diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7de75be6b10..b4486f2e833 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -33,6 +33,7 @@ Docs: https://docs.openclaw.ai
 - Reply/secrets: resolve active reply channel/account SecretRefs before reply-run message-action discovery so channel token SecretRefs (for example Discord) do not degrade into discovery-time unresolved-secret failures. (#66796) Thanks @joshavant.
 - Agents/Anthropic: ignore non-positive Anthropic Messages token overrides and fail locally when no positive token budget remains, so invalid `max_tokens` values no longer reach the provider API. (#66664) thanks @jalehman
 - Agents/context engines: preserve prompt-only token counts, not full request totals, when deferred maintenance reuses after-turn runtime context so background compaction bookkeeping matches the active prompt window. (#66820) thanks @jalehman.
+- BlueBubbles/inbound: add a persistent file-backed GUID dedupe so MessagePoller webhook replays after BB Server restart or reconnect no longer cause the agent to re-reply to already-handled messages. (#19176, #12053, #66816) Thanks @omarshahine.
 
 ## 2026.4.14
 
diff --git a/extensions/bluebubbles/src/inbound-dedupe.test.ts b/extensions/bluebubbles/src/inbound-dedupe.test.ts
new file mode 100644
index 00000000000..cd78be834bc
--- /dev/null
+++ b/extensions/bluebubbles/src/inbound-dedupe.test.ts
@@ -0,0 +1,58 @@
+import { beforeEach, describe, expect, it } from "vitest";
+import {
+  _resetBlueBubblesInboundDedupForTest,
+  claimBlueBubblesInboundMessage,
+} from "./inbound-dedupe.js";
+
+async function claimAndFinalize(guid: string | undefined, accountId: string): Promise<string> {
+  const claim = await claimBlueBubblesInboundMessage({ guid, accountId });
+  if (claim.kind === "claimed") {
+    await claim.finalize();
+  }
+  return claim.kind;
+}
+
+describe("claimBlueBubblesInboundMessage", () => {
+  beforeEach(() => {
+    _resetBlueBubblesInboundDedupForTest();
+  });
+
+  it("claims a new guid and rejects committed duplicates", async () => {
+    expect(await claimAndFinalize("g1", "acc")).toBe("claimed");
+    expect(await claimAndFinalize("g1", "acc")).toBe("duplicate");
+  });
+
+  it("scopes dedupe per account", async () => {
+    expect(await claimAndFinalize("g1", "a")).toBe("claimed");
+    expect(await claimAndFinalize("g1", "b")).toBe("claimed");
+  });
+
+  it("reports skip when guid is missing or blank", async () => {
+    expect((await claimBlueBubblesInboundMessage({ guid: undefined, accountId: "acc" })).kind).toBe(
+      "skip",
+    );
+    expect((await claimBlueBubblesInboundMessage({ guid: "", accountId: "acc" })).kind).toBe(
+      "skip",
+    );
+    expect((await claimBlueBubblesInboundMessage({ guid: "   ", accountId: "acc" })).kind).toBe(
+      "skip",
+    );
+  });
+
+  it("rejects overlong guids to cap on-disk size", async () => {
+    const huge = "x".repeat(10_000);
+    expect((await claimBlueBubblesInboundMessage({ guid: huge, accountId: "acc" })).kind).toBe(
+      "skip",
+    );
+  });
+
+  it("releases the claim so a later replay can retry after a transient failure", async () => {
+    const first = await claimBlueBubblesInboundMessage({ guid: "g1", accountId: "acc" });
+    expect(first.kind).toBe("claimed");
+    if (first.kind === "claimed") {
+      first.release();
+    }
+    // Released claims should be re-claimable on the next delivery.
+    expect(await claimAndFinalize("g1", "acc")).toBe("claimed");
+  });
+});
diff --git a/extensions/bluebubbles/src/inbound-dedupe.ts b/extensions/bluebubbles/src/inbound-dedupe.ts
new file mode 100644
index 00000000000..8327b899710
--- /dev/null
+++ b/extensions/bluebubbles/src/inbound-dedupe.ts
@@ -0,0 +1,172 @@
+import { createHash } from "node:crypto";
+import path from "node:path";
+import { type ClaimableDedupe, createClaimableDedupe } from "openclaw/plugin-sdk/persistent-dedupe";
+import { resolveStateDir } from "openclaw/plugin-sdk/state-paths";
+import { resolvePreferredOpenClawTmpDir } from "openclaw/plugin-sdk/temp-path";
+import type { NormalizedWebhookMessage } from "./monitor-normalize.js";
+
+// BlueBubbles has no sequence/ack in its webhook protocol, and its
+// MessagePoller replays its ~1-week lookback window as `new-message` events
+// after BB Server restarts or reconnects. Without persistent dedup, the
+// gateway can reply to messages that were already handled before a restart
+// (see issues #19176, #12053).
