diff --git a/src/core.ts b/src/core.ts
index 75977d1..4a39f40 100644
--- a/src/core.ts
+++ b/src/core.ts
@@ -277,7 +277,9 @@ export abstract class MochaAdapterCore {
 
 				const execArgv = [ ...config.nodeArgv ];
 				if (debug && !config.launcherScript) {
-					execArgv.push(`--inspect-brk=${config.debuggerPort}`);
+					config.launcherScript
+					? config.env.MOCHA_WORKER_DEBUG = true	
+					: execArgv.push(`--inspect-brk=${config.debuggerPort}`);
 				}
 
 				this.runningTestProcess = this.launchWorkerProcess(config, childProcScript, execArgv);