fix shop research

RETRIEX_SHOP_META_CONTEXT_AND_SSE_REPLAY_FIX_README.md

@@ -0,0 +1,84 @@
+# RetrieX Shop-Meta-Context + SSE-Reconnect-Replay Fix
+
+## Problem
+
+Kurze referenzielle Shop-Befehle wie:
+
+```text
+suche im shop
+```
+
+konnten trotz vorheriger Antwort scheitern mit:
+
+```text
+Ich habe keine konkrete Shop-Suchanfrage erkannt.
+```
+
+Das passierte besonders nach langen oder reconnect-anfälligen SSE-Antworten, weil der Shop-Fallback vollständig von der serverseitig bereits geschriebenen History und einer stabilen Client-ID abhängig war.
+
+Zusätzlich war das Job-ID-/SSE-Verhalten fragil: ein automatischer `EventSource`-Reconnect auf einen bereits laufenden Job konnte weiterhin als Duplicate-Stream behandelt werden.
+
+## Lösung
+
+### 1. SSE-Reconnect-Replay
+
+- Antwort-Chunks werden pro Job mit fortlaufender SSE-`id` gesendet.
+- Chunks werden zusätzlich in `var/stream_jobs/*.stream.ndjson` gepuffert.
+- Reconnects mit `Last-Event-ID` replayen fehlende Chunks und tailen den laufenden Job.
+- Doppelte Events werden im Frontend defensiv ignoriert.
+- Completed/failed/interrupted Jobs werden sauber beendet.
+
+### 2. Ephemeral Client Context Hint
+
+- Das Frontend merkt sich den zuletzt vollständig abgeschlossenen Turn.
+- `/ask-jobs` sendet diesen Turn als `contextHint` mit.
+- Der Server speichert diesen Hint im Stream-Job und reicht ihn an `AgentRunner` weiter.
+- `AgentRunner` hängt den Hint nur temporär an den Commerce-History-Kontext an.
+- Der Hint wird nicht als eigener History-Eintrag persistiert.
+
+Damit kann `suche im shop` auch dann auf die letzte Nutzerfrage/Antwort zurückfallen, wenn die serverseitige History gerade noch nicht zuverlässig greift oder die Client-ID-/Cookie-Situation im Browser wackelt.
+
+### 3. Shop-Fallback-Tokenfilter geschärft
+
+- `messung` wird im Shop-Context-Fallback nicht mehr entfernt, weil Begriffe wie `redox messung` fachlich relevant sind.
+- Zusätzliche Füllwörter wie `ist`, `sind`, `gut`, `geeignet` werden entfernt.
+
+Beispiel aus dem Fehlerfall:
+
+```text
+welcher pockettester ist für Redox messung gut
+suche im shop
+```
+
+Der zweite Befehl kann nun aus dem Kontext wieder auf `pockettester redox messung` bzw. eine vergleichbare Shop-Query kommen, statt ohne konkrete Shop-Suchanfrage abzubrechen.
+
+## Geänderte Dateien
+
+```text
+src/Controller/AskSseController.php
+src/Agent/AgentRunner.php
+src/Config/AgentRunnerConfig.php
+config/retriex/agent.yaml
+public/assets/js/base.js
+```
+
+## Prüfung
+
+```bash
+php -n -l src/Controller/AskSseController.php
+php -n -l src/Agent/AgentRunner.php
+php -n -l src/Config/AgentRunnerConfig.php
+node --check public/assets/js/base.js
+```
+
+`vendor/autoload.php` war in der ZIP-Arbeitskopie nicht enthalten, daher wurde `bin/console mto:agent:config:validate` hier nicht ausgeführt.
+
+## Nach dem Einspielen
+
+```bash
+php bin/console cache:clear
+php bin/console mto:agent:config:validate
+php bin/console mto:agent:regression:test
+```
+
+Danach den Browser hart neu laden, weil `public/assets/js/base.js` geändert wurde.

