diff --git a/tests/test_core.py b/tests/test_core.py
index aaf2faf..5024c56 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -638,3 +638,49 @@ def test_args_secret_warning_env_not_triggered():
 def test_args_secret_warning_empty():
     assert c.args_secret_warning({}) is None
     assert c.args_secret_warning({"args": []}) is None
+
+
+# --------------------------------------------------------------------------- #
+# server_log_path (in-app log viewer — issue #6)
+# --------------------------------------------------------------------------- #
+def test_server_log_path_macos_when_file_exists(tmp_path, monkeypatch):
+    monkeypatch.setattr(sys, "platform", "darwin")
+    monkeypatch.setattr(c.Path, "home", lambda: tmp_path)
+    log_dir = tmp_path / "Library" / "Logs" / "Claude"
+    log_dir.mkdir(parents=True)
+    (log_dir / "mcp-server-brave-search.log").write_text("hello")
+
+    result = c.server_log_path("brave-search")
+    assert result == log_dir / "mcp-server-brave-search.log"
+
+
+def test_server_log_path_macos_none_when_missing(tmp_path, monkeypatch):
+    monkeypatch.setattr(sys, "platform", "darwin")
+    monkeypatch.setattr(c.Path, "home", lambda: tmp_path)
+    assert c.server_log_path("brave-search") is None
+
+
+def test_server_log_path_windows_when_file_exists(tmp_path, monkeypatch):
+    # server_log_path branches on sys.platform only (never os.name), so the
+    # test doesn't have to touch os.name -- mutating that globally mid-test
+    # would also flip which concrete Path subclass pathlib hands out.
+    monkeypatch.setattr(sys, "platform", "win32")
+    monkeypatch.setenv("APPDATA", str(tmp_path))
+    log_dir = tmp_path / "Claude" / "logs"
+    log_dir.mkdir(parents=True)
+    (log_dir / "mcp.log").write_text("hello")
+
+    result = c.server_log_path("brave-search")
+    assert result == log_dir / "mcp.log"
+
+
+def test_server_log_path_windows_none_when_missing(tmp_path, monkeypatch):
+    monkeypatch.setattr(sys, "platform", "win32")
+    monkeypatch.setenv("APPDATA", str(tmp_path))
+    assert c.server_log_path("brave-search") is None
+
+
+def test_server_log_path_unsupported_platform_returns_none(tmp_path, monkeypatch):
+    monkeypatch.setattr(sys, "platform", "linux")
+    monkeypatch.setattr(c.Path, "home", lambda: tmp_path)
+    assert c.server_log_path("brave-search") is None