diff --git a/scripts/hooks/plugin-hook-bootstrap.js b/scripts/hooks/plugin-hook-bootstrap.js
index 6f6152c8..aef94aab 100644
--- a/scripts/hooks/plugin-hook-bootstrap.js
+++ b/scripts/hooks/plugin-hook-bootstrap.js
@@ -31,6 +31,20 @@ function passthrough(raw, result) {
   }
 }
 
+function normalizePluginRootForPlatform(rootDir, platform = process.platform) {
+  if (platform !== 'win32' || typeof rootDir !== 'string') {
+    return rootDir;
+  }
+
+  const match = rootDir.match(/^\/([a-zA-Z])(?:\/(.*))?$/);
+  if (!match) {
+    return rootDir;
+  }
+
+  const [, driveLetter, rest = ''] = match;
+  return `${driveLetter.toUpperCase()}:/${rest}`;
+}
+
 function resolveTarget(rootDir, relPath) {
   const resolvedRoot = path.resolve(rootDir);
   const resolvedTarget = path.resolve(rootDir, relPath);
@@ -110,7 +124,9 @@ function spawnShell(rootDir, relPath, raw, args) {
 function main() {
   const [, , mode, relPath, ...args] = process.argv;
   const raw = readStdinRaw();
-  const rootDir = process.env.CLAUDE_PLUGIN_ROOT || process.env.ECC_PLUGIN_ROOT;
+  const rootDir = normalizePluginRootForPlatform(
+    process.env.CLAUDE_PLUGIN_ROOT || process.env.ECC_PLUGIN_ROOT
+  );
 
   if (!mode || !relPath || !rootDir) {
     process.stdout.write(raw);
@@ -150,4 +166,11 @@ function main() {
   process.exit(Number.isInteger(result.status) ? result.status : 0);
 }
 
-main();
+if (require.main === module) {
+  main();
+}
+
+module.exports = {
+  main,
+  normalizePluginRootForPlatform,
+};
diff --git a/tests/hooks/plugin-hook-bootstrap.test.js b/tests/hooks/plugin-hook-bootstrap.test.js
index 0b54f3c7..b5a913d3 100644
--- a/tests/hooks/plugin-hook-bootstrap.test.js
+++ b/tests/hooks/plugin-hook-bootstrap.test.js
@@ -11,6 +11,7 @@ const path = require('path');
 const { spawnSync } = require('child_process');
 
 const SCRIPT = path.join(__dirname, '..', '..', 'scripts', 'hooks', 'plugin-hook-bootstrap.js');
+const { normalizePluginRootForPlatform } = require(SCRIPT);
 
 function createTempDir() {
   return fs.mkdtempSync(path.join(os.tmpdir(), 'plugin-hook-bootstrap-'));
@@ -68,6 +69,50 @@ function runTests() {
     assert.strictEqual(result.stderr, '');
   })) passed++; else failed++;
 
+  if (test('normalizes Windows Git Bash POSIX drive roots', () => {
+    assert.strictEqual(
+      normalizePluginRootForPlatform('/c/Users/x/.claude/plugins/ecc', 'win32'),
+      'C:/Users/x/.claude/plugins/ecc'
+    );
+    assert.strictEqual(
+      normalizePluginRootForPlatform('/z/Work/ECC/scripts/hooks/check-console-log.js', 'win32'),
+      'Z:/Work/ECC/scripts/hooks/check-console-log.js'
+    );
+  })) passed++; else failed++;
+
+  if (test('leaves already-Windows roots unchanged', () => {
+    assert.strictEqual(
+      normalizePluginRootForPlatform('C:/Users/x/.claude/plugins/ecc', 'win32'),
+      'C:/Users/x/.claude/plugins/ecc'
+    );
+    assert.strictEqual(
+      normalizePluginRootForPlatform('D:\\Users\\x\\.claude\\plugins\\ecc', 'win32'),
+      'D:\\Users\\x\\.claude\\plugins\\ecc'
+    );
+  })) passed++; else failed++;
+
+  if (test('leaves POSIX-looking roots unchanged off Windows', () => {
+    assert.strictEqual(
+      normalizePluginRootForPlatform('/c/Users/x/.claude/plugins/ecc', 'darwin'),
+      '/c/Users/x/.claude/plugins/ecc'
+    );
+    assert.strictEqual(
+      normalizePluginRootForPlatform('/c/Users/x/.claude/plugins/ecc', 'linux'),
+      '/c/Users/x/.claude/plugins/ecc'
+    );
+  })) passed++; else failed++;
+
+  if (test('does not mangle UNC or non-drive absolute paths on Windows', () => {
+    assert.strictEqual(
+      normalizePluginRootForPlatform('\\\\server\\share\\ecc', 'win32'),
+      '\\\\server\\share\\ecc'
+    );
+    assert.strictEqual(
+      normalizePluginRootForPlatform('/workspace/ecc', 'win32'),
+      '/workspace/ecc'
+    );
+  })) passed++; else failed++;
+
   if (test('node mode runs target script with plugin root environment', () => {
     const root = createTempDir();
     try {