fix: preserve inherited fork context and live history attachments

packages/server/src/server/agent/activity-curator.test.ts

@@ -572,3 +572,57 @@ it("preserves every message in fork history below the character budget", () => {
     `<chat-history-summary>\nChat history from a previous Paseo agent.\n\n[User] ${text}\n</chat-history-summary>`,
   );
 });
+
+it.each(["", "Continue in B"])("carries inherited history through repeated forks (%s)", (text) => {
+  const original = buildAgentForkContextAttachment({
+    rows: [
+      row(1, { type: "user_message", text: "Question in A" }),
+      row(2, { type: "assistant_message", text: "Answer in A" }),
+    ],
+  });
+  const child = buildAgentForkContextAttachment({
+    rows: [
+      row(1, {
+        type: "user_message",
+        text,
+        chatHistory: { ...original.attachment, contextKind: "chat_history" },
+      }),
+      row(2, { type: "assistant_message", text: "Answer in B" }),
+    ],
+  });
+  const grandchild = buildAgentForkContextAttachment({
+    rows: [
+      row(1, {
+        type: "user_message",
+        text: "Continue in C",
+        chatHistory: { ...child.attachment, contextKind: "chat_history" },
+      }),
+      row(2, { type: "assistant_message", text: "Answer in C" }),
+    ],
+  });
+  expect(grandchild.attachment.text).toContain("[User] Question in A\n[Assistant] Answer in A");
+  expect(grandchild.attachment.text).toContain("[Assistant] Answer in B");
+  expect(grandchild.attachment.text).toContain("[User] Continue in C\n[Assistant] Answer in C");
+  expect(grandchild.attachment.text.match(/<chat-history-summary>/g)).toHaveLength(1);
+});
+
+it("keeps the fork budget when inherited history exceeds the remaining space", () => {
+  const result = buildAgentForkContextAttachment({
+    rows: [
+      row(1, {
+        type: "user_message",
+        text: "Current question",
+        chatHistory: {
+          type: "text",
+          mimeType: "text/plain",
+          contextKind: "chat_history",
+          text: "Old ".repeat(30_000),
+        },
+      }),
+      row(2, { type: "assistant_message", text: "Latest answer" }),
+    ],
+  });
+  expect(result.attachment.text.length).toBeLessThanOrEqual(100_000);
+  expect(result.attachment.text).toContain("[Earlier chat history omitted]");
+  expect(result.attachment.text).toContain("[User] Current question\n[Assistant] Latest answer");
+});

packages/server/src/server/agent/activity-curator.ts

@@ -1,3 +1,4 @@
+import { extractChatHistoryBody } from "@getpaseo/protocol/chat-history";
 import type { AgentTimelineItem } from "./agent-sdk-types.js";
 import type { AgentMessage } from "@getpaseo/protocol/agent-message";
 import type { AgentAttachment } from "@getpaseo/protocol/messages";
@@ -21,6 +22,7 @@ const FORK_CONTEXT_KINDS: readonly AgentTimelineItem["type"][] = [
 ];
 
 interface ActivityCuratorOptions {
+  includeChatHistory?: boolean;
   maxItems?: number;
   labelAssistantMessages?: boolean;
   includeKinds?: readonly AgentTimelineItem["type"][];
@@ -37,6 +39,17 @@ function activityEntry(text: string): ActivityEntry {
   return { text };
 }
 
+function appendUserEntry(
+  entries: ActivityEntry[],
+  item: Extract<AgentTimelineItem, { type: "user_message" }>,
+  options?: ActivityCuratorOptions,
+) {
+  if (options?.includeChatHistory && item.chatHistory) {
+    entries.push(activityEntry(extractChatHistoryBody(item.chatHistory.text)));
+  }
+  entries.push(activityEntry(`[User] ${item.text.trim()}`));
+}
+
 function appendTextEntry(
   entries: ActivityEntry[],
   item: Extract<AgentTimelineItem, { type: "assistant_message" | "reasoning" }>,
@@ -158,7 +171,7 @@ function curateProjectedActivityEntries(
 
     switch (item.type) {
       case "user_message":
-        entries.push(activityEntry(`[User] ${item.text.trim()}`));
+        appendUserEntry(entries, item, options);
         break;
       case "assistant_message":
       case "reasoning":
@@ -361,6 +374,7 @@ export function buildAgentForkContextAttachment(input: {
   });
   const entries = curateProjectedActivityEntries(selected.items, {
     maxItems: 0,
+    includeChatHistory: true,
     labelAssistantMessages: true,
     includeKinds: FORK_CONTEXT_KINDS,
     includeExternalToolInput: false,