Azure · gossion · Sep 5, 2025 · Sep 4, 2025 · Sep 4, 2025
diff --git a/internal/components/azaks/registry.go b/internal/components/azaks/registry.go
@@ -77,6 +77,8 @@ func generateToolDescription(accessLevel string) string {
 	// Only show write operation examples if access level allows it
 	if accessLevel == "readwrite" || accessLevel == "admin" {
 		desc += "- Scale cluster: operation=\"scale\", args=\"--name myCluster --resource-group myRG --node-count 5\"\n"
+		desc += "- Update cluster (enable autoscaler): operation=\"update\", args=\"--name myCluster --resource-group myRG --enable-cluster-autoscaler --min-count 1 --max-count 5\"\n"
+		desc += "- Update cluster (disable autoscaler): operation=\"update\", args=\"--name myCluster --resource-group myRG --disable-cluster-autoscaler\"\n"
 	}

 	return desc

diff --git a/internal/tools/handler.go b/internal/tools/handler.go
@@ -59,6 +59,10 @@ func CreateToolHandler(executor CommandExecutor, cfg *config.ConfigData) func(ct
 		}

 		if err != nil {
+			// Include command output (often stderr) in the error for context
+			if result != "" {
+				return mcp.NewToolResultError(fmt.Sprintf("%s\n%s", err.Error(), result)), nil
+			}
 			return mcp.NewToolResultError(err.Error()), nil
 		}

@@ -96,6 +100,10 @@ func CreateResourceHandler(handler ResourceHandler, cfg *config.ConfigData) func
 		}

 		if err != nil {
+			// Include handler output in the error message for better diagnostics
+			if result != "" {
+				return mcp.NewToolResultError(fmt.Sprintf("%s\n%s", err.Error(), result)), nil
+			}
 			return mcp.NewToolResultError(err.Error()), nil
 		}