RETRIEX_SHOP_META_CONTEXT_HINT_FRONTEND_FIX_README.md

@@ -0,0 +1,62 @@
+# RetrieX Shop Meta Context Hint Frontend Fix
+
+Patch-only fix for the referential shop follow-up flow:
+
+```text
+welcher pockettester ist fuer Redox messung gut
+suche im shop
+```
+
+## Problem
+
+The backend fallback for meta-only shop prompts such as `suche im shop` can only resolve a concrete shop query when the previous turn is available through server history or through the frontend `contextHint`.
+
+The previous frontend hint used only the in-memory `lastCompletedUserPrompt` / `lastCompletedAssistantText` state. If that state was empty, overwritten, or lost after a reload/reconnect sequence, the next `/ask-jobs` request sent an empty hint. The backend then had no concrete product/search context and returned:
+
+```text
+Ich habe keine konkrete Shop-Suchanfrage erkannt. Bitte nenne das Produkt, Zubehör oder die Artikelnummer.
+```
+
+A failed meta-only turn could also overwrite the frontend's last useful context, making immediate retries fragile.
+
+## Fix
+
+`public/assets/js/base.js` now builds the request `contextHint` more defensively:
+
+1. Reconstruct the latest completed visible chat turn from the DOM before sending a new prompt.
+2. Persist the last completed turn in `sessionStorage` as a per-tab fallback.
+3. Do not overwrite the useful last turn with the generic no-concrete-shop-query response for meta-only prompts.
+4. Clear the stored fallback when the user clears the chat history.
+
+## Scope
+
+Changed file:
+
+```text
+public/assets/js/base.js
+```
+
+No changes to retrieval, scoring, PromptBuilder, AgentRunner, ShopSearchService, SSE job replay, or YAML prompt logic.
+
+## Validation
+
+```bash
+node --check public/assets/js/base.js
+```
+
+Expected regression flow:
+
+```text
+Was ist der niedrigste Grenzwert fuer die Wasserhaerte, welcher mit einem Testomaten ueberwacht werden kann?
+mit welchem indikator wird der wert gemessen
+was kostet der indikator
+```
+
+Expected shop meta flow:
+
+```text
+welcher pockettester ist fuer Redox messung gut
+suche im shop
+```
+
+The second prompt should reuse the previous Redox/Pockettester context and no longer return the generic no-concrete-shop-query message.

RETRIEX_SSE_RECONNECT_REPLAY_FIX_README.md

@@ -0,0 +1,43 @@
+# RetrieX SSE reconnect replay fix
+
+Patch-only fix for fragile browser streaming after the job-based EventSource flow.
+
+## Problem
+
+EventSource is allowed to reconnect automatically when the browser, proxy or PHP/Nginx connection is interrupted. The previous job guard treated a second `/ask-sse/{jobId}` connection while the job was still `running` as an application error. In the UI this could append messages like:
+
+```text
+event: error
+data: Der Antwort-Stream läuft bereits oder wurde nach einem Verbindungsabbruch erneut geöffnet...
+```
+
+This happened especially in slower Shopware/search flows, but it could also happen in pure RAG answers.
+
+## Change
+
+- Streamed answer chunks now receive monotonically increasing SSE `id:` values.
+- Each streamed chunk is additionally written to a per-job replay buffer under `var/stream_jobs/*.stream.ndjson`.
+- If EventSource reconnects to a job that is already `running`, the controller no longer emits the misleading duplicate-stream error.
+- Instead, the reconnecting request reads `Last-Event-ID`, replays missing chunks and tails the still-running job until it completes, fails or is marked interrupted.
+- Completed jobs can replay any missing chunks and then emit `done`.
+- The frontend tracks `event.lastEventId` and ignores duplicate/replayed chunks defensively.
+- Expired job cleanup also removes the replay buffer sidecar file.
+
+## Changed files
+
+- `src/Controller/AskSseController.php`
+- `public/assets/js/base.js`
+
+## Safety
+
+This patch does not change retrieval, PromptBuilder, AgentRunner, scoring, intent detection, Shopware query generation or RAG behavior. It only changes the transport/reconnect layer for SSE.
+
+## After installing
+
+```bash
+php bin/console cache:clear
+php bin/console mto:agent:config:validate
+php bin/console mto:agent:regression:test
+```
+
+Hard-refresh the browser or clear browser cache because `public/assets/js/base.js` changed.

