diff --git a/letta/constants.py b/letta/constants.py
index 4fa9aa1f..2c11d968 100644
--- a/letta/constants.py
+++ b/letta/constants.py
@@ -245,6 +245,7 @@ LLM_MAX_TOKENS = {
     "gpt-5.1-2025-11-13": 272000,
     "gpt-5.1-codex": 272000,
     "gpt-5.1-codex-mini": 272000,
+    "gpt-5.1-codex-max": 272000,
     # reasoners
     "o1": 200000,
     # "o1-pro": 200000,  # responses API only