Refactors DemoMCP tool handler to integrate with DemoGRPC for fact retrieval and updates server instructions.

pkg/demo/demomcp/tool.go

@@ -0,0 +1,58 @@
+package demomcp
+
+import (
+	"context"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+	"k8s.io/utils/ptr"
+
+	demo "gitea.libretechconsulting.com/rmcguire/go-server-with-otel/api/demo/app/v1alpha1"
+)
+
+var DemoTool = &mcp.Tool{
+	Name:        "Demo Tool",
+	Title:       "Demo Random Fact Tool",
+	Description: "Returns a random fact for demo or boredom purposes",
+	Annotations: &mcp.ToolAnnotations{
+		ReadOnlyHint:  true,
+		OpenWorldHint: ptr.To(true),
+	},
+}
+
+type DemoToolParams struct {
+	Language string `json:"language,omitempty" jsonschema:"Random Fact Language Abbreviation (e.g. en)"`
+}
+
+func (d *DemoMCPServer) addDemoRandomFactTool() {
+	d.server.AddTool(
+		mcp.ToolFor(DemoTool, d.demoToolHandler),
+	)
+}
+
+func (d *DemoMCPServer) demoToolHandler(ctx context.Context, req *mcp.CallToolRequest, args *DemoToolParams) (
+	*mcp.CallToolResult, any, error,
+) {
+	fact, err := d.demoGRPC.GetDemo(ctx, &demo.GetDemoRequest{
+		Language: &args.Language,
+	})
+	if err != nil {
+		return &mcp.CallToolResult{
+			IsError: true,
+			Meta: mcp.Meta{
+				"error": err,
+			},
+		}, nil, err
+	}
+
+	return &mcp.CallToolResult{
+		Meta: mcp.Meta{
+			"language": fact.GetLanguage(),
+			"source":   fact.GetSource(),
+		},
+		Content: []mcp.Content{
+			&mcp.TextContent{
+				Text: fact.GetFact(),
+			},
+		},
+	}, nil, nil
+}