diff --git a/packages/mcp-core/src/api-client/schema.ts b/packages/mcp-core/src/api-client/schema.ts
index d8343551..58dd34cf 100644
--- a/packages/mcp-core/src/api-client/schema.ts
+++ b/packages/mcp-core/src/api-client/schema.ts
@@ -1960,7 +1960,7 @@ export const TransactionProfileSchema = z
       frames: z.array(ProfileFrameSchema),
       samples: z.array(TransactionProfileSampleSchema),
       stacks: z.array(z.array(z.number())),
-      thread_metadata: ProfileThreadMetadataSchema,
+      thread_metadata: z.preprocess((value) => value ?? {}, ProfileThreadMetadataSchema),
     }),
     transaction: z
       .object({