diff --git a/src/auto-reply/reply/acp-projector.test.ts b/src/auto-reply/reply/acp-projector.test.ts
index e413b07888f..7402e07d1cc 100644
--- a/src/auto-reply/reply/acp-projector.test.ts
+++ b/src/auto-reply/reply/acp-projector.test.ts
@@ -201,7 +201,7 @@ describe("createAcpReplyProjector", () => {
     expect(onProgress).toHaveBeenCalledTimes(2);
   });
 
-  it("coalesces text deltas into bounded block chunks", async () => {
+  it("buffers default final-only text into one final reply", async () => {
     const { deliveries, projector } = createProjectorHarness();
 
     await projector.onEvent({
@@ -211,10 +211,7 @@ describe("createAcpReplyProjector", () => {
     });
     await projector.flush(true);
 
-    expect(deliveries).toEqual([
-      { kind: "block", text: "a".repeat(64) },
-      { kind: "block", text: "a".repeat(6) },
-    ]);
+    expect(deliveries).toEqual([{ kind: "final", text: "a".repeat(70) }]);
   });
 
   it("does not suppress identical short text across terminal turn boundaries", async () => {
@@ -363,7 +360,7 @@ describe("createAcpReplyProjector", () => {
       text: prefixSystemMessage("available commands updated (7)"),
     });
     expectToolCallSummary(deliveries[1]);
-    expect(deliveries[2]).toEqual({ kind: "block", text: "What now?" });
+    expect(deliveries[2]).toEqual({ kind: "final", text: "What now?" });
   });
 
   it("flushes buffered status/tool output on error in deliveryMode=final_only", async () => {
diff --git a/src/auto-reply/reply/acp-projector.ts b/src/auto-reply/reply/acp-projector.ts
index 0ab3887476d..3b919a2b3d4 100644
--- a/src/auto-reply/reply/acp-projector.ts
+++ b/src/auto-reply/reply/acp-projector.ts
@@ -204,6 +204,7 @@ export function createAcpReplyProjector(params: {
   let lastVisibleOutputTail: string | undefined;
   let pendingHiddenBoundary = false;
   let liveBufferText = "";
+  let finalOnlyOutputText = "";
   let liveIdleTimer: NodeJS.Timeout | undefined;
   const pendingToolDeliveries: BufferedToolDelivery[] = [];
   const toolLifecycleById = new Map<string, ToolLifecycleState>();
@@ -272,6 +273,7 @@ export function createAcpReplyProjector(params: {
     lastVisibleOutputTail = undefined;
     pendingHiddenBoundary = false;
     liveBufferText = "";
+    finalOnlyOutputText = "";
     pendingToolDeliveries.length = 0;
     toolLifecycleById.clear();
   };
@@ -291,7 +293,15 @@ export function createAcpReplyProjector(params: {
       flushLiveBuffer({ force: true });
     }
     await flushBufferedToolDeliveries(force);
-    drainChunker(force);
+    if (settings.deliveryMode === "final_only") {
+      if (force && finalOnlyOutputText.trim().length > 0) {
+        const text = finalOnlyOutputText;
+        finalOnlyOutputText = "";
+        await params.deliver("final", { text });
+      }
+    } else {
+      drainChunker(force);
+    }
     await blockReplyPipeline.flush({ force });
   };
 
@@ -445,8 +455,7 @@ export function createAcpReplyProjector(params: {
             scheduleLiveIdleFlush();
           }
         } else {
-          chunker.append(accepted);
-          drainChunker(false);
+          finalOnlyOutputText += accepted;
         }
       }
       if (accepted.length < text.length) {
diff --git a/src/auto-reply/reply/dispatch-acp-delivery.ts b/src/auto-reply/reply/dispatch-acp-delivery.ts
index fac3af6bd20..276b1dfb06e 100644
--- a/src/auto-reply/reply/dispatch-acp-delivery.ts
+++ b/src/auto-reply/reply/dispatch-acp-delivery.ts
@@ -140,6 +140,7 @@ type AcpDispatchDeliveryState = {
   accumulatedBlockText: string;
   accumulatedVisibleBlockText: string;
   accumulatedBlockTtsText: string;
+  accumulatedFinalText: string;
   cleanBlockTtsDirectiveText?: ReturnType<typeof createTtsDirectiveTextStreamCleaner>;
   blockCount: number;
   deliveredFinalReply: boolean;
@@ -162,6 +163,7 @@ export type AcpDispatchDeliveryCoordinator = {
   getAccumulatedBlockText: () => string;
   getAccumulatedVisibleBlockText: () => string;
   getAccumulatedBlockTtsText: () => string;
+  getAccumulatedFinalText: () => string;
   settleVisibleText: () => Promise<void>;
   hasDeliveredFinalReply: () => boolean;
   hasDeliveredVisibleText: () => boolean;
@@ -202,6 +204,7 @@ export function createAcpDispatchDeliveryCoordinator(params: {
     accumulatedBlockText: "",
     accumulatedVisibleBlockText: "",
     accumulatedBlockTtsText: "",
+    accumulatedFinalText: "",
     cleanBlockTtsDirectiveText: shouldCleanTtsDirectiveText({
       cfg: params.cfg,
       ttsAuto: params.sessionTtsAuto,
@@ -330,6 +333,13 @@ export function createAcpDispatchDeliveryCoordinator(params: {
         state.accumulatedVisibleBlockText += visiblePayload.text;
       }
     }
+    const rawFinalText = kind === "final" ? normalizeOptionalString(payload.text) : undefined;
+    if (rawFinalText) {
+      if (state.accumulatedFinalText.length > 0) {
+        state.accumulatedFinalText += "\n";
+      }
+      state.accumulatedFinalText += rawFinalText;
+    }
 
