fix(sessions): history pagination skips projected messages or stops advancing (#129099)

* fix(sessions): preserve history pagination replay and progress

* fix(sessions): avoid shadowing history cursor sequence

src/agents/tools/sessions-history-tool.test.ts

@@ -481,6 +481,55 @@ describe("sessions_history redaction", () => {
     });
   });
 
+  it("preserves the Gateway replay cursor for projected siblings from the same row", async () => {
+    const tool = createSessionsHistoryTool({
+      config: {},
+      callGateway: async <T = Record<string, unknown>>(): Promise<T> =>
+        ({
+          messages: [
+            { role: "assistant", content: "projected sibling", __openclaw: { seq: 8 } },
+            { role: "assistant", content: "latest", __openclaw: { seq: 9 } },
+          ],
+          offset: 0,
+          nextOffset: 2,
+          hasMore: true,
+          totalMessages: 10,
+        }) as T,
+    });
+
+    const result = await tool.execute("projected-replay", { sessionKey: "main", offset: 0 });
+
+    expect(result.details).toMatchObject({
+      offset: 0,
+      nextOffset: 2,
+      hasMore: true,
+      totalMessages: 10,
+    });
+  });
+
+  it("keeps history pagination advancing past an already-returned row", async () => {
+    const tool = createSessionsHistoryTool({
+      config: {},
+      callGateway: async <T = Record<string, unknown>>(): Promise<T> =>
+        ({
+          messages: [{ role: "assistant", content: "visible", __openclaw: { seq: 7 } }],
+          offset: 4,
+          nextOffset: 5,
+          hasMore: true,
+          totalMessages: 10,
+        }) as T,
+    });
+
+    const result = await tool.execute("cursor-progress", { sessionKey: "main", offset: 4 });
+
+    expect(result.details).toMatchObject({
+      offset: 4,
+      nextOffset: 5,
+      hasMore: true,
+      totalMessages: 10,
+    });
+  });
+
   it("honors a scoped incarnation grant through the sandbox visibility clamp", async () => {
     const requesterSessionKey = "agent:main:clickclack:discussion-proof";
     const targetSessionKey = "agent:main:main";

src/agents/tools/sessions-history-tool.ts

@@ -338,17 +338,15 @@ function resolveSessionsHistoryPaginationMetadata(params: {
     };
   }
 
-  // Gateway offsets count newest transcript rows already returned. Recompute
-  // from the oldest surviving seq after this tool's own filter/cap passes.
-  const oldestSeq = params.messages
+  // Respect Gateway replay cursors and this tool's own byte cap while always advancing.
+  const seq = params.messages
     .map((message) => readHistoryMessageSeq(message))
-    .find((seq): seq is number => typeof seq === "number");
+    .find((value): value is number => typeof value === "number");
+  const gatewayOffset = result?.nextOffset;
   const nextOffset =
-    oldestSeq !== undefined
-      ? Math.max(offset, totalMessages - oldestSeq + 1)
-      : typeof result?.nextOffset === "number"
-        ? result.nextOffset
-        : undefined;
+    seq === undefined
+      ? gatewayOffset
+      : Math.max(offset + 1, Math.min(gatewayOffset ?? totalMessages, totalMessages - seq + 1));
   const hasMore =
     nextOffset !== undefined
       ? nextOffset < totalMessages