diff --git a/proto/bender.thrift b/proto/bender.thrift
index 61265ba..6cd89af 100644
--- a/proto/bender.thrift
+++ b/proto/bender.thrift
@@ -6,11 +6,18 @@ include "proto/msgpack.thrift"
 typedef string ExternalID
 typedef string InternalID
 
+exception InternalIDNotFound {}
+
 struct GenerationResult {
     1: required InternalID internal_id
     2: optional msgpack.Value context
 }
 
+struct GetInternalIDResult {
+    1: required InternalID internal_id
+    2: required msgpack.Value context
+}
+
 union GenerationSchema {
     1: SnowflakeSchema snowflake
     2: ConstantSchema constant
@@ -33,4 +40,7 @@ service Bender {
 
     GenerationResult GenerateID (1: ExternalID external_id, 2: GenerationSchema schema, 3: msgpack.Value context)
 
+    GetInternalIDResult GetInternalID (1: ExternalID external_id) 
+        throws (1: InternalIDNotFound ex1)
+
 }