+//
+// TTL matches BB's lookback window so any replay is guaranteed to land on
+// a remembered GUID, and the file-backed store survives gateway restarts.
+const DEDUP_TTL_MS = 7 * 24 * 60 * 60 * 1_000;
+const MEMORY_MAX_SIZE = 5_000;
+const FILE_MAX_ENTRIES = 50_000;
+// Cap GUID length so a malformed or hostile payload can't bloat the on-disk
+// dedupe file. Real BB GUIDs are short (<64 chars); 512 is generous.
+const MAX_GUID_CHARS = 512;
+
+function resolveStateDirFromEnv(env: NodeJS.ProcessEnv = process.env): string {
+  if (env.VITEST || env.NODE_ENV === "test") {
+    // Isolate tests from real ~/.openclaw state without sharing across tests.
+    // Stable-per-pid so the scoped dedupe test can observe persistence.
+    const name = "openclaw-vitest-" + process.pid;
+    return path.join(resolvePreferredOpenClawTmpDir(), name);
+  }
+  // Canonical OpenClaw state dir: honors OPENCLAW_STATE_DIR (with `~` expansion
+  // via resolveUserPath), plus legacy/new fallback. Using the shared helper
+  // keeps this plugin's persistence aligned with the rest of OpenClaw state.
+  return resolveStateDir(env);
+}
+
+function resolveNamespaceFilePath(namespace: string): string {
+  // Keep a readable prefix for operator debugging, but suffix with a short
+  // hash of the raw namespace so account IDs that only differ by
+  // filesystem-unsafe characters (e.g. "acct/a" vs "acct:a") don't collapse
+  // onto the same file.
+  const safePrefix = namespace.replace(/[^a-zA-Z0-9_-]/g, "_") || "ns";
+  const hash = createHash("sha256").update(namespace, "utf8").digest("hex").slice(0, 12);
+  return path.join(
+    resolveStateDirFromEnv(),
+    "bluebubbles",
+    "inbound-dedupe",
+    `${safePrefix}__${hash}.json`,
+  );
+}
+
+function buildPersistentImpl(): ClaimableDedupe {
+  return createClaimableDedupe({
+    ttlMs: DEDUP_TTL_MS,
+    memoryMaxSize: MEMORY_MAX_SIZE,
+    fileMaxEntries: FILE_MAX_ENTRIES,
+    resolveFilePath: resolveNamespaceFilePath,
+  });
+}
+
+function buildMemoryOnlyImpl(): ClaimableDedupe {
+  return createClaimableDedupe({
+    ttlMs: DEDUP_TTL_MS,
+    memoryMaxSize: MEMORY_MAX_SIZE,
+  });
+}
+
+let impl: ClaimableDedupe = buildPersistentImpl();
+
+function sanitizeGuid(guid: string | undefined | null): string | null {
+  const trimmed = guid?.trim();
+  if (!trimmed) {
+    return null;
+  }
+  if (trimmed.length > MAX_GUID_CHARS) {
+    return null;
+  }
+  return trimmed;
+}
+
+/**
+ * Resolve the canonical dedupe key for a BlueBubbles inbound message.
+ *
+ * Mirrors `monitor-debounce.ts`'s `buildKey`: BlueBubbles sends URL-preview
+ * / sticker "balloon" events with a different `messageId` than the text
+ * message they belong to, and the debouncer coalesces the two only when
+ * both `balloonBundleId` AND `associatedMessageGuid` are present. We gate
+ * on the same pair so that regular replies — which also set
+ * `associatedMessageGuid` (pointing at the parent message) but have no
+ * `balloonBundleId` — are NOT collapsed onto their parent's dedupe key.
+ *
+ * Known tradeoff: `combineDebounceEntries` clears `balloonBundleId` on
+ * merged entries while keeping `associatedMessageGuid`, so a post-merge
+ * balloon+text message here will fall back to its `messageId`. A later
+ * MessagePoller replay that arrives in a different text-first/balloon-first
+ * order could therefore produce a different `messageId` at merge time and
+ * bypass this dedupe for that one message. That edge case is strictly
+ * narrower than the alternative — which would dedupe every distinct user
+ * reply against the same parent GUID and silently drop real messages.
+ */
+export function resolveBlueBubblesInboundDedupeKey(
+  message: Pick<
+    NormalizedWebhookMessage,
+    "messageId" | "balloonBundleId" | "associatedMessageGuid"
+  >,
+): string | undefined {
+  const balloonBundleId = message.balloonBundleId?.trim();
+  const associatedMessageGuid = message.associatedMessageGuid?.trim();
+  if (balloonBundleId && associatedMessageGuid) {
+    return associatedMessageGuid;
+  }
+  return message.messageId?.trim() || undefined;
+}
+
+export type InboundDedupeClaim =
+  | { kind: "claimed"; finalize: () => Promise<void>; release: () => void }
+  | { kind: "duplicate" }
+  | { kind: "inflight" }
+  | { kind: "skip" };
+
+/**
+ * Attempt to claim an inbound BlueBubbles message GUID.
