diff --git a/codex-rs/exec-server/src/connection.rs b/codex-rs/exec-server/src/connection.rs
index 01b3a40cc9..29c553b5d2 100644
--- a/codex-rs/exec-server/src/connection.rs
+++ b/codex-rs/exec-server/src/connection.rs
@@ -30,6 +30,8 @@ use tokio::io::BufReader;
 use tokio::io::BufWriter;
 
 pub(crate) const CHANNEL_CAPACITY: usize = 128;
+// Match the existing serialized JSON-RPC message ceiling used by Noise and
+// WebSocket transports so stdio has the same per-message bound.
 const MAX_STDIO_JSONRPC_MESSAGE_LEN: usize = 64 * 1024 * 1024;
 const STDIO_TERMINATION_GRACE_PERIOD: Duration = Duration::from_secs(2);
 #[cfg(test)]