diff --git a/codex-rs/protocol/src/protocol.rs b/codex-rs/protocol/src/protocol.rs
index bc45bd4085..3b65aa05c4 100644
--- a/codex-rs/protocol/src/protocol.rs
+++ b/codex-rs/protocol/src/protocol.rs
@@ -1951,7 +1951,7 @@ pub struct TurnContextItem {
     pub cwd: PathBuf,
     pub approval_policy: AskForApproval,
     pub sandbox_policy: SandboxPolicy,
-    #[serde(default)]
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub network: Option<TurnContextNetworkItem>,
     pub model: String,
     #[serde(skip_serializing_if = "Option::is_none")]