diff --git a/internal/tools/handler_test.go b/internal/tools/handler_test.go
@@ -0,0 +1,297 @@
+package tools
+
+import (
+	"context"
+	"errors"
+	"strings"
+	"testing"
+
+	"github.com/Azure/aks-mcp/internal/config"
+	"github.com/Azure/aks-mcp/internal/telemetry"
+	"github.com/mark3labs/mcp-go/mcp"
+)
+
+// helper to extract first text content from result
+func firstText(result *mcp.CallToolResult) string {
+	for _, c := range result.Content {
+		if tc, ok := mcp.AsTextContent(c); ok {
+			return tc.Text
+		}
+	}
+	return ""
+}
+
+func TestCreateToolHandler_ErrorIncludesResultOutput(t *testing.T) {
+	cfg := config.NewConfig()
+
+	// Fake executor returns stderr-like output with an error
+	exec := CommandExecutorFunc(func(params map[string]interface{}, _ *config.ConfigData) (string, error) {
+		return "ERROR: Azure CLI detailed message", errors.New("exit status 1")
+	})
+
+	handler := CreateToolHandler(exec, cfg)
+
+	req := mcp.CallToolRequest{
+		Params: mcp.CallToolParams{
+			Name:      "dummy_tool",
+			Arguments: map[string]any{"operation": "test"},
+		},
+	}
+
+	res, err := handler(context.Background(), req)
+	if err != nil {
+		t.Fatalf("handler returned error: %v", err)
+	}
+	if res == nil {
+		t.Fatalf("nil result returned")
+	}
+	if !res.IsError {
+		t.Fatalf("expected IsError=true on result")
+	}
+	msg := firstText(res)
+	if !strings.Contains(msg, "exit status 1") || !strings.Contains(msg, "ERROR: Azure CLI detailed message") {
+		t.Fatalf("expected combined error + output, got: %q", msg)
+	}
+}
+
+func TestCreateToolHandler_ErrorWithoutOutput(t *testing.T) {
+	cfg := config.NewConfig()
+
+	exec := CommandExecutorFunc(func(params map[string]interface{}, _ *config.ConfigData) (string, error) {
+		return "", errors.New("exit status 1")
+	})
+
+	handler := CreateToolHandler(exec, cfg)
+
+	req := mcp.CallToolRequest{
+		Params: mcp.CallToolParams{
+			Name:      "dummy_tool",
+			Arguments: map[string]any{"operation": "test"},
+		},
+	}
+
+	res, err := handler(context.Background(), req)
+	if err != nil {
+		t.Fatalf("handler returned error: %v", err)
+	}
+	if res == nil || !res.IsError {
+		t.Fatalf("expected error result, got: %+v", res)
+	}
+	msg := firstText(res)
+	if msg != "exit status 1" {
+		t.Fatalf("expected only error text, got: %q", msg)
+	}
+}
+
+func TestCreateResourceHandler_ErrorIncludesResultOutput(t *testing.T) {
+	cfg := config.NewConfig()
+
+	rh := ResourceHandlerFunc(func(params map[string]interface{}, _ *config.ConfigData) (string, error) {
+		return "API: detailed failure context", errors.New("bad request")
+	})
+
+	handler := CreateResourceHandler(rh, cfg)
+
+	req := mcp.CallToolRequest{
+		Params: mcp.CallToolParams{
+			Name:      "dummy_resource",
+			Arguments: map[string]any{"operation": "test"},
+		},
+	}
+
+	res, err := handler(context.Background(), req)
+	if err != nil {
+		t.Fatalf("handler returned error: %v", err)
+	}
+	if res == nil || !res.IsError {
+		t.Fatalf("expected error result, got: %+v", res)
+	}
+	msg := firstText(res)
+	if !strings.Contains(msg, "bad request") || !strings.Contains(msg, "API: detailed failure context") {
+		t.Fatalf("expected combined error + output, got: %q", msg)
+	}
+}
+
+func TestCreateResourceHandler_ErrorWithoutOutput(t *testing.T) {
+	cfg := config.NewConfig()
+
+	rh := ResourceHandlerFunc(func(params map[string]interface{}, _ *config.ConfigData) (string, error) {
+		return "", errors.New("bad request")
+	})
+
+	handler := CreateResourceHandler(rh, cfg)
+
+	req := mcp.CallToolRequest{
+		Params: mcp.CallToolParams{
+			Name:      "dummy_resource",
+			Arguments: map[string]any{"operation": "test"},
+		},
+	}
+
+	res, err := handler(context.Background(), req)
+	if err != nil {
+		t.Fatalf("handler returned error: %v", err)
+	}
+	if res == nil || !res.IsError {
+		t.Fatalf("expected error result, got: %+v", res)
+	}
+	msg := firstText(res)
+	if msg != "bad request" {
+		t.Fatalf("expected only error text, got: %q", msg)
+	}
+}
+
+func TestCreateToolHandler_Success_Verbose_Telemetry_LongResult(t *testing.T) {
+	cfg := config.NewConfig()
+	cfg.Verbose = true // exercise logToolCall + logToolResult
+	// Provide non-nil telemetry to exercise TrackToolInvocation path
+	cfg.TelemetryService = telemetry.NewService(telemetry.NewConfig("svc", "1.0"))