+ *
+ * - `claimed`: caller should process the message, then call `finalize()` on
+ *   success (persists the GUID) or `release()` on failure (lets a later
+ *   replay try again).
+ * - `duplicate`: we've already committed this GUID; caller should drop.
+ * - `inflight`: another claim is currently in progress; caller should drop
+ *   rather than race.
+ * - `skip`: GUID was missing or invalid — caller should continue processing
+ *   without dedup (no finalize/release needed).
+ */
+export async function claimBlueBubblesInboundMessage(params: {
+  guid: string | undefined | null;
+  accountId: string;
+  onDiskError?: (error: unknown) => void;
+}): Promise<InboundDedupeClaim> {
+  const normalized = sanitizeGuid(params.guid);
+  if (!normalized) {
+    return { kind: "skip" };
+  }
+  const claim = await impl.claim(normalized, {
+    namespace: params.accountId,
+    onDiskError: params.onDiskError,
+  });
+  if (claim.kind === "duplicate") {
+    return { kind: "duplicate" };
+  }
+  if (claim.kind === "inflight") {
+    return { kind: "inflight" };
+  }
+  return {
+    kind: "claimed",
+    finalize: async () => {
+      await impl.commit(normalized, {
+        namespace: params.accountId,
+        onDiskError: params.onDiskError,
+      });
+    },
+    release: () => {
+      impl.release(normalized, { namespace: params.accountId });
+    },
+  };
+}
+
+/**
+ * Reset inbound dedupe state between tests. Installs an in-memory-only
+ * implementation so tests do not hit disk, avoiding file-lock timing issues
+ * in the webhook flush path.
+ */
+export function _resetBlueBubblesInboundDedupForTest(): void {
+  impl = buildMemoryOnlyImpl();
+}
diff --git a/extensions/bluebubbles/src/monitor-processing.ts b/extensions/bluebubbles/src/monitor-processing.ts
index 93f083feb83..e2ef93c070f 100644
--- a/extensions/bluebubbles/src/monitor-processing.ts
+++ b/extensions/bluebubbles/src/monitor-processing.ts
@@ -13,6 +13,10 @@ import { downloadBlueBubblesAttachment } from "./attachments.js";
 import { markBlueBubblesChatRead, sendBlueBubblesTyping } from "./chat.js";
 import { resolveBlueBubblesConversationRoute } from "./conversation-route.js";
 import { fetchBlueBubblesHistory } from "./history.js";
+import {
+  claimBlueBubblesInboundMessage,
+  resolveBlueBubblesInboundDedupeKey,
+} from "./inbound-dedupe.js";
 import { sendBlueBubblesMedia } from "./media-send.js";
 import {
   buildMessagePlaceholder,
@@ -581,11 +585,102 @@ function buildInboundHistorySnapshot(params: {
   return selected;
 }
 
+function sanitizeForLog(value: unknown, maxLen = 200): string {
+  const cleaned = String(value).replace(/[\r\n\t\p{C}]/gu, " ");
+  return cleaned.length > maxLen ? cleaned.slice(0, maxLen) + "..." : cleaned;
+}
+
+/**
+ * Signal object threaded through `processMessageAfterDedupe` so the outer
+ * wrapper can distinguish "reply delivery failed silently" from "returned
+ * normally after an intentional drop" (fromMe cache, pairing flow, allowlist
+ * block, empty text, etc.).
+ *
+ * Reply delivery errors in the BlueBubbles path surface through the
+ * dispatcher's `onError` callback rather than as thrown exceptions, so a
+ * plain try/catch cannot detect them — see review thread `rwF8` on #66230.
+ */
+type InboundDedupeDeliverySignal = { deliveryFailed: boolean };
+
+/**
+ * Claim → process → finalize/release wrapper around the real inbound flow.
+ *
+ * Claim before doing any work so restart replays and in-flight concurrent
+ * redeliveries both drop cleanly. Finalize (persist the GUID) only when
+ * processing completed cleanly AND any reply dispatch reported success;
+ * release (let a later replay try again) when processing threw OR the reply
+ * pipeline reported a delivery failure via its onError callback.
+ *
+ * The dedupe key follows the same canonicalization rules as the debouncer
+ * (`monitor-debounce.ts`): balloon events (URL previews, stickers) share
+ * a logical identity with their originating text message via
+ * `associatedMessageGuid`, so balloon-first vs text-first event ordering
+ * cannot produce two distinct dedupe keys for the same logical message.
