diff --git a/tests/conftest.py b/tests/conftest.py
index 6a68ed2..d35478d 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,6 +1,7 @@
 import pytest
 from pathlib import Path
 import tempfile
+from minimax_mcp.client import MinimaxAPIClient
 
 
 @pytest.fixture
@@ -21,3 +22,8 @@ def sample_video_file(temp_dir):
     video_file = temp_dir / "test.mp4"
     video_file.touch()
     return video_file
+
+
+@pytest.fixture
+def api_client():
+    return MinimaxAPIClient(api_key="test-key", api_host="https://api.test.com")
diff --git a/tests/test_client.py b/tests/test_client.py
new file mode 100644
index 0000000..b232e81
--- /dev/null
+++ b/tests/test_client.py
@@ -0,0 +1,109 @@
+import pytest
+from unittest.mock import patch, MagicMock
+import requests
+from minimax_mcp.client import MinimaxAPIClient
+from minimax_mcp.exceptions import MinimaxAuthError, MinimaxRequestError
+
+
+def test_initialization(api_client):
+    assert api_client.api_key == "test-key"
+    assert api_client.api_host == "https://api.test.com"
+    assert api_client.session.headers["Authorization"] == "Bearer test-key"
+    assert api_client.session.headers["MM-API-Source"] == "Minimax-MCP"
+
+
+def test_successful_json_post(api_client):
+    mock_response = MagicMock()
+    mock_response.json.return_value = {
+        "base_resp": {"status_code": 0},
+        "data": {"result": "ok"},
+    }
+    mock_response.raise_for_status = MagicMock()
+    mock_response.headers = {"Trace-Id": "abc123"}
+
+    with patch.object(api_client.session, "request", return_value=mock_response):
+        result = api_client.post("/v1/test", json={"key": "value"})
+
+    assert result["data"]["result"] == "ok"
+    assert api_client.session.headers["Content-Type"] == "application/json"
+
+
+def test_successful_get(api_client):
+    mock_response = MagicMock()
+    mock_response.json.return_value = {
+        "base_resp": {"status_code": 0},
+        "status": "Success",
+    }
+    mock_response.raise_for_status = MagicMock()
+    mock_response.headers = {"Trace-Id": "abc123"}
+
+    with patch.object(api_client.session, "request", return_value=mock_response) as mock_req:
+        result = api_client.get("/v1/query?task_id=123")
+
+    mock_req.assert_called_once_with("GET", "https://api.test.com/v1/query?task_id=123")
+    assert result["status"] == "Success"
+
+
+def test_file_upload_removes_content_type(api_client):
+    api_client.session.headers["Content-Type"] = "application/json"
+
+    mock_response = MagicMock()
+    mock_response.json.return_value = {
+        "base_resp": {"status_code": 0},
+        "file": {"file_id": "abc"},
+    }
+    mock_response.raise_for_status = MagicMock()
+    mock_response.headers = {"Trace-Id": "abc123"}
+
+    with patch.object(api_client.session, "request", return_value=mock_response):
+        result = api_client.post("/v1/files/upload", files={"file": b"data"}, data={"purpose": "voice_clone"})
+
+    assert "Content-Type" not in api_client.session.headers
+    assert result["file"]["file_id"] == "abc"
+
+
+def test_auth_error_1004(api_client):
+    mock_response = MagicMock()
+    mock_response.json.return_value = {
+        "base_resp": {"status_code": 1004, "status_msg": "invalid api key"},
+    }
+    mock_response.raise_for_status = MagicMock()
+    mock_response.headers = {"Trace-Id": "abc123"}
+
+    with patch.object(api_client.session, "request", return_value=mock_response):
+        with pytest.raises(MinimaxAuthError, match="API key"):
+            api_client.post("/v1/test", json={})
+
+
+def test_verification_error_2038(api_client):
+    mock_response = MagicMock()
+    mock_response.json.return_value = {
+        "base_resp": {"status_code": 2038, "status_msg": "need verification"},
+    }
+    mock_response.raise_for_status = MagicMock()
+    mock_response.headers = {"Trace-Id": "abc123"}
+
+    with patch.object(api_client.session, "request", return_value=mock_response):
+        with pytest.raises(MinimaxRequestError, match="real-name verification"):
+            api_client.post("/v1/test", json={})
+
+
+def test_generic_api_error(api_client):
+    mock_response = MagicMock()
+    mock_response.json.return_value = {
+        "base_resp": {"status_code": 9999, "status_msg": "unknown error"},
+    }
+    mock_response.raise_for_status = MagicMock()
+    mock_response.headers = {"Trace-Id": "abc123"}
+
+    with patch.object(api_client.session, "request", return_value=mock_response):
+        with pytest.raises(MinimaxRequestError, match="9999"):
+            api_client.post("/v1/test", json={})
+
+
+def test_network_request_failure(api_client):
+    with patch.object(
+        api_client.session, "request", side_effect=requests.exceptions.ConnectionError("Connection refused")
+    ):
+        with pytest.raises(MinimaxRequestError, match="Request failed"):
+            api_client.get("/v1/test")