diff --git a/lua/avante/llm_tools/replace_in_file.lua b/lua/avante/llm_tools/replace_in_file.lua
index 65f2332..af1d336 100644
--- a/lua/avante/llm_tools/replace_in_file.lua
+++ b/lua/avante/llm_tools/replace_in_file.lua
@@ -163,7 +163,8 @@ function M.func(input, opts)
     elseif is_searching then
       table.insert(current_old_lines, line)
     elseif is_replacing then
-      table.insert(current_new_lines, line)
+      -- Remove trailing spaces from each line before adding to new_lines
+      table.insert(current_new_lines, (line:gsub("%s+$", "")))
     end
   end
 
diff --git a/lua/avante/llm_tools/str_replace.lua b/lua/avante/llm_tools/str_replace.lua
index 32a32ec..f3a8080 100644
--- a/lua/avante/llm_tools/str_replace.lua
+++ b/lua/avante/llm_tools/str_replace.lua
@@ -56,6 +56,11 @@ M.returns = {
 ---@type AvanteLLMToolFunc<{ path: string, old_str: string, new_str: string }>
 function M.func(input, opts)
   local replace_in_file = require("avante.llm_tools.replace_in_file")
+  local Utils = require("avante.utils")
+
+  -- Remove trailing spaces from the new string
+  input.new_str = Utils.remove_trailing_spaces(input.new_str)
+
   local diff = "------- SEARCH\n" .. input.old_str .. "\n=======\n" .. input.new_str
   if not opts.streaming then diff = diff .. "\n+++++++ REPLACE" end
   local new_input = {
diff --git a/lua/avante/llm_tools/write_to_file.lua b/lua/avante/llm_tools/write_to_file.lua
index 09d59cd..4bf278a 100644
--- a/lua/avante/llm_tools/write_to_file.lua
+++ b/lua/avante/llm_tools/write_to_file.lua
@@ -70,6 +70,8 @@ function M.func(input, opts)
     Utils.debug("Trimming escapes from content")
     input.the_content = Utils.trim_escapes(input.the_content)
   end
+  -- Remove trailing spaces from each line
+  input.the_content = Utils.remove_trailing_spaces(input.the_content)
   local old_lines = Utils.read_file_from_buf_or_disk(abs_path)
   local old_content = table.concat(old_lines or {}, "\n")
   local str_replace = require("avante.llm_tools.str_replace")
diff --git a/lua/avante/utils/init.lua b/lua/avante/utils/init.lua
index 8752ac4..810f1aa 100644
--- a/lua/avante/utils/init.lua
+++ b/lua/avante/utils/init.lua
@@ -554,6 +554,18 @@ end
 
 function M.trim_spaces(s) return s:match("^%s*(.-)%s*$") end
 
+---Remove trailing spaces from each line in a string
+---@param content string The content to process
+---@return string The content with trailing spaces removed from each line
+function M.remove_trailing_spaces(content)
+  if not content then return content end
+  local lines = vim.split(content, "\n")
+  for i, line in ipairs(lines) do
+    lines[i] = line:gsub("%s+$", "")
+  end
+  return table.concat(lines, "\n")
+end
+
 function M.fallback(v, default_value) return type(v) == "nil" and default_value or v end
 
 ---Join URL parts together, handling slashes correctly