diff --git a/lib/permissions/thread-permissions.js b/lib/permissions/thread-permissions.js
--- a/lib/permissions/thread-permissions.js
+++ b/lib/permissions/thread-permissions.js
@@ -2,17 +2,16 @@
 
 import invariant from 'invariant';
 
-import { getThickThreadRolePermissionsBlob } from './dm-permissions.js';
-import {
-  type RolePermissionBlobs,
-  getThinThreadPermissionsBlobs,
-} from './keyserver-permissions.js';
+import { type RolePermissionBlobs } from './keyserver-permissions.js';
 import {
   parseThreadPermissionString,
   constructThreadPermissionString,
   includeThreadPermissionForThreadType,
 } from './prefixes.js';
-import { threadTypeIsAnnouncementThread } from '../shared/threads/thread-specs.js';
+import {
+  threadSpecs,
+  threadTypeIsAnnouncementThread,
+} from '../shared/threads/thread-specs.js';
 import {
   threadPermissionPropagationPrefixes,
   threadPermissions,
@@ -26,13 +25,7 @@
   ThreadPermissionsInfo,
   ThreadRolePermissionsBlob,
 } from '../types/thread-permission-types.js';
-import {
-  type ThreadType,
-  threadTypes,
-  threadTypeIsThick,
-  assertThickThreadType,
-  assertThinThreadType,
-} from '../types/thread-types-enum.js';
+import { type ThreadType, threadTypes } from '../types/thread-types-enum.js';
 
 function permissionLookup(
   permissions: ?ThreadPermissionsBlob | ?ThreadPermissionsInfo,
@@ -201,17 +194,7 @@
 }
 
 function getRolePermissionBlobs(threadType: ThreadType): RolePermissionBlobs {
-  if (threadTypeIsThick(threadType)) {
-    const thickThreadType = assertThickThreadType(threadType);
-    const memberPermissions =
-      getThickThreadRolePermissionsBlob(thickThreadType);
-    return {
-      Members: memberPermissions,
-    };
-  }
-
-  const thinThreadType = assertThinThreadType(threadType);
-  return getThinThreadPermissionsBlobs(thinThreadType);
+  return threadSpecs[threadType].protocol.getRolePermissionBlobs(threadType);
 }
 
 export {
diff --git a/lib/shared/threads/protocols/dm-thread-protocol.js b/lib/shared/threads/protocols/dm-thread-protocol.js
--- a/lib/shared/threads/protocols/dm-thread-protocol.js
+++ b/lib/shared/threads/protocols/dm-thread-protocol.js
@@ -4,6 +4,7 @@
 import uuid from 'uuid';
 
 import { fetchMessagesBeforeCursorActionTypes } from '../../../actions/message-actions.js';
+import { getThickThreadRolePermissionsBlob } from '../../../permissions/dm-permissions.js';
 import type { TunnelbrokerSocketState } from '../../../tunnelbroker/tunnelbroker-context.js';
 import type {
   DMChangeThreadReadStatusOperation,
@@ -33,6 +34,7 @@
   assertThickThreadType,
   thickThreadTypes,
   threadTypes,
+  type ThreadType,
 } from '../../../types/thread-types-enum.js';
 import type {
   ChangeThreadSettingsPayload,
@@ -791,6 +793,15 @@
       };
     },
 
+    getRolePermissionBlobs: (threadType: ThreadType) => {
+      const thickThreadType = assertThickThreadType(threadType);
+      const memberPermissions =
+        getThickThreadRolePermissionsBlob(thickThreadType);
+      return {
+        Members: memberPermissions,
+      };
+    },
+
     allowsDeletingSidebarSource: false,
 
     presentationDetails: {
diff --git a/lib/shared/threads/protocols/keyserver-thread-protocol.js b/lib/shared/threads/protocols/keyserver-thread-protocol.js
--- a/lib/shared/threads/protocols/keyserver-thread-protocol.js
+++ b/lib/shared/threads/protocols/keyserver-thread-protocol.js
@@ -24,6 +24,7 @@
   encryptedMediaBlobURI,
   encryptedVideoThumbnailBlobURI,
 } from '../../../media/media-utils.js';
+import { getThinThreadPermissionsBlobs } from '../../../permissions/keyserver-permissions.js';
 import type { TunnelbrokerSocketState } from '../../../tunnelbroker/tunnelbroker-context.js';
 import type { BlobOperation } from '../../../types/holder-types.js';
 import {
@@ -55,6 +56,7 @@
   assertThinThreadType,
   thinThreadTypes,
   threadTypes,
+  type ThreadType,
 } from '../../../types/thread-types-enum.js';
 import type { ClientDBThreadInfo } from '../../../types/thread-types.js';
 import {
@@ -590,6 +592,11 @@
       };
     },
 
+    getRolePermissionBlobs: (threadType: ThreadType) => {
+      const thinThreadType = assertThinThreadType(threadType);
+      return getThinThreadPermissionsBlobs(thinThreadType);
+    },
+
     allowsDeletingSidebarSource: true,
 
     presentationDetails: {
diff --git a/lib/shared/threads/thread-spec.js b/lib/shared/threads/thread-spec.js
--- a/lib/shared/threads/thread-spec.js
+++ b/lib/shared/threads/thread-spec.js
@@ -23,6 +23,7 @@
   LeaveThreadInput,
   LeaveThreadResult,
 } from '../../hooks/thread-hooks.js';
+import type { RolePermissionBlobs } from '../../permissions/keyserver-permissions.js';
 import type { ProcessOutboundP2PMessagesResult } from '../../tunnelbroker/peer-to-peer-context.js';
 import type { TunnelbrokerSocketState } from '../../tunnelbroker/tunnelbroker-context.js';
 import type {
@@ -336,6 +337,7 @@
     +threadID: string,
     +threadType: ThreadType,
   }>,
+  +getRolePermissionBlobs: (threadType: ThreadType) => RolePermissionBlobs,
   +allowsDeletingSidebarSource: boolean,
   +presentationDetails: {
     +membershipChangesShownInThreadPreview: boolean,