diff --git a/lua/CopilotChat/config/mappings.lua b/lua/CopilotChat/config/mappings.lua
index c7a257b5..5d5e6ea4 100644
--- a/lua/CopilotChat/config/mappings.lua
+++ b/lua/CopilotChat/config/mappings.lua
@@ -376,7 +376,7 @@ return {
             end
             local change_lines = vim.split(file_diff.change, '\n')
             for i, line in ipairs(change_lines) do
-              table.insert(modified, start_idx + i, line)
+              table.insert(modified, start_idx + i - 1, line)
             end
           end