diff --git a/instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/instrumenter/EndTimeExtractor.java b/instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/instrumenter/EndTimeExtractor.java
index 2e4cfdaa6c36..be5ece35a59d 100644
--- a/instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/instrumenter/EndTimeExtractor.java
+++ b/instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/instrumenter/EndTimeExtractor.java
@@ -17,5 +17,7 @@
 public interface EndTimeExtractor<REQUEST, RESPONSE> {
 
   /** Returns the timestamp marking the end of the response processing. */
+  // passing error for consistency with other extractors of always passing response and error
+  // together (we don't know of a use case yet for extracting end time from error)
   Instant extract(REQUEST request, @Nullable RESPONSE response, @Nullable Throwable error);
 }