diff --git a/codex-rs/core/tests/common/test_codex.rs b/codex-rs/core/tests/common/test_codex.rs
index bcc93d7d09..026c84ee2c 100644
--- a/codex-rs/core/tests/common/test_codex.rs
+++ b/codex-rs/core/tests/common/test_codex.rs
@@ -383,9 +383,16 @@ impl TestCodexBuilder {
             .exec_server_url
             .clone()
             .or_else(|| test_env.exec_server_url.clone());
+        #[cfg(target_os = "linux")]
+        let codex_linux_sandbox_exe = Some(
+            crate::find_codex_linux_sandbox_exe()
+                .context("should find binary for codex-linux-sandbox")?,
+        );
+        #[cfg(not(target_os = "linux"))]
+        let codex_linux_sandbox_exe = None;
         let local_runtime_paths = codex_exec_server::ExecServerRuntimePaths::new(
             std::env::current_exe()?,
-            /*codex_linux_sandbox_exe*/ None,
+            codex_linux_sandbox_exe,
         )?;
         let environment_manager = Arc::new(
             codex_exec_server::EnvironmentManager::create_for_tests(