From 0d0d60600d2ab85946b586db38d915f4710a41cc Mon Sep 17 00:00:00 2001
From: Carlos Escalante <cescalante2988@gmail.com>
Date: Sat, 4 Jul 2026 20:23:05 -0600
Subject: [PATCH] Assistant: intercept connect on the single-route transport
 too
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The connect intercept only matched POST …/connect, but CopilotKit talks
to the runtime in single-route mode: everything POSTs to
/api/copilotkit with the operation in the body envelope
({method:"agent/connect"}). So the in-memory runner kept replaying the
BFF process's full event history on every CopilotChat mount — every
conversation since server start, across clears — which is exactly the
stacked resurrected conversations seen in prod after navigating away
and back. Now both transports get the immediately-completed stream.

Verified with the reported repro: three conversations with clears
between, navigate away and back → only the third remains; reload
hydration unaffected.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 frontend/server.ts | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/frontend/server.ts b/frontend/server.ts
index c05efc5..a429435 100644
--- a/frontend/server.ts
+++ b/frontend/server.ts
@@ -384,17 +384,38 @@ app.use("*", async (c, next) => {
 });
 
 app.all("/api/copilotkit/*", async (c) => {
-  // CopilotChat fires POST …/agent/<id>/connect for explicit threadIds and
-  // the runtime's in-memory runner replays THIS PROCESS's event history —
-  // stale relative to the DB store (it resurrects cleared conversations and
-  // double-feeds page-load hydration). The empty-messages hydration run
-  // against MAF is our single restore path, so connect gets an
-  // immediately-completed stream instead.
-  if (new URL(c.req.url).pathname.endsWith("/connect")) {
-    return new Response("", {
+  // CopilotChat fires "connect" on every mount with an explicit threadId,
+  // and the runtime's in-memory runner answers it by replaying THIS
+  // PROCESS's event history — every run since the server started, across
+  // "Nueva conversación" clears (the DB delete can't touch process memory).
+  // That resurrected cleared conversations on navigation. The
+  // empty-messages hydration run against MAF's snapshot store is our single
+  // restore path, so connect gets an immediately-completed stream instead.
+  //
+  // Two transports must be caught: multi-route (POST …/agent/<id>/connect)
+  // and single-route (POST /api/copilotkit with {method:"agent/connect"} in
+  // the body — the one CopilotKit actually uses here; the URL-only check
+  // silently missed it).
+  const emptyStream = () =>
+    new Response("", {
       status: 200,
       headers: { "Content-Type": "text/event-stream" },
     });
+  if (new URL(c.req.url).pathname.endsWith("/connect")) {
+    return emptyStream();
+  }
+  if (
+    c.req.method === "POST" &&
+    (c.req.header("content-type") ?? "").includes("application/json")
+  ) {
+    try {
+      const envelope = (await c.req.raw.clone().json()) as { method?: string };
+      if (envelope?.method === "agent/connect") {
+        return emptyStream();
+      }
+    } catch {
+      // not JSON — fall through to the runtime
+    }
   }
 
   const cookieHeader = c.req.header("cookie") ?? "";