diff --git a/src/agents/tools/gateway-tool.test.ts b/src/agents/tools/gateway-tool.test.ts
index 75039fc53d1..6e0c9e14e51 100644
--- a/src/agents/tools/gateway-tool.test.ts
+++ b/src/agents/tools/gateway-tool.test.ts
@@ -12,6 +12,7 @@ const mocks = vi.hoisted(() => ({
   formatDoctorNonInteractiveHint: vi.fn(() => ""),
   callGatewayTool: vi.fn(async () => ({})),
   readGatewayCallOptions: vi.fn(() => ({})),
+  resolveGatewayTarget: vi.fn(() => undefined),
 }));
 
 vi.mock("../../config/commands.js", () => ({ isRestartEnabled: mocks.isRestartEnabled }));
@@ -31,6 +32,7 @@ vi.mock("../../infra/restart.js", () => ({
 vi.mock("./gateway.js", () => ({
   callGatewayTool: mocks.callGatewayTool,
   readGatewayCallOptions: mocks.readGatewayCallOptions,
+  resolveGatewayTarget: mocks.resolveGatewayTarget,
 }));
 
 import { createGatewayTool } from "./gateway-tool.js";
@@ -174,6 +176,7 @@ describe("createGatewayTool – live delivery context guard", () => {
     // destination on the remote host.
     mocks.callGatewayTool.mockClear();
     mocks.readGatewayCallOptions.mockReturnValueOnce({ gatewayUrl: "wss://remote-gw.example.com" });
+    mocks.resolveGatewayTarget.mockReturnValueOnce("remote");
     const tool = createGatewayTool({
       agentSessionKey: "agent:main:main",
       agentChannel: "discord",
@@ -193,6 +196,37 @@ describe("createGatewayTool – live delivery context guard", () => {
     expect(forwardedParams?.deliveryContext).toBeUndefined();
   });
 
+  it("forwards live RPC delivery context when gatewayUrl is a local loopback override", async () => {
+    // A gatewayUrl pointing to 127.0.0.1/localhost/[::1] is still the local server;
+    // deliveryContext must be forwarded so restart sentinels use the correct chat destination.
+    mocks.callGatewayTool.mockClear();
+    mocks.readGatewayCallOptions.mockReturnValueOnce({
+      gatewayUrl: "ws://127.0.0.1:18789",
+    });
+    mocks.resolveGatewayTarget.mockReturnValueOnce("local");
+    const tool = createGatewayTool({
+      agentSessionKey: "agent:main:main",
+      agentChannel: "discord",
+      agentTo: "123456789",
+    });
+
+    await execTool(tool, {
+      action: "config.patch",
+      raw: '{"key":"value"}',
+      baseHash: "abc123",
+      sessionKey: "agent:main:main",
+      note: "local loopback patch",
+      gatewayUrl: "ws://127.0.0.1:18789",
+    });
+
+    const forwardedParams = getCallArg<Record<string, unknown>>(mocks.callGatewayTool, 0, 2);
+    expect(forwardedParams?.deliveryContext).toEqual({
+      channel: "discord",
+      to: "123456789",
+      accountId: undefined,
+    });
+  });
+
   it("does not forward live RPC delivery context when a non-default agent passes sessionKey='main'", async () => {
     // "main" resolves to "agent:main:main" (default agent), which differs from the
     // current session "agent:shopping-claw:main". Live context must NOT be forwarded.
diff --git a/src/agents/tools/gateway-tool.ts b/src/agents/tools/gateway-tool.ts
index 50e0698b588..b47293f0106 100644
--- a/src/agents/tools/gateway-tool.ts
+++ b/src/agents/tools/gateway-tool.ts
@@ -12,7 +12,7 @@ import { scheduleGatewaySigusr1Restart } from "../../infra/restart.js";
 import { createSubsystemLogger } from "../../logging/subsystem.js";
 import { stringEnum } from "../schema/typebox.js";
 import { type AnyAgentTool, jsonResult, readStringParam } from "./common.js";
-import { callGatewayTool, readGatewayCallOptions } from "./gateway.js";
+import { callGatewayTool, readGatewayCallOptions, resolveGatewayTarget } from "./gateway.js";
 
 const log = createSubsystemLogger("gateway-tool");
 
@@ -274,7 +274,12 @@ export function createGatewayTool(opts?: {
         // would write a sentinel with the wrong chat destination on the remote host,
         // causing post-restart wake messages to be sent to the caller's chat instead
         // of the session on the remote gateway. See #18612.
-        const isRemoteGateway = Boolean(gatewayOpts.gatewayUrl?.trim());
+        // Only suppress deliveryContext for truly remote gateways. A gatewayUrl
+        // override pointing to a local loopback address (127.0.0.1, localhost,
+        // [::1]) is still the local server and should forward context normally;
+        // treating it as remote would fall back to extractDeliveryInfo(sessionKey)
+        // and reintroduce the stale heartbeat routing this patch was meant to fix.
+        const isRemoteGateway = resolveGatewayTarget(gatewayOpts) === "remote";
         const deliveryContext =
           isTargetingOtherSession || isRemoteGateway ? undefined : liveDeliveryContextForRpc;
         return { sessionKey, note, restartDelayMs, deliveryContext };
diff --git a/src/agents/tools/gateway.ts b/src/agents/tools/gateway.ts
index c31b7751e10..1c372403f2a 100644
--- a/src/agents/tools/gateway.ts
+++ b/src/agents/tools/gateway.ts
@@ -13,7 +13,7 @@ export type GatewayCallOptions = {
   timeoutMs?: number;
 };
 
-type GatewayOverrideTarget = "local" | "remote";
+export type GatewayOverrideTarget = "local" | "remote";
 
 export function readGatewayCallOptions(params: Record<string, unknown>): GatewayCallOptions {
   return {
@@ -113,6 +113,23 @@ function resolveGatewayOverrideToken(params: {
   }).token;
 }
 
+/**
+ * Resolves whether a GatewayCallOptions points to a local or remote gateway.
+ * Returns undefined when no gatewayUrl override is present (default local gateway).
+ * Local loopback overrides (127.0.0.1, localhost, [::1]) return "local";
+ * all other URL overrides return "remote".
+ */
+export function resolveGatewayTarget(opts?: GatewayCallOptions): GatewayOverrideTarget | undefined {
+  if (trimToUndefined(opts?.gatewayUrl) === undefined) {
+    return undefined;
+  }
+  const cfg = loadConfig();
+  return validateGatewayUrlOverrideForAgentTools({
+    cfg,
+    urlOverride: String(opts?.gatewayUrl),
+  }).target;
+}
+
 export function resolveGatewayOptions(opts?: GatewayCallOptions) {
   const cfg = loadConfig();
   const validatedOverride =