feat: build_search_prompt accepts recent_domains for source diversity

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/services/prompts.rs

@@ -19,10 +19,12 @@ use crate::models::synthesis::ScrapedNewsItem;
 /// * `settings` — User's configured settings (theme, categories, etc.)
 /// * `sources` — User's custom sources to prioritize
 /// * `current_date` — Formatted date string for the prompt
+/// * `recent_domains` — Domains used in recent syntheses to avoid if possible
 pub fn build_search_prompt(
     settings: &UserSettings,
     sources: &[Source],
     current_date: &str,
+    recent_domains: &[String],
 ) -> (String, String) {
     let sources_text = if sources.is_empty() {
         String::new()
@@ -88,6 +90,16 @@ pub fn build_search_prompt(
         max_items = settings.max_items_per_category,
     );
 
+    let user_prompt = if recent_domains.is_empty() {
+        user_prompt
+    } else {
+        let domains_list = recent_domains.join(", ");
+        format!(
+            "{}\n\nEvite si possible les sources deja utilisees dans les syntheses precedentes : {}.",
+            user_prompt, domains_list
+        )
+    };
+
     (system_prompt, user_prompt)
 }
 
@@ -159,21 +171,21 @@ mod tests {
     #[test]
     fn search_prompt_includes_theme() {
         let settings = test_settings();
-        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026");
+        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026", &[]);
         assert!(user_prompt.contains("Intelligence Artificielle"));
     }
 
     #[test]
     fn search_prompt_includes_date() {
         let settings = test_settings();
-        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026");
+        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026", &[]);
         assert!(user_prompt.contains("lundi 21 mars 2026"));
     }
 
     #[test]
     fn search_prompt_includes_max_age() {
         let settings = test_settings();
-        let (system, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026");
+        let (system, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026", &[]);
         assert!(user_prompt.contains("7 derniers jours"));
         assert!(system.contains("7"));
     }
@@ -181,7 +193,7 @@ mod tests {
     #[test]
     fn search_prompt_includes_categories() {
         let settings = test_settings();
-        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026");
+        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026", &[]);
         assert!(user_prompt.contains("1. Annonces majeures"));
         assert!(user_prompt.contains("2. Recherche et innovation"));
         assert!(user_prompt.contains("2 grandes sections"));
@@ -190,7 +202,7 @@ mod tests {
     #[test]
     fn search_prompt_includes_max_items() {
         let settings = test_settings();
-        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026");
+        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026", &[]);
         assert!(user_prompt.contains("4 actualites"));
     }
 
@@ -214,7 +226,7 @@ mod tests {
             },
         ];
 
-        let (_, user_prompt) = build_search_prompt(&settings, &sources, "lundi 21 mars 2026");
+        let (_, user_prompt) = build_search_prompt(&settings, &sources, "lundi 21 mars 2026", &[]);
         assert!(user_prompt.contains("TechCrunch (https://techcrunch.com)"));
         assert!(user_prompt.contains("The Verge (https://theverge.com)"));
         assert!(user_prompt.contains("sources personnalisees"));
@@ -223,7 +235,7 @@ mod tests {
     #[test]
     fn search_prompt_no_sources_no_section() {
         let settings = test_settings();
-        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026");
+        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026", &[]);
         assert!(!user_prompt.contains("sources personnalisees"));
     }
 
@@ -233,7 +245,7 @@ mod tests {
         settings.search_agent_behavior =
             "Concentre-toi sur les sources europeennes.".to_string();
 
-        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026");
+        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026", &[]);
         assert!(user_prompt.contains("Concentre-toi sur les sources europeennes."));
         assert!(!user_prompt.contains("recherche Google"));
     }
@@ -241,14 +253,14 @@ mod tests {
     #[test]
     fn search_prompt_default_behavior_when_empty() {
         let settings = test_settings();
-        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026");
+        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026", &[]);
         assert!(user_prompt.contains("recherche Google"));
     }
 
     #[test]
     fn search_prompt_warns_against_homepage_urls() {
         let settings = test_settings();
-        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026");
+        let (_, user_prompt) = build_search_prompt(&settings, &[], "lundi 21 mars 2026", &[]);
         assert!(user_prompt.contains("pages d'accueil"));
         assert!(user_prompt.contains("articles specifiques"));
     }
@@ -284,4 +296,25 @@ mod tests {
         // Should still produce a valid prompt with empty data
         assert!(user_prompt.contains("Donnees des articles"));
     }
+
+    #[test]
+    fn search_prompt_includes_recent_domains_avoidance() {
+        let settings = test_settings();
+        let sources = vec![];
+        let date = "lundi 17 mars 2026";
+        let domains = vec!["techcrunch.com".to_string(), "theverge.com".to_string()];
+        let (_, user_prompt) = build_search_prompt(&settings, &sources, date, &domains);
+        assert!(user_prompt.contains("Evite si possible"));
+        assert!(user_prompt.contains("techcrunch.com"));
+        assert!(user_prompt.contains("theverge.com"));
+    }
+
+    #[test]
+    fn search_prompt_no_avoidance_when_domains_empty() {
+        let settings = test_settings();
+        let sources = vec![];
+        let date = "lundi 17 mars 2026";
+        let (_, user_prompt) = build_search_prompt(&settings, &sources, date, &[]);
+        assert!(!user_prompt.contains("Evite si possible"));
+    }
 }

backend/src/services/synthesis.rs

@@ -301,7 +301,7 @@ async fn run_generation_inner(
         .format("%A %d %B %Y")
         .to_string();
     let (system_prompt, user_prompt) =
-        prompts::build_search_prompt(&settings, &sources, &current_date);
+        prompts::build_search_prompt(&settings, &sources, &current_date, &[]);
 
     let raw_results = provider
         .generate_search_pass(&model_research, &system_prompt, &user_prompt, &schema)