diff --git a/CHANGELOG.md b/CHANGELOG.md
index 20d004dabc1..7f92e479b0c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -44,6 +44,7 @@ Docs: https://docs.openclaw.ai
 - Release validation: install the cross-OS TypeScript harness through Windows-safe Node/npm shims so native Windows package checks reach the OpenClaw smoke suites instead of exiting before artifact capture. Thanks @vincentkoc.
 - Release validation: let Windows packaged-upgrade checks continue after the shipped 2026.5.2 updater hits its native-module swap cleanup fallback, verifying the fallback-installed candidate through package metadata and downstream smoke instead of crashing on the immediate update-status probe. Thanks @vincentkoc.
 - Doctor/plugins: skip channel-derived official plugin installs when another configured plugin is the effective owner for the same channel, so `doctor --repair` does not reinstall `feishu` while `openclaw-lark` handles `channels.feishu`. Fixes #76623. Thanks @fuyizheng3120.
+- Channels/delivery: mark message-tool-only turns with generated-but-suppressed visible output as `source-reply-delivery-suppressed` in diagnostics, including rich presentation replies, so successful-but-private channel runs are easier to identify. Fixes #76980.
 - Agents/bootstrap: keep pending `BOOTSTRAP.md` and bootstrap truncation notices in system-prompt Project Context instead of copying setup text or raw warning diagnostics into WebChat user/runtime context. Fixes #76946.
 - Channels/WhatsApp: allow `@whiskeysockets/libsignal-node` in `onlyBuiltDependencies` so pnpm v9+ `blockExoticSubdeps` no longer rejects the baileys git-tarball subdep and silences all inbound agent replies. Fixes #76539. Thanks @ottodeng and @vincentkoc.
 - Gateway/install: keep `.env`-managed values in the macOS LaunchAgent env file while still tracking `OPENCLAW_SERVICE_MANAGED_ENV_KEYS`, so regenerated services do not boot without managed auth/provider keys. Fixes #75374.
diff --git a/src/agents/pi-embedded-subscribe.handlers.messages.test.ts b/src/agents/pi-embedded-subscribe.handlers.messages.test.ts
index 8e5370090bc..38d85bfdfaa 100644
--- a/src/agents/pi-embedded-subscribe.handlers.messages.test.ts
+++ b/src/agents/pi-embedded-subscribe.handlers.messages.test.ts
@@ -82,6 +82,7 @@ function createMessageEndContext(
     finalizeAssistantTexts?: ReturnType<typeof vi.fn>;
     consumeReplyDirectives?: ReturnType<typeof vi.fn>;
     warn?: ReturnType<typeof vi.fn>;
+    debug?: ReturnType<typeof vi.fn>;
     builtinToolNames?: ReadonlySet<string>;
     state?: Record<string, unknown>;
   } = {},
@@ -125,7 +126,7 @@ function createMessageEndContext(
     noteLastAssistant: vi.fn(),
     recordAssistantUsage: vi.fn(),
     commitAssistantUsage: vi.fn(),
-    log: { debug: vi.fn(), warn: params.warn ?? vi.fn() },
+    log: { debug: params.debug ?? vi.fn(), warn: params.warn ?? vi.fn() },
     builtinToolNames: params.builtinToolNames,
     stripBlockTags: (text: string) => text,
     finalizeAssistantTexts: params.finalizeAssistantTexts ?? vi.fn(),
@@ -756,11 +757,13 @@ describe("handleMessageEnd", () => {
   });
 
   it("does not duplicate block reply for text_end channels even when stripping differs", () => {
+    const debug = vi.fn();
     const onBlockReply = vi.fn();
     const emitBlockReply = vi.fn();
     // Same pattern: directive accumulator returns null for empty final flush
     const consumeReplyDirectives = vi.fn((text: string) => (text ? { text } : null));
     const ctx = createMessageEndContext({
+      debug,
       onBlockReply,
       emitBlockReply,
       consumeReplyDirectives,
@@ -789,6 +792,9 @@ describe("handleMessageEnd", () => {
     // send should NOT fire for text_end channels. The only consumeReplyDirectives
     // call is the final empty flush which returns null.
     expect(emitBlockReply).not.toHaveBeenCalled();
+    expect(debug).toHaveBeenCalledWith(
+      "Skipping message_end safety send for text_end channel - content already emitted via text_end",
+    );
   });
 
   it("emits a replacement final assistant event when final_answer appears only at message_end", () => {
diff --git a/src/agents/pi-embedded-subscribe.handlers.messages.ts b/src/agents/pi-embedded-subscribe.handlers.messages.ts
index a1c56e085ef..78578460d68 100644
--- a/src/agents/pi-embedded-subscribe.handlers.messages.ts
+++ b/src/agents/pi-embedded-subscribe.handlers.messages.ts
@@ -856,7 +856,7 @@ export function handleMessageEnd(
       // lastBlockReplyText is still null and message_end must deliver.
       if (ctx.state.blockReplyBreak === "text_end" && ctx.state.lastBlockReplyText != null) {
         ctx.log.debug(
-          `Skipping message_end safety send for text_end channel - content already delivered via text_end`,
+          `Skipping message_end safety send for text_end channel - content already emitted via text_end`,
         );
       } else {
         // Check for duplicates before emitting (same logic as emitBlockChunk).
diff --git a/src/auto-reply/reply/dispatch-from-config.test.ts b/src/auto-reply/reply/dispatch-from-config.test.ts
index edb37f73ad6..9b9c6121382 100644
--- a/src/auto-reply/reply/dispatch-from-config.test.ts
+++ b/src/auto-reply/reply/dispatch-from-config.test.ts
@@ -4587,6 +4587,50 @@ describe("sendPolicy deny — suppress delivery, not processing (#53328)", () =>
     expect(dispatcher.sendFinalReply).not.toHaveBeenCalled();
   });
 