config/retriex/agent.yaml

@@ -101,6 +101,10 @@ parameters:
           - welches
           - welchem
           - welchen
+          - ist
+          - sind
+          - gut
+          - geeignet
           - was
           - wie
           - wo
@@ -123,7 +127,6 @@ parameters:
           - fuer
           - messen
           - gemessen
-          - messung
         meta_only_terms:
           - shop
           - shopsuche

public/assets/js/base.js

@@ -5,6 +5,7 @@ document.addEventListener('DOMContentLoaded', () => {
     const abortBtn = document.getElementById('abort');
     const clearBtn = document.getElementById('clear');
     const aiCloudEl = document.getElementById('ai-cloud');
+    const LAST_TURN_STORAGE_KEY = 'retriex:lastCompletedTurn';
 
     const state = {
         abortRequested: false,
@@ -15,6 +16,8 @@ document.addEventListener('DOMContentLoaded', () => {
         eventSource: null,
         completeStream: null,
         failStream: null,
+        lastCompletedUserPrompt: '',
+        lastCompletedAssistantText: '',
     };
 
     marked.setOptions({breaks: true});
@@ -23,6 +26,163 @@ document.addEventListener('DOMContentLoaded', () => {
         return DOMPurify.sanitize(marked.parse(text));
     }
 
+    function normalizeContextHintText(value) {
+        return String(value || '')
+            .replace(/\r\n/g, '\n')
+            .replace(/\r/g, '\n')
+            .replace(/[\t ]+/g, ' ')
+            .replace(/\n{3,}/g, '\n\n')
+            .trim();
+    }
+
+    function tokenizeClientMetaGuardText(value) {
+        return normalizeContextHintText(value)
+            .toLowerCase()
+            .replace(/[-/_]/g, ' ')
+            .replace(/[^\p{L}\p{N}]+/gu, ' ')
+            .trim()
+            .split(/\s+/u)
+            .filter(Boolean);
+    }
+
+    function isClientMetaOnlyShopPrompt(value) {
+        const tokens = tokenizeClientMetaGuardText(value);
+
+        if (!tokens.length) {
+            return true;
+        }
+
+        const metaTerms = new Set([
+            'shop', 'shopsuche', 'suche', 'suchen', 'such', 'finde', 'find',
+            'zeige', 'zeig', 'bitte', 'mal', 'im', 'in', 'nach', 'den', 'die',
+            'das', 'der', 'dem',
+        ]);
+
+        return tokens.every((token) => metaTerms.has(token));
+    }
+
+    function isNoConcreteShopResponse(value) {
+        return normalizeContextHintText(value)
+            .toLowerCase()
+            .includes('keine konkrete shop-suchanfrage erkannt');
+    }
+
+    function rememberCompletedTurn(userPrompt, assistantText) {
+        const normalizedPrompt = normalizeContextHintText(userPrompt);
+        const normalizedAssistantText = normalizeContextHintText(assistantText);
+
+        if (!normalizedPrompt) {
+            return;
+        }
+
+        if (isClientMetaOnlyShopPrompt(normalizedPrompt) && isNoConcreteShopResponse(normalizedAssistantText)) {
+            return;
+        }
+
+        state.lastCompletedUserPrompt = normalizedPrompt.slice(0, 800);
+        state.lastCompletedAssistantText = normalizedAssistantText.slice(0, 3000);
+
+        try {
+            window.sessionStorage?.setItem(LAST_TURN_STORAGE_KEY, JSON.stringify({
+                userPrompt: state.lastCompletedUserPrompt,
+                assistantText: state.lastCompletedAssistantText,
+                rememberedAt: Date.now(),
+            }));
+        } catch (err) {
+            console.debug('Could not persist last completed turn:', err);
+        }
+    }
+
+    function loadStoredCompletedTurn() {
+        try {
+            const raw = window.sessionStorage?.getItem(LAST_TURN_STORAGE_KEY) || '';
+
+            if (!raw) {
+                return null;
+            }
+
+            const data = JSON.parse(raw);
+            const userPrompt = normalizeContextHintText(data?.userPrompt || '');
+            const assistantText = normalizeContextHintText(data?.assistantText || '');
+
+            if (!userPrompt) {
+                return null;
+            }
+
+            return {
+                userPrompt: userPrompt.slice(0, 800),
+                assistantText: assistantText.slice(0, 3000),
+            };
+        } catch (err) {
+            console.debug('Could not read last completed turn:', err);
+            return null;
+        }
+    }
+
+    function extractLatestVisibleCompletedTurn() {
+        if (!chatEl) {
+            return null;
+        }
+
+        const messages = Array.from(chatEl.querySelectorAll('.message'));
+        let pendingUserPrompt = '';
+        let latestTurn = null;
+
+        messages.forEach((message) => {
+            const bubble = message.querySelector('.bubble');
+            const text = normalizeContextHintText(bubble?.innerText || bubble?.textContent || '');
+
+            if (!text) {
+                return;
+            }
+
+            if (message.classList.contains('user')) {
+                pendingUserPrompt = text;
+                return;
+            }
+
+            if (!message.classList.contains('assistant') || !pendingUserPrompt) {
+                return;
+            }
+
+            if (bubble?.classList.contains('loader')) {
+                return;
+            }
+
+            if (isClientMetaOnlyShopPrompt(pendingUserPrompt) && isNoConcreteShopResponse(text)) {
+                pendingUserPrompt = '';
+                return;
+            }
+
+            latestTurn = {
+                userPrompt: pendingUserPrompt,
+                assistantText: text,
+            };
+            pendingUserPrompt = '';
+        });
+
+        return latestTurn;
+    }
+
+    function buildClientContextHint() {
+        const visibleTurn = extractLatestVisibleCompletedTurn();
+        const storedTurn = loadStoredCompletedTurn();
+        const userPrompt = visibleTurn?.userPrompt || state.lastCompletedUserPrompt || storedTurn?.userPrompt || '';
+        const assistantText = visibleTurn?.assistantText || state.lastCompletedAssistantText || storedTurn?.assistantText || '';
+
+        if (!userPrompt) {
+            return '';
+        }
+
+        const lines = [`Question: ${userPrompt.slice(0, 800)}`];
+
+        if (assistantText) {
+            lines.push(assistantText.slice(0, 3000));
+        }
+
+        return normalizeContextHintText(lines.join('\n')).slice(0, 4000);
+    }
+
     function scrollChatToBottom() {
         if (!chatEl) {
             return;
@@ -368,10 +528,20 @@ document.addEventListener('DOMContentLoaded', () => {
             }
 
