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apps/mcp-server/tool-presentation.ts

@@ -0,0 +1,41 @@
+import type { CallToolResult, Tool } from "@modelcontextprotocol/sdk/types.js";
+
+const READ_ONLY_PREFIXES = ["get_", "list_", "search_", "validate_", "audit_", "ping_"];
+const DESTRUCTIVE_PREFIXES = ["delete_", "remove_", "restore_", "sync_"];
+
+/** Advertise intent without changing the existing tool names or input contracts. */
+export function presentToolDefinitions(tools: Tool[]): Tool[] {
+  return tools.map((tool) => {
+    const readOnly = READ_ONLY_PREFIXES.some((prefix) => tool.name.startsWith(prefix));
+    const destructive = DESTRUCTIVE_PREFIXES.some((prefix) => tool.name.startsWith(prefix));
+
+    return {
+      ...tool,
+      annotations: {
+        ...tool.annotations,
+        readOnlyHint: readOnly,
+        ...(readOnly ? { idempotentHint: true, destructiveHint: false } : {}),
+        ...(destructive ? { destructiveHint: true } : {}),
+        ...(tool.name === "upload_product_image_from_url" ? { openWorldHint: true } : {}),
+      },
+    };
+  });
+}
+
+/** Keep text responses for existing clients while exposing JSON as machine-readable data. */
+export function withStructuredContent(result: CallToolResult): CallToolResult {
+  if (result.structuredContent) return result;
+  const textBlocks = result.content.filter((item) => item.type === "text");
+  if (textBlocks.length !== 1) return result;
+
+  try {
+    const parsed: unknown = JSON.parse(textBlocks[0]!.text);
+    if (parsed === null || typeof parsed !== "object") return result;
+    return {
+      ...result,
+      structuredContent: Array.isArray(parsed) ? { data: parsed } : parsed as Record<string, unknown>,
+    };
+  } catch {
+    return result;
+  }
+}