diff --git a/src/client/src/chatGroups.ts b/src/client/src/chatGroups.ts
index f9dd4bf..3dd268a 100644
--- a/src/client/src/chatGroups.ts
+++ b/src/client/src/chatGroups.ts
@@ -35,6 +35,8 @@ export function groupChatMessages(messages: ChatLine[], indexOffset = 0): ChatGr
 }
 
 export function summarizeChatGroup(messages: ChatLine[]): string {
+  if (messages.every((message) => message.source === "compaction")) return `${String(messages.length)} history compaction ${messages.length === 1 ? "summary" : "summaries"}`;
+  if (messages.every((message) => message.source === "branch_summary")) return `${String(messages.length)} branch ${messages.length === 1 ? "summary" : "summaries"}`;
   const counts = messages.reduce<Record<string, number>>((acc, message) => {
     acc[message.role] = (acc[message.role] ?? 0) + 1;
     return acc;
@@ -44,5 +46,6 @@ export function summarizeChatGroup(messages: ChatLine[]): string {
 }
 
 function isReadablePart(message: ChatLine, part: ChatPart): boolean {
+  if (message.source === "compaction" || message.source === "branch_summary") return false;
   return part.type === "text" && (message.role === "user" || message.role === "assistant" || message.role === "system" || message.role === "bash");
 }
diff --git a/src/client/src/chatMessages.ts b/src/client/src/chatMessages.ts
index 06c0a0d..1158208 100644
--- a/src/client/src/chatMessages.ts
+++ b/src/client/src/chatMessages.ts
@@ -24,10 +24,17 @@ function normalizeMessage(message: unknown): ChatLine[] {
   if (getString(message, "role") === "bashExecution") return [normalizeBashExecution(message)];
   const role = normalizeRole(getString(message, "role"));
   const parts = normalizeContent(getProperty(message, "content"), message);
-  if (role === "tool") return [{ role, parts }];
+  const source = normalizeSource(message, parts);
+  if (role === "tool") return [{ role, parts, ...(source === undefined ? {} : { source }) }];
 
   const visible = parts.filter((part) => part.type !== "empty");
-  return visible.length > 0 ? [{ role, parts: visible }] : [];
+  return visible.length > 0 ? [{ role, parts: visible, ...(source === undefined ? {} : { source }) }] : [];
+}
+
+function normalizeSource(message: unknown, _parts: ChatPart[]): ChatLine["source"] | undefined {
+  const source = getString(message, "source");
+  if (source === "compaction" || source === "branch_summary") return source;
+  return undefined;
 }
 
 function normalizeBashExecution(message: unknown): ChatLine {
diff --git a/src/client/src/components/shared.ts b/src/client/src/components/shared.ts
index 37eb143..218324c 100644
--- a/src/client/src/components/shared.ts
+++ b/src/client/src/components/shared.ts
@@ -10,6 +10,7 @@ export type ChatPart =
 export interface ChatLine {
   role: "user" | "assistant" | "tool" | "system" | "bash";
   parts: ChatPart[];
+  source?: "compaction" | "branch_summary";
 }
 
 export interface CompletionItem {
diff --git a/src/server/sessions/piSessionService.ts b/src/server/sessions/piSessionService.ts
index 5d988a6..4968013 100644
--- a/src/server/sessions/piSessionService.ts
+++ b/src/server/sessions/piSessionService.ts
@@ -308,8 +308,8 @@ function historyMessages(session: AgentSession): unknown[] {
   for (const entry of session.sessionManager.getBranch()) {
     if (entry.type === "message") messages.push(entry.message);
     else if (entry.type === "custom_message" && entry.display) messages.push({ role: "custom", content: entry.content, customType: entry.customType, details: entry.details });
-    else if (entry.type === "compaction") messages.push({ role: "system", content: `Compacted history:\n\n${entry.summary}` });
-    else if (entry.type === "branch_summary") messages.push({ role: "system", content: `Branch summary:\n\n${entry.summary}` });
+    else if (entry.type === "compaction") messages.push({ role: "system", source: "compaction", content: `Compacted history:\n\n${entry.summary}` });
+    else if (entry.type === "branch_summary") messages.push({ role: "system", source: "branch_summary", content: `Branch summary:\n\n${entry.summary}` });
   }
   return messages;
 }