diff --git a/sentence_api/models.py b/sentence_api/models.py
index 5236958..8e461e7 100644
--- a/sentence_api/models.py
+++ b/sentence_api/models.py
@@ -156,7 +156,7 @@ class AuthResponse(BaseModel):
 
 
 class SsoExchangeRequest(BaseModel):
-    access_token: str = Field(min_length=1, max_length=256)
+    access_token: str = Field(min_length=1, max_length=4096)
 
 
 class SsoExchangeResponse(BaseModel):