diff --git a/codex-rs/app-server/src/codex_message_processor.rs b/codex-rs/app-server/src/codex_message_processor.rs
index 6c3b4e6562..400b12cf6d 100644
--- a/codex-rs/app-server/src/codex_message_processor.rs
+++ b/codex-rs/app-server/src/codex_message_processor.rs
@@ -2489,8 +2489,8 @@ impl CodexMessageProcessor {
             sandbox_mode: sandbox.map(SandboxMode::to_core),
             codex_linux_sandbox_exe: self.arg0_paths.codex_linux_sandbox_exe.clone(),
             main_execve_wrapper_exe: self.arg0_paths.main_execve_wrapper_exe.clone(),
-            base_instructions: thread_instruction_override(base_instructions),
-            developer_instructions: thread_instruction_override(developer_instructions),
+            base_instructions: base_instructions.map(Option::unwrap_or_default),
+            developer_instructions: developer_instructions.map(Option::unwrap_or_default),
             personality,
             ..Default::default()
         }
@@ -7843,14 +7843,6 @@ fn normalize_thread_list_cwd_filter(
         })
 }
 
-fn thread_instruction_override(instructions: Option<Option<String>>) -> Option<String> {
-    match instructions {
-        None => None,
-        Some(None) => Some(String::new()),
-        Some(Some(instructions)) => Some(instructions),
-    }
-}
-
 #[cfg(test)]
 mod thread_list_cwd_filter_tests {
     use super::normalize_thread_list_cwd_filter;
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 8852dcf716..77f60e0efd 100644
--- a/codex-rs/app-server/tests/suite/v2/turn_start.rs
+++ b/codex-rs/app-server/tests/suite/v2/turn_start.rs
@@ -241,8 +241,8 @@ async fn turn_start_honors_explicit_null_thread_instructions() -> Result<()> {
         );
         let developer_texts = request.message_input_texts("developer");
         assert!(
-            developer_texts.is_empty(),
-            "did not expect developer instruction messages: {developer_texts:?}"
+            developer_texts.iter().all(|text| !text.is_empty()),
+            "did not expect empty developer instruction messages: {developer_texts:?}"
         );
     }