Use content instead of structuredContent in examples

Not all MCP clients support structuredContent in MCP tool results, so
examples now return data as JSON in content and parse it client-side.

Pattern used:
- Server: content: [{ type: "text", text: JSON.stringify(data) }]
- Client: JSON.parse(result.content!.filter(...).map(...).join(""))

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

examples/cohort-heatmap-server/server.ts

@@ -149,17 +149,6 @@ function generateCohortData(
   };
 }
 
-function formatCohortSummary(data: CohortData): string {
-  const avgRetention = data.cohorts
-    .flatMap((c) => c.cells)
-    .filter((cell) => cell.periodIndex > 0)
-    .reduce((sum, cell, _, arr) => sum + cell.retention / arr.length, 0);
-
-  return `Cohort Analysis: ${data.cohorts.length} cohorts, ${data.periods.length} periods
-Average retention: ${(avgRetention * 100).toFixed(1)}%
-Metric: ${data.metric}, Period: ${data.periodType}`;
-}
-
 const server = new McpServer({
   name: "Cohort Heatmap Server",
   version: "1.0.0",
@@ -176,7 +165,6 @@ const server = new McpServer({
       description:
         "Returns cohort retention heatmap data showing customer retention over time by signup month",
       inputSchema: GetCohortDataInputSchema.shape,
-      outputSchema: CohortDataSchema.shape,
       _meta: { [RESOURCE_URI_META_KEY]: resourceUri },
     },
     async ({ metric, periodType, cohortCount, maxPeriods }) => {
@@ -188,8 +176,7 @@ const server = new McpServer({
       );
 
       return {
-        content: [{ type: "text", text: formatCohortSummary(data) }],
-        structuredContent: data,
+        content: [{ type: "text", text: JSON.stringify(data) }],
       };
     },
   );

examples/cohort-heatmap-server/src/mcp-app.tsx

@@ -103,7 +103,13 @@ function CohortHeatmapInner({ app }: { app: App }) {
           maxPeriods: 12,
         },
       });
-      setData(result.structuredContent as unknown as CohortData);
+      const text = result
+        .content!.filter(
+          (c): c is { type: "text"; text: string } => c.type === "text",
+        )
+        .map((c) => c.text)
+        .join("");
+      setData(JSON.parse(text) as CohortData);
     } catch (e) {
       console.error("Failed to fetch cohort data:", e);
     } finally {