diff --git a/src/dolibarr_mcp/dolibarr_mcp_server.py b/src/dolibarr_mcp/dolibarr_mcp_server.py
index 8da97a7..2bdb44c 100644
--- a/src/dolibarr_mcp/dolibarr_mcp_server.py
+++ b/src/dolibarr_mcp/dolibarr_mcp_server.py
@@ -1389,6 +1389,7 @@ async def handle_call_tool(name: str, arguments: dict):
 async def test_api_connection(config: Config | None = None):
     """Test API connection and yield client if successful."""
     created_config = False
+    api_ok = False
     try:
         if config is None:
             config = Config()
@@ -1399,14 +1400,14 @@ async def test_api_connection(config: Config | None = None):
             print("⚠️  Warning: DOLIBARR_URL not configured in .env file", file=sys.stderr)
             print("⚠️  Using placeholder URL - API calls will fail", file=sys.stderr)
             print("📝 Please configure your .env file with valid Dolibarr credentials", file=sys.stderr)
-            yield True  # Allow server to start anyway
+            yield False  # Configuration incomplete
             return
             
         if not config.api_key or config.api_key == "your_dolibarr_api_key_here":
             print("⚠️  Warning: DOLIBARR_API_KEY not configured in .env file", file=sys.stderr)
             print("⚠️  API authentication will fail", file=sys.stderr)
             print("📝 Please configure your .env file with valid Dolibarr credentials", file=sys.stderr)
-            yield True  # Allow server to start anyway
+            yield False  # Configuration incomplete
             return
         
         async with DolibarrClient(config) as client:
@@ -1415,17 +1416,19 @@ async def test_api_connection(config: Config | None = None):
             if 'success' in result or 'dolibarr_version' in str(result):
                 print("✅ Dolibarr API connection successful", file=sys.stderr)
                 print("🎯 Full CRUD operations available for all Dolibarr modules", file=sys.stderr)
-                yield True
+                api_ok = True
             else:
                 print(f"⚠️  API test returned unexpected result: {result}", file=sys.stderr)
                 print("⚠️  Server will start but API calls may fail", file=sys.stderr)
-                yield True  # Allow server to start anyway
+                api_ok = False
     except Exception as e:
         print(f"⚠️  API test error: {e}", file=sys.stderr)
         if config is None or created_config:
             print("💡 Check your .env file configuration", file=sys.stderr)
         print("⚠️  Server will start but API calls may fail", file=sys.stderr)
-        yield True  # Allow server to start anyway
+        api_ok = False
+    
+    yield api_ok
 
 
 async def _run_stdio_server(_config: Config) -> None:
diff --git a/tests/test_server_connection.py b/tests/test_server_connection.py
new file mode 100644
index 0000000..66b3df9
--- /dev/null
+++ b/tests/test_server_connection.py
@@ -0,0 +1,71 @@
+"""Tests for MCP server connection checks."""
+
+import pytest
+
+from dolibarr_mcp import dolibarr_mcp_server
+from dolibarr_mcp.config import Config
+from dolibarr_mcp.dolibarr_client import DolibarrAPIError
+
+
+class _DummyClient:
+    """Simple dummy client for test_api_connection success path."""
+
+    async def __aenter__(self):
+        return self
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb):
+        return False
+
+    async def get_status(self):
+        return {"success": {"dolibarr_version": "1.0.0"}}
+
+
+class _ErrorClient:
+    """Dummy client that raises for test_api_connection error path."""
+
+    async def __aenter__(self):
+        return self
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb):
+        return False
+
+    async def get_status(self):
+        raise DolibarrAPIError("boom")
+
+
+@pytest.mark.asyncio
+async def test_api_connection_success(monkeypatch):
+    """Yields True when the Dolibarr API status call succeeds."""
+    monkeypatch.setattr(dolibarr_mcp_server, "DolibarrClient", lambda config: _DummyClient())
+    config = Config(
+        dolibarr_url="https://example.com/api/index.php",
+        dolibarr_api_key="test_key",
+    )
+
+    async with dolibarr_mcp_server.test_api_connection(config) as api_ok:
+        assert api_ok is True
+
+
+@pytest.mark.asyncio
+async def test_api_connection_missing_configuration():
+    """Yields False when the configuration is incomplete."""
+    config = Config(
+        dolibarr_url="https://your-dolibarr-instance.com/api/index.php",
+        dolibarr_api_key="placeholder_api_key",
+    )
+
+    async with dolibarr_mcp_server.test_api_connection(config) as api_ok:
+        assert api_ok is False
+
+
+@pytest.mark.asyncio
+async def test_api_connection_with_client_error(monkeypatch):
+    """Yields False when the Dolibarr client raises errors."""
+    monkeypatch.setattr(dolibarr_mcp_server, "DolibarrClient", lambda config: _ErrorClient())
+    config = Config(
+        dolibarr_url="https://example.com/api/index.php",
+        dolibarr_api_key="test_key",
+    )
+
+    async with dolibarr_mcp_server.test_api_connection(config) as api_ok:
+        assert api_ok is False