diff --git a/browse/test/claude-bin.test.ts b/browse/test/claude-bin.test.ts
index 25aee32c..0b9d7eb9 100644
--- a/browse/test/claude-bin.test.ts
+++ b/browse/test/claude-bin.test.ts
@@ -40,10 +40,14 @@ describe('claude-bin', () => {
 
   test('PATH-resolvable override goes through Bun.which (the bug the fork shipped)', () => {
     // Make a fake binary in a temp dir, point PATH at it, set override to bare command name.
+    // Windows requires the file to have a PATHEXT-listed extension to be discoverable
+    // via Bun.which — without the extension Bun.which returns undefined.
     const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'claude-bin-test-'));
-    const fakeBin = path.join(tmpDir, 'fake-claude-cli');
-    fs.writeFileSync(fakeBin, '#!/bin/sh\necho fake\n');
-    fs.chmodSync(fakeBin, 0o755);
+    const isWindows = process.platform === 'win32';
+    const fakeBinName = isWindows ? 'fake-claude-cli.cmd' : 'fake-claude-cli';
+    const fakeBin = path.join(tmpDir, fakeBinName);
+    fs.writeFileSync(fakeBin, isWindows ? '@echo fake\r\n' : '#!/bin/sh\necho fake\n');
+    if (!isWindows) fs.chmodSync(fakeBin, 0o755);
     try {
       const got = resolveClaudeCommand({
         PATH: tmpDir,
diff --git a/scripts/test-free-shards.ts b/scripts/test-free-shards.ts
index ed1a71c2..6ad9e1da 100755
--- a/scripts/test-free-shards.ts
+++ b/scripts/test-free-shards.ts
@@ -63,6 +63,11 @@ const WINDOWS_FRAGILE_PATTERNS: Array<{ pattern: RegExp; reason: string }> = [
   { pattern: /\.mode\s*&\s*0o[0-7]+/, reason: 'POSIX file mode bitmask (mode & 0o600 etc — Windows fakes mode bits)' },
   { pattern: /\.endsWith\(['"]\//, reason: 'hardcoded forward-slash path assertion (Windows uses \\\\)' },
   { pattern: /['"]\.\/[a-zA-Z][^"']*['"]\)\s*\.\s*toBe\(true\)/, reason: 'forward-slash path comparison' },
+  // Tests that spawn a bash shebang script in bin/ via spawnSync. Git Bash on
+  // Windows can run `bash /path/to/script` but spawnSync(scriptPath, ...)
+  // tries to execute the file directly via CreateProcess, which fails on the
+  // shebang. Catches gstack-question-log.test.ts, gstack-paths.test.ts, etc.
+  { pattern: /path\.join\([^)]*,\s*['"]bin['"]\s*[,)]/, reason: 'spawns bin/ shebang script (Windows CreateProcess does not parse shebangs)' },
 ];
 
 export const DEFAULT_SHARD_COUNT = 20;