diff --git a/tools/ui/src/lib/components/app/chat/ChatMessages/ChatMessages.svelte b/tools/ui/src/lib/components/app/chat/ChatMessages/ChatMessages.svelte
index 4750a9f7c1..0a90097318 100644
--- a/tools/ui/src/lib/components/app/chat/ChatMessages/ChatMessages.svelte
+++ b/tools/ui/src/lib/components/app/chat/ChatMessages/ChatMessages.svelte
@@ -97,9 +97,17 @@
 		const conversation = conversationsStore.activeConversation;
 
 		if (conversation) {
-			conversationsStore.getConversationMessages(conversation.id).then((messages) => {
-				allConversationMessages = messages;
-			});
+			// reuse the array loadConversation just read, when present; branch
+			// actions fall through to a fresh fetch
+			const preloaded = conversationsStore.consumeLastLoadedMessages(conversation.id);
+
+			if (preloaded) {
+				allConversationMessages = preloaded;
+			} else {
+				conversationsStore.getConversationMessages(conversation.id).then((messages) => {
+					allConversationMessages = messages;
+				});
+			}
 		} else {
 			allConversationMessages = [];
 		}
diff --git a/tools/ui/src/lib/stores/conversations/index.svelte.ts b/tools/ui/src/lib/stores/conversations/index.svelte.ts
index caefe67901..c4fea2e4ee 100644
--- a/tools/ui/src/lib/stores/conversations/index.svelte.ts
+++ b/tools/ui/src/lib/stores/conversations/index.svelte.ts
@@ -52,6 +52,13 @@ class ConversationsStore implements ConversationsPreferencesHost {
 	/** In-flight init run; shared by concurrent callers, reset on failure to allow retry */
 	private initPromise: Promise<void> | null = null;
 
+	/**
+	 * Messages loadConversation just read, handed off once so the chat
+	 * screen can reuse them for sibling info instead of re-fetching the
+	 * whole conversation a second time.
+	 */
+	private lastLoadedMessages: { convId: string; messages: DatabaseMessage[] } | null = null;
+
 	/**
 	 * Memo of the last findMessageIndex() lookup. Streaming calls it once per
 	 * chunk for the same message, so a validated cache hit keeps that O(1)
@@ -239,6 +246,17 @@ class ConversationsStore implements ConversationsPreferencesHost {
 		this.preferences.resetPending();
 	}
 
+	/** One-shot handoff of the messages the last loadConversation read. */
+	consumeLastLoadedMessages(convId: string): DatabaseMessage[] | null {
+		if (this.lastLoadedMessages?.convId !== convId) return null;
+
+		const messages = this.lastLoadedMessages.messages;
+
+		this.lastLoadedMessages = null;
+
+		return messages;
+	}
+
 	/**
 	 * Creates a new conversation and navigates to it
 	 * @param name - Optional name for the conversation
@@ -512,22 +530,15 @@ class ConversationsStore implements ConversationsPreferencesHost {
 			// it doesn't belong to this conversation.
 			this.preferences.pendingCwd = null;
 
+			const allMessages = await DatabaseService.getConversationMessages(convId);
+
+			// set conversation and messages in one sync block so effects never see
+			// the new conversation with the previous conversation's messages
+			this.lastLoadedMessages = { convId, messages: allMessages };
 			this.activeConversation = conversation;
-
-			if (conversation.currNode) {
-				const allMessages = await DatabaseService.getConversationMessages(convId);
-				const filteredMessages = filterByLeafNodeId(
-					allMessages,
-					conversation.currNode,
-					false
-				) as DatabaseMessage[];
-
-				this.activeMessages = filteredMessages;
-			} else {
-				const messages = await DatabaseService.getConversationMessages(convId);
-
-				this.activeMessages = messages;
-			}
+			this.activeMessages = conversation.currNode
+				? (filterByLeafNodeId(allMessages, conversation.currNode, false) as DatabaseMessage[])
+				: allMessages;
 
 			return true;
 		} catch (error) {