From 14a11d24b4b5b397ba30369e260976aba6aeb736 Mon Sep 17 00:00:00 2001
From: 0xbyt4 <35742124+0xbyt4@users.noreply.github.com>
Date: Thu, 5 Mar 2026 23:09:11 +0300
Subject: [PATCH] fix: handle None args in build_tool_preview

When an LLM returns null/empty tool call arguments, json.loads()
produces None. build_tool_preview then crashes with
"argument of type 'NoneType' is not iterable" on the `in` check.
Return None early when args is falsy.
---
 agent/display.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/agent/display.py b/agent/display.py
index 17595ce27..fbd40f8f2 100644
--- a/agent/display.py
+++ b/agent/display.py
@@ -22,6 +22,8 @@ _RESET = "\033[0m"
 
 def build_tool_preview(tool_name: str, args: dict, max_len: int = 40) -> str:
     """Build a short preview of a tool call's primary argument for display."""
+    if not args:
+        return None
     primary_args = {
         "terminal": "command", "web_search": "query", "web_extract": "urls",
         "read_file": "path", "write_file": "path", "patch": "path",