diff --git a/authzed/api/v1/core.proto b/authzed/api/v1/core.proto
index ca49675..bd2d391 100644
--- a/authzed/api/v1/core.proto
+++ b/authzed/api/v1/core.proto
@@ -155,6 +155,7 @@ message Cursor {
 // this operation will no-op.
 message RelationshipUpdate {
   enum Operation {
+    // OPERATION_UNSPECIFIED is not a valid operation and will be rejected.
     OPERATION_UNSPECIFIED = 0;
     OPERATION_CREATE = 1;
     OPERATION_TOUCH = 2;
@@ -202,6 +203,7 @@ message PermissionRelationshipTree {
 // present in the first operand, and none of the other operands.
 message AlgebraicSubjectSet {
   enum Operation {
+    // OPERATION_UNSPECIFIED is not a valid operation and will not be returned.
     OPERATION_UNSPECIFIED = 0;
     OPERATION_UNION = 1;
     OPERATION_INTERSECTION = 2;
diff --git a/authzed/api/v1/debug.proto b/authzed/api/v1/debug.proto
index 03ae189..ac4a310 100644
--- a/authzed/api/v1/debug.proto
+++ b/authzed/api/v1/debug.proto
@@ -30,12 +30,14 @@ message DebugInformation {
 // API call.
 message CheckDebugTrace {
   enum PermissionType {
+    // PERMISSION_TYPE_UNSPECIFIED is not a valid type and will not be returned.
     PERMISSION_TYPE_UNSPECIFIED = 0;
     PERMISSION_TYPE_RELATION = 1;
     PERMISSION_TYPE_PERMISSION = 2;
   }
 
   enum Permissionship {
+    // PERMISSIONSHIP_UNSPECIFIED is not a valid result and will not be returned.
     PERMISSIONSHIP_UNSPECIFIED = 0;
     PERMISSIONSHIP_NO_PERMISSION = 1;
     PERMISSIONSHIP_HAS_PERMISSION = 2;
@@ -130,6 +132,7 @@ message CheckDebugTrace {
 // CaveatEvalInfo holds information about a caveat expression that was evaluated.
 message CaveatEvalInfo {
   enum Result {
+    // RESULT_UNSPECIFIED is not a valid result and will not be returned.
     RESULT_UNSPECIFIED = 0;
 
     RESULT_UNEVALUATED = 1;
diff --git a/authzed/api/v1/permission_service.proto b/authzed/api/v1/permission_service.proto
index 6337588..6918274 100644
--- a/authzed/api/v1/permission_service.proto
+++ b/authzed/api/v1/permission_service.proto
@@ -352,6 +352,7 @@ message ReadRelationshipsResponse {
 // relationships that match the filter.
 message Precondition {
   enum Operation {
+    // OPERATION_UNSPECIFIED is not a valid operation and will be rejected.
     OPERATION_UNSPECIFIED = 0;
     OPERATION_MUST_NOT_MATCH = 1;
     OPERATION_MUST_MATCH = 2;
@@ -444,6 +445,7 @@ message DeleteRelationshipsRequest {
 
 message DeleteRelationshipsResponse {
   enum DeletionProgress {
+    // DELETION_PROGRESS_UNSPECIFIED is not a valid status and will not be returned.
     DELETION_PROGRESS_UNSPECIFIED = 0;
 
     // DELETION_PROGRESS_COMPLETE indicates that all remaining relationships matching the filter
@@ -784,6 +786,7 @@ message LookupResourcesResponse {
 // which the subject exists, streaming back the IDs of those subjects.
 message LookupSubjectsRequest {
   enum WildcardOption {
+    // WILDCARD_OPTION_UNSPECIFIED is the default and is equivalent to WILDCARD_OPTION_INCLUDE_WILDCARDS.
     WILDCARD_OPTION_UNSPECIFIED = 0;
     WILDCARD_OPTION_INCLUDE_WILDCARDS = 1;
     WILDCARD_OPTION_EXCLUDE_WILDCARDS = 2;