diff --git a/src/agents/embedded-agent-runner/compaction-successor-transcript.post-compaction-duplicate-prompt.test.ts b/src/agents/embedded-agent-runner/compaction-successor-transcript.post-compaction-duplicate-prompt.test.ts
new file mode 100644
index 000000000000..cd050db5dbde
--- /dev/null
+++ b/src/agents/embedded-agent-runner/compaction-successor-transcript.post-compaction-duplicate-prompt.test.ts
@@ -0,0 +1,82 @@
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+import { SessionManager } from "openclaw/plugin-sdk/agent-sessions";
+import { afterEach, describe, expect, it } from "vitest";
+import { makeAgentAssistantMessage } from "../test-helpers/agent-message-fixtures.js";
+import { rotateTranscriptAfterCompaction } from "./compaction-successor-transcript.js";
+import { readTranscriptFileState } from "./transcript-file-state.js";
+
+let tmpDir: string | undefined;
+afterEach(async () => {
+  if (tmpDir) {
+    await fs.rm(tmpDir, { recursive: true, force: true }).catch(() => undefined);
+    tmpDir = undefined;
+  }
+});
+
+function makeAssistant(text: string, timestamp: number) {
+  return makeAgentAssistantMessage({ content: [{ type: "text", text }], timestamp });
+}
+
+function readUserTexts(entries: { type: string; message?: unknown }[]): string[] {
+  return entries
+    .filter(
+      (entry) =>
+        entry.type === "message" &&
+        (entry.message as { role?: unknown } | undefined)?.role === "user",
+    )
+    .map((entry) => {
+      const content = (entry.message as { content?: unknown } | undefined)?.content;
+      if (typeof content === "string") {
+        return content;
+      }
+      if (Array.isArray(content)) {
+        return content.map((block) => (block as { text?: string })?.text ?? "").join("");
+      }
+      return "";
+    });
+}
+
+const PROMPT = "Run the deployment script for staging now";
+
+describe("rotateTranscriptAfterCompaction post-compaction duplicate", () => {
+  it("keeps a real post-compaction user turn that repeats a kept-tail prompt", async () => {
+    tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), "successor-dup-post-"));
+    const manager = SessionManager.create(tmpDir, tmpDir);
+
+    manager.appendMessage({ role: "user", content: "set up the project", timestamp: 1000 });
+    manager.appendMessage(makeAssistant("Project ready.", 1001));
+
+    const firstKeptId = manager.appendMessage({
+      role: "user",
+      content: PROMPT,
+      timestamp: 2000,
+    });
+    manager.appendMessage(makeAssistant("Deploying to staging.", 2001));
+    manager.appendCompaction("Summary of project setup.", firstKeptId, 2050);
+
+    manager.appendMessage({ role: "user", content: PROMPT, timestamp: 2080 });
+    manager.appendMessage(makeAssistant("Redeploying to staging (second run).", 2081));
+
+    const sessionFile = manager.getSessionFile();
+    if (!sessionFile) {
+      throw new Error("no session file");
+    }
+
+    const result = await rotateTranscriptAfterCompaction({ sessionManager: manager, sessionFile });
+    expect(result.rotated).toBe(true);
+    const successorFile = result.sessionFile;
+    if (!successorFile) {
+      throw new Error("no successor file");
+    }
+
+    const successor = await readTranscriptFileState(successorFile);
+    const userPromptTexts = readUserTexts(
+      successor.getEntries() as { type: string; message?: unknown }[],
+    );
+
+    const occurrences = userPromptTexts.filter((text) => text.includes(PROMPT)).length;
+    expect(occurrences).toBe(2);
+  });
+});
diff --git a/src/agents/embedded-agent-runner/compaction-successor-transcript.ts b/src/agents/embedded-agent-runner/compaction-successor-transcript.ts
index 19ccb91cdd00..c3a53cbea0f0 100644
--- a/src/agents/embedded-agent-runner/compaction-successor-transcript.ts
+++ b/src/agents/embedded-agent-runner/compaction-successor-transcript.ts
@@ -143,9 +143,14 @@ function buildSuccessorEntries(params: {
   }
 
   const removedIds = new Set<string>();
-  const keptBranchEntries = branch.filter((entry) => !summarizedBranchIds.has(entry.id));
-  const duplicateUserMessageIds =
-    collectDuplicateUserMessageEntryIdsForCompaction(keptBranchEntries);
+  const keptPreCompactionEntries = branch
+    .slice(0, latestCompactionIndex)
+    .filter((entry) => !summarizedBranchIds.has(entry.id));
+  const postCompactionEntries = branch.slice(latestCompactionIndex + 1);
+  const duplicateUserMessageIds = new Set<string>([
+    ...collectDuplicateUserMessageEntryIdsForCompaction(keptPreCompactionEntries),
+    ...collectDuplicateUserMessageEntryIdsForCompaction(postCompactionEntries),
+  ]);
   for (const entry of allEntries) {
     if (
       (summarizedBranchIds.has(entry.id) && entry.type === "message") ||