diff --git a/packages/cli/__tests__/scripts/doctor-script.test.ts b/packages/cli/__tests__/scripts/doctor-script.test.ts
index 12744d98c..514100cac 100644
--- a/packages/cli/__tests__/scripts/doctor-script.test.ts
+++ b/packages/cli/__tests__/scripts/doctor-script.test.ts
@@ -35,7 +35,14 @@ function createHealthyRepo(tempRoot: string): string {
   mkdirSync(join(fakeRepo, "packages", "core", "dist"), { recursive: true });
   mkdirSync(join(fakeRepo, "packages", "cli", "dist"), { recursive: true });
   mkdirSync(join(fakeRepo, "packages", "web"), { recursive: true });
-  writeFileSync(join(fakeRepo, "packages", "core", "dist", "index.js"), "export {};\n");
+  writeFileSync(
+    join(fakeRepo, "packages", "core", "package.json"),
+    JSON.stringify({ type: "module", main: "dist/index.js" }, null, 2),
+  );
+  writeFileSync(
+    join(fakeRepo, "packages", "core", "dist", "index.js"),
+    'export function getNodePtyPrebuildsSubdir() { return process.platform + "-" + process.arch; }\n',
+  );
   writeFileSync(join(fakeRepo, "packages", "cli", "dist", "index.js"), "export {};\n");
   writeFileSync(
     join(fakeRepo, "packages", "ao", "bin", "ao.js"),
diff --git a/packages/cli/src/assets/scripts/ao-doctor.sh b/packages/cli/src/assets/scripts/ao-doctor.sh
index 424daf9e2..2b20735bf 100755
--- a/packages/cli/src/assets/scripts/ao-doctor.sh
+++ b/packages/cli/src/assets/scripts/ao-doctor.sh
@@ -414,6 +414,7 @@ resolve_node_pty_spawn_helper() {
 const fs = require("node:fs");
 const { createRequire } = require("node:module");
 const path = require("node:path");
+const { pathToFileURL } = require("node:url");
 
 const repoRoot = process.argv[2];
 
@@ -442,34 +443,57 @@ function resolveNodeModulesPackage(fromDir, ...segments) {
   return fs.existsSync(path.resolve(packageDir, "package.json")) ? packageDir : null;
 }
 
-const packageJsonPath =
-  resolvePackageJson(repoRoot) ??
-  (() => {
-    const directNodePtyDir = findPackageUp(repoRoot, "node-pty");
-    if (directNodePtyDir) return path.join(directNodePtyDir, "package.json");
+function resolveCoreEntrypoint() {
+  const sourceCoreDir = path.resolve(repoRoot, "packages", "core");
+  const coreDir =
+    (fs.existsSync(path.join(sourceCoreDir, "package.json")) ? sourceCoreDir : null) ??
+    findPackageUp(repoRoot, "@aoagents", "ao-core") ??
+    resolveNodeModulesPackage(repoRoot, "@aoagents", "ao-core");
+  if (!coreDir) return null;
 
-    const sourceWebDir = path.resolve(repoRoot, "packages", "web");
-    const webDir =
-      (fs.existsSync(path.join(sourceWebDir, "package.json")) ? sourceWebDir : null) ??
-      findPackageUp(repoRoot, "@aoagents", "ao-web") ??
-      resolveNodeModulesPackage(repoRoot, "@aoagents", "ao-web");
-    if (!webDir) return null;
+  try {
+    const pkg = JSON.parse(fs.readFileSync(path.join(coreDir, "package.json"), "utf8"));
+    const entry = pkg.exports?.["."]?.import ?? pkg.module ?? pkg.main ?? "dist/index.js";
+    return path.resolve(coreDir, entry);
+  } catch {
+    return null;
+  }
+}
 
-    const webNodePtyDir =
-      resolveNodeModulesPackage(webDir, "node-pty") ?? findPackageUp(webDir, "node-pty");
-    return webNodePtyDir ? path.join(webNodePtyDir, "package.json") : null;
-  })();
+async function getNodePtyPrebuildsSubdir() {
+  const coreEntrypoint = resolveCoreEntrypoint();
+  if (!coreEntrypoint || !fs.existsSync(coreEntrypoint)) return null;
 
-if (!packageJsonPath) process.exit(0);
+  const core = await import(pathToFileURL(coreEntrypoint).href);
+  return typeof core.getNodePtyPrebuildsSubdir === "function"
+    ? core.getNodePtyPrebuildsSubdir()
+    : null;
+}
 
-console.log(
-  path.join(
-    path.dirname(packageJsonPath),
-    "prebuilds",
-    `${process.platform}-${process.arch}`,
-    "spawn-helper",
-  ),
-);
+(async () => {
+  const packageJsonPath =
+    resolvePackageJson(repoRoot) ??
+    (() => {
+      const directNodePtyDir = findPackageUp(repoRoot, "node-pty");
+      if (directNodePtyDir) return path.join(directNodePtyDir, "package.json");
+
+      const sourceWebDir = path.resolve(repoRoot, "packages", "web");
+      const webDir =
+        (fs.existsSync(path.join(sourceWebDir, "package.json")) ? sourceWebDir : null) ??
+        findPackageUp(repoRoot, "@aoagents", "ao-web") ??
+        resolveNodeModulesPackage(repoRoot, "@aoagents", "ao-web");
+      if (!webDir) return null;
+
+      const webNodePtyDir =
+        resolveNodeModulesPackage(webDir, "node-pty") ?? findPackageUp(webDir, "node-pty");
+      return webNodePtyDir ? path.join(webNodePtyDir, "package.json") : null;
+    })();
+
+  const prebuildsSubdir = await getNodePtyPrebuildsSubdir();
+  if (!packageJsonPath || !prebuildsSubdir) process.exit(0);
+
+  console.log(path.join(path.dirname(packageJsonPath), "prebuilds", prebuildsSubdir, "spawn-helper"));
+})().catch(() => process.exit(0));
 NODE
 }
 
