diff --git a/gateway/run.py b/gateway/run.py
index b2dea3d3c47..d685e9849aa 100644
--- a/gateway/run.py
+++ b/gateway/run.py
@@ -6216,10 +6216,9 @@ class GatewayRunner:
                 return None
             logger.debug("PRIORITY interrupt for session %s", _quick_key)
             running_agent.interrupt(event.text)
-            if _quick_key in self._pending_messages:
-                self._pending_messages[_quick_key] += "\n" + event.text
-            else:
-                self._pending_messages[_quick_key] = event.text
+            # NOTE: self._pending_messages was write-only (never consumed).
+            # The actual interrupt message is delivered via adapter._pending_messages
+            # which is read by _run_agent. Removed to prevent unbounded growth.
             return None
 
         # Check for commands
@@ -6491,13 +6490,23 @@ class GatewayRunner:
                     exec_cmd = qcmd.get("command", "")
                     if exec_cmd:
                         try:
+                            # Sanitize env to prevent credential leakage —
+                            # quick commands run in the gateway process which
+                            # has all API keys in os.environ.
+                            from tools.environments.local import _sanitize_subprocess_env
+                            sanitized_env = _sanitize_subprocess_env(os.environ.copy())
                             proc = await asyncio.create_subprocess_shell(
                                 exec_cmd,
                                 stdout=asyncio.subprocess.PIPE,
                                 stderr=asyncio.subprocess.PIPE,
+                                env=sanitized_env,
                             )
                             stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout=30)
                             output = (stdout or stderr).decode().strip()
+                            # Redact any remaining sensitive patterns in output
+                            if output:
+                                from agent.redact import redact_sensitive_text
+                                output = redact_sensitive_text(output)
                             return output if output else "Command returned no output."
                         except asyncio.TimeoutError:
                             return "Quick command timed out (30s)."
diff --git a/tests/cli/test_quick_commands.py b/tests/cli/test_quick_commands.py
index c89d639d13e..35903170bc0 100644
--- a/tests/cli/test_quick_commands.py
+++ b/tests/cli/test_quick_commands.py
@@ -1,4 +1,5 @@
 """Tests for user-defined quick commands that bypass the agent loop."""
+import os
 import subprocess
 from unittest.mock import MagicMock, patch, AsyncMock
 from rich.text import Text
@@ -159,6 +160,41 @@ class TestGatewayQuickCommands:
         result = await runner._handle_message(event)
         assert result == "ok"
 
+    @pytest.mark.asyncio
+    async def test_exec_command_does_not_leak_credentials(self):
+        """Quick command exec must sanitize env — API keys must not appear in output."""
+        from gateway.run import GatewayRunner
+
+        runner = GatewayRunner.__new__(GatewayRunner)
+        runner.config = {"quick_commands": {"leak": {"type": "exec", "command": "env"}}}
+        runner._running_agents = {}
+        runner._pending_messages = {}
+        runner._is_user_authorized = MagicMock(return_value=True)
+
+        event = self._make_event("leak")
+        with patch.dict(os.environ, {"OPENROUTER_API_KEY": "sk-or-secret-12345"}):
+            result = await runner._handle_message(event)
+
+        assert "sk-or-secret-12345" not in result, \
+            "Quick command leaked OPENROUTER_API_KEY — exec runs without env sanitization"
+
+    @pytest.mark.asyncio
+    async def test_exec_command_output_is_redacted(self):
+        """Quick command output must redact sensitive patterns before returning."""
+        from gateway.run import GatewayRunner
+
+        runner = GatewayRunner.__new__(GatewayRunner)
+        runner.config = {"quick_commands": {"token": {"type": "exec", "command": "echo sk-ant-api03-supersecretkey1234567890"}}}
+        runner._running_agents = {}
+        runner._pending_messages = {}
+        runner._is_user_authorized = MagicMock(return_value=True)
+
+        event = self._make_event("token")
+        result = await runner._handle_message(event)
+
+        assert "supersecretkey1234567890" not in result, \
+            "Quick command output not redacted — raw API key returned to user"
+
     @pytest.mark.asyncio
     async def test_unsupported_type_returns_error(self):
         from gateway.run import GatewayRunner