Optimize execute_tool with process execution, and robustify JSON argument parsing

backend.py

@@ -373,10 +373,8 @@ async def execute_tool(name: str, arguments: dict) -> str:
             search_path = arguments.get("path", ".")
             path = _safe_path(search_path)
             
-            # Escape single quotes in pattern for safety
-            escaped_pattern = pattern.replace("'", "'\\''")
-            process = await asyncio.create_subprocess_shell(
-                f"grep -rn --include=* '{escaped_pattern}' '{path}'",
+            process = await asyncio.create_subprocess_exec(
+                "grep", "-rn", "--include=*", pattern, str(path),
                 stdout=asyncio.subprocess.PIPE,
                 stderr=asyncio.subprocess.PIPE,
                 cwd=WORKSPACE_DIR,
@@ -1805,7 +1803,19 @@ async def forge_execute(req: ForgeExecuteRequest, authorization: str = Header(No
                 
             for tc in msg.tool_calls:
                 func_name = tc.function.name
-                func_args = json.loads(tc.function.arguments)
+                raw_args_str = tc.function.arguments
+                try:
+                    func_args = json.loads(raw_args_str)
+                except Exception:
+                    repaired_str = raw_args_str.strip()
+                    if not repaired_str.startswith("{"):
+                        repaired_str = "{" + repaired_str
+                    if not repaired_str.endswith("}"):
+                        repaired_str = repaired_str + "}"
+                    try:
+                        func_args = json.loads(repaired_str)
+                    except Exception:
+                        func_args = {}
                 result = await execute_tool(func_name, func_args)
                 
                 final_messages.append({