     if (hasOutboundReplyContent(visiblePayload, { trimText: true })) {
       await startReplyLifecycleOnce();
@@ -445,6 +455,7 @@ export function createAcpDispatchDeliveryCoordinator(params: {
     getAccumulatedBlockText: () => state.accumulatedBlockText,
     getAccumulatedVisibleBlockText: () => state.accumulatedVisibleBlockText,
     getAccumulatedBlockTtsText: () => state.accumulatedBlockTtsText,
+    getAccumulatedFinalText: () => state.accumulatedFinalText,
     settleVisibleText: settleDirectVisibleText,
     hasDeliveredFinalReply: () => state.deliveredFinalReply,
     hasDeliveredVisibleText: () => state.deliveredVisibleText,
diff --git a/src/auto-reply/reply/dispatch-acp.test.ts b/src/auto-reply/reply/dispatch-acp.test.ts
index 708d6a894f5..ac66ae2b8f9 100644
--- a/src/auto-reply/reply/dispatch-acp.test.ts
+++ b/src/auto-reply/reply/dispatch-acp.test.ts
@@ -377,7 +377,11 @@ describe("tryDispatchAcpReply", () => {
     channelPluginMocks.getChannelPlugin.mockClear();
     messageActionMocks.runMessageAction.mockReset();
     messageActionMocks.runMessageAction.mockResolvedValue({ ok: true as const });
-    ttsMocks.maybeApplyTtsToPayload.mockClear();
+    ttsMocks.maybeApplyTtsToPayload.mockReset();
+    ttsMocks.maybeApplyTtsToPayload.mockImplementation(async (paramsUnknown: unknown) => {
+      const params = paramsUnknown as { payload: unknown };
+      return params.payload;
+    });
     ttsMocks.resolveTtsConfig.mockReset();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "final" });
     mediaUnderstandingMocks.applyMediaUnderstanding.mockReset();
@@ -393,7 +397,7 @@ describe("tryDispatchAcpReply", () => {
     globalThis.fetch = originalFetch;
   });
 
-  it("routes ACP block output to originating channel", async () => {
+  it("routes default ACP output to the originating channel as a final reply", async () => {
     setReadyAcpResolution();
     mockRoutedTextTurn("hello");
 
@@ -404,14 +408,17 @@ describe("tryDispatchAcpReply", () => {
       shouldRouteToOriginating: true,
     });
 
-    expect(result?.counts.block).toBe(1);
+    expect(result?.counts.block).toBe(0);
+    expect(result?.counts.final).toBe(1);
     expect(routeMocks.routeReply).toHaveBeenCalledWith(
       expect.objectContaining({
         channel: "telegram",
         to: "telegram:thread-1",
+        payload: expect.objectContaining({ text: "hello" }),
       }),
     );
     expect(dispatcher.sendBlockReply).not.toHaveBeenCalled();
+    expect(dispatcher.sendFinalReply).not.toHaveBeenCalled();
   });
 
   it("persists ACP transcript when routed delivery fails", async () => {
@@ -1187,18 +1194,18 @@ describe("tryDispatchAcpReply", () => {
     );
   });
 
-  it("does not deliver final fallback text when routed block text was already visible", async () => {
+  it("does not add a fallback when routed ACP text was already delivered as final", async () => {
     setReadyAcpResolution();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "final" });
     queueTtsReplies({ text: "CODEX_OK" }, {} as ReturnType<typeof ttsMocks.maybeApplyTtsToPayload>);
     const { result } = await runRoutedAcpTextTurn("CODEX_OK");
 
