WhatsApp: guard main DM last-route to single owner

src/web/auto-reply/monitor/process-message.inbound-contract.test.ts

@@ -344,4 +344,76 @@ describe("web processMessage inbound contract", () => {
 
     expect(updateLastRouteMock).not.toHaveBeenCalled();
   });
+
+  it("does not update main last route for non-owner sender when main DM scope is pinned", async () => {
+    const updateLastRouteMock = vi.mocked(updateLastRouteInBackground);
+    updateLastRouteMock.mockClear();
+
+    const args = makeProcessMessageArgs({
+      routeSessionKey: "agent:main:main",
+      groupHistoryKey: "+3000",
+      cfg: {
+        channels: {
+          whatsapp: {
+            allowFrom: ["+1000"],
+          },
+        },
+        messages: {},
+        session: { store: sessionStorePath, dmScope: "main" },
+      } as unknown as ReturnType<typeof import("../../../config/config.js").loadConfig>,
+      msg: {
+        id: "msg-last-route-3",
+        from: "+3000",
+        to: "+2000",
+        chatType: "direct",
+        body: "hello",
+        senderE164: "+3000",
+      },
+    });
+    args.route = {
+      ...args.route,
+      sessionKey: "agent:main:main",
+      mainSessionKey: "agent:main:main",
+    };
+
+    await processMessage(args);
+
+    expect(updateLastRouteMock).not.toHaveBeenCalled();
+  });
+
+  it("updates main last route for owner sender when main DM scope is pinned", async () => {
+    const updateLastRouteMock = vi.mocked(updateLastRouteInBackground);
+    updateLastRouteMock.mockClear();
+
+    const args = makeProcessMessageArgs({
+      routeSessionKey: "agent:main:main",
+      groupHistoryKey: "+1000",
+      cfg: {
+        channels: {
+          whatsapp: {
+            allowFrom: ["+1000"],
+          },
+        },
+        messages: {},
+        session: { store: sessionStorePath, dmScope: "main" },
+      } as unknown as ReturnType<typeof import("../../../config/config.js").loadConfig>,
+      msg: {
+        id: "msg-last-route-4",
+        from: "+1000",
+        to: "+2000",
+        chatType: "direct",
+        body: "hello",
+        senderE164: "+1000",
+      },
+    });
+    args.route = {
+      ...args.route,
+      sessionKey: "agent:main:main",
+      mainSessionKey: "agent:main:main",
+    };
+
+    await processMessage(args);
+
+    expect(updateLastRouteMock).toHaveBeenCalledTimes(1);
+  });
 });

src/web/auto-reply/monitor/process-message.ts

@@ -107,6 +107,28 @@ async function resolveWhatsAppCommandAuthorized(params: {
   return access.commandAuthorized;
 }
 
+function resolvePinnedMainDmRecipient(params: {
+  cfg: ReturnType<typeof loadConfig>;
+  msg: WebInboundMsg;
+}): string | null {
+  if ((params.cfg.session?.dmScope ?? "main") !== "main") {
+    return null;
+  }
+  const account = resolveWhatsAppAccount({ cfg: params.cfg, accountId: params.msg.accountId });
+  const rawAllowFrom = account.allowFrom ?? [];
+  if (rawAllowFrom.includes("*")) {
+    return null;
+  }
+  const normalizedOwners = Array.from(
+    new Set(
+      rawAllowFrom
+        .map((entry) => normalizeE164(String(entry)))
+        .filter((entry): entry is string => Boolean(entry)),
+    ),
+  );
+  return normalizedOwners.length === 1 ? normalizedOwners[0] : null;
+}
+
 export async function processMessage(params: {
   cfg: ReturnType<typeof loadConfig>;
   msg: WebInboundMsg;
@@ -320,7 +342,17 @@ export async function processMessage(params: {
   // Only update main session's lastRoute when DM actually IS the main session.
   // When dmScope="per-channel-peer", the DM uses an isolated sessionKey,
   // and updating mainSessionKey would corrupt routing for the session owner.
-  if (dmRouteTarget && params.route.sessionKey === params.route.mainSessionKey) {
+  const pinnedMainDmRecipient = resolvePinnedMainDmRecipient({
+    cfg: params.cfg,
+    msg: params.msg,
+  });
+  const shouldUpdateMainLastRoute =
+    !pinnedMainDmRecipient || pinnedMainDmRecipient === dmRouteTarget;
+  if (
+    dmRouteTarget &&
+    params.route.sessionKey === params.route.mainSessionKey &&
+    shouldUpdateMainLastRoute
+  ) {
     updateLastRouteInBackground({
       cfg: params.cfg,
       backgroundTasks: params.backgroundTasks,
@@ -332,6 +364,14 @@ export async function processMessage(params: {
       ctx: ctxPayload,
       warn: params.replyLogger.warn.bind(params.replyLogger),
     });
+  } else if (
+    dmRouteTarget &&
+    params.route.sessionKey === params.route.mainSessionKey &&
+    pinnedMainDmRecipient
+  ) {
+    logVerbose(
+      `Skipping main-session last route update for ${dmRouteTarget} (pinned owner ${pinnedMainDmRecipient})`,
+    );
   }
 
   const metaTask = recordSessionMetaFromInbound({