fix p44

src/Agent/AgentRunner.php

@@ -2682,6 +2682,7 @@ final readonly class AgentRunner
     {
         $fullOutput = '';
         $thinkingNoticeShown = false;
+        $stoppedByFinalAnswerGuard = false;
         $chunker = new StreamChunker();
 
         $this->thinkSuppressor->reset();
@@ -2706,11 +2707,36 @@ final readonly class AgentRunner
                     continue;
                 }
 
-                $fullOutput .= $cleanToken;
+                $guardReason = null;
+                $cleanToken = $this->guardFinalAnswerToken($fullOutput, $cleanToken, $guardReason);
 
-                $chunk = $chunker->push($cleanToken);
-                if ($chunk !== null) {
-                    yield $this->systemMsg($chunk, 'answer');
+                if ($cleanToken !== '') {
+                    $fullOutput .= $cleanToken;
+
+                    $chunk = $chunker->push($cleanToken);
+                    if ($chunk !== null) {
+                        yield $this->systemMsg($chunk, 'answer');
+                    }
+                }
+
+                if ($guardReason !== null) {
+                    $stoppedByFinalAnswerGuard = true;
+
+                    $finalChunk = $chunker->flush();
+                    if ($finalChunk !== null) {
+                        yield $this->systemMsg($finalChunk, 'answer');
+                    }
+
+                    $guardMessage = $this->agentRunnerConfig->getFinalAnswerGuardTruncationMessage();
+                    $fullOutput .= $guardMessage;
+                    yield $this->systemMsg($guardMessage, 'answer');
+
+                    $this->agentLogger->warning('Final answer guard stopped LLM output', [
+                        'reason' => $guardReason,
+                        'outputLength' => mb_strlen($fullOutput, 'UTF-8'),
+                    ]);
+
+                    break;
                 }
             }
         } catch (Throwable $e) {
@@ -2730,6 +2756,10 @@ final readonly class AgentRunner
             return $fullOutput;
         }
 
+        if ($stoppedByFinalAnswerGuard) {
+            return $fullOutput;
+        }
+
         $finalChunk = $chunker->flush();
         if ($finalChunk !== null) {
             yield $this->systemMsg($finalChunk, 'answer');
@@ -2747,6 +2777,112 @@ final readonly class AgentRunner
         return $fullOutput;
     }
 
+    private function guardFinalAnswerToken(string $currentOutput, string $nextToken, ?string &$reason): string
+    {
+        $reason = null;
+
+        if (!$this->agentRunnerConfig->isFinalAnswerGuardEnabled()) {
+            return $nextToken;
+        }
+
+        $maxOutputChars = max(1000, $this->agentRunnerConfig->getFinalAnswerGuardMaxOutputChars());
+        $currentChars = mb_strlen($currentOutput, 'UTF-8');
+        $nextChars = mb_strlen($nextToken, 'UTF-8');
+
+        if (($currentChars + $nextChars) > $maxOutputChars) {
+            $reason = 'max_output_chars';
+            $remainingChars = max(0, $maxOutputChars - $currentChars);
+
+            return $remainingChars > 0 ? mb_substr($nextToken, 0, $remainingChars, 'UTF-8') : '';
+        }
+
+        $candidate = $currentOutput . $nextToken;
+        $cutoffBytes = $this->detectRepeatedFinalAnswerLineCutoff($candidate);
+
+        if ($cutoffBytes === null) {
+            return $nextToken;
+        }
+
+        $reason = 'repeated_line';
+        $currentBytes = strlen($currentOutput);
+
+        if ($cutoffBytes <= $currentBytes) {
+            return '';
+        }
+
+        return mb_strcut($nextToken, 0, $cutoffBytes - $currentBytes, 'UTF-8');
+    }
+
+    private function detectRepeatedFinalAnswerLineCutoff(string $text): ?int
+    {
+        if (!$this->agentRunnerConfig->isFinalAnswerRepeatedLineGuardEnabled()) {
+            return null;
+        }
+
+        if (mb_strlen($text, 'UTF-8') < max(0, $this->agentRunnerConfig->getFinalAnswerRepeatedLineMinOutputChars())) {
+            return null;
+        }
+
+        if (preg_match_all('/[^\r\n]+/u', $text, $matches, PREG_OFFSET_CAPTURE) === false) {
+            return null;
+        }
+
+        $lines = $matches[0] ?? [];
+        $window = max(10, $this->agentRunnerConfig->getFinalAnswerRepeatedLineTrailingWindowLines());
+        if (count($lines) > $window) {
+            $lines = array_slice($lines, -$window);
+        }
+
+        $counts = [];
+        $maxRepetitions = max(1, $this->agentRunnerConfig->getFinalAnswerRepeatedLineMaxRepetitions());
+
+        foreach ($lines as $lineMatch) {
+            $line = (string) ($lineMatch[0] ?? '');
+            $offset = (int) ($lineMatch[1] ?? 0);
+            $normalizedLine = $this->normalizeFinalAnswerLineForRepetitionGuard($line);
+
+            if ($normalizedLine === '') {
+                continue;
+            }
+
+            $counts[$normalizedLine] = ($counts[$normalizedLine] ?? 0) + 1;
+
+            if ($counts[$normalizedLine] > $maxRepetitions) {
+                return $offset;
+            }
+        }
+
+        return null;
+    }
+
+    private function normalizeFinalAnswerLineForRepetitionGuard(string $line): string
+    {
+        $line = html_entity_decode(strip_tags($line), ENT_QUOTES | ENT_HTML5, 'UTF-8');
+        $line = preg_replace('/^\s*(?:[-*•]+|\d+[.)])\s*/u', '', $line) ?? $line;
+        $line = preg_replace('/\s+/u', ' ', $line) ?? $line;
+        $line = trim($line, " \t\n\r\0\x0B:;.-");
+
+        if ($line === '') {
+            return '';
+        }
+
+        foreach ($this->agentRunnerConfig->getFinalAnswerRepeatedLineIgnorePatterns() as $pattern) {
+            try {
+                if (@preg_match($pattern, $line) === 1) {
+                    return '';
+                }
+            } catch (Throwable) {
+                continue;
+            }
+        }
+
+        if (mb_strlen($line, 'UTF-8') < max(1, $this->agentRunnerConfig->getFinalAnswerRepeatedLineMinLineChars())) {
+            return '';
+        }
+
+        return mb_strtolower($line, 'UTF-8');
+    }
+
     /**
      * Build a deterministic safety answer for environments where the LLM returns no tokens.
      *