to control terminal visibility:

"presentation": {
	"reveal": "silent",
	"panel": "dedicated",
	"showReuseMessage": false
}

Combine with task dependencies to create complete startup workflows:

{
	"label": "Dev Environment",
	"dependsOn": ["Start Backend", "Start Frontend", "Watch CSS"],
	"dependsOrder": "parallel",
	"runOptions": {
		"runOn": "folderOpen",
	},
}

Use prompts for confirmation if you don’t always want the task to run:

"inputs": [
	{
		"id": "confirmStart",
		"type": "pickString",
		"description": "Start development server?",
		"options": ["Yes", "No"],
		"default": "Yes"
	}
],