diff --git a/lib/permissions/minimally-encoded-raw-thread-info-validators.js b/lib/permissions/minimally-encoded-raw-thread-info-validators.js
--- a/lib/permissions/minimally-encoded-raw-thread-info-validators.js
+++ b/lib/permissions/minimally-encoded-raw-thread-info-validators.js
@@ -8,7 +8,7 @@
 } from './minimally-encoded-thread-permissions.js';
 import { specialRoleValidator } from './special-roles.js';
 import type {
-  MemberInfo,
+  MemberInfoWithPermissions,
   ThreadCurrentUserInfo,
   RawThreadInfo,
   RoleInfo,
@@ -62,11 +62,12 @@
     isDefault: t.maybe(t.Boolean),
   });
 
-const memberInfoValidator: TInterface<MemberInfo> = tShape<MemberInfo>({
-  ...legacyMemberInfoValidator.meta.props,
-  minimallyEncoded: tBool(true),
-  permissions: tHexEncodedPermissionsBitmask,
-});
+const memberInfoValidator: TInterface<MemberInfoWithPermissions> =
+  tShape<MemberInfoWithPermissions>({
+    ...legacyMemberInfoValidator.meta.props,
+    minimallyEncoded: tBool(true),
+    permissions: tHexEncodedPermissionsBitmask,
+  });
 
 const rawThreadInfoValidator: TInterface<RawThreadInfo> = tShape<RawThreadInfo>(
   {
diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -42,7 +42,7 @@
 import type {
   RelativeMemberInfo,
   RawThreadInfo,
-  MemberInfo,
+  MemberInfoWithPermissions,
   RoleInfo,
   ThreadInfo,
 } from '../types/minimally-encoded-thread-permissions-types.js';
@@ -135,7 +135,7 @@
     return _mapValues((threadInfo: ThreadInfo) => {
       const keyedMembers = _keyBy('id')(threadInfo.members);
       const keyedMembersToRole = _mapValues(
-        (member: MemberInfo | RelativeMemberInfo) => {
+        (member: MemberInfoWithPermissions | RelativeMemberInfo) => {
           return member.role ? threadInfo.roles[member.role] : null;
         },
       )(keyedMembers);
@@ -300,7 +300,7 @@
 }
 
 function threadActualMembers(
-  memberInfos: $ReadOnlyArray<MemberInfo | RelativeMemberInfo>,
+  memberInfos: $ReadOnlyArray<MemberInfoWithPermissions | RelativeMemberInfo>,
 ): $ReadOnlyArray<string> {
   return memberInfos
     .filter(memberInfo => memberInfo.role)
@@ -308,7 +308,7 @@
 }
 
 function threadOtherMembers<
-  T: LegacyMemberInfo | MemberInfo | RelativeMemberInfo,
+  T: LegacyMemberInfo | MemberInfoWithPermissions | RelativeMemberInfo,
 >(memberInfos: $ReadOnlyArray<T>, viewerID: ?string): $ReadOnlyArray<T> {
   return memberInfos.filter(
     memberInfo => memberInfo.role && memberInfo.id !== viewerID,
@@ -966,7 +966,7 @@
 // Since we don't have access to all of the ancestor ThreadInfos, we approximate
 // "parent admin" as anybody with CHANGE_ROLE permissions.
 function memberHasAdminPowers(
-  memberInfo: LegacyMemberInfo | MemberInfo | ServerMemberInfo,
+  memberInfo: LegacyMemberInfo | MemberInfoWithPermissions | ServerMemberInfo,
 ): boolean {
   if (memberInfo.minimallyEncoded) {
     return hasPermission(memberInfo.permissions, threadPermissions.CHANGE_ROLE);
diff --git a/lib/types/minimally-encoded-thread-permissions-types.js b/lib/types/minimally-encoded-thread-permissions-types.js
--- a/lib/types/minimally-encoded-thread-permissions-types.js
+++ b/lib/types/minimally-encoded-thread-permissions-types.js
@@ -99,7 +99,7 @@
   };
 };
 
-export type MemberInfo = $ReadOnly<{
+export type MemberInfoWithPermissions = $ReadOnly<{
   ...LegacyMemberInfo,
   +minimallyEncoded: true,
   +permissions: string,
@@ -107,7 +107,7 @@
 
 const minimallyEncodeMemberInfo = (
   memberInfo: LegacyMemberInfo,
-): MemberInfo => {
+): MemberInfoWithPermissions => {
   invariant(
     !('minimallyEncoded' in memberInfo),
     'memberInfo is already minimally encoded.',
@@ -120,7 +120,7 @@
 };
 
 const decodeMinimallyEncodedMemberInfo = (
-  minimallyEncodedMemberInfo: MemberInfo,
+  minimallyEncodedMemberInfo: MemberInfoWithPermissions,
 ): LegacyMemberInfo => {
   const { minimallyEncoded, ...rest } = minimallyEncodedMemberInfo;
   return {
@@ -143,7 +143,7 @@
 export type RawThreadInfo = $ReadOnly<{
   ...LegacyRawThreadInfo,
   +minimallyEncoded: true,
-  +members: $ReadOnlyArray<MemberInfo>,
+  +members: $ReadOnlyArray<MemberInfoWithPermissions>,
   +roles: { +[id: string]: RoleInfo },
   +currentUser: ThreadCurrentUserInfo,
 }>;
diff --git a/lib/utils/thread-ops-utils.js b/lib/utils/thread-ops-utils.js
--- a/lib/utils/thread-ops-utils.js
+++ b/lib/utils/thread-ops-utils.js
@@ -8,7 +8,7 @@
   threadCurrentUserInfoValidator,
 } from '../permissions/minimally-encoded-raw-thread-info-validators.js';
 import type {
-  MemberInfo,
+  MemberInfoWithPermissions,
   RawThreadInfo,
   RoleInfo,
 } from '../types/minimally-encoded-thread-permissions-types.js';
@@ -46,8 +46,8 @@
 ): RawThreadInfo {
   // 1. Validate and potentially minimally encode `rawMembers`.
   const rawMembers = JSON.parse(clientDBThreadInfo.members);
-  const minimallyEncodedMembers: $ReadOnlyArray<MemberInfo> = rawMembers.map(
-    rawMember => {
+  const minimallyEncodedMembers: $ReadOnlyArray<MemberInfoWithPermissions> =
+    rawMembers.map(rawMember => {
       invariant(
         memberInfoValidator.is(rawMember) ||
           legacyMemberInfoValidator.is(rawMember),
@@ -56,8 +56,7 @@
       return rawMember.minimallyEncoded
         ? rawMember
         : minimallyEncodeMemberInfo(rawMember);
-    },
-  );
+    });
 
   // 2. Validate and potentially minimally encode `rawRoles`.
   const rawRoles = JSON.parse(clientDBThreadInfo.roles);