Hide empty MAINT slots from get_server_health output by default

Reduces MCP response from ~12.3k tokens (~1000 lines) to only active servers.
Empty pool slots (MAINT with no health check) are filtered by default.
Added show_all parameter to optionally show all slots.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

haproxy_mcp/tools/health.py

@@ -195,9 +195,14 @@ def register_health_tools(mcp):
 
     @mcp.tool()
     def haproxy_get_server_health(
-        backend: Annotated[str, Field(default="", description="Optional: Backend name to filter (e.g., 'pool_1'). Empty = all backends")] = ""
+        backend: Annotated[str, Field(default="", description="Optional: Backend name to filter (e.g., 'pool_1'). Empty = all backends")] = "",
+        show_all: Annotated[bool, Field(default=False, description="Show all slots including empty MAINT slots. Default: only active/configured servers")] = False,
     ) -> str:
-        """Get health status of all servers (low-level view). For domain-specific, use haproxy_domain_health."""
+        """Get health status of all servers (low-level view). For domain-specific, use haproxy_domain_health.
+
+        By default, hides empty pool slots (MAINT with no health check) to reduce output size.
+        Use show_all=True to see all slots including unconfigured ones.
+        """
         if backend and not validate_backend_name(backend):
             return "Error: Invalid backend name (use alphanumeric, underscore, hyphen only)"
         try:
@@ -207,6 +212,9 @@ def register_health_tools(mcp):
                 if stat["svname"] not in ["FRONTEND", "BACKEND", ""]:
                     if backend and stat["pxname"] != backend:
                         continue
+                    # Skip empty pool slots (MAINT with no health check = unconfigured)
+                    if not show_all and stat["status"] == "MAINT" and not stat["check_status"]:
+                        continue
                     servers.append(
                         f"• {stat['pxname']}/{stat['svname']}: {stat['status']} "
                         f"(weight: {stat['weight']}, check: {stat['check_status']})"

tests/unit/tools/test_health.py

@@ -406,6 +406,93 @@ class TestHaproxyGetServerHealth:
 
         assert "No servers found" in result
 
+    def test_get_server_health_hides_empty_maint_slots(self, mock_socket_class, mock_select, patch_config_paths, response_builder):
+        """Empty MAINT slots (no health check) are hidden by default."""
+        mock_sock = mock_socket_class(responses={
+            "show stat": response_builder.stat_csv([
+                {"pxname": "pool_1", "svname": "pool_1_1", "status": "UP", "weight": 1, "check_status": "L4OK"},
+                {"pxname": "pool_1", "svname": "pool_1_2", "status": "MAINT", "weight": 1, "check_status": ""},
+                {"pxname": "pool_1", "svname": "pool_1_3", "status": "MAINT", "weight": 1, "check_status": ""},
+                {"pxname": "pool_2", "svname": "pool_2_1", "status": "MAINT", "weight": 1, "check_status": ""},
+            ]),
+        })
+
+        with patch("socket.socket", return_value=mock_sock):
+            from haproxy_mcp.tools.health import register_health_tools
+            mcp = MagicMock()
+            registered_tools = {}
+
+            def capture_tool():
+                def decorator(func):
+                    registered_tools[func.__name__] = func
+                    return func
+                return decorator
+
+            mcp.tool = capture_tool
+            register_health_tools(mcp)
+
+            result = registered_tools["haproxy_get_server_health"](backend="")
+
+        assert "pool_1_1" in result
+        assert "pool_1_2" not in result
+        assert "pool_1_3" not in result
+        assert "pool_2" not in result
+
+    def test_get_server_health_show_all_includes_empty_slots(self, mock_socket_class, mock_select, patch_config_paths, response_builder):
+        """show_all=True includes empty MAINT slots."""
+        mock_sock = mock_socket_class(responses={
+            "show stat": response_builder.stat_csv([
+                {"pxname": "pool_1", "svname": "pool_1_1", "status": "UP", "weight": 1, "check_status": "L4OK"},
+                {"pxname": "pool_1", "svname": "pool_1_2", "status": "MAINT", "weight": 1, "check_status": ""},
+            ]),
+        })
+
+        with patch("socket.socket", return_value=mock_sock):
+            from haproxy_mcp.tools.health import register_health_tools
+            mcp = MagicMock()
+            registered_tools = {}
+
+            def capture_tool():
+                def decorator(func):
+                    registered_tools[func.__name__] = func
+                    return func
+                return decorator
+
+            mcp.tool = capture_tool
+            register_health_tools(mcp)
+
+            result = registered_tools["haproxy_get_server_health"](backend="", show_all=True)
+
+        assert "pool_1_1" in result
+        assert "pool_1_2" in result
+
+    def test_get_server_health_keeps_maint_with_check(self, mock_socket_class, mock_select, patch_config_paths, response_builder):
+        """MAINT servers with health check status are kept (intentionally maintained)."""
+        mock_sock = mock_socket_class(responses={
+            "show stat": response_builder.stat_csv([
+                {"pxname": "pool_1", "svname": "pool_1_1", "status": "MAINT", "weight": 1, "check_status": "L4OK"},
+            ]),
+        })
+
+        with patch("socket.socket", return_value=mock_sock):
+            from haproxy_mcp.tools.health import register_health_tools
+            mcp = MagicMock()
+            registered_tools = {}
+
+            def capture_tool():
+                def decorator(func):
+                    registered_tools[func.__name__] = func
+                    return func
+                return decorator
+
+            mcp.tool = capture_tool
+            register_health_tools(mcp)
+
+            result = registered_tools["haproxy_get_server_health"](backend="")
+
+        assert "pool_1_1" in result
+        assert "MAINT" in result
+
     def test_get_server_health_haproxy_error(self, mock_socket_class, mock_select, patch_config_paths):
         """HAProxy error returns error message."""
         def raise_error(*args, **kwargs):