diff --git a/src/Command/SystemRebuildCommand.php b/src/Command/SystemRebuildCommand.php
new file mode 100644
index 0000000..2804f3a
--- /dev/null
+++ b/src/Command/SystemRebuildCommand.php
@@ -0,0 +1,204 @@
+<?php
+
+
+declare(strict_types=1);
+
+namespace App\Command;
+
+use App\Entity\IngestJob;
+use App\Index\IndexMetaManager;
+use App\Service\IngestJobService;
+use App\Service\IngestOrchestrator;
+use App\Tag\TagNdjsonExporter;
+use App\Tag\TagVectorIndexBuilder;
+use App\Vector\VectorIndexHealthService;
+use Symfony\Component\Console\Attribute\AsCommand;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Style\SymfonyStyle;
+use Symfony\Component\Process\Process;
+
+#[AsCommand(
+    name: 'mto:agent:system:rebuild',
+    description: 'Hard rebuild: global reindex (chunks+vector), rebuild tag index, then reload vector service'
+)]
+final class SystemRebuildCommand extends Command
+{
+    public function __construct(
+        private readonly IngestJobService         $jobService,
+        private readonly IngestOrchestrator       $orchestrator,
+        private readonly TagNdjsonExporter        $tagExporter,
+        private readonly TagVectorIndexBuilder    $tagIndexBuilder,
+        private readonly IndexMetaManager         $metaManager,
+        private readonly VectorIndexHealthService $health,
+        private readonly string                   $projectDir,
+    )
+    {
+        parent::__construct();
+    }
+
+    protected function configure(): void
+    {
+        $this
+            ->addOption('hard', null, InputOption::VALUE_NONE, 'Required safety switch. Without --hard, the command aborts.')
+            ->addOption('no-tags', null, InputOption::VALUE_NONE, 'Skip tag rebuild')
+            ->addOption('no-reload', null, InputOption::VALUE_NONE, 'Skip vector service reload/start')
+            ->addOption('no-health', null, InputOption::VALUE_NONE, 'Skip health check (not recommended)')
+            ->addOption('dry-run', null, InputOption::VALUE_NONE, 'Simulate ingest steps (no writes)');
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output): int
+    {
+        $io = new SymfonyStyle($input, $output);
+
+        if (!$input->getOption('hard')) {
+            $io->error('Safety switch missing: you must pass --hard to run this command.');
+            $io->writeln('Example: bin/console mto:agent:system:rebuild --hard');
+            return Command::FAILURE;
+        }
+
+        $dryRun = (bool)$input->getOption('dry-run');
+
+        $io->title('mto:agent:system:rebuild --hard');
+
+        // ---------------------------------------------------------
+        // 1) GLOBAL REINDEX (chunks rewrite + vector rebuild)
+        // ---------------------------------------------------------
+        $io->section('1/4 Global reindex (chunks + vector index)');
+
+        $job = $this->jobService->startJob(
+            IngestJob::TYPE_GLOBAL_REINDEX,
+            null,
+            null,
+            null,
+            null,
+            IngestJob::STATUS_QUEUED
+        );
+
+        try {
+            $this->orchestrator->runExistingJob($job, $dryRun);
+            $io->success('Global reindex completed.');
+        } catch (\Throwable $e) {
+            $io->error('Global reindex failed: ' . $e->getMessage());
+            return Command::FAILURE;
+        }
+
+        // ---------------------------------------------------------
+        // 2) TAG REBUILD (tags.ndjson + vector_tags.index)
+        // ---------------------------------------------------------
+        if (!$input->getOption('no-tags')) {
+            $io->section('2/4 Tag rebuild (tags.ndjson + vector_tags.index)');
+
+            if ($dryRun) {
+                $io->note('dry-run enabled: tag rebuild skipped (would export + build tag index).');
+            } else {
+                try {
+                    $export = $this->tagExporter->export();
+
+                    $io->writeln('<info>Exported tags.ndjson</info>');
+                    $io->writeln('Path:  ' . $export['path']);
+                    $io->writeln('Tags:  ' . $export['tags']);
+                    $io->writeln('Lines: ' . $export['lines']);
+                    $io->writeln('Bytes: ' . $export['bytes']);