+  it("marks diagnostics when message-tool-only suppresses generated visible output", async () => {
+    setNoAbort();
+    const cfg = { diagnostics: { enabled: true } } as OpenClawConfig;
+    const dispatcher = createDispatcher();
+    const richPayload = {
+      presentation: {
+        blocks: [
+          {
+            type: "buttons",
+            buttons: [{ label: "Open", url: "https://example.test/result" }],
+          },
+        ],
+      },
+    } satisfies ReplyPayload;
+    const replyResolver = vi.fn(async (_ctx: MsgContext, opts?: GetReplyOptions) => {
+      await opts?.onBlockReply?.(richPayload);
+      return richPayload;
+    });
+
+    const result = await dispatchReplyFromConfig({
+      ctx: buildTestCtx({
+        ChatType: "channel",
+        Provider: "discord",
+        Surface: "discord",
+        SessionKey: "test:discord:channel:C1",
+      }),
+      cfg,
+      dispatcher,
+      replyResolver,
+    });
+
+    expect(replyResolver).toHaveBeenCalledTimes(1);
+    expect(result.queuedFinal).toBe(false);
+    expect(dispatcher.sendBlockReply).not.toHaveBeenCalled();
+    expect(dispatcher.sendFinalReply).not.toHaveBeenCalled();
+    expect(diagnosticMocks.logMessageProcessed).toHaveBeenCalledWith(
+      expect.objectContaining({
+        outcome: "completed",
+        reason: "source-reply-delivery-suppressed",
+        sessionKey: "test:discord:channel:C1",
+      }),
+    );
+  });
+
   it("does not auto-route same-provider group/channel final replies in message-tool-only mode", async () => {
     setNoAbort();
     mocks.routeReply.mockClear();
diff --git a/src/auto-reply/reply/dispatch-from-config.ts b/src/auto-reply/reply/dispatch-from-config.ts
index fccb38f84b6..cfda161eb44 100644
--- a/src/auto-reply/reply/dispatch-from-config.ts
+++ b/src/auto-reply/reply/dispatch-from-config.ts
@@ -41,6 +41,7 @@ import {
 import { isDiagnosticsEnabled } from "../../infra/diagnostic-events.js";
 import { formatErrorMessage } from "../../infra/errors.js";
 import { getSessionBindingService } from "../../infra/outbound/session-binding-service.js";
+import { hasReplyPayloadContent } from "../../interactive/payload.js";
 import {
   logMessageProcessed,
   logMessageQueued,
@@ -760,6 +761,21 @@ export async function dispatchReplyFromConfig(
     sourceReplyDeliveryMode === "message_tool_only"
       ? { ...result, sourceReplyDeliveryMode }
       : result;
+  let suppressedSourceReplyContent = false;
+  const markSuppressedSourceReplyContent = (payload: ReplyPayload) => {
+    if (!suppressDelivery || payload.isReasoning === true) {
+      return;
+    }
+    if (!hasReplyPayloadContent(payload, { extraContent: payload.audioAsVoice })) {
+      return;
+    }
+    if (!suppressedSourceReplyContent) {
+      logVerbose(
+        `automatic source reply content suppressed by ${deliverySuppressionReason || "delivery policy"}; visible output requires the message tool or automatic visible replies`,
+      );
+    }
+    suppressedSourceReplyContent = true;
+  };
 
   let pluginFallbackReason:
     | "plugin-bound-fallback-missing-plugin"
@@ -1352,6 +1368,7 @@ export async function dispatchReplyFromConfig(
               markInboundDedupeReplayUnsafe();
             }
             if (suppressDelivery) {
+              markSuppressedSourceReplyContent(payload);
               return;
             }
             // Suppress reasoning payloads — channels using this generic dispatch
@@ -1540,6 +1557,10 @@ export async function dispatchReplyFromConfig(
           );
         }
       }
+    } else {
+      for (const reply of replies) {
+        markSuppressedSourceReplyContent(reply);
+      }
     }
 
     const counts = dispatcher.getQueuedCounts();
@@ -1547,7 +1568,11 @@ export async function dispatchReplyFromConfig(
     commitInboundDedupeIfClaimed();
     recordProcessed(
       "completed",
-      pluginFallbackReason ? { reason: pluginFallbackReason } : undefined,
+      pluginFallbackReason
+        ? { reason: pluginFallbackReason }
+        : suppressedSourceReplyContent
+          ? { reason: "source-reply-delivery-suppressed" }
+          : undefined,
     );
     markIdle("message_completed");
     return attachSourceReplyDeliveryMode({ queuedFinal, counts });