diff --git a/src/isolate/connections/grpc/_base.py b/src/isolate/connections/grpc/_base.py
index b258de0..7ede914 100644
--- a/src/isolate/connections/grpc/_base.py
+++ b/src/isolate/connections/grpc/_base.py
@@ -145,14 +145,28 @@ def find_free_port() -> Tuple[str, int]:
 
     def abort_agent(self) -> None:
         if self._process is not None:
+            return_code: int | None = None
             try:
-                print("Terminating the agent process...")
-                self._process.terminate()
-                self._process.wait(timeout=PROCESS_SHUTDOWN_TIMEOUT_SECONDS)
-                print("Agent process shutdown gracefully")
+                if self._process.poll() is not None:
+                    # already finished
+                    return_code = self._process.returncode
+                else:
+                    print("Terminating the agent process...")
+                    self._process.terminate()
+                    return_code = self._process.wait(
+                        timeout=PROCESS_SHUTDOWN_TIMEOUT_SECONDS
+                    )
+                    print("Agent process shutdown gracefully")
             except Exception as exc:
                 print(f"Failed to shutdown the agent process gracefully: {exc}")
                 self._process.kill()
+                return_code = self._process.wait()
+
+            self.log(
+                f"Isolate agent finished (exit code: {return_code})",
+                level=LogLevel.INFO,
+                source=LogSource.BRIDGE,
+            )
             self._process = None
 
     def is_alive(self) -> bool:
diff --git a/tests/test_connections_grpc_base.py b/tests/test_connections_grpc_base.py
new file mode 100644
index 0000000..7e6e249
--- /dev/null
+++ b/tests/test_connections_grpc_base.py
@@ -0,0 +1,77 @@
+from pathlib import Path
+from unittest.mock import Mock
+
+from isolate.backends.local import LocalPythonEnvironment
+from isolate.connections import LocalPythonGRPC
+from isolate.logs import LogLevel, LogSource
+
+
+def make_connection(tmp_path: Path) -> LocalPythonGRPC:
+    environment = LocalPythonEnvironment()
+    return LocalPythonGRPC(environment, tmp_path)
+
+
+def test_abort_agent_logs_return_code_for_already_exited_process(
+    tmp_path: Path,
+) -> None:
+    connection = make_connection(tmp_path)
+    process = Mock()
+    process.poll.return_value = 0
+    process.returncode = 0
+    connection._process = process
+
+    connection.log = Mock()
+    connection.abort_agent()
+
+    process.terminate.assert_not_called()
+    process.wait.assert_not_called()
+    process.kill.assert_not_called()
+    connection.log.assert_called_once_with(
+        "Isolate agent finished (exit code: 0)",
+        level=LogLevel.INFO,
+        source=LogSource.BRIDGE,
+    )
+    assert connection._process is None
+
+
+def test_abort_agent_logs_return_code_for_graceful_termination(tmp_path: Path) -> None:
+    connection = make_connection(tmp_path)
+    process = Mock()
+    process.poll.return_value = None
+    process.wait.return_value = -15
+    connection._process = process
+
+    connection.log = Mock()
+    connection.abort_agent()
+
+    process.terminate.assert_called_once()
+    process.wait.assert_called_once()
+    process.kill.assert_not_called()
+    connection.log.assert_called_once_with(
+        "Isolate agent finished (exit code: -15)",
+        level=LogLevel.INFO,
+        source=LogSource.BRIDGE,
+    )
+    assert connection._process is None
+
+
+def test_abort_agent_logs_return_code_after_kill_fallback(tmp_path: Path) -> None:
+    connection = make_connection(tmp_path)
+    process = Mock()
+    process.poll.return_value = None
+    process.terminate.side_effect = RuntimeError("terminate failed")
+    process.wait.return_value = -9
+    connection._process = process
+
+    connection.log = Mock()
+    connection.abort_agent()
+
+    process.terminate.assert_called_once()
+    process.kill.assert_called_once()
+    process.wait.assert_called_once()
+    connection.log.assert_called_once_with(
+        "Isolate agent finished (exit code: -9)",
+        level=LogLevel.INFO,
+        source=LogSource.BRIDGE,
+    )
+    assert connection._process is None