diff --git a/modules/home/ai-agent/default.nix b/modules/home/ai-agent/default.nix
index 3ec1ab0..d98950a 100644
--- a/modules/home/ai-agent/default.nix
+++ b/modules/home/ai-agent/default.nix
@@ -47,7 +47,7 @@ let
         nativeBuildInputs = [ pkgs.makeWrapper ];
         postBuild = ''
           wrapProgram "$out/bin/codex" --add-flags '-c tui.terminal_title=[] -c tui.alternate_screen=always --enable hooks' \
-            --add-flags '-c tui.keymap.chat.edit_queued_message=ctrl-up -c tui.keymap.chat.prompt_stack_back=ctrl-down'
+            --add-flags '-c tui.keymap.chat.edit_queued_message=ctrl-up'
         '';
       }
     else
@@ -131,6 +131,13 @@ in
       hooks.UserPromptSubmit = sessionTitlePromptHook;
     };
 
+    home.activation.removeCodexPromptStackBack = lib.hm.dag.entryAfter [ "writeBoundary" ] ''
+      codexConfig=${lib.escapeShellArg "${config.home.homeDirectory}/.codex/config.toml"}
+      if [ -f "$codexConfig" ]; then
+        run ${pkgs.gnused}/bin/sed -i '/^\[tui\.keymap\.chat\]$/,/^\[/ { /^[[:space:]]*prompt_stack_back[[:space:]]*=/d; }' "$codexConfig"
+      fi
+    '';
+
     home.file.".config/opencode/opencode.jsonc" = lib.mkIf (config.ai-agent.agent == "opencode") {
       source = lib.mkDefault (
         if config.home.username == "alebat01" then mergedArmOpencodeConfig else ./opencode/config.jsonc