A page's time budget is sent to the runtime, and a verb the runtime lacks is told by its code (issue 1966)

Claude-Session: https://claude.ai/code/session_01NcbgfFSnn24M3GcqttoU7i

go/stdio.go

@@ -150,7 +150,12 @@ type refused struct {
 func (r *refused) Error() string { return r.message }
 
 // Is makes a compare-and-set the runtime refused because another writer was first ErrChanged.
-func (r *refused) Is(target error) bool { return target == ErrChanged && r.code == CodeChanged }
+func (r *refused) Is(target error) bool {
+	return target == ErrChanged && r.code == CodeChanged || target == errors.ErrUnsupported && r.code == CodeNoMethod
+}
+
+// CodeNoMethod is the error code the runtime answers a verb it does not have with (JSON-RPC's method not found).
+const CodeNoMethod = -32601
 
 // ErrChanged is a compare-and-set that lost: the key was made or changed by another writer first (novox/hq
 // ADR 0259). Told apart by the runtime's error code, never by its words.