diff --git a/CHANGELOG.md b/CHANGELOG.md
index 34b250f2f75..a2175fcf9fa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -662,6 +662,7 @@ Docs: https://docs.openclaw.ai
 - Memory flush/bootstrap file protection: restrict memory-flush runs to append-only `read`/`write` tools and route host-side memory appends through root-enforced safe file handles so flush turns cannot overwrite bootstrap files via `exec` or unsafe raw rewrites. (#38574) Thanks @frankekn.
 - Mattermost/DM media uploads: resolve bare 26-character Mattermost IDs user-first for direct messages so media sends no longer fail with `403 Forbidden` when targets are configured as unprefixed user IDs. (#29925) Thanks @teconomix.
 - Voice-call/OpenAI TTS config parity: add missing `speed`, `instructions`, and `baseUrl` fields to the OpenAI TTS config schema and gate `instructions` to supported models so voice-call overrides validate and route cleanly through core TTS. (#39226) Thanks @ademczuk.
+- ACP/client final-message delivery: preserve terminal assistant text snapshots before resolving `end_turn`, so ACP clients no longer drop the last visible reply when the gateway sends the final message body on the terminal chat event. (#17615) Thanks @pjeby.
 
 ## 2026.3.2
 
diff --git a/src/acp/translator.session-rate-limit.test.ts b/src/acp/translator.session-rate-limit.test.ts
index 554dc87e2b8..3e3f254d0ee 100644
--- a/src/acp/translator.session-rate-limit.test.ts
+++ b/src/acp/translator.session-rate-limit.test.ts
@@ -1020,3 +1020,144 @@ describe("acp prompt size hardening", () => {
     });
   });
 });
+
+describe("acp final chat snapshots", () => {
+  async function createSnapshotHarness() {
+    const sessionStore = createInMemorySessionStore();
+    const connection = createAcpConnection();
+    const sessionUpdate = connection.__sessionUpdateMock;
+    const request = vi.fn(async (method: string) => {
+      if (method === "chat.send") {
+        return new Promise(() => {});
+      }
+      return { ok: true };
+    }) as GatewayClient["request"];
+    const agent = new AcpGatewayAgent(connection, createAcpGateway(request), {
+      sessionStore,
+    });
+    await agent.loadSession(createLoadSessionRequest("snapshot-session"));
+    sessionUpdate.mockClear();
+    const promptPromise = agent.prompt(createPromptRequest("snapshot-session", "hello"));
+    const runId = sessionStore.getSession("snapshot-session")?.activeRunId;
+    if (!runId) {
+      throw new Error("Expected ACP prompt run to be active");
+    }
+    return { agent, sessionUpdate, promptPromise, runId, sessionStore };
+  }
+
+  it("emits final snapshot text before resolving end_turn", async () => {
+    const { agent, sessionUpdate, promptPromise, runId, sessionStore } =
+      await createSnapshotHarness();
+
+    await agent.handleGatewayEvent({
+      event: "chat",
+      payload: {
+        sessionKey: "snapshot-session",
+        runId,
+        state: "final",
+        stopReason: "end_turn",
+        message: {
+          content: [{ type: "text", text: "FINAL TEXT SHOULD BE EMITTED" }],
+        },
+      },
+    } as unknown as EventFrame);
+
+    await expect(promptPromise).resolves.toEqual({ stopReason: "end_turn" });
+    expect(sessionUpdate).toHaveBeenCalledWith({
+      sessionId: "snapshot-session",
+      update: {
+        sessionUpdate: "agent_message_chunk",
+        content: { type: "text", text: "FINAL TEXT SHOULD BE EMITTED" },
+      },
+    });
+    expect(sessionStore.getSession("snapshot-session")?.activeRunId).toBeNull();
+    sessionStore.clearAllSessionsForTest();
+  });
+
+  it("does not duplicate text when final repeats the last delta snapshot", async () => {
+    const { agent, sessionUpdate, promptPromise, runId, sessionStore } =
+      await createSnapshotHarness();
+
+    await agent.handleGatewayEvent({
+      event: "chat",
+      payload: {
+        sessionKey: "snapshot-session",
+        runId,
+        state: "delta",
+        message: {
+          content: [{ type: "text", text: "Hello world" }],
+        },
+      },
+    } as unknown as EventFrame);
+
+    await agent.handleGatewayEvent({
+      event: "chat",
+      payload: {
+        sessionKey: "snapshot-session",
+        runId,
+        state: "final",
+        stopReason: "end_turn",
+        message: {
+          content: [{ type: "text", text: "Hello world" }],
+        },
+      },
+    } as unknown as EventFrame);
+
+    await expect(promptPromise).resolves.toEqual({ stopReason: "end_turn" });
+    const chunks = sessionUpdate.mock.calls.filter(
+      (call: unknown[]) =>
+        (call[0] as Record<string, unknown>)?.update &&
+        (call[0] as Record<string, Record<string, unknown>>).update?.sessionUpdate ===
+          "agent_message_chunk",
+    );
+    expect(chunks).toHaveLength(1);
+    sessionStore.clearAllSessionsForTest();
+  });
+
+  it("emits only the missing tail when the final snapshot extends prior deltas", async () => {
+    const { agent, sessionUpdate, promptPromise, runId, sessionStore } =
+      await createSnapshotHarness();
+
+    await agent.handleGatewayEvent({
+      event: "chat",
+      payload: {
+        sessionKey: "snapshot-session",
+        runId,
+        state: "delta",
+        message: {
+          content: [{ type: "text", text: "Hello" }],
+        },
+      },
+    } as unknown as EventFrame);
+
+    await agent.handleGatewayEvent({
+      event: "chat",
+      payload: {
+        sessionKey: "snapshot-session",
+        runId,
+        state: "final",
+        stopReason: "max_tokens",
+        message: {
+          content: [{ type: "text", text: "Hello world" }],
+        },
+      },
+    } as unknown as EventFrame);
+
+    await expect(promptPromise).resolves.toEqual({ stopReason: "max_tokens" });
+    expect(sessionUpdate).toHaveBeenCalledWith({
+      sessionId: "snapshot-session",
+      update: {
+        sessionUpdate: "agent_message_chunk",
+        content: { type: "text", text: "Hello" },
+      },
+    });
+    expect(sessionUpdate).toHaveBeenCalledWith({
+      sessionId: "snapshot-session",
+      update: {
+        sessionUpdate: "agent_message_chunk",
+        content: { type: "text", text: " world" },
+      },
+    });
+    sessionStore.clearAllSessionsForTest();
+  });
+});
diff --git a/src/acp/translator.ts b/src/acp/translator.ts
index b5a6802d07b..8ab1f821fc8 100644
--- a/src/acp/translator.ts
+++ b/src/acp/translator.ts
@@ -800,9 +800,15 @@ export class AcpGatewayAgent implements Agent {
       return;
     }
 
-    if (state === "delta" && messageData) {
+    const shouldHandleMessageSnapshot = messageData && (state === "delta" || state === "final");
+    if (shouldHandleMessageSnapshot) {
+      // Gateway chat events can carry the latest full assistant snapshot on both
+      // incremental updates and the terminal final event. Process the snapshot
+      // first so ACP clients never drop the last visible assistant text.
       await this.handleDeltaEvent(pending.sessionId, messageData);
-      return;
+      if (state === "delta") {
+        return;
+      }
     }
 
     if (state === "final") {