             const messages = await res.json();
+            let latestLoadedUserPrompt = '';
 
             messages.forEach((message) => {
                 const bubble = addMessage(message.role);
                 renderBubbleContent(bubble, message.text);
+
+                if (message.role === 'user') {
+                    latestLoadedUserPrompt = normalizeContextHintText(message.text);
+                    return;
+                }
+
+                if (message.role === 'assistant' && latestLoadedUserPrompt) {
+                    rememberCompletedTurn(latestLoadedUserPrompt, message.text);
+                }
             });
 
             enhanceChatLinks(chatEl);
@@ -396,6 +566,8 @@ document.addEventListener('DOMContentLoaded', () => {
             return;
         }
 
+        const contextHint = buildClientContextHint();
+
         addMessage('user', renderMarkdown(prompt));
         promptEl.value = '';
 
@@ -449,6 +621,7 @@ document.addEventListener('DOMContentLoaded', () => {
                 body: JSON.stringify({
                     prompt,
                     fullContext: false,
+                    contextHint,
                 }),
                 signal: state.abortController.signal,
             });
@@ -466,6 +639,7 @@ document.addEventListener('DOMContentLoaded', () => {
 
             await new Promise((resolve, reject) => {
                 let finished = false;
+                let lastSseEventId = 0;
                 const source = new EventSource(`/ask-sse/${encodeURIComponent(jobId)}`);
                 state.eventSource = source;
 
@@ -521,12 +695,23 @@ document.addEventListener('DOMContentLoaded', () => {
                         return;
                     }
 
+                    const numericEventId = Number.parseInt(event.lastEventId || '', 10);
+
+                    if (Number.isFinite(numericEventId) && numericEventId > 0) {
+                        if (numericEventId <= lastSseEventId) {
+                            return;
+                        }
+
+                        lastSseEventId = numericEventId;
+                    }
+
                     appendChunk(event.data);
                 };
 
                 source.addEventListener('done', () => {
                     if (!state.abortRequested) {
                         finalizeStream(bubble, raw);
+                        rememberCompletedTurn(prompt, raw);
                     }
 
                     complete();
@@ -609,6 +794,13 @@ document.addEventListener('DOMContentLoaded', () => {
             console.error('History delete failed:', err);
         }
 
+        state.lastCompletedUserPrompt = '';
+        state.lastCompletedAssistantText = '';
+        try {
+            window.sessionStorage?.removeItem(LAST_TURN_STORAGE_KEY);
+        } catch (err) {
+            console.debug('Could not clear last completed turn:', err);
+        }
         chatEl.innerHTML = '';
         addMessage('assistant', '<em>History cleared.</em>');
     });

src/Agent/AgentRunner.php

@@ -39,7 +39,7 @@ final readonly class AgentRunner
         $this->systemMsgOn = true;
     }
 
