fix retrieve final

src/Agent/AgentRunner.php

@@ -291,8 +291,9 @@ final readonly class AgentRunner
 
         $history = $this->contextService->buildUserContextWithinBudget($userId, 3000);
         $previousQuestions = $this->extractRecentUserQuestions($history, 2);
+        $referenceAnchors = $this->extractLatestAssistantReferenceAnchors($history);
 
-        if ($previousQuestions === []) {
+        if ($previousQuestions === [] && $referenceAnchors === []) {
             return $prompt;
         }
 
@@ -302,6 +303,11 @@ final readonly class AgentRunner
             $lines[] = 'Vorherige Nutzerfrage: ' . $question;
         }
 
+        if ($referenceAnchors !== []) {
+            $lines[] = 'Vorherige technische Referenzanker (nur zur Referenzauflösung, keine Faktenquelle): '
+                . implode(' ', $referenceAnchors);
+        }
+
         $lines[] = 'Aktuelle Folgefrage: ' . $prompt;
 
         return implode("\n", $lines);
@@ -408,6 +414,101 @@ final readonly class AgentRunner
         return array_slice($questions, -$limit);
     }
 
+    /**
+     * Extracts stable reference anchors from the latest assistant answer.
+     *
+     * These anchors are only used to resolve follow-up references such as
+     * "der Wert" or "welcher Indikator". They are not factual evidence for
+     * the final answer. To avoid propagating wrong earlier answers, only the
+     * first explicit Testomat model reference and the first explicit °dH value
+     * are kept. Indicator names, reagent codes, prices, URLs and product
+     * numbers are intentionally ignored here.
+     *
+     * @return string[]
+     */
+    private function extractLatestAssistantReferenceAnchors(string $history): array
+    {
+        $turn = $this->extractLatestHistoryTurn($history);
+
+        if ($turn === '') {
+            return [];
+        }
+
+        $answer = preg_replace('/^Question:\s*.*(?:\R|$)/u', '', $turn, 1) ?? '';
+        $answer = trim($answer);
+
+        if ($answer === '') {
+            return [];
+        }
+
+        $anchors = [];
+
+        $model = $this->extractFirstTestomatModelAnchor($answer);
+        if ($model !== '') {
+            $anchors[] = $model;
+        }
+
+        $hardnessValue = $this->extractFirstHardnessValueAnchor($answer);
+        if ($hardnessValue !== '') {
+            $anchors[] = $hardnessValue;
+        }
+
+        return array_values(array_unique($anchors));
+    }
+
+    private function extractLatestHistoryTurn(string $history): string
+    {
+        $history = trim($history);
+
+        if ($history === '') {
+            return '';
+        }
+
+        $parts = preg_split('/(?=^Question:\s)/m', $history);
+
+        if ($parts === false || $parts === []) {
+            return '';
+        }
+
+        $turns = array_values(array_filter(
+            array_map(static fn(string $part): string => trim($part), $parts),
+            static fn(string $part): bool => $part !== ''
+        ));
+
+        if ($turns === []) {
+            return '';
+        }
+
+        return (string) end($turns);
+    }
+
+    private function extractFirstTestomatModelAnchor(string $text): string
+    {
+        $pattern = '/\bTestomat(?:®)?\s+'
+            . '(?:\d{3,4}|EVO(?:\s+[A-Z]{2,6})?|ECO(?:[-\s]?(?:PLUS|C))?|DUO(?:\s+\d{3,4})?|LAB(?:\s+[A-Z]{2,6})?)'
+            . '\b/iu';
+
+        if (preg_match($pattern, $text, $matches) !== 1) {
+            return '';
+        }
+
+        $value = $this->sanitizeHistoryQuestion((string) ($matches[0] ?? ''));
+        $value = preg_replace('/\s+/u', ' ', $value) ?? $value;
+
+        return trim(str_replace('®', '', $value));
+    }
+
+    private function extractFirstHardnessValueAnchor(string $text): string
+    {
+        if (preg_match('/\b\d+(?:[,.]\d+)?\s*°\s*dH\b/iu', $text, $matches) !== 1) {
+            return '';
+        }
+
+        $value = preg_replace('/\s+/u', ' ', (string) ($matches[0] ?? '')) ?? '';
+
+        return trim($value);
+    }
+
     private function sanitizeHistoryQuestion(string $question): string
     {
         $question = trim((string) preg_replace('/\s+/u', ' ', $question));