From 64255fe42ae66cf53b32f6ad1e9dc0b90a8a6cdd Mon Sep 17 00:00:00 2001
From: "Vincent (Wen Yu) Ge" <gewenyu99@gmail.com>
Date: Thu, 3 Sep 2026 13:06:54 -0400
Subject: [PATCH] fix: keep fetch on HTTP/1.1 so Node 26 does not exit the
 wizard mid-run

Node 26 bundles undici 8, which turns HTTP/2 on for fetch. The MCP SDK
aborts its GET event stream on close() before the response headers arrive,
node:http2 creates an orphan ClientHttp2Stream for the server's late HEADERS,
and undici's idle-session reaper destroys the socket 4s later with an
InformationalError that the orphan re-emits with no listener. posthog-node's
exception autocapture exits the process on it.

Force HTTP/1.1 on the global dispatcher, the same call pi's CLI makes.

Closes #1198

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
---
 bin.ts         | 14 ++++++++++++++
 package.json   |  1 +
 pnpm-lock.yaml |  3 +++
 3 files changed, 18 insertions(+)

diff --git a/bin.ts b/bin.ts
index f4bb1bd58..2f0b20363 100644
--- a/bin.ts
+++ b/bin.ts
@@ -1,5 +1,6 @@
 #!/usr/bin/env node
 import { satisfies } from 'semver';
+import { Agent, setGlobalDispatcher } from 'undici';
 import { ErrorCodes } from './src/lib/errors/codes.js';
 import { emitWizardError } from './src/lib/errors/emit.js';
 
@@ -9,6 +10,19 @@ import { emitWizardError } from './src/lib/errors/emit.js';
 // TypeError on Node < 22.10).
 const NODE_VERSION_RANGE = '>=22.22.0';
 
+/*
+ * TODO(#1198): remove when fetch over HTTP/2 is safe on Node 26. Remove when all
+ * of these are true:
+ *  - nodejs/node no longer creates an orphan ClientHttp2Stream when a client
+ *    session gets HEADERS for a stream id it already reset. Repro: abort a fetch
+ *    before its response headers, then idle 4s on Node 26. Fixed when the
+ *    process survives.
+ *  - modelcontextprotocol/typescript-sdk#2526 is closed.
+ *  - pi-coding-agent's CLI drops `allowH2: false` from its http-dispatcher.
+ * Same workaround as pi's CLI and typescript-sdk#2526: HTTP/1.1 only.
+ */
+setGlobalDispatcher(new Agent({ allowH