-    public function run(string $prompt, string $userId, bool $forceFullContext = false): Generator
+    public function run(string $prompt, string $userId, bool $forceFullContext = false, string $requestContextHint = ''): Generator
     {
         $prompt = trim($prompt);
 
@@ -109,7 +109,7 @@ final readonly class AgentRunner
             if ($this->isCommerceIntent($commerceIntent)) {
                 yield $this->systemMsg($this->agentRunnerConfig->getOptimizeSearchMessage(), 'think');
 
-                $commerceHistoryContext = $this->buildCommerceHistoryContext($userId);
+                $commerceHistoryContext = $this->buildCommerceHistoryContext($userId, $requestContextHint);
 
                 if ($commerceHistoryContext !== '') {
                     $this->addSource($sources, $this->agentRunnerConfig->getConversationHistorySourceLabel());
@@ -136,6 +136,7 @@ final readonly class AgentRunner
                         'optimizedShopQuery' => $optimizedShopQuery,
                         'hasCommerceHistoryContext' => $commerceHistoryContext !== '',
                         'commerceHistoryContextLength' => mb_strlen($commerceHistoryContext),
+                        'hasRequestContextHint' => trim($requestContextHint) !== '',
                     ]);
 
                     yield $this->systemMsg(
@@ -925,12 +926,42 @@ final readonly class AgentRunner
         }
     }
 
-    private function buildCommerceHistoryContext(string $userId): string
+    private function buildCommerceHistoryContext(string $userId, string $requestContextHint = ''): string
     {
-        return $this->contextService->buildUserContextWithinBudget(
+        $history = $this->contextService->buildUserContextWithinBudget(
             $userId,
             $this->agentRunnerConfig->getCommerceHistoryBudgetChars()
         );
+
+        $requestContextHint = $this->sanitizeRequestContextHintForCommerce($requestContextHint);
+
+        if ($requestContextHint === '') {
+            return $history;
+        }
+
+        if ($history === '') {
+            return $requestContextHint;
+        }
+
+        return trim($history) . "\n\n" . $requestContextHint;
+    }
+
+    private function sanitizeRequestContextHintForCommerce(string $requestContextHint): string
+    {
+        $requestContextHint = str_replace(["\r\n", "\r"], "\n", $requestContextHint);
+        $requestContextHint = preg_replace('/[\t ]+/u', ' ', $requestContextHint) ?? $requestContextHint;
+        $requestContextHint = preg_replace('/\n{3,}/u', "\n\n", $requestContextHint) ?? $requestContextHint;
+        $requestContextHint = trim($requestContextHint);
+
+        if ($requestContextHint === '') {
+            return '';
+        }
+
+        if (mb_strlen($requestContextHint, 'UTF-8') > 4000) {
+            $requestContextHint = mb_substr($requestContextHint, 0, 4000, 'UTF-8');
+        }
+
+        return trim($requestContextHint);
     }
 
     private function limitKnowledgeChunks(array $knowledgeChunks, string $commerceIntent): array

src/Config/AgentRunnerConfig.php

@@ -460,6 +460,10 @@ final class AgentRunnerConfig
             'welches',
             'welchem',
             'welchen',
+            'ist',
+            'sind',
+            'gut',
+            'geeignet',
             'was',
             'wie',
             'wo',
@@ -482,7 +486,6 @@ final class AgentRunnerConfig
             'fuer',
             'messen',
             'gemessen',
-            'messung',
         ]);
     }
 

src/Controller/AskSseController.php

@@ -51,6 +51,8 @@ final readonly class AskSseController
             FILTER_VALIDATE_BOOL
         );
 
+        $requestContextHint = $this->sanitizeRequestContextHint((string) ($data['contextHint'] ?? ''));
+
         $cookieResponse = new Response();
         $clientId = $this->clientIdResolver->resolve($request, $cookieResponse);
 
@@ -63,6 +65,7 @@ final readonly class AskSseController
                 'prompt' => $prompt,
                 'clientId' => $clientId,
                 'includeFullContext' => $includeFullContext,
+                'requestContextHint' => $requestContextHint,
                 'createdAt' => $now,
                 'updatedAt' => $now,
             ]);
@@ -83,19 +86,20 @@ final readonly class AskSseController
     }
 
