From b0d7b942defd75f7b83c4f7ecefb202c92881ed4 Mon Sep 17 00:00:00 2001
From: graehl <graehl@gmail.com>
Date: Wed, 5 Aug 2026 09:08:20 +0000
Subject: [PATCH] fix: disable Bun idle timeout that cut long generations

Bun.serve defaults idleTimeout to 10s of socket silence. Copilot
/v1/messages sends no bytes while a tool_use input is generated (all
input_json deltas arrive in one burst at the end), so any tool call
taking >10s to produce - e.g. a large Claude Code Edit - was cut
mid-stream, surfacing client-side as "API Error: Connection closed
mid-response". Long time-to-first-byte responses hit the same limit.
Observed a 41s silent gap before an ~1900-delta burst on a large tool
input; with the timeout disabled the stream completes cleanly.
---
 src/start.ts | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/start.ts b/src/start.ts
index 14abbbdff..e429a2e10 100644
--- a/src/start.ts
+++ b/src/start.ts
@@ -117,6 +117,13 @@ export async function runServer(options: RunServerOptions): Promise<void> {
   serve({
     fetch: server.fetch as ServerHandler,
     port: options.port,
+    // Bun.serve defaults idleTimeout to 10s, which kills any connection with
+    // no socket activity for 10s. Copilot's /v1/messages holds the response
+    // (headers and/or mid-stream) for the length of upstream generation, so
+    // large completions (e.g. a big Claude Code Edit) routinely exceed 10s of
+    // silence and get cut, surfacing in clients as "Connection closed
+    // mid-response". 0 disables the timeout entirely.
+    bun: { idleTimeout: 0 },
   })
 }