huskies: merge 652_story_pass_resume_session_id_on_agent_respawn_so_new_sessions_inherit_prior_reasoning

server/src/agents/pool/start/mod.rs

@@ -292,6 +292,22 @@ impl AgentPool {
             .map(|a| a.inactivity_timeout_secs)
             .unwrap_or(300);
 
+        // If no explicit session_id_to_resume was provided, look up from the
+        // persistent session store.  The key includes the model so a model
+        // change (e.g. sonnet → opus) produces a cache miss — intentional.
+        let effective_session_id = session_id_to_resume.or_else(|| {
+            let model = config
+                .find_agent(&resolved_name)
+                .and_then(|a| a.model.clone())
+                .unwrap_or_default();
+            crate::agents::session_store::lookup_session(
+                project_root,
+                story_id,
+                &resolved_name,
+                &model,
+            )
+        });
+
         // Clone all values needed inside the background spawn.
         // Spawn the background task. Worktree creation and agent launch happen here
         // so `start_agent` returns immediately after registering the agent as
@@ -300,7 +316,7 @@ impl AgentPool {
             project_root.to_path_buf(),
             config.clone(),
             resume_context.map(str::to_string),
-            session_id_to_resume,
+            effective_session_id,
             story_id.to_string(),
             resolved_name.clone(),
             tx.clone(),