diff --git a/apps/web/app/api/chat/subagent-stream/route.ts b/apps/web/app/api/chat/subagent-stream/route.ts
index a0d1c8f74ba..75a93999587 100644
--- a/apps/web/app/api/chat/subagent-stream/route.ts
+++ b/apps/web/app/api/chat/subagent-stream/route.ts
@@ -1,4 +1,4 @@
-import { subscribeToSubagent, hasActiveSubagent, isSubagentRunning, ensureRegisteredFromDisk } from "@/lib/subagent-runs";
+import { subscribeToSubagent, hasActiveSubagent, isSubagentRunning, ensureRegisteredFromDisk, ensureSubagentStreamable } from "@/lib/subagent-runs";
 import type { SseEvent } from "@/lib/subagent-runs";
 import { existsSync, readFileSync } from "node:fs";
 import { join } from "node:path";
@@ -51,6 +51,10 @@ export async function GET(req: Request) {
 		return new Response("Subagent not found", { status: 404 });
 	}
 
+	// For still-running subagents rehydrated from disk, activate the gateway
+	// WebSocket subscription so new events arrive in real time.
+	ensureSubagentStreamable(sessionKey);
+
 	const isActive = isSubagentRunning(sessionKey);
 	const encoder = new TextEncoder();
 	let closed = false;