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
@@ -105,6 +105,20 @@
   +permissions: string,
 }>;
 
+export type MemberInfoSansPermissions = {
+  +id: string,
+  +role: ?string,
+  +isSender: boolean,
+  +minimallyEncoded: true,
+};
+
+function stripPermissionsFromMemberInfo(
+  memberInfo: MemberInfoWithPermissions,
+): MemberInfoSansPermissions {
+  const { permissions, ...rest } = memberInfo;
+  return rest;
+}
+
 const minimallyEncodeMemberInfo = (
   memberInfo: LegacyMemberInfo,
 ): MemberInfoWithPermissions => {
@@ -219,6 +233,7 @@
   decodeMinimallyEncodedRoleInfo,
   minimallyEncodeThreadCurrentUserInfo,
   decodeMinimallyEncodedThreadCurrentUserInfo,
+  stripPermissionsFromMemberInfo,
   minimallyEncodeMemberInfo,
   decodeMinimallyEncodedMemberInfo,
   minimallyEncodeRawThreadInfo,
diff --git a/lib/types/minimally-encoded-thread-permissions-types.test.js b/lib/types/minimally-encoded-thread-permissions-types.test.js
new file mode 100644
--- /dev/null
+++ b/lib/types/minimally-encoded-thread-permissions-types.test.js
@@ -0,0 +1,29 @@
+// @flow
+
+import type {
+  MemberInfoSansPermissions,
+  MemberInfoWithPermissions,
+} from './minimally-encoded-thread-permissions-types.js';
+import { stripPermissionsFromMemberInfo } from './minimally-encoded-thread-permissions-types.js';
+
+describe('stripPermissionsFromMemberInfo', () => {
+  test('should produce valid MemberInfoSansPermissions', () => {
+    const memberInfoWithPermissions: MemberInfoWithPermissions = {
+      id: '1',
+      role: '2',
+      isSender: true,
+      minimallyEncoded: true,
+      permissions: '3',
+    };
+
+    const memberInfoSansPermissions: MemberInfoSansPermissions =
+      stripPermissionsFromMemberInfo(memberInfoWithPermissions);
+
+    expect(memberInfoSansPermissions).toEqual({
+      id: '1',
+      role: '2',
+      isSender: true,
+      minimallyEncoded: true,
+    });
+  });
+});