diff --git a/lib/shared/dm-ops/dm-op-utils.js b/lib/shared/dm-ops/dm-op-utils.js
--- a/lib/shared/dm-ops/dm-op-utils.js
+++ b/lib/shared/dm-ops/dm-op-utils.js
@@ -2,6 +2,7 @@
 
 import uuid from 'uuid';
 
+import type { MessageSourceMetadata } from '../../types/db-ops-types.js';
 import type { DMOperation } from '../../types/dm-ops.js';
 import {
   outboundP2PMessageStatuses,
@@ -44,7 +45,15 @@
   return outboundP2PMessages;
 }
 
-export type DMOperationSpecification = {
+export const dmOperationSpecificationTypes = Object.freeze({
+  OUTBOUND: 'OutboundDMOperationSpecification',
+  INBOUND: 'InboundDMOperationSpecification',
+});
+
+// The operation generated on the sending client, causes changes to
+// the state and broadcasting information to peers.
+export type OutboundDMOperationSpecification = {
+  +type: 'OutboundDMOperationSpecification',
   +op: DMOperation,
   +supportsAutoRetry: boolean,
   +recipients:
@@ -52,8 +61,20 @@
     | { +type: 'some_users', +userIDs: $ReadOnlyArray<string> },
 };
 
+// The operation received from other peers, causes changes to
+// the state and after processing, sends confirmation to the sender.
+export type InboundDMOperationSpecification = {
+  +type: 'InboundDMOperationSpecification',
+  +op: DMOperation,
+  +metadata: ?MessageSourceMetadata,
+};
+
+export type DMOperationSpecification =
+  | OutboundDMOperationSpecification
+  | InboundDMOperationSpecification;
+
 async function createMessagesToPeersFromDMOp(
-  operation: DMOperationSpecification,
+  operation: OutboundDMOperationSpecification,
   allPeerUserIDAndDeviceIDs: $ReadOnlyArray<{
     +userID: string,
     +deviceID: string,
diff --git a/lib/shared/dm-ops/process-dm-ops.js b/lib/shared/dm-ops/process-dm-ops.js
--- a/lib/shared/dm-ops/process-dm-ops.js
+++ b/lib/shared/dm-ops/process-dm-ops.js
@@ -5,7 +5,7 @@
 import uuid from 'uuid';
 
 import { dmOpSpecs } from './dm-op-specs.js';
-import type { DMOperationSpecification } from './dm-op-utils.js';
+import type { OutboundDMOperationSpecification } from './dm-op-utils.js';
 import { useLoggedInUserInfo } from '../../hooks/account-hooks.js';
 import { useGetLatestMessageEdit } from '../../hooks/latest-message-edit.js';
 import { useDispatchWithMessageSource } from '../../hooks/ops-hooks.js';
@@ -156,13 +156,13 @@
 }
 
 function useProcessAndSendDMOperation(): (
-  dmOperationSpecification: DMOperationSpecification,
+  dmOperationSpecification: OutboundDMOperationSpecification,
 ) => Promise<void> {
   const processDMOps = useProcessDMOperation();
   const { sendDMOperation } = usePeerToPeerCommunication();
 
   return React.useCallback(
-    async (dmOperationSpecification: DMOperationSpecification) => {
+    async (dmOperationSpecification: OutboundDMOperationSpecification) => {
       await processDMOps(dmOperationSpecification.op);
       await sendDMOperation(dmOperationSpecification);
     },
diff --git a/lib/tunnelbroker/peer-to-peer-context.js b/lib/tunnelbroker/peer-to-peer-context.js
--- a/lib/tunnelbroker/peer-to-peer-context.js
+++ b/lib/tunnelbroker/peer-to-peer-context.js
@@ -12,7 +12,7 @@
 import { getAllPeerUserIDAndDeviceIDs } from '../selectors/user-selectors.js';
 import {
   createMessagesToPeersFromDMOp,
-  type DMOperationSpecification,
+  type OutboundDMOperationSpecification,
 } from '../shared/dm-ops/dm-op-utils.js';
 import {
   type AuthMetadata,
@@ -38,7 +38,7 @@
     outboundMessageIDs: ?$ReadOnlyArray<string>,
     dmOpID: ?string,
   ) => void,
-  +sendDMOperation: (op: DMOperationSpecification) => Promise<void>,
+  +sendDMOperation: (op: OutboundDMOperationSpecification) => Promise<void>,
   +broadcastEphemeralMessage: (
     contentPayload: string,
     recipients: $ReadOnlyArray<{ +userID: string, +deviceID: string }>,
@@ -179,7 +179,7 @@
   const currentUserInfo = useSelector(state => state.currentUserInfo);
 
   const sendDMOperation = React.useCallback(
-    async (op: DMOperationSpecification) => {
+    async (op: OutboundDMOperationSpecification) => {
       const dmOpID = uuid.v4();
       const promise = new Promise<void>((resolve, reject) => {
         dmOpsSendingPromiseResolvers.current.set(dmOpID, { resolve, reject });