diff --git a/tests/test_mcp_client_paths.py b/tests/test_mcp_client_paths.py
new file mode 100644
index 00000000..ef329b9e
--- /dev/null
+++ b/tests/test_mcp_client_paths.py
@@ -0,0 +1,67 @@
+import pytest
+from pathlib import Path
+from src import mcp_client
+from src.result_types import Result, ErrorKind, ErrorInfo, NilPath
+
+
+@pytest.fixture(autouse=True)
+def _allow_tmp_path(tmp_path: Path):
+ original_bases = list(mcp_client._base_dirs)
+ original_primary = mcp_client._primary_base_dir
+ mcp_client.configure([{"path": str(tmp_path)}], [str(tmp_path)])
+ yield
+ mcp_client.configure([{"path": str(b)} for b in original_bases], None)
+ mcp_client._primary_base_dir = original_primary
+
+
+def test_resolve_and_check_result_returns_result_type(tmp_path: Path) -> None:
+ r = mcp_client._resolve_and_check_result(str(tmp_path))
+ assert isinstance(r, Result)
+ assert hasattr(r, "data")
+ assert hasattr(r, "errors")
+ assert hasattr(r, "ok")
+ assert r.ok is True
+ assert isinstance(r.data, Path)
+
+
+def test_resolve_and_check_result_invalid_path_returns_nil_with_error() -> None:
+ r = mcp_client._resolve_and_check_result("\x00invalid\x00path\x00")
+ assert r.ok is False
+ assert isinstance(r.data, NilPath)
+ assert len(r.errors) >= 1
+ assert r.errors[0].kind in (ErrorKind.INVALID_INPUT, ErrorKind.PERMISSION)
+
+
+def test_read_file_result_returns_result_str(tmp_path: Path) -> None:
+ r = mcp_client.read_file_result(str(tmp_path))
+ assert isinstance(r, Result)
+ assert hasattr(r, "data")
+ assert r.data == ""
+ assert r.ok is False
+ assert len(r.errors) >= 1
+ assert r.errors[0].kind in (ErrorKind.NOT_FOUND, ErrorKind.PERMISSION, ErrorKind.INVALID_INPUT)
+
+
+def test_read_file_result_reads_existing_file(tmp_path: Path) -> None:
+ f = tmp_path / "test.txt"
+ f.write_text("hello world", encoding="utf-8")
+ r = mcp_client.read_file_result(str(f))
+ assert r.ok is True
+ assert r.data == "hello world"
+ assert r.errors == []
+
+
+def test_list_directory_result_returns_result_str(tmp_path: Path) -> None:
+ r = mcp_client.list_directory_result(str(tmp_path))
+ assert isinstance(r, Result)
+ assert r.ok is True
+ assert "Directory:" in r.data
+
+
+def test_search_files_result_returns_result_str(tmp_path: Path) -> None:
+ f = tmp_path / "test.py"
+ f.write_text("# test", encoding="utf-8")
+ r = mcp_client.search_files_result(str(tmp_path), "*.py")
+ assert isinstance(r, Result)
+ assert r.ok is True
+ assert "test.py" in r.data