diff --git a/src/install/deps.ts b/src/install/deps.ts
index 68d73b6..fd66561 100644
--- a/src/install/deps.ts
+++ b/src/install/deps.ts
@@ -352,16 +352,6 @@ export async function resolveWindowsCommandPath(
   return undefined;
 }
 
-function quoteWindowsShellArgument(argument: string): string {
-  if (argument.length === 0) {
-    return '""';
-  }
-
-  return /[\s"&()<>^|]/u.test(argument)
-    ? `"${argument.replaceAll('"', '""')}"`
-    : argument;
-}
-
 function createCommandNotFoundError(command: string): NodeJS.ErrnoException {
   const error = new Error(`spawn ${command} ENOENT`) as NodeJS.ErrnoException;
 
@@ -408,12 +398,8 @@ export async function prepareInstallCommand(
     };
   }
 
-  const commandLine = [resolvedCommandPath, ...args]
-    .map(quoteWindowsShellArgument)
-    .join(" ");
-
   return {
-    args: ["/d", "/s", "/c", commandLine],
+    args: ["/d", "/s", "/c", resolvedCommandPath, ...args],
     command:
       getEnvironmentValue(normalizedEnv, "ComSpec", platform) ?? "cmd.exe",
     windowsHide: true,
diff --git a/test/install/deps.test.ts b/test/install/deps.test.ts
index 7e5d41c..a48da53 100644
--- a/test/install/deps.test.ts
+++ b/test/install/deps.test.ts
@@ -64,7 +64,10 @@ test("prepareInstallCommand routes Windows .cmd shims through ComSpec", async ()
     "/d",
     "/s",
     "/c",
-    '"C:\\Program Files\\OpenCode\\opencode.CMD" debug config --pure',
+    "C:\\Program Files\\OpenCode\\opencode.CMD",
+    "debug",
+    "config",
+    "--pure",
   ]);
 });
 
diff --git a/test/install/verify-effective.test.ts b/test/install/verify-effective.test.ts
index 5aed726..21d1ca9 100644
--- a/test/install/verify-effective.test.ts
+++ b/test/install/verify-effective.test.ts
@@ -1192,3 +1192,42 @@ test("the fake opencode harness also supports plain debug config invocations for
     await harness.cleanup();
   }
 });
+
+test("the fake opencode harness supports debug config --pure invocations through the real command runner", async () => {
+  const harness = await createInstallIntegrationHarness();
+
+  try {
+    await harness.installFakeOpenCodeOnPath({
+      debugConfigPureOutput: '{\n  "mode": "pure"\n}\n',
+      output: "opencode-ai 1.4.0",
+    });
+
+    const dependencies = harness.createDependencies();
+    const result = await dependencies.commands.run(
+      "opencode",
+      ["debug", "config", "--pure"],
+      {
+        cwd: dependencies.runtime.cwd,
+        env: dependencies.runtime.env,
+      },
+    );
+
+    assert.equal(result.exitCode, 0);
+    assert.match(result.stdout, /"mode": "pure"/);
+
+    const invocations = await harness.readFakeOpenCodeInvocations();
+
+    assert.equal(
+      invocations.some(
+        (args) =>
+          args.length === 3 &&
+          args[0] === "debug" &&
+          args[1] === "config" &&
+          args[2] === "--pure",
+      ),
+      true,
+    );
+  } finally {
+    await harness.cleanup();
+  }
+});