     #[Route('/ask-sse/{jobId}', name: 'ask_sse_job', methods: ['GET'], requirements: ['jobId' => '[a-f0-9]{48}'])]
-    public function streamJob(string $jobId): StreamedResponse
+    public function streamJob(Request $request, string $jobId): StreamedResponse
     {
+        $lastEventId = $this->resolveLastEventId($request);
+
         return new StreamedResponse(
-            function () use ($jobId): void {
+            function () use ($jobId, $lastEventId): void {
                 $claimed = $this->claimJob($jobId);
 
                 if (($claimed['ok'] ?? false) !== true) {
                     $this->prepareStreamRuntime();
-                    echo "retry: 15000\n\n";
+                    echo "retry: 30000\n\n";
 
-                    if ($this->shouldSilentlyCloseDuplicateJobStream($claimed)) {
+                    if ($this->canReplayOrTailClaimedJob($claimed)) {
-                        $this->sendComment('duplicate-or-finished-stream');
+                        $this->streamStoredJobResponse($jobId, $lastEventId);
-                        $this->sendEvent('done', '[DONE]');
                         return;
                     }
 
@@ -112,7 +116,8 @@ final readonly class AskSseController
                     clientId: (string) ($job['clientId'] ?? ''),
                     includeFullContext: (bool) ($job['includeFullContext'] ?? false),
                     cookieResponse: null,
-                    jobId: $jobId
+                    jobId: $jobId,
+                    requestContextHint: is_string($job['requestContextHint'] ?? null) ? (string) $job['requestContextHint'] : ''
                 );
             },
             Response::HTTP_OK,
@@ -136,17 +141,20 @@ final readonly class AskSseController
             FILTER_VALIDATE_BOOL
         );
 
+        $requestContextHint = $this->sanitizeRequestContextHint((string) ($data['contextHint'] ?? ''));
+
         $cookieResponse = new Response();
         $clientId = $this->clientIdResolver->resolve($request, $cookieResponse);
 
         return new StreamedResponse(
-            function () use ($prompt, $clientId, $cookieResponse, $includeFullContext): void {
+            function () use ($prompt, $clientId, $cookieResponse, $includeFullContext, $requestContextHint): void {
                 $this->streamAgentResponse(
                     prompt: $prompt,
                     clientId: $clientId,
                     includeFullContext: $includeFullContext,
                     cookieResponse: $cookieResponse,
-                    jobId: null
+                    jobId: null,
+                    requestContextHint: $requestContextHint
                 );
             },
             Response::HTTP_OK,
@@ -159,7 +167,8 @@ final readonly class AskSseController
         string $clientId,
         bool $includeFullContext,
         ?Response $cookieResponse,
-        ?string $jobId = null
+        ?string $jobId = null,
+        string $requestContextHint = ''
     ): void {
         $this->prepareStreamRuntime();
         $this->registerStreamShutdownErrorHandler($jobId);
@@ -181,7 +190,7 @@ final readonly class AskSseController
         }
 
         try {
-            foreach ($this->agentRunner->run($prompt, $clientId, $includeFullContext) as $chunk) {
+            foreach ($this->agentRunner->run($prompt, $clientId, $includeFullContext, $requestContextHint) as $chunk) {
                 if (connection_aborted() === 1) {
                     $this->markJobStatus(
                         $jobId,
@@ -192,7 +201,8 @@ final readonly class AskSseController
                 }
 
                 $chunk = str_replace(["\r\n", "\r"], "\n", $chunk);
-                $this->sendData($chunk);
+                $eventId = $this->appendJobOutput($jobId, $chunk);
+                $this->sendData($chunk, $eventId);
             }
         } catch (\Throwable $e) {
             $message = 'Stream abgebrochen: ' . $this->formatThrowableForClient($e);
@@ -261,6 +271,24 @@ final readonly class AskSseController
         });
     }
 