+
+	long := strings.Repeat("x", 600)
+	exec := CommandExecutorFunc(func(params map[string]interface{}, _ *config.ConfigData) (string, error) {
+		return long, nil
+	})
+
+	handler := CreateToolHandler(exec, cfg)
+
+	req := mcp.CallToolRequest{
+		Params: mcp.CallToolParams{
+			Name: "dummy_tool",
+			Arguments: map[string]any{
+				"operation": "op",
+			},
+		},
+	}
+
+	res, err := handler(context.Background(), req)
+	if err != nil {
+		t.Fatalf("handler returned error: %v", err)
+	}
+	if res == nil || res.IsError {
+		t.Fatalf("expected success result, got: %+v", res)
+	}
+	if got := firstText(res); got != long {
+		t.Fatalf("unexpected result text length=%d", len(got))
+	}
+}
+
+func TestCreateToolHandler_InvalidArguments_Verbose_LogsFallback_TracksTelemetry(t *testing.T) {
+	cfg := config.NewConfig()
+	cfg.Verbose = true
+	cfg.TelemetryService = telemetry.NewService(telemetry.NewConfig("svc", "1.0"))
+
+	exec := CommandExecutorFunc(func(params map[string]interface{}, _ *config.ConfigData) (string, error) {
+		return "should not run", nil
+	})
+
+	handler := CreateToolHandler(exec, cfg)
+
+	// Use an argument type that fails json.Marshal to exercise logToolCall fallback branch
+	ch := make(chan int)
+	req := mcp.CallToolRequest{
+		Params: mcp.CallToolParams{
+			Name:      "dummy_tool",
+			Arguments: ch,
+		},
+	}
+
+	res, err := handler(context.Background(), req)
+	if err != nil {
+		t.Fatalf("handler returned error: %v", err)
+	}
+	if res == nil || !res.IsError {
+		t.Fatalf("expected error result, got: %+v", res)
+	}
+	msg := firstText(res)
+	if !strings.Contains(msg, "arguments must be a map[string]interface{}") {
+		t.Fatalf("unexpected error message: %q", msg)
+	}
+}
+
+func TestCreateResourceHandler_ShortSuccess_Verbose_Telemetry(t *testing.T) {
+	cfg := config.NewConfig()
+	cfg.Verbose = true
+	cfg.TelemetryService = telemetry.NewService(telemetry.NewConfig("svc", "1.0"))
+
+	rh := ResourceHandlerFunc(func(params map[string]interface{}, _ *config.ConfigData) (string, error) {
+		return "ok", nil
+	})
+
+	handler := CreateResourceHandler(rh, cfg)
+
+	req := mcp.CallToolRequest{
+		Params: mcp.CallToolParams{
+			Name:      "dummy_resource",
+			Arguments: map[string]any{"operation": "x"},
+		},
+	}
+
+	res, err := handler(context.Background(), req)
+	if err != nil {
+		t.Fatalf("handler returned error: %v", err)
+	}
+	if res == nil || res.IsError {
+		t.Fatalf("expected success result, got: %+v", res)
+	}
+	if got := firstText(res); got != "ok" {
+		t.Fatalf("unexpected text: %q", got)
+	}
+}
+
+func TestCreateResourceHandler_InvalidArguments_Verbose_LogsFallback_TracksTelemetry(t *testing.T) {
+	cfg := config.NewConfig()
+	cfg.Verbose = true
+	cfg.TelemetryService = telemetry.NewService(telemetry.NewConfig("svc", "1.0"))
+
+	rh := ResourceHandlerFunc(func(params map[string]interface{}, _ *config.ConfigData) (string, error) {
+		return "should not run", nil
+	})
+
+	handler := CreateResourceHandler(rh, cfg)
+
+	// Unmarshalable type to drive logToolCall fallback branch
+	ch := make(chan int)
+	req := mcp.CallToolRequest{
+		Params: mcp.CallToolParams{
+			Name:      "dummy_resource",
+			Arguments: ch,
+		},
+	}
+
+	res, err := handler(context.Background(), req)
+	if err != nil {
+		t.Fatalf("handler returned error: %v", err)
+	}
+	if res == nil || !res.IsError {
+		t.Fatalf("expected error result, got: %+v", res)
+	}
+	if msg := firstText(res); !strings.Contains(msg, "arguments must be a map[string]interface{}") {
+		t.Fatalf("unexpected error message: %q", msg)
+	}
+}
+
+func TestCreateToolHandler_Error_Verbose_LogErrorBranch(t *testing.T) {
+	cfg := config.NewConfig()
+	cfg.Verbose = true
+
+	exec := CommandExecutorFunc(func(params map[string]interface{}, _ *config.ConfigData) (string, error) {
+		return "", errors.New("boom")
+	})
+
+	handler := CreateToolHandler(exec, cfg)
+
+	req := mcp.CallToolRequest{
+		Params: mcp.CallToolParams{
+			Name:      "dummy_tool",
+			Arguments: map[string]any{"operation": "op"},
+		},
+	}
+
+	res, err := handler(context.Background(), req)
+	if err != nil {
+		t.Fatalf("handler returned error: %v", err)
+	}
+	if res == nil || !res.IsError {
+		t.Fatalf("expected error result, got: %+v", res)
+	}
+}