+
+                    $this->tagIndexBuilder->build();
+                    $io->writeln('<info>Built vector_tags.index</info>');
+
+                    $this->metaManager->touchRuntime([
+                        'last_tags_rebuild_at' => (new \DateTimeImmutable())->format(DATE_ATOM),
+                    ]);
+                    $io->success('Tag rebuild completed.');
+                } catch (\Throwable $e) {
+                    $io->error('Tag rebuild failed: ' . $e->getMessage());
+                    return Command::FAILURE;
+                }
+            }
+        } else {
+            $io->section('2/4 Tag rebuild');
+            $io->note('Skipped due to --no-tags.');
+        }
+
+        // ---------------------------------------------------------
+        // 3) VECTOR SERVICE (install deps + start + reload)
+        // ---------------------------------------------------------
+        if (!$input->getOption('no-reload')) {
+            $io->section('3/4 Vector service reload (uvicorn)');
+
+            if ($dryRun) {
+                $io->note('dry-run enabled: service reload skipped.');
+            } else {
+                $cmd = [
+                    '.venv/bin/python',
+                    'python/vector/vector_control.py',
+                    '--install',
+                    '--start',
+                    '--reload',
+                    '--port', '8090',
+                    '--host', '0.0.0.0'
+                ];
+
+                $process = new Process($cmd, $this->projectDir);
+                $process->setTimeout(600);
+                $process->run();
+
+                $out = trim($process->getOutput());
+                $err = trim($process->getErrorOutput());
+
+                if ($out !== '') {
+                    $io->writeln($out);
+                }
+                if ($err !== '') {
+                    $io->writeln('<comment>' . $err . '</comment>');
+                }
+
+                if (!$process->isSuccessful()) {
+                    $io->error('Vector service reload failed (non-zero exit code).');
+                    return Command::FAILURE;
+                }
+
+                $io->success('Vector service reloaded.');
+            }
+        } else {
+            $io->section('3/4 Vector service reload');
+            $io->note('Skipped due to --no-reload.');
+        }
+
+        // ---------------------------------------------------------
+        // 4) HEALTH CHECK (NDJSON vs vector meta)
+        // ---------------------------------------------------------
+        if (!$input->getOption('no-health')) {
+            $io->section('4/4 Health check');
+
+            try {
+                $report = $this->health->check();
+            } catch (\Throwable $e) {
+                $io->error('Health check failed: ' . $e->getMessage());
+                return Command::FAILURE;
+            }
+
+            $io->definitionList(
+                ['ndjson_exists' => $report['ndjson_exists'] ? 'yes' : 'no'],
+                ['ndjson_chunk_count' => (string)$report['ndjson_chunk_count']],
+                ['vector_exists' => $report['vector_exists'] ? 'yes' : 'no'],
+                ['meta_exists' => $report['meta_exists'] ? 'yes' : 'no'],
+                ['vector_chunk_count' => (string)$report['vector_chunk_count']],
+                ['status' => (string)$report['status']],
+            );
+
+            if (!in_array($report['status'], ['OK', 'OK_EMPTY'], true)) {
+                $io->error('Health check not OK: ' . $report['status']);
+                return Command::FAILURE;
+            }
+
+            $io->success('Health check OK.');
+        } else {
+            $io->section('4/4 Health check');
+            $io->note('Skipped due to --no-health.');
+        }
+
+        $io->success('System rebuild finished.');
+        return Command::SUCCESS;
+    }
+}
\ No newline at end of file
diff --git a/src/Knowledge/Ingest/KnowledgeIngestService.php b/src/Knowledge/Ingest/KnowledgeIngestService.php
index 78a93b3..adf299f 100644
--- a/src/Knowledge/Ingest/KnowledgeIngestService.php
+++ b/src/Knowledge/Ingest/KnowledgeIngestService.php
@@ -6,7 +6,6 @@ namespace App\Knowledge\Ingest;
 
