diff --git a/src/payload/InteractionWriter.ts b/src/payload/InteractionWriter.ts
index fcf59b5..448247a 100644
--- a/src/payload/InteractionWriter.ts
+++ b/src/payload/InteractionWriter.ts
@@ -5,11 +5,10 @@ import type { PayloadClient } from './PayloadClient.js'
 
 const log = getLogger('interaction-writer')
 
-/**
- * Writes messages to community_interactions via Payload REST API.
- * When direct DB access becomes available, this can be swapped to a
- * pg Pool-based implementation for higher throughput.
- */
+// WhatsApp platform + account IDs in CMS
+const WHATSAPP_PLATFORM_ID = 4
+const WHATSAPP_ACCOUNT_ID = 1
+
 export class InteractionWriter {
   constructor(private payloadClient: PayloadClient) {}
 
@@ -22,22 +21,28 @@ export class InteractionWriter {
     analysis: LLMResponse | null,
   ): Promise<number> {
     try {
+      const data: Record<string, unknown> = {
+        platform: WHATSAPP_PLATFORM_ID,
+        socialAccount: WHATSAPP_ACCOUNT_ID,
+        type: 'dm',
+        externalId: message.messageId,
+        author: {
+          name: message.senderName || message.from,
+          handle: message.from,
+        },
+        message: message.text ?? `[${message.type}]`,
+        publishedAt: new Date().toISOString(),
+        status: 'new',
+      }
+
+      if (analysis?.isMedicalQuestion) {
+        data.flags = { isMedicalQuestion: true }
+        data.analysis = { sentiment: 'question' }
+      }
+
       const doc = await this.payloadClient.create<{ id: number }>(
         'community-interactions',
-        {
-          type: 'dm',
-          externalId: message.messageId,
-          authorName: message.senderName,
-          authorHandle: message.from,
-          message: message.text ?? `[${message.type}]`,
-          messageType: message.type,
-          ...(analysis && {
-            analysisSentiment: 'neutral',
-            analysisIsMedicalQuestion: analysis.isMedicalQuestion,
-          }),
-          status: 'new',
-          tenant: 10,
-        },
+        data,
       )
 
       log.debug({ id: doc.id, messageId: message.messageId }, 'Incoming message stored')
@@ -51,25 +56,31 @@ export class InteractionWriter {
   async writeOutgoing(
     to: string,
     text: string,
-    replyToMessageId: string,
+    _replyToMessageId: string,
   ): Promise<number> {
     try {
       const doc = await this.payloadClient.create<{ id: number }>(
         'community-interactions',
         {
+          platform: WHATSAPP_PLATFORM_ID,
+          socialAccount: WHATSAPP_ACCOUNT_ID,
           type: 'dm',
-          authorName: 'CCS Bot',
-          authorHandle: 'bot',
+          externalId: `bot-reply-${Date.now()}`,
+          author: {
+            name: 'CCS Bot',
+            handle: 'bot',
+          },
           message: text,
-          messageType: 'text',
-          status: 'responded',
-          responseText: text,
-          responseType: 'bot',
-          tenant: 10,
+          publishedAt: new Date().toISOString(),
+          status: 'replied',
+          response: {
+            text,
+            sentAt: new Date().toISOString(),
+          },
         },
       )
 
-      log.debug({ id: doc.id, to, replyTo: replyToMessageId }, 'Outgoing message stored')
+      log.debug({ id: doc.id, to }, 'Outgoing message stored')
       return doc.id
     } catch (err) {
       log.error({ error: (err as Error).message }, 'Failed to store outgoing message')