fix

apps/api/cmd/mock-llm/main.go

@@ -140,10 +140,19 @@ func (s *server) handleChatCompletions(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	system, user := splitMessages(req.Messages)
-	comp, err := processing.HeuristicCompleter{}.Complete(context.Background(), system, user)
-	if err != nil {
-		http.Error(w, `{"error":{"message":"completer failed"}}`, http.StatusInternalServerError)
-		return
+	var comp processing.Completion
+	// A category formula in the prompt is answered in that formula's shape, so a
+	// local run proves the formula reached the model and the reply passes the
+	// pipeline's formula gate. Everything else keeps the heuristic fallback.
+	if text, ok := buildFormulaReply(system, user); ok {
+		comp = processing.Completion{Text: text}
+	} else {
+		var err error
+		comp, err = processing.HeuristicCompleter{}.Complete(context.Background(), system, user)
+		if err != nil {
+			http.Error(w, `{"error":{"message":"completer failed"}}`, http.StatusInternalServerError)
+			return
+		}
 	}
 	model := strings.TrimSpace(req.Model)
 	if model == "" {