+    private function sanitizeRequestContextHint(string $contextHint): string
+    {
+        $contextHint = str_replace(["\r\n", "\r"], "\n", $contextHint);
+        $contextHint = preg_replace('/[\t ]+/u', ' ', $contextHint) ?? $contextHint;
+        $contextHint = preg_replace('/\n{3,}/u', "\n\n", $contextHint) ?? $contextHint;
+        $contextHint = trim($contextHint);
+
+        if ($contextHint === '') {
+            return '';
+        }
+
+        if (mb_strlen($contextHint, 'UTF-8') > 4000) {
+            $contextHint = mb_substr($contextHint, 0, 4000, 'UTF-8');
+        }
+
+        return trim($contextHint);
+    }
+
     private function formatThrowableForClient(\Throwable $e): string
     {
         $message = trim($e->getMessage());
@@ -297,13 +325,17 @@ final readonly class AskSseController
         ];
     }
 
-    private function sendData(string $data): void
+    private function sendData(string $data, ?int $eventId = null): void
     {
         if ($data === '') {
             $this->sendComment('keepalive');
             return;
         }
 
+        if ($eventId !== null && $eventId > 0) {
+            echo 'id: ' . $eventId . "\n";
+        }
+
         $lines = explode("\n", $data);
 
         foreach ($lines as $line) {
@@ -511,22 +543,239 @@ final readonly class AskSseController
             }
         }
     }
+    private function resolveLastEventId(Request $request): int
+    {
+        $header = trim((string) $request->headers->get('Last-Event-ID', ''));
+
+        if ($header === '' || !ctype_digit($header)) {
+            return 0;
+        }
+
+        return max(0, (int) $header);
+    }
+
     /**
-     * EventSource may reconnect to an already running or already completed job.
-     * Those duplicate connections should be closed quietly so the UI does not
-     * append a misleading error after the real stream already produced output.
-     *
      * @param array<string, mixed> $claim
      */
-    private function shouldSilentlyCloseDuplicateJobStream(array $claim): bool
+    private function canReplayOrTailClaimedJob(array $claim): bool
     {
         if (($claim['reason'] ?? null) !== 'not_pending') {
             return false;
         }
 
-        $status = (string) ($claim['status'] ?? '');
+        return in_array(
+            (string) ($claim['status'] ?? ''),
+            [
+                self::JOB_STATUS_RUNNING,
+                self::JOB_STATUS_COMPLETED,
+                self::JOB_STATUS_INTERRUPTED,
+                self::JOB_STATUS_FAILED,
+            ],
+            true
+        );
+    }
 