-    expect(result?.counts.block).toBe(1);
-    expect(result?.counts.final).toBe(0);
+    expect(result?.counts.block).toBe(0);
+    expect(result?.counts.final).toBe(1);
     expect(routeMocks.routeReply).toHaveBeenCalledTimes(1);
   });
 
-  it("does not deliver final fallback text when routed discord block text was already visible", async () => {
+  it("routes default ACP text as one final reply to Discord", async () => {
     setReadyAcpResolution();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "final" });
     queueTtsReplies(
@@ -1216,8 +1223,8 @@ describe("tryDispatchAcpReply", () => {
       originatingTo: "channel:1478836151241412759",
     });
 
-    expect(result?.counts.block).toBe(1);
-    expect(result?.counts.final).toBe(0);
+    expect(result?.counts.block).toBe(0);
+    expect(result?.counts.final).toBe(1);
     expect(routeMocks.routeReply).toHaveBeenCalledTimes(1);
     expect(routeMocks.routeReply).toHaveBeenCalledWith(
       expect.objectContaining({
@@ -1228,7 +1235,7 @@ describe("tryDispatchAcpReply", () => {
     );
   });
 
-  it("does not deliver final fallback text when routed Slack block text was already visible", async () => {
+  it("routes default ACP text as one final reply to Slack", async () => {
     setReadyAcpResolution();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "final" });
     queueTtsReplies(
@@ -1246,8 +1253,8 @@ describe("tryDispatchAcpReply", () => {
       originatingTo: "channel:C123",
     });
 
-    expect(result?.counts.block).toBe(1);
-    expect(result?.counts.final).toBe(0);
+    expect(result?.counts.block).toBe(0);
+    expect(result?.counts.final).toBe(1);
     expect(routeMocks.routeReply).toHaveBeenCalledTimes(1);
     expect(routeMocks.routeReply).toHaveBeenCalledWith(
       expect.objectContaining({
@@ -1258,7 +1265,7 @@ describe("tryDispatchAcpReply", () => {
     );
   });
 
-  it("does not deliver final fallback text when direct block text was already visible", async () => {
+  it("delivers default Telegram ACP text directly as a final reply", async () => {
     setReadyAcpResolution();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "final" });
     queueTtsReplies({ text: "CODEX_OK" }, {} as ReturnType<typeof ttsMocks.maybeApplyTtsToPayload>);
@@ -1278,13 +1285,14 @@ describe("tryDispatchAcpReply", () => {
     expect(result?.counts.final).toBe(0);
     expect(counts.block).toBe(0);
     expect(counts.final).toBe(0);
-    expect(dispatcher.sendBlockReply).toHaveBeenCalledWith(
+    expect(result?.queuedFinal).toBe(true);
+    expect(dispatcher.sendBlockReply).not.toHaveBeenCalled();
+    expect(dispatcher.sendFinalReply).toHaveBeenCalledWith(
       expect.objectContaining({ text: "CODEX_OK" }),
     );
-    expect(dispatcher.sendFinalReply).not.toHaveBeenCalled();
   });
 
-  it("does not deliver final fallback text when direct discord block text was already visible", async () => {
+  it("delivers default Discord ACP text directly as a final reply", async () => {
     setReadyAcpResolution();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "final" });
     queueTtsReplies(
@@ -1307,13 +1315,14 @@ describe("tryDispatchAcpReply", () => {
     expect(result?.counts.final).toBe(0);
     expect(counts.block).toBe(0);
     expect(counts.final).toBe(0);
-    expect(dispatcher.sendBlockReply).toHaveBeenCalledWith(
+    expect(result?.queuedFinal).toBe(true);
+    expect(dispatcher.sendBlockReply).not.toHaveBeenCalled();
+    expect(dispatcher.sendFinalReply).toHaveBeenCalledWith(
       expect.objectContaining({ text: "Received." }),
     );
-    expect(dispatcher.sendFinalReply).not.toHaveBeenCalled();
   });
 
-  it("does not deliver final fallback text when direct Slack block text was already visible", async () => {
+  it("delivers default Slack ACP text directly as a final reply", async () => {
     setReadyAcpResolution();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "final" });
     queueTtsReplies(
@@ -1336,13 +1345,14 @@ describe("tryDispatchAcpReply", () => {
     expect(result?.counts.final).toBe(0);
     expect(counts.block).toBe(0);
     expect(counts.final).toBe(0);
-    expect(dispatcher.sendBlockReply).toHaveBeenCalledWith(
+    expect(result?.queuedFinal).toBe(true);
+    expect(dispatcher.sendBlockReply).not.toHaveBeenCalled();
+    expect(dispatcher.sendFinalReply).toHaveBeenCalledWith(
       expect.objectContaining({ text: "Slack says hi." }),
     );
-    expect(dispatcher.sendFinalReply).not.toHaveBeenCalled();
   });
 
