fix(cache): clear history on model scope changes (#1052)

crates/tui/src/commands/core.rs

@@ -99,14 +99,19 @@ pub fn model(app: &mut App, model_name: Option<&str>) -> CommandResult {
     if let Some(name) = model_name {
         if name.trim().eq_ignore_ascii_case("auto") {
             let old_model = app.model_display_label();
+            let model_changed = !app.auto_model || app.model != "auto";
             app.auto_model = true;
             app.model = "auto".to_string();
             app.last_effective_model = None;
             app.reasoning_effort = ReasoningEffort::Auto;
             app.last_effective_reasoning_effort = None;
             app.update_model_compaction_budget();
-            app.session.last_prompt_tokens = None;
-            app.session.last_completion_tokens = None;
+            if model_changed {
+                app.clear_model_scoped_telemetry();
+            } else {
+                app.session.last_prompt_tokens = None;
+                app.session.last_completion_tokens = None;
+            }
             return CommandResult::with_message_and_action(
                 tr(app.ui_locale, MessageId::ModelChanged)
                     .replace("{old}", &old_model)
@@ -121,12 +126,17 @@ pub fn model(app: &mut App, model_name: Option<&str>) -> CommandResult {
             ));
         };
         let old_model = app.model_display_label();
+        let model_changed = app.auto_model || app.model != model_id;
         app.auto_model = false;
         app.model = model_id.clone();
         app.last_effective_model = None;
         app.update_model_compaction_budget();
-        app.session.last_prompt_tokens = None;
-        app.session.last_completion_tokens = None;
+        if model_changed {
+            app.clear_model_scoped_telemetry();
+        } else {
+            app.session.last_prompt_tokens = None;
+            app.session.last_completion_tokens = None;
+        }
         CommandResult::with_message_and_action(
             tr(app.ui_locale, MessageId::ModelChanged)
                 .replace("{old}", &old_model)
@@ -485,6 +495,42 @@ mod tests {
         assert_eq!(app.session.last_completion_tokens, None);
     }
 
+    #[test]
+    fn model_switch_clears_turn_cache_history() {
+        let mut app = create_test_app();
+        app.push_turn_cache_record(TurnCacheRecord {
+            input_tokens: 100,
+            output_tokens: 25,
+            cache_hit_tokens: Some(70),
+            cache_miss_tokens: Some(30),
+            reasoning_replay_tokens: Some(12),
+            recorded_at: Instant::now(),
+        });
+
+        let result = model(&mut app, Some("deepseek-v4-flash"));
+
+        assert!(result.message.is_some());
+        assert!(app.session.turn_cache_history.is_empty());
+    }
+
+    #[test]
+    fn model_reset_same_model_keeps_turn_cache_history() {
+        let mut app = create_test_app();
+        app.push_turn_cache_record(TurnCacheRecord {
+            input_tokens: 100,
+            output_tokens: 25,
+            cache_hit_tokens: Some(70),
+            cache_miss_tokens: Some(30),
+            reasoning_replay_tokens: Some(12),
+            recorded_at: Instant::now(),
+        });
+
+        let result = model(&mut app, Some("deepseek-v4-pro"));
+
+        assert!(result.message.is_some());
+        assert_eq!(app.session.turn_cache_history.len(), 1);
+    }
+
     #[test]
     fn test_model_auto_enables_auto_thinking() {
         let mut app = create_test_app();

crates/tui/src/tui/app.rs

@@ -1081,6 +1081,15 @@ impl App {
         }
     }
 
+    pub(crate) fn clear_model_scoped_telemetry(&mut self) {
+        self.session.last_prompt_tokens = None;
+        self.session.last_completion_tokens = None;
+        self.session.last_prompt_cache_hit_tokens = None;
+        self.session.last_prompt_cache_miss_tokens = None;
+        self.session.last_reasoning_replay_tokens = None;
+        self.session.turn_cache_history.clear();
+    }
+
     pub fn tr(&self, id: MessageId) -> &'static str {
         tr(self.ui_locale, id)
     }

crates/tui/src/tui/ui.rs

@@ -3884,11 +3884,7 @@ async fn apply_model_picker_choice(
         app.last_effective_model = None;
         app.model = model.clone();
         app.update_model_compaction_budget();
-        app.session.last_prompt_tokens = None;
-        app.session.last_completion_tokens = None;
-        app.session.last_prompt_cache_hit_tokens = None;
-        app.session.last_prompt_cache_miss_tokens = None;
-        app.session.last_reasoning_replay_tokens = None;
+        app.clear_model_scoped_telemetry();
     }
     if effort_changed {
         app.reasoning_effort = effort;
@@ -4006,11 +4002,16 @@ async fn switch_provider(
     }
 
     let new_model = config.default_model();
+    let cache_scope_changed = previous_provider != target || previous_model != new_model;
     app.api_provider = target;
     app.model = new_model.clone();
     app.update_model_compaction_budget();
-    app.session.last_prompt_tokens = None;
-    app.session.last_completion_tokens = None;
+    if cache_scope_changed {
+        app.clear_model_scoped_telemetry();
+    } else {
+        app.session.last_prompt_tokens = None;
+        app.session.last_completion_tokens = None;
+    }
 
     let _ = engine_handle.send(Op::Shutdown).await;
     let engine_config = build_engine_config(app, config);

crates/tui/src/tui/ui/tests.rs

@@ -1,5 +1,5 @@
 use super::*;
-use crate::config::Config;
+use crate::config::{ApiProvider, Config};
 use crate::config_ui::{self, WebConfigSession, WebConfigSessionEvent};
 use crate::core::engine::mock_engine_handle;
 use crate::tui::file_mention::{
@@ -899,6 +899,33 @@ async fn model_change_update_syncs_engine_model_before_compaction() {
     }
 }
 
+#[tokio::test]
+async fn provider_switch_clears_turn_cache_history() {
+    let mut app = create_test_app();
+    app.push_turn_cache_record(crate::tui::app::TurnCacheRecord {
+        input_tokens: 100,
+        output_tokens: 25,
+        cache_hit_tokens: Some(70),
+        cache_miss_tokens: Some(30),
+        reasoning_replay_tokens: Some(12),
+        recorded_at: Instant::now(),
+    });
+    let mut engine = mock_engine_handle();
+    let mut config = Config::default();
+
+    switch_provider(
+        &mut app,
+        &mut engine.handle,
+        &mut config,
+        ApiProvider::Ollama,
+        None,
+    )
+    .await;
+
+    assert_eq!(app.api_provider, ApiProvider::Ollama);
+    assert!(app.session.turn_cache_history.is_empty());
+}
+
 #[tokio::test]
 async fn dispatch_user_message_failed_send_clears_loading_state() {
     let mut app = create_test_app();