+ */
 export async function processMessage(
   message: NormalizedWebhookMessage,
   target: WebhookTarget,
+): Promise<void> {
+  const { account, core, runtime } = target;
+
+  const dedupeKey = resolveBlueBubblesInboundDedupeKey(message);
+
+  // Drop BlueBubbles MessagePoller replays after server restart (#19176, #12053).
+  const claim = await claimBlueBubblesInboundMessage({
+    guid: dedupeKey,
+    accountId: account.accountId,
+    onDiskError: (error) =>
+      logVerbose(core, runtime, `inbound-dedupe disk error: ${sanitizeForLog(error)}`),
+  });
+  if (claim.kind === "duplicate" || claim.kind === "inflight") {
+    logVerbose(
+      core,
+      runtime,
+      `drop: ${claim.kind} inbound key=${sanitizeForLog(dedupeKey ?? "")} sender=${sanitizeForLog(message.senderId)}`,
+    );
+    return;
+  }
+
+  const signal: InboundDedupeDeliverySignal = { deliveryFailed: false };
+  try {
+    await processMessageAfterDedupe(message, target, signal);
+  } catch (error) {
+    if (claim.kind === "claimed") {
+      claim.release();
+    }
+    throw error;
+  }
+  if (claim.kind === "claimed") {
+    if (signal.deliveryFailed) {
+      logVerbose(
+        core,
+        runtime,
+        `inbound-dedupe: releasing claim for key=${sanitizeForLog(dedupeKey ?? "")} after reply delivery failure (will retry on replay)`,
+      );
+      claim.release();
+    } else {
+      try {
+        await claim.finalize();
+      } catch (finalizeError) {
+        // commit() already clears inflight state in its finally block, so
+        // no explicit release() needed here — just log the persistence error.
+        logVerbose(
+          core,
+          runtime,
+          `inbound-dedupe: finalize failed for key=${sanitizeForLog(dedupeKey ?? "")}: ${sanitizeForLog(finalizeError)}`,
+        );
+      }
+    }
+  }
+}
+
+async function processMessageAfterDedupe(
+  message: NormalizedWebhookMessage,
+  target: WebhookTarget,
+  dedupeSignal: InboundDedupeDeliverySignal,
 ): Promise<void> {
   const { account, config, runtime, core, statusSink } = target;
+
   const pairing = createChannelPairingController({
     core,
     channel: "bluebubbles",
@@ -1597,6 +1692,19 @@ export async function processMessage(
         onReplyStart: typingCallbacks?.onReplyStart,
         onIdle: typingCallbacks?.onIdle,
         onError: (err, info) => {
+          // Flag the outer dedupe wrapper so it releases the claim instead
+          // of committing. Without this, a transient BlueBubbles send failure
+          // would permanently block replay-retry for 7 days and the user
+          // would never receive a reply to that message.
+          //
+          // Only the terminal `final` delivery represents the user-visible
+          // answer. The dispatcher continues past `tool` / `block` failures
+          // and may still deliver `final` successfully — releasing the
+          // dedupe claim for those would invite a replay that re-runs tool
+          // side effects and resends partially-delivered content.
+          if (info.kind === "final") {
+            dedupeSignal.deliveryFailed = true;
+          }
           runtime.error?.(`BlueBubbles ${info.kind} reply failed: ${String(err)}`);
         },
       },
diff --git a/extensions/bluebubbles/src/test-support/monitor-test-support.ts b/extensions/bluebubbles/src/test-support/monitor-test-support.ts
index 3f2d2a47745..03ee6b2343d 100644
--- a/extensions/bluebubbles/src/test-support/monitor-test-support.ts
+++ b/extensions/bluebubbles/src/test-support/monitor-test-support.ts
@@ -1,6 +1,7 @@
 import type { HistoryEntry, PluginRuntime } from "openclaw/plugin-sdk/bluebubbles";
 import { vi } from "vitest";
 import { createPluginRuntimeMock } from "../../../../test/helpers/plugins/plugin-runtime-mock.js";
+import { _resetBlueBubblesInboundDedupForTest } from "../inbound-dedupe.js";
 import {
   _resetBlueBubblesShortIdState,
   clearBlueBubblesWebhookSecurityStateForTest,
@@ -118,6 +119,7 @@ export function resetBlueBubblesMonitorTestState(params: {
 }) {
   vi.clearAllMocks();
   _resetBlueBubblesShortIdState();
+  _resetBlueBubblesInboundDedupForTest();
   clearBlueBubblesWebhookSecurityStateForTest();
   params.extraReset?.();
   params.fetchHistoryMock.mockResolvedValue({ entries: [], resolved: true });