-        return $status === self::JOB_STATUS_COMPLETED;
+    private function streamStoredJobResponse(string $jobId, int $lastEventId): void
+    {
+        $afterEventId = max(0, $lastEventId);
+        $lastKeepaliveAt = 0;
+
+        while (true) {
+            if (connection_aborted() === 1) {
+                return;
+            }
+
+            foreach ($this->readJobOutputAfter($jobId, $afterEventId) as $event) {
+                $eventId = (int) ($event['id'] ?? 0);
+                $data = is_string($event['data'] ?? null) ? (string) $event['data'] : '';
+
+                if ($eventId <= $afterEventId || $data === '') {
+                    continue;
+                }
+
+                $this->sendData($data, $eventId);
+                $afterEventId = $eventId;
+            }
+
+            $job = $this->readJob($jobId);
+            $status = is_array($job) ? (string) ($job['status'] ?? '') : '';
+            $message = is_array($job) && is_string($job['message'] ?? null)
+                ? trim((string) $job['message'])
+                : '';
+
+            if ($status === self::JOB_STATUS_COMPLETED) {
+                $this->sendComment('replayed-completed-stream');
+                $this->sendEvent('done', '[DONE]');
+                return;
+            }
+
+            if ($status === self::JOB_STATUS_FAILED) {
+                $this->sendEvent(
+                    'error',
+                    $message !== ''
+                        ? 'Der Antwort-Stream ist fehlgeschlagen: ' . $message
+                        : 'Der Antwort-Stream ist fehlgeschlagen. Bitte sende die Anfrage erneut.'
+                );
+                $this->sendEvent('done', '[DONE]');
+                return;
+            }
+
+            if ($status === self::JOB_STATUS_INTERRUPTED) {
+                $this->sendEvent(
+                    'error',
+                    $message !== ''
+                        ? $message
+                        : 'Der Antwort-Stream wurde durch einen Verbindungsabbruch unterbrochen. Bitte sende die Anfrage erneut, falls die Antwort unvollständig ist.'
+                );
+                $this->sendEvent('done', '[DONE]');
+                return;
+            }
+
+            if ($status !== self::JOB_STATUS_RUNNING) {
+                $this->sendEvent('error', $this->jobClaimErrorMessage([
+                    'reason' => 'not_pending',
+                    'status' => $status,
+                    'message' => $message,
+                ]));
+                $this->sendEvent('done', '[DONE]');
+                return;
+            }
+
+            if (time() - $lastKeepaliveAt >= 10) {
+                $this->sendComment('waiting-for-running-stream');
+                $lastKeepaliveAt = time();
+            }
+
+            usleep(250000);
+        }
+    }
+
+    /**
+     * @return list<array{id: int, data: string}>
+     */
+    private function readJobOutputAfter(string $jobId, int $afterEventId): array
+    {
+        $path = $this->jobOutputPath($jobId);
+
+        if (!is_file($path)) {
+            return [];
+        }
+
+        $lines = @file($path, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
+
+        if (!is_array($lines)) {
+            return [];
+        }
+
+        $events = [];
+
+        foreach ($lines as $line) {
+            if (!is_string($line) || trim($line) === '') {
+                continue;
+            }
+
+            $decoded = json_decode($line, true);
+
+            if (!is_array($decoded)) {
+                continue;
+            }
+
+            $id = (int) ($decoded['id'] ?? 0);
+            $data = is_string($decoded['data'] ?? null) ? (string) $decoded['data'] : '';
+
+            if ($id > $afterEventId && $data !== '') {
+                $events[] = ['id' => $id, 'data' => $data];
+            }
+        }
+
+        return $events;
+    }
+
+    private function appendJobOutput(?string $jobId, string $data): ?int
+    {
+        if ($jobId === null || $data === '' || !preg_match('/\A[a-f0-9]{48}\z/', $jobId)) {
+            return null;
+        }
+
+        $eventId = null;
+
+        try {
+            $this->mutateJobWithLock($jobId, function (?array $job) use (&$eventId): array {
+                if ($job === null) {
+                    return [
+                        'persist' => false,
+                        'result' => ['ok' => false],
+                    ];
+                }
+
+                $eventId = max(0, (int) ($job['lastEventId'] ?? 0)) + 1;
+                $job['lastEventId'] = $eventId;
+                $job['updatedAt'] = time();
+
+                return [
+                    'data' => $job,
+                    'result' => ['ok' => true],
+                ];
+            });
+
+            if ($eventId === null || $eventId <= 0) {
+                return null;
+            }
+
+            $line = json_encode(
+                ['id' => $eventId, 'data' => $data],
+                JSON_THROW_ON_ERROR | JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES
+            ) . "\n";
+
+            if (file_put_contents($this->jobOutputPath($jobId), $line, FILE_APPEND | LOCK_EX) === false) {
+                return null;
+            }
+        } catch (\Throwable) {
+            return null;
+        }
+
+        return $eventId;
+    }
+
+    /**
+     * @return array<string, mixed>|null
+     */
+    private function readJob(string $jobId): ?array
+    {
+        if (!preg_match('/\A[a-f0-9]{48}\z/', $jobId)) {
+            return null;
+        }
+
+        $path = $this->jobPath($jobId);
+
+        if (!is_file($path)) {
+            return null;
+        }
+
+        $handle = @fopen($path, 'r');
+
+        if ($handle === false) {
+            return null;
+        }
+
+        try {
+            if (!flock($handle, LOCK_SH)) {
+                return null;
+            }
+
+            $content = stream_get_contents($handle);
+            flock($handle, LOCK_UN);
+        } finally {
+            fclose($handle);
+        }
+
+        if (!is_string($content) || trim($content) === '') {
+            return null;
+        }
+
+        $decoded = json_decode($content, true);
+
+        return is_array($decoded) ? $decoded : null;
     }
 
     /**
@@ -590,7 +839,9 @@ final readonly class AskSseController
             $mtime = filemtime($path);
 
             if ($mtime === false || $mtime < $threshold) {
+                $base = preg_replace('/\.json\z/', '', $path) ?? $path;
                 @unlink($path);
+                @unlink($base . '.stream.ndjson');
             }
         }
     }
@@ -600,6 +851,11 @@ final readonly class AskSseController
         return $this->jobDirectory() . '/' . $jobId . '.json';
     }
 
+    private function jobOutputPath(string $jobId): string
+    {
+        return $this->jobDirectory() . '/' . $jobId . '.stream.ndjson';
+    }
+
     private function jobDirectory(): string
     {
         return rtrim($this->projectDir, '/\\') . '/var/stream_jobs';