diff --git a/src/auto-reply/reply/dispatch-acp.ts b/src/auto-reply/reply/dispatch-acp.ts
index 20b700807e2..7f40f253e2d 100644
--- a/src/auto-reply/reply/dispatch-acp.ts
+++ b/src/auto-reply/reply/dispatch-acp.ts
@@ -345,13 +345,15 @@ export async function tryDispatchAcpReply(params: {
     params.ctx.OriginatingChannel ?? params.ctx.Surface ?? params.ctx.Provider,
   );
   const explicitDispatchAccountId = normalizeOptionalString(params.ctx.AccountId);
+  const dispatchChannels = params.cfg.channels as
+    | Record<string, { defaultAccount?: unknown } | undefined>
+    | undefined;
+  const defaultDispatchAccount =
+    normalizedDispatchChannel == null
+      ? undefined
+      : dispatchChannels?.[normalizedDispatchChannel]?.defaultAccount;
   const effectiveDispatchAccountId =
-    explicitDispatchAccountId ??
-    normalizeOptionalString(
-      (
-        params.cfg.channels as Record<string, { defaultAccount?: unknown } | undefined> | undefined
-      )?.[normalizedDispatchChannel]?.defaultAccount,
-    );
+    explicitDispatchAccountId ?? normalizeOptionalString(defaultDispatchAccount);
   const projector = createAcpReplyProjector({
     cfg: params.cfg,
     shouldSendToolSummaries: params.shouldSendToolSummaries,