diff --git a/packages/core/src/__tests__/platform.test.ts b/packages/core/src/__tests__/platform.test.ts
index 06667db02..0e3fcfb80 100644
--- a/packages/core/src/__tests__/platform.test.ts
+++ b/packages/core/src/__tests__/platform.test.ts
@@ -44,6 +44,14 @@ describe("platform adapter", () => {
     });
   });
 
+  describe("getNodePtyPrebuildsSubdir", () => {
+    it("centralizes node-pty prebuild platform/arch naming", async () => {
+      setPlatform("darwin");
+      const mod = await import("../platform.js");
+      expect(mod.getNodePtyPrebuildsSubdir()).toBe(`darwin-${process.arch}`);
+    });
+  });
+
   describe("getShell", () => {
     it("always returns /bin/sh on unix (ignores $SHELL)", async () => {
       setPlatform("linux");
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 5c5936c82..cbf2024a7 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -366,6 +366,7 @@ export {
   isMac,
   isLinux,
   getDefaultRuntime,
+  getNodePtyPrebuildsSubdir,
   getShell,
   killProcessTree,
   findPidByPort,
diff --git a/packages/core/src/platform.ts b/packages/core/src/platform.ts
index 5cde1af87..2f4323555 100644
--- a/packages/core/src/platform.ts
+++ b/packages/core/src/platform.ts
@@ -28,6 +28,10 @@ export function getDefaultRuntime(): "tmux" | "process" {
   return isWindows() ? "process" : "tmux";
 }
 
+export function getNodePtyPrebuildsSubdir(): string {
+  return `${process.platform}-${process.arch}`;
+}
+
 // -- Shell resolution --
 
 interface ShellInfo {
diff --git a/packages/web/server/__tests__/mux-websocket.test.ts b/packages/web/server/__tests__/mux-websocket.test.ts
index e33bd8186..3f5cc0216 100644
--- a/packages/web/server/__tests__/mux-websocket.test.ts
+++ b/packages/web/server/__tests__/mux-websocket.test.ts
@@ -5,7 +5,7 @@ import { tmpdir } from "node:os";
 import { join } from "node:path";
 import type { Socket } from "node:net";
 import { WebSocket } from "ws";
-import { appendDashboardNotification, type OrchestratorEvent } from "@aoagents/ao-core";
+import { appendDashboardNotification, isWindows, type OrchestratorEvent } from "@aoagents/ao-core";
 import type { SessionBroadcaster as SessionBroadcasterType } from "../mux-websocket";
 
 // vi.mock factories run before module-level statements. Hoist the mock
@@ -967,7 +967,7 @@ describe("TerminalManager.open — tmux target args (regression for #1714)", ()
     expect(args).toEqual(["attach-session", "-t", "=ao-177"]);
   });
 
-  it("chmods node-pty spawn-helper and retries once after posix_spawnp failure", () => {
+  it("repairs node-pty spawn-helper when applicable and retries once after posix_spawnp failure", () => {
     const tempRoot = mkdtempSync(join(tmpdir(), "ao-mux-spawn-helper-"));
     const helperPath = join(tempRoot, "spawn-helper");
     writeFileSync(helperPath, "#!/bin/sh\nexit 0\n");
@@ -993,7 +993,9 @@ describe("TerminalManager.open — tmux target args (regression for #1714)", ()
       mgr.open("ao-177");
 
       expect(mockPtySpawn).toHaveBeenCalledTimes(2);
-      expect((statSync(helperPath).mode & 0o111) !== 0).toBe(true);
+      if (!isWindows()) {
+        expect((statSync(helperPath).mode & 0o111) !== 0).toBe(true);
+      }
     } finally {
       delete process.env.AO_NODE_PTY_SPAWN_HELPER_PATH;
       rmSync(tempRoot, { recursive: true, force: true });
diff --git a/packages/web/server/mux-websocket.ts b/packages/web/server/mux-websocket.ts
index 26df58d18..9be199e2c 100644
--- a/packages/web/server/mux-websocket.ts
+++ b/packages/web/server/mux-websocket.ts
@@ -16,6 +16,7 @@ import {
   DEFAULT_DASHBOARD_NOTIFICATION_LIMIT,
   getEnvDefaults,
   getDashboardNotificationStorePath,
+  getNodePtyPrebuildsSubdir,
   isWindows,
   loadConfig,
   normalizeDashboardNotificationLimit,
@@ -395,12 +396,7 @@ export function resolveNodePtySpawnHelperPath(): string | null {
 
   try {
     const packageJsonPath = nodePtyRequire.resolve("node-pty/package.json");
-    return join(
-      dirname(packageJsonPath),
-      "prebuilds",
-      `${process.platform}-${process.arch}`,
-      "spawn-helper",
-    );
+    return join(dirname(packageJsonPath), "prebuilds", getNodePtyPrebuildsSubdir(), "spawn-helper");
   } catch {
     return null;
   }