diff --git a/codex-rs/protocol/src/parse_command.rs b/codex-rs/protocol/src/parse_command.rs
index 495562a76..63399acc6 100644
--- a/codex-rs/protocol/src/parse_command.rs
+++ b/codex-rs/protocol/src/parse_command.rs
@@ -2,6 +2,7 @@ use serde::Deserialize;
 use serde::Serialize;
 
 #[derive(Debug, Clone, PartialEq, Eq, Deserialize, Serialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
 pub enum ParsedCommand {
     Read {
         cmd: String,