diff --git a/extensions/ext-bundler-esbuild/src/esbuild-bundler.test.ts b/extensions/ext-bundler-esbuild/src/esbuild-bundler.test.ts
index f97f01256a..d827d9e52b 100644
--- a/extensions/ext-bundler-esbuild/src/esbuild-bundler.test.ts
+++ b/extensions/ext-bundler-esbuild/src/esbuild-bundler.test.ts
@@ -9,7 +9,7 @@ import { assertEquals, assertExists, assertRejects, assertStringIncludes } from
 import { describe, it } from "@std/testing/bdd";
 import { createRequire } from "node:module";
 
-import { EsbuildBundler } from "./esbuild-bundler.ts";
+import { EsbuildBundler, isLiveEsbuildServiceProcess } from "./esbuild-bundler.ts";
 import { rebuildContextWithSignal } from "./context-build-lifecycle.ts";
 
 const childProcess = createRequire(import.meta.url)("node:child_process") as {
@@ -90,6 +90,19 @@ describe("EsbuildBundler.transform", () => {
   });
 });
 
+describe("esbuild service lifecycle", () => {
+  it("treats a Node-compatible child with unset exit fields as live", () => {
+    assertEquals(
+      isLiveEsbuildServiceProcess({
+        killed: false,
+        exitCode: undefined,
+        signalCode: undefined,
+      } as Pick<ReturnType<typeof childProcess.spawn>, "killed" | "exitCode" | "signalCode">),
+      true,
+    );
+  });
+});
+
 describe("abortable esbuild context lifecycle", () => {
   it("cancels active work and preserves the primary abort over cleanup failures", async () => {
     const controller = new AbortController();
diff --git a/extensions/ext-bundler-esbuild/src/esbuild-bundler.ts b/extensions/ext-bundler-esbuild/src/esbuild-bundler.ts
index e4f56e90ea..1092a02dca 100644
--- a/extensions/ext-bundler-esbuild/src/esbuild-bundler.ts
+++ b/extensions/ext-bundler-esbuild/src/esbuild-bundler.ts
@@ -214,10 +214,22 @@ function isEsbuildServiceSpawn(spawnArgs: unknown[]): boolean {
     args.includes("--ping");
 }
 
+/**
+ * Keep lifecycle tracking tolerant of Node-compatible child-process shims.
+ *
+ * Native Node represents an active child with `null` exit fields. Some
+ * compatible runtimes leave those fields undefined until the child exits.
+ */
+export function isLiveEsbuildServiceProcess(
+  child: Pick<ChildProcess, "killed" | "exitCode" | "signalCode">,
+): boolean {
+  return !child.killed &&
+    (child.exitCode === null || child.exitCode === undefined) &&
+    (child.signalCode === null || child.signalCode === undefined);
+}
+
 function isLiveService(service: EsbuildService): boolean {
-  return !service.child.killed &&
-    service.child.exitCode === null &&
-    service.child.signalCode === null;
+  return isLiveEsbuildServiceProcess(service.child);
 }
 
 function invokeEsbuild<T extends Promise<unknown>>(operation: () => T): T {