diff --git a/codex-rs/core/src/codex.rs b/codex-rs/core/src/codex.rs
index 5a3257f2ed..6c4ea65811 100644
--- a/codex-rs/core/src/codex.rs
+++ b/codex-rs/core/src/codex.rs
@@ -1994,10 +1994,10 @@ async fn handle_response_item(
             arguments,
             timeout_ms,
         } => {
-            let call_id = id
-                .clone()
-                .or_else(|| session_id.clone())
-                .unwrap_or_else(|| format!("unified_exec:{}", Uuid::new_v4()));
+            let call_id = id.clone().unwrap_or_else(|| match &session_id {
+                Some(session_id) => format!("unified_exec:{session_id}:{}", Uuid::new_v4()),
+                None => format!("unified_exec:{}", Uuid::new_v4()),
+            });
             Some(
                 handle_unified_exec_tool_call(
                     sess,
diff --git a/codex-rs/core/src/unified_exec/mod.rs b/codex-rs/core/src/unified_exec/mod.rs
index 82ee714b2e..f09223558d 100644
--- a/codex-rs/core/src/unified_exec/mod.rs
+++ b/codex-rs/core/src/unified_exec/mod.rs
@@ -29,7 +29,7 @@ use path::command_from_chunks;
 use path::join_input_chunks;
 use path::resolve_command_path;
 
-const DEFAULT_TIMEOUT_MS: u64 = 250;
+const DEFAULT_TIMEOUT_MS: u64 = 1_000;
 const MAX_TIMEOUT_MS: u64 = 60_000;
 const UNIFIED_EXEC_OUTPUT_MAX_BYTES: usize = 128 * 1024; // 128 KiB