diff --git a/codex-rs/app-server/tests/suite/v2/thread_archive.rs b/codex-rs/app-server/tests/suite/v2/thread_archive.rs
index 3c830ed3e0..eb65f4419c 100644
--- a/codex-rs/app-server/tests/suite/v2/thread_archive.rs
+++ b/codex-rs/app-server/tests/suite/v2/thread_archive.rs
@@ -8,7 +8,7 @@ use codex_app_server_protocol::ThreadArchiveResponse;
 use codex_app_server_protocol::ThreadStartParams;
 use codex_app_server_protocol::ThreadStartResponse;
 use codex_core::ARCHIVED_SESSIONS_SUBDIR;
-use codex_core::SESSIONS_SUBDIR;
+use codex_core::find_conversation_path_by_id_str;
 use std::path::Path;
 use tempfile::TempDir;
 use tokio::time::timeout;
@@ -27,16 +27,7 @@ async fn thread_archive_moves_rollout_into_archived_directory() -> Result<()> {
     let start_id = mcp
         .send_thread_start_request(ThreadStartParams {
             model: Some("mock-model".to_string()),
-            model_provider: None,
-            profile: None,
-            cwd: None,
-            approval_policy: None,
-            sandbox: None,
-            config: None,
-            base_instructions: None,
-            developer_instructions: None,
-            compact_prompt: None,
-            include_apply_patch_tool: None,
+            ..Default::default()
         })
         .await?;
     let start_resp: JSONRPCResponse = timeout(
@@ -47,11 +38,10 @@ async fn thread_archive_moves_rollout_into_archived_directory() -> Result<()> {
     let ThreadStartResponse { thread } = to_response::<ThreadStartResponse>(start_resp)?;
     assert!(!thread.id.is_empty());
 
-    // Construct the rollout path derived from the id we got back.
-    let rollout_path = codex_home
-        .path()
-        .join(SESSIONS_SUBDIR)
-        .join(format!("{}.jsonl", thread.id));
+    // Locate the rollout path recorded for this thread id.
+    let rollout_path = find_conversation_path_by_id_str(codex_home.path(), &thread.id)
+        .await?
+        .expect("expected rollout path for thread id to exist");
     assert!(
         rollout_path.exists(),
         "expected {} to exist",
@@ -73,7 +63,9 @@ async fn thread_archive_moves_rollout_into_archived_directory() -> Result<()> {
 
     // Verify file moved.
     let archived_directory = codex_home.path().join(ARCHIVED_SESSIONS_SUBDIR);
-    let archived_rollout_path = archived_directory.join(format!("{}.jsonl", thread.id));
+    // The archived file keeps the original filename (rollout-...-<id>.jsonl).
+    let archived_rollout_path =
+        archived_directory.join(rollout_path.file_name().expect("rollout file name"));
     assert!(
         !rollout_path.exists(),
         "expected rollout path {} to be moved",
diff --git a/codex-rs/app-server/tests/suite/v2/thread_resume.rs b/codex-rs/app-server/tests/suite/v2/thread_resume.rs
index bb91ec74bf..c503d8138e 100644
--- a/codex-rs/app-server/tests/suite/v2/thread_resume.rs
+++ b/codex-rs/app-server/tests/suite/v2/thread_resume.rs
@@ -26,16 +26,7 @@ async fn thread_resume_returns_existing_thread() -> Result<()> {
     let start_id = mcp
         .send_thread_start_request(ThreadStartParams {
             model: Some("o3".to_string()),
-            model_provider: None,
-            profile: None,
-            cwd: None,
-            approval_policy: None,
-            sandbox: None,
-            config: None,
-            base_instructions: None,
-            developer_instructions: None,
-            compact_prompt: None,
-            include_apply_patch_tool: None,
+            ..Default::default()
         })
         .await?;
     let start_resp: JSONRPCResponse = timeout(
diff --git a/codex-rs/app-server/tests/suite/v2/thread_start.rs b/codex-rs/app-server/tests/suite/v2/thread_start.rs
index 63c3bfc232..da25b5eb03 100644
--- a/codex-rs/app-server/tests/suite/v2/thread_start.rs
+++ b/codex-rs/app-server/tests/suite/v2/thread_start.rs
@@ -31,16 +31,7 @@ async fn thread_start_creates_thread_and_emits_started() -> Result<()> {
     let req_id = mcp
         .send_thread_start_request(ThreadStartParams {
             model: Some("o3".to_string()),
-            model_provider: None,
-            profile: None,
-            cwd: None,
-            approval_policy: None,
-            sandbox: None,
-            config: None,
-            base_instructions: None,
-            developer_instructions: None,
-            compact_prompt: None,
-            include_apply_patch_tool: None,
+            ..Default::default()
         })
         .await?;
 
diff --git a/codex-rs/app-server/tests/suite/v2/turn_start.rs b/codex-rs/app-server/tests/suite/v2/turn_start.rs
index 55c1537322..312779b9f9 100644
--- a/codex-rs/app-server/tests/suite/v2/turn_start.rs
+++ b/codex-rs/app-server/tests/suite/v2/turn_start.rs
@@ -39,16 +39,7 @@ async fn turn_start_emits_notifications_and_accepts_model_override() -> Result<(
     let thread_req = mcp
         .send_thread_start_request(ThreadStartParams {
             model: Some("mock-model".to_string()),
-            model_provider: None,
-            profile: None,
-            cwd: None,
-            approval_policy: None,
-            sandbox: None,
-            config: None,
-            base_instructions: None,
-            developer_instructions: None,
-            compact_prompt: None,
-            include_apply_patch_tool: None,
+            ..Default::default()
         })
         .await?;
     let thread_resp: JSONRPCResponse = timeout(
@@ -148,16 +139,7 @@ async fn turn_start_accepts_local_image_input() -> Result<()> {
     let thread_req = mcp
         .send_thread_start_request(ThreadStartParams {
             model: Some("mock-model".to_string()),
-            model_provider: None,
-            profile: None,
-            cwd: None,
-            approval_policy: None,
-            sandbox: None,
-            config: None,
-            base_instructions: None,
-            developer_instructions: None,
-            compact_prompt: None,
-            include_apply_patch_tool: None,
+            ..Default::default()
         })
         .await?;
     let thread_resp: JSONRPCResponse = timeout(