diff --git a/crates/copilot/src/copilot_chat.rs b/crates/copilot/src/copilot_chat.rs
index 54b8217596126df3ed762a84c3e833180ccc757d..19cff56c911b2d85f91b5075f238f8320f846e3f 100644
--- a/crates/copilot/src/copilot_chat.rs
+++ b/crates/copilot/src/copilot_chat.rs
@@ -318,15 +318,9 @@ pub struct ResponseEvent {
 pub struct Usage {
     pub completion_tokens: u64,
     pub prompt_tokens: u64,
-    pub prompt_tokens_details: PromptTokensDetails,
     pub total_tokens: u64,
 }
 
-#[derive(Deserialize, Debug)]
-pub struct PromptTokensDetails {
-    pub cached_tokens: u64,
-}
-
 #[derive(Debug, Deserialize)]
 pub struct ResponseChoice {
     pub index: usize,