diff --git a/lib/hooks/websearch-transformer.cjs b/lib/hooks/websearch-transformer.cjs
index 6da24c3e..eb198cba 100644
--- a/lib/hooks/websearch-transformer.cjs
+++ b/lib/hooks/websearch-transformer.cjs
@@ -874,7 +874,10 @@ function runGeminiCommand(args, timeoutMs) {
     timeout: timeoutMs,
     maxBuffer: 1024 * 1024 * 2,
     stdio: ['pipe', 'pipe', 'pipe'],
-    shell: isWindows,
+    // Never route query-derived prompts through a shell. Node concatenates
+    // arguments for shell-backed Windows spawns, which lets shell metacharacters
+    // in WebSearch queries escape the intended CLI invocation.
+    shell: false,
   });
 
   if (result.error) {
@@ -929,7 +932,10 @@ function tryOpenCodeSearch(query, timeoutSec = DEFAULT_TIMEOUT_SEC) {
         timeout: timeoutSec * 1000,
         maxBuffer: 1024 * 1024 * 2,
         stdio: ['pipe', 'pipe', 'pipe'],
-        shell: isWindows,
+        // Never route query-derived prompts through a shell. Node concatenates
+        // arguments for shell-backed Windows spawns, which lets shell metacharacters
+        // in WebSearch queries escape the intended CLI invocation.
+        shell: false,
       }
     );
 
@@ -965,7 +971,10 @@ function tryGrokSearch(query, timeoutSec = DEFAULT_TIMEOUT_SEC) {
       timeout: timeoutSec * 1000,
       maxBuffer: 1024 * 1024 * 2,
       stdio: ['pipe', 'pipe', 'pipe'],
-      shell: isWindows,
+      // Never route query-derived prompts through a shell. Node concatenates
+      // arguments for shell-backed Windows spawns, which lets shell metacharacters
+      // in WebSearch queries escape the intended CLI invocation.
+      shell: false,
     });
 
     if (result.error) {
diff --git a/tests/unit/hooks/websearch-transformer.test.ts b/tests/unit/hooks/websearch-transformer.test.ts
index 646d1530..f05f9765 100644
--- a/tests/unit/hooks/websearch-transformer.test.ts
+++ b/tests/unit/hooks/websearch-transformer.test.ts
@@ -131,6 +131,15 @@ function runHookWithMockedFetch(mode: 'success' | 'empty' | 'non-result' | 'fail
   }
 }
 
+describe('websearch-transformer legacy CLI safety', () => {
+  it('does not enable shell execution for query-derived legacy CLI prompts', () => {
+    const source = readFileSync(hookPath, 'utf8');
+
+    expect(source).not.toContain('shell: isWindows');
+    expect(source.match(/shell: false/g) || []).toHaveLength(3);
+  });
+});
+
 describe('websearch-transformer hook helpers', () => {
   it('parses Retry-After seconds and HTTP dates', () => {
     expect(hook.parseRetryAfterSeconds('2')).toBe(2);