server error if tool declares outputSchema but no structuredContent in result

2025-05-21 15:42:14 -04:00 · 2025-05-21 15:42:14 -04:00 · aeb7b8d741
commit aeb7b8d741
parent a41b174330
1 changed files with 72 additions and 1 deletions
--- a/src/server/mcp.ts
+++ b/src/server/mcp.ts
@ -198,7 +198,14 @@ export class McpServer {
          }
        }

-        if (tool.outputSchema && result.structuredContent) {
+        if (tool.outputSchema) {
+          if (!result.structuredContent) {
+            throw new McpError(
+              ErrorCode.InvalidParams,
+              `Tool ${request.params.name} has an output schema but no structured content was provided`,
+            );
+          }
+
          // if the tool has an output schema, validate structured content
          const parseResult = await tool.outputSchema.safeParseAsync(
            result.structuredContent,