diff --git a/scripts/prepare-extension-package-boundary-artifacts.mjs b/scripts/prepare-extension-package-boundary-artifacts.mjs
index 0399dc5fbe7..8a0761ea115 100644
--- a/scripts/prepare-extension-package-boundary-artifacts.mjs
+++ b/scripts/prepare-extension-package-boundary-artifacts.mjs
@@ -33,11 +33,19 @@ export function createPrefixedOutputWriter(label, target) {
   };
 }
 
-function runNodeStep(label, args, timeoutMs) {
+function abortSiblingSteps(abortController) {
+  if (abortController && !abortController.signal.aborted) {
+    abortController.abort();
+  }
+}
+
+export function runNodeStep(label, args, timeoutMs, params = {}) {
+  const abortController = params.abortController;
   return new Promise((resolvePromise, rejectPromise) => {
     const child = spawn(process.execPath, args, {
       cwd: repoRoot,
       env: process.env,
+      signal: abortController?.signal,
       stdio: ["ignore", "pipe", "pipe"],
     });
 
@@ -52,6 +60,7 @@ function runNodeStep(label, args, timeoutMs) {
       settled = true;
       stdoutWriter.flush();
       stderrWriter.flush();
+      abortSiblingSteps(abortController);
       rejectPromise(new Error(`${label} timed out after ${timeoutMs}ms`));
     }, timeoutMs);
 
@@ -71,6 +80,11 @@ function runNodeStep(label, args, timeoutMs) {
       settled = true;
       stdoutWriter.flush();
       stderrWriter.flush();
+      if (error.name === "AbortError" && abortController?.signal.aborted) {
+        rejectPromise(new Error(`${label} canceled after sibling failure`));
+        return;
+      }
+      abortSiblingSteps(abortController);
       rejectPromise(new Error(`${label} failed to start: ${error.message}`));
     });
     child.on("close", (code) => {
@@ -85,24 +99,36 @@ function runNodeStep(label, args, timeoutMs) {
         resolvePromise();
         return;
       }
+      abortSiblingSteps(abortController);
       rejectPromise(new Error(`${label} failed with exit code ${code ?? 1}`));
     });
   });
 }
 
+export async function runNodeStepsInParallel(steps) {
+  const abortController = new AbortController();
+  const results = await Promise.allSettled(
+    steps.map((step) => runNodeStep(step.label, step.args, step.timeoutMs, { abortController })),
+  );
+  const firstFailure = results.find((result) => result.status === "rejected");
+  if (firstFailure) {
+    throw firstFailure.reason;
+  }
+}
+
 export async function main() {
   try {
-    await Promise.all([
-      runNodeStep(
-        "plugin-sdk boundary dts",
-        [tscBin, "-p", "tsconfig.plugin-sdk.dts.json"],
-        300_000,
-      ),
-      runNodeStep(
-        "plugin-sdk package boundary dts",
-        [tscBin, "-p", "packages/plugin-sdk/tsconfig.json"],
-        300_000,
-      ),
+    await runNodeStepsInParallel([
+      {
+        label: "plugin-sdk boundary dts",
+        args: [tscBin, "-p", "tsconfig.plugin-sdk.dts.json"],
+        timeoutMs: 300_000,
+      },
+      {
+        label: "plugin-sdk package boundary dts",
+        args: [tscBin, "-p", "packages/plugin-sdk/tsconfig.json"],
+        timeoutMs: 300_000,
+      },
     ]);
     await runNodeStep(
       "plugin-sdk boundary root shims",
diff --git a/test/scripts/prepare-extension-package-boundary-artifacts.test.ts b/test/scripts/prepare-extension-package-boundary-artifacts.test.ts
index 4f4b8fdcbf7..09dbd6ab984 100644
--- a/test/scripts/prepare-extension-package-boundary-artifacts.test.ts
+++ b/test/scripts/prepare-extension-package-boundary-artifacts.test.ts
@@ -1,5 +1,8 @@
 import { describe, expect, it } from "vitest";
-import { createPrefixedOutputWriter } from "../../scripts/prepare-extension-package-boundary-artifacts.mjs";
+import {
+  createPrefixedOutputWriter,
+  runNodeStepsInParallel,
+} from "../../scripts/prepare-extension-package-boundary-artifacts.mjs";
 
 describe("prepare-extension-package-boundary-artifacts", () => {
   it("prefixes each completed line and flushes the trailing partial line", () => {
@@ -16,4 +19,25 @@ describe("prepare-extension-package-boundary-artifacts", () => {
 
     expect(output).toBe("[boundary] first line\n[boundary] second line\n[boundary] third");
   });
+
+  it("aborts sibling steps after the first failure", async () => {
+    const startedAt = Date.now();
+
+    await expect(
+      runNodeStepsInParallel([
+        {
+          label: "fail-fast",
+          args: ["--eval", "setTimeout(() => process.exit(2), 10)"],
+          timeoutMs: 5_000,
+        },
+        {
+          label: "slow-step",
+          args: ["--eval", "setTimeout(() => {}, 10_000)"],
+          timeoutMs: 5_000,
+        },
+      ]),
+    ).rejects.toThrow("fail-fast failed with exit code 2");
+
+    expect(Date.now() - startedAt).toBeLessThan(2_000);
+  });
 });