chore: add changeset for onerror callback fix

codewithkenzo · felixweinberger · commit c87985e8b69d · 2026-03-12T11:54:50.000Z
diff --git a/.changeset/fix-onerror-callbacks.md b/.changeset/fix-onerror-callbacks.md
@@ -0,0 +1,5 @@
+---
+'@modelcontextprotocol/server': patch
+---
+
+Fix transport errors being silently swallowed by adding missing `onerror` callback invocations before all `createJsonErrorResponse` calls in `WebStandardStreamableHTTPServerTransport`. This ensures errors like parse failures, invalid headers, and session validation errors are properly reported via the `onerror` callback.

-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +'@modelcontextprotocol/server': patch
 +---
++
 +Fix transport errors being silently swallowed by adding missing `onerror` callback invocations before all `createJsonErrorResponse` calls in `WebStandardStreamableHTTPServerTransport`. This ensures errors like parse failures, invalid headers, and session validation errors are properly reported via the `onerror` callback.