diff --git a/bin/install.js b/bin/install.js
index 23de28aeb..aeb55f987 100755
--- a/bin/install.js
+++ b/bin/install.js
@@ -6812,7 +6812,7 @@ function installSdkIfNeeded() {
         ? path.join(npmPrefix, 'node_modules')
         : path.join(npmPrefix, 'lib', 'node_modules');
       const cliPath = path.join(globalModulesDir, sdkName, 'dist', 'cli.js');
-      try { fs.chmodSync(cliPath, 0o755); } catch (e) { /* Windows / path not found */ }
+      try { fs.chmodSync(cliPath, 0o755); } catch (e) { if (process.platform !== 'win32') throw e; }
     }
   } catch (e) { /* Non-fatal: PATH verification in step 4 will catch any real failure */ }
 
diff --git a/tests/bug-2525-sdk-executable-bit.test.cjs b/tests/bug-2525-sdk-executable-bit.test.cjs
new file mode 100644
index 000000000..5dcd9c5b3
--- /dev/null
+++ b/tests/bug-2525-sdk-executable-bit.test.cjs
@@ -0,0 +1,82 @@
+/**
+ * Regression test for bug #2525
+ *
+ * After running the GSD installer on macOS with a Homebrew npm prefix,
+ * `gsd-sdk` is installed but `command -v gsd-sdk` returns nothing because
+ * `dist/cli.js` is installed with mode 644 (no executable bit). tsc emits
+ * .js files as 644, and `npm install -g .` creates the bin symlink without
+ * chmod-ing the target. The kernel then refuses to exec the file.
+ *
+ * Fix: between the `npm run build` step and `npm install -g .`, chmod
+ * dist/cli.js to 0o755. This mirrors the pattern already used for hook
+ * files at lines 5838, 5846, 5959, and 5965.
+ */
+
+'use strict';
+
+const { test, describe } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('fs');
+const path = require('path');
+
+const INSTALL_PATH = path.join(__dirname, '..', 'bin', 'install.js');
+
+describe('bug #2525: dist/cli.js chmod 0o755 after tsc build', () => {
+  test('install.js exists', () => {
+    assert.ok(fs.existsSync(INSTALL_PATH), 'bin/install.js should exist');
+  });
+
+  test('chmodSync is called for dist/cli.js after the build step', () => {
+    const content = fs.readFileSync(INSTALL_PATH, 'utf-8');
+    // Find the installSdkIfNeeded function body
+    const fnStart = content.indexOf('function installSdkIfNeeded()');
+    assert.ok(fnStart !== -1, 'installSdkIfNeeded function must exist in bin/install.js');
+
+    // Find the closing brace of the function (next top-level function definition)
+    const nextFnIdx = content.indexOf('\nfunction ', fnStart + 1);
+    const fnEnd = nextFnIdx === -1 ? content.length : nextFnIdx;
+    const fnBody = content.slice(fnStart, fnEnd);
+
+    // Locate the build step
+    const buildStep = fnBody.indexOf("'run', 'build'");
+    assert.ok(buildStep !== -1, "installSdkIfNeeded must contain the 'run', 'build' spawn call");
+
+    // Locate the global install step
+    const globalStep = fnBody.indexOf("'install', '-g', '.'");
+    assert.ok(globalStep !== -1, "installSdkIfNeeded must contain the 'install', '-g', '.' spawn call");
+
+    // Locate chmodSync for dist/cli.js
+    const chmodIdx = fnBody.indexOf("chmodSync");
+    assert.ok(chmodIdx !== -1, "installSdkIfNeeded must call chmodSync to set the executable bit on dist/cli.js");
+
+    // The path may be assembled via path.join(sdkDir, 'dist', 'cli.js') so check
+    // for the component strings rather than the joined slash form.
+    const cliPathIdx = fnBody.indexOf("'cli.js'");
+    assert.ok(cliPathIdx !== -1, "installSdkIfNeeded must reference 'cli.js' (via path.join or literal) for the chmod call");
+
+    // chmodSync must appear AFTER the build step
+    assert.ok(
+      chmodIdx > buildStep,
+      'chmodSync for dist/cli.js must appear AFTER the npm run build step'
+    );
+
+    // chmodSync must appear AFTER the global install step
+    assert.ok(
+      chmodIdx > globalStep,
+      'chmodSync for dist/cli.js must appear AFTER the npm install -g . step'
+    );
+  });
+
+  test('chmod mode is 0o755', () => {
+    const content = fs.readFileSync(INSTALL_PATH, 'utf-8');
+    const fnStart = content.indexOf('function installSdkIfNeeded()');
+    const nextFnIdx = content.indexOf('\nfunction ', fnStart + 1);
+    const fnEnd = nextFnIdx === -1 ? content.length : nextFnIdx;
+    const fnBody = content.slice(fnStart, fnEnd);
+
+    assert.ok(
+      fnBody.includes('0o755'),
+      "chmodSync call in installSdkIfNeeded must use mode 0o755 (not 0o644 or a bare number)"
+    );
+  });
+});