diff --git a/backend/src/services/synthesis.rs b/backend/src/services/synthesis.rs
index a09201d..3c99714 100644
--- a/backend/src/services/synthesis.rs
+++ b/backend/src/services/synthesis.rs
@@ -259,6 +259,20 @@ async fn run_generation_inner(
     emit_progress(tx, "settings", "Chargement des parametres...", 5);
     let settings = db::settings::get_or_create_default(&state.pool, user_id).await?;
 
+    // Cleanup old article history entries
+    if settings.article_history_days > 0 {
+        let deleted = db::article_history::cleanup_old(
+            &state.pool,
+            user_id,
+            settings.article_history_days,
+        )
+        .await
+        .unwrap_or(0);
+        if deleted > 0 {
+            tracing::info!(deleted = deleted, "Cleaned up old article history entries");
+        }
+    }
+
     if settings.categories.is_empty() {
         return Err(AppError::BadRequest(
             "Aucune categorie configuree. Veuillez configurer vos parametres.".into(),
@@ -375,13 +389,87 @@ async fn run_generation_inner(
                 .filter(|a| !a.scraped_content.trim().is_empty())
                 .collect();
 
+            // 1d. Filter against article history (cross-synthesis dedup)
+            let mut valid_articles = if settings.article_history_days > 0 {
+                let hashes: Vec<String> = valid_articles.iter().map(|a| hash_article_url(&a.url)).collect();
+                let existing = db::article_history::check_urls_exist(&state.pool, user_id, &hashes)
+                    .await
+                    .unwrap_or_default();
+                if !existing.is_empty() {
+                    tracing::info!(filtered = existing.len(), "Phase 1: filtered articles already in history");
+                }
+                valid_articles
+                    .into_iter()
+                    .filter(|a| !existing.contains(&hash_article_url(&a.url)))
+                    .collect::<Vec<_>>()
+            } else {
+                valid_articles
+            };
+
+            // 1e. Retry if under-filled after history filtering (1 attempt)
+            let target = settings.categories.len() * settings.max_items_per_category as usize;
+            if valid_articles.len() < target && settings.article_history_days > 0 {
+                tracing::info!(
+                    have = valid_articles.len(),
+                    need = target,
+                    "Phase 1 under-filled after history filter, retrying"
+                );
+
+                let already_fetched: std::collections::HashSet<String> = candidate_urls
+                    .iter()
+                    .map(|u| u.to_lowercase())
+                    .collect();
+
+                let mut retry_urls: Vec<String> = Vec::new();
+                for source in sources.iter().take(max_sources) {
+                    let links = if settings.use_llm_for_source_links {
+                        source_scraper::extract_article_links_with_llm(
+                            &state.http_client, &source.url, max_links_per_source,
+                            &provider, &model_research,
+                        ).await
+                    } else {
+                        source_scraper::extract_article_links(
+                            &state.http_client, &source.url, max_links_per_source,
+                        ).await
+                    };
+                    if let Ok(links) = links {
+                        for link in links {
+                            if !already_fetched.contains(&link.to_lowercase()) {
+                                retry_urls.push(link);
+                            }
+                        }
+                    }
+                }
+
+                if !retry_urls.is_empty() {
+                    let retry_scraped = scrape_flat_urls(
+                        state, &retry_urls, settings.max_age_days as i64, tx,
+                        llm_for_scraping.clone(),
+                    ).await;
+                    let mut retry_valid: Vec<ScrapedNewsItem> = retry_scraped
+                        .into_iter()
+                        .filter(|a| !a.scraped_content.trim().is_empty())
+                        .collect();
+
+                    if !retry_valid.is_empty() && settings.article_history_days > 0 {
+                        let hashes: Vec<String> = retry_valid.iter().map(|a| hash_article_url(&a.url)).collect();
+                        let existing = db::article_history::check_urls_exist(&state.pool, user_id, &hashes)
+                            .await.unwrap_or_default();
+                        retry_valid.retain(|a| !existing.contains(&hash_article_url(&a.url)));
+                    }
+
+                    valid_articles.extend(retry_valid);
+                    tracing::info!(total = valid_articles.len(), "Phase 1 after retry");
+                }
+            }
+
             tracing::info!(
                 valid_count = valid_articles.len(),
                 "Phase 1: valid articles from personalized sources"
             );
 
             if !valid_articles.is_empty() {
-                // 1d. LLM classification call
+                // 1f. LLM classification call
                 emit_progress(tx, "classifying", "Classification des articles...", 35);
                 check_rate_limit(state, &user_rate_limiter, &provider_name)?;
 
@@ -551,6 +639,32 @@ async fn run_generation_inner(
         let parsed = dedup_by_url(parsed);
         let parsed = limit_articles_per_source(parsed, settings.max_articles_per_source);
 
+        // Filter against article history BEFORE scraping (saves HTTP requests)
+        let parsed = if settings.article_history_days > 0 {
+            let all_urls: Vec<String> = parsed.iter()
+                .flat_map(|(_, items)| items.iter().map(|i| i.url.clone()))
+                .collect();
+            let hashes: Vec<String> = all_urls.iter().map(|u| hash_article_url(u)).collect();
+            let existing = db::article_history::check_urls_exist(&state.pool, user_id, &hashes)
+                .await
+                .unwrap_or_default();
+            if !existing.is_empty() {
+                tracing::info!(filtered = existing.len(), "Phase 2: filtered articles already in history");
+            }
+            parsed
+                .into_iter()
+                .map(|(cat_key, items)| {
+                    let filtered = items
+                        .into_iter()
+                        .filter(|item| !existing.contains(&hash_article_url(&item.url)))
+                        .collect();
+                    (cat_key, filtered)
+                })
+                .collect()
+        } else {
+            parsed
+        };
+
         // Scrape web search results
         emit_progress(tx, "scraping", "Verification des sources web...", 60);
         let scraped = scrape_articles(state, &parsed, settings.max_age_days as i64, tx, llm_for_scraping.clone()).await;
@@ -637,6 +751,18 @@ async fn run_generation_inner(
     let synthesis =
         db::syntheses::create(&state.pool, user_id, &week, &sections_json).await?;
 
+    // Record article URLs in history for cross-synthesis dedup
+    if settings.article_history_days > 0 {
+        let article_urls: Vec<(String, String)> = final_sections
+            .iter()
+            .flat_map(|section| section.items.iter())
+            .map(|item| (item.url.clone(), hash_article_url(&item.url)))
+            .collect();
+        db::article_history::insert_urls(&state.pool, user_id, &article_urls)
+            .await
+            .ok(); // Don't fail synthesis if history insert fails
+    }
+
     Ok(synthesis.id)
 }