*
     * @param userMessage the user's original message
     * @param failedQuery the query that failed
     * @param failureReason the reason for failure ("no_results" or "no_relevant_results")
     * @param history the conversation history
     * @return a new query string, or the userMessage if regeneration fails
     */

        history.add(LlmMessage.assistant("Fess is a search server."));

        final String result = client.regenerateQuery("How about Docker?", "title:\"Fess\"^2 +Docker", "no_relevant_results", history);

        assertEquals("Docker setup", result);

        // Verify history was included in the request
        final LlmChatRequest capturedRequest = client.getLastChatRequest();

                        logger.info("[RAG] No relevant results in evaluation, regenerating query. originalQuery={}", query);
                        final String newQuery = llmClientManager.regenerateQuery(userMessage, query, "no_relevant_results", history);

                        boolean fallbackSucceeded = false;
                        if (StringUtil.isNotBlank(newQuery) && !newQuery.equals(query)) {

        assertTrue(result.getRelevantIndexes().isEmpty());
    }

    @Test
    public void test_noRelevantResults() {
        RelevanceEvaluationResult result = RelevanceEvaluationResult.noRelevantResults();

        assertFalse(result.isHasRelevantResults());
        assertNotNull(result.getRelevantDocIds());
        assertTrue(result.getRelevantDocIds().isEmpty());
        assertNotNull(result.getRelevantIndexes());

    }

    /**
     * Creates a result with no relevant documents found.
     *
     * @return evaluation result with no relevant documents
     */
    public static RelevanceEvaluationResult noRelevantResults() {
        return new RelevanceEvaluationResult(Collections.emptyList(), Collections.emptyList(), false);
    }

    /**
     * Creates a fallback result that includes all documents as relevant.

        try {
            final boolean hasRelevant = extractJsonBoolean(response, "has_relevant");
            if (!hasRelevant) {
                return RelevanceEvaluationResult.noRelevantResults();
            }

            final List<Integer> indexes = extractJsonIntArray(response, "relevant_indexes");
            final List<String> docIds = indexes.stream()