ACPX extension: support acpx any-version probe via --help

extensions/acpx/src/ensure.test.ts

@@ -45,6 +45,11 @@ describe("acpx ensure", () => {
       version: ACPX_PINNED_VERSION,
       expectedVersion: ACPX_PINNED_VERSION,
     });
+    expect(spawnAndCollectMock).toHaveBeenCalledWith({
+      command: "/plugin/node_modules/.bin/acpx",
+      args: ["--version"],
+      cwd: "/plugin",
+    });
   });
 
   it("reports version mismatch", async () => {
@@ -70,9 +75,9 @@ describe("acpx ensure", () => {
     });
   });
 
-  it("accepts any installed version when expectedVersion is unset", async () => {
+  it("accepts command availability when expectedVersion is unset", async () => {
     spawnAndCollectMock.mockResolvedValueOnce({
-      stdout: "acpx 9.9.9\n",
+      stdout: "Usage: acpx [options]\n",
       stderr: "",
       code: 0,
       error: null,
@@ -86,9 +91,14 @@ describe("acpx ensure", () => {
 
     expect(result).toEqual({
       ok: true,
-      version: "9.9.9",
+      version: "unknown",
       expectedVersion: undefined,
     });
+    expect(spawnAndCollectMock).toHaveBeenCalledWith({
+      command: "/custom/acpx",
+      args: ["--help"],
+      cwd: "/custom",
+    });
   });
 
   it("installs and verifies pinned acpx when precheck fails", async () => {

extensions/acpx/src/ensure.ts

@@ -25,6 +25,10 @@ function extractVersion(stdout: string, stderr: string): string | null {
   return match?.[0] ?? null;
 }
 
+function isExpectedVersionConfigured(value: string | undefined): value is string {
+  return typeof value === "string" && value.trim().length > 0;
+}
+
 export async function checkAcpxVersion(params: {
   command: string;
   cwd?: string;
@@ -33,9 +37,11 @@ export async function checkAcpxVersion(params: {
   const expectedVersion = params.expectedVersion?.trim() || undefined;
   const installCommand = buildAcpxLocalInstallCommand(expectedVersion ?? ACPX_PINNED_VERSION);
   const cwd = params.cwd ?? ACPX_PLUGIN_ROOT;
+  const hasExpectedVersion = isExpectedVersionConfigured(expectedVersion);
+  const probeArgs = hasExpectedVersion ? ["--version"] : ["--help"];
   const result = await spawnAndCollect({
     command: params.command,
-    args: ["--version"],
+    args: probeArgs,
     cwd,
   });
 
@@ -64,12 +70,22 @@ export async function checkAcpxVersion(params: {
     return {
       ok: false,
       reason: "execution-failed",
-      message: stderr || `acpx --version failed with code ${result.code ?? "unknown"}`,
+      message:
+        stderr ||
+        `acpx ${hasExpectedVersion ? "--version" : "--help"} failed with code ${result.code ?? "unknown"}`,
       expectedVersion,
       installCommand,
     };
   }
 
+  if (!hasExpectedVersion) {
+    return {
+      ok: true,
+      version: "unknown",
+      expectedVersion,
+    };
+  }
+
   const installedVersion = extractVersion(result.stdout, result.stderr);
   if (!installedVersion) {
     return {