-  it("treats visible telegram ACP block delivery as a successful final response", async () => {
+  it("treats Telegram ACP final delivery as a successful final response", async () => {
     setReadyAcpResolution();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "final" });
     queueTtsReplies({ text: "CODEX_OK" }, {} as ReturnType<typeof ttsMocks.maybeApplyTtsToPayload>);
@@ -1359,13 +1369,13 @@ describe("tryDispatchAcpReply", () => {
     });
 
     expect(result?.queuedFinal).toBe(true);
-    expect(dispatcher.sendBlockReply).toHaveBeenCalledWith(
+    expect(dispatcher.sendBlockReply).not.toHaveBeenCalled();
+    expect(dispatcher.sendFinalReply).toHaveBeenCalledWith(
       expect.objectContaining({ text: "CODEX_OK" }),
     );
-    expect(dispatcher.sendFinalReply).not.toHaveBeenCalled();
   });
 
-  it("preserves final fallback when direct block text is filtered by channels without a visibility override", async () => {
+  it("delivers default ACP text as final for channels without a visibility override", async () => {
     setReadyAcpResolution();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "final" });
     queueTtsReplies({ text: "CODEX_OK" }, {} as ReturnType<typeof ttsMocks.maybeApplyTtsToPayload>);
@@ -1385,9 +1395,8 @@ describe("tryDispatchAcpReply", () => {
     expect(result?.counts.final).toBe(0);
     expect(counts.block).toBe(0);
     expect(counts.final).toBe(0);
-    expect(dispatcher.sendBlockReply).toHaveBeenCalledWith(
-      expect.objectContaining({ text: "CODEX_OK" }),
-    );
+    expect(result?.queuedFinal).toBe(true);
+    expect(dispatcher.sendBlockReply).not.toHaveBeenCalled();
     expect(dispatcher.sendFinalReply).toHaveBeenCalledWith(
       expect.objectContaining({ text: "CODEX_OK" }),
     );
@@ -1450,6 +1459,12 @@ describe("tryDispatchAcpReply", () => {
   it("honors the configured default account for ACP projector chunking when AccountId is omitted", async () => {
     setReadyAcpResolution();
     const cfg = createAcpTestConfig({
+      acp: {
+        enabled: true,
+        stream: {
+          deliveryMode: "live",
+        },
+      },
       channels: {
         discord: {
           defaultAccount: "work",
@@ -1489,7 +1504,7 @@ describe("tryDispatchAcpReply", () => {
     );
   });
 
-  it("does not add a second routed payload when routed block text was already visible", async () => {
+  it("does not add a second routed payload when routed final text was already visible", async () => {
     setReadyAcpResolution();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "final" });
     queueTtsReplies({ text: "Task completed" }, {
@@ -1498,21 +1513,21 @@ describe("tryDispatchAcpReply", () => {
     } as MockTtsReply);
     const { result } = await runRoutedAcpTextTurn("Task completed");
 
-    expect(result?.counts.block).toBe(1);
-    expect(result?.counts.final).toBe(0);
+    expect(result?.counts.block).toBe(0);
+    expect(result?.counts.final).toBe(1);
     expect(routeMocks.routeReply).toHaveBeenCalledTimes(1);
     expectRoutedPayload(1, {
       text: "Task completed",
     });
   });
 
-  it("skips fallback when TTS mode is all (blocks already processed with TTS)", async () => {
+  it("skips fallback when TTS mode is all and final delivery already succeeded", async () => {
     setReadyAcpResolution();
     ttsMocks.resolveTtsConfig.mockReturnValue({ mode: "all" });
     const { result } = await runRoutedAcpTextTurn("Response");
 
-    expect(result?.counts.block).toBe(1);
-    expect(result?.counts.final).toBe(0);
+    expect(result?.counts.block).toBe(0);
+    expect(result?.counts.final).toBe(1);
     expect(routeMocks.routeReply).toHaveBeenCalledTimes(1);
   });
 
diff --git a/src/auto-reply/reply/dispatch-acp.ts b/src/auto-reply/reply/dispatch-acp.ts
index 66642503af9..1b1f22b435a 100644
--- a/src/auto-reply/reply/dispatch-acp.ts
+++ b/src/auto-reply/reply/dispatch-acp.ts
@@ -519,7 +519,7 @@ export async function tryDispatchAcpReply(params: {
         cfg: params.cfg,
         sessionKey: canonicalSessionKey,
         promptText,
-        finalText: delivery.getAccumulatedBlockText(),
+        finalText: delivery.getAccumulatedFinalText() || delivery.getAccumulatedBlockText(),
         meta: acpResolution.meta,
         threadId: params.ctx.MessageThreadId,
       });