 use App\Entity\DocumentVersion;
 use App\Repository\DocumentVersionRepository;
-use Symfony\Component\Uid\Uuid;
 
 final class KnowledgeIngestService
 {
@@ -18,7 +17,7 @@ final class KnowledgeIngestService
     }
 
     /**
-     * Lokaler Ingest: erzeugt NDJSON-Records für genau diese Version.
+     * Lokaler Ingest: erzeugt deterministische NDJSON-Records.
      *
      * @return iterable<array<string,mixed>>
      */
@@ -34,25 +33,34 @@ final class KnowledgeIngestService
         $documentId = $doc->getId()->toRfc4122();
         $versionId  = $version->getId()->toRfc4122();
 
-        // ✅ Regel: Wenn title gefüllt ist, kommt er in jeden Chunk
         $title = trim((string) $doc->getTitle());
 
         $index = 0;
 
         foreach ($chunks as $chunkText) {
 
-            // ✅ Prefix nur wenn title vorhanden; keine Flags, keine Meta-Schalter
+            // Titel optional weiterhin prefixen (wenn du das behalten willst)
             if ($title !== '' && !str_starts_with($chunkText, $title)) {
                 $chunkText = $title . "\n\n" . $chunkText;
             }
 
+            $chunkText = trim($chunkText);
+
+            // 🔥 deterministische Chunk-ID
+            $normalizedForId = $this->normalizeForId($chunkText);
+
+            $chunkId = sha1(
+                $documentId . '|' .
+                $versionId . '|' .
+                $normalizedForId
+            );
+
             yield [
-                'chunk_id'    => Uuid::v4()->toRfc4122(),
+                'chunk_id'    => $chunkId,
                 'document_id' => $documentId,
                 'version_id'  => $versionId,
                 'chunk_index' => $index++,
                 'text'        => $chunkText,
-                // ✅ checksum muss den finalen Text abbilden (inkl. Titel)
                 'checksum'    => sha1($chunkText),
                 'metadata'    => $this->buildMetadata($version),
             ];
@@ -60,10 +68,7 @@ final class KnowledgeIngestService
     }
 
     /**
-     * Global Reindex: iteriert streamingfähig über alle aktiven Versionen.
-     * Keine RAM-Explosion, da alles generatorbasiert bleibt.
-     *
-     * @return iterable<array<string,mixed>>
+     * Global Reindex
      */
     public function buildAllActiveChunkRecords(): iterable
     {
@@ -76,8 +81,18 @@ final class KnowledgeIngestService
     {
         $text = preg_replace("/\n{3,}/", "\n\n", $text);
         $text = preg_replace("/[ \t]+$/m", "", $text);
+        return trim($text);
+    }
 
-        return $text;
+    /**
+     * Normalisierung für stabile ID-Berechnung.
+     * Wichtig: ID darf nicht durch Whitespace minimal variieren.
+     */
+    private function normalizeForId(string $text): string
+    {
+        $text = mb_strtolower($text);
+        $text = preg_replace('/\s+/u', ' ', $text);
+        return trim($text);
     }
 
     /**
@@ -87,7 +102,6 @@ final class KnowledgeIngestService
     {
         $doc = $version->getDocument();
 
-        // Optional: Titel/Name, falls vorhanden
         $title = null;
         if (method_exists($doc, 'getTitle')) {
             $title = $doc->getTitle();
@@ -97,8 +111,10 @@ final class KnowledgeIngestService
 
         return array_filter([
             'document_title' => $title,
-            'version_number' => method_exists($version, 'getVersionNumber') ? $version->getVersionNumber() : null,
+            'version_number' => method_exists($version, 'getVersionNumber')
+                ? $version->getVersionNumber()
+                : null,
             'file_path'      => $version->getFilePath(),
         ], static fn($v) => $v !== null && $v !== '');
     }
-}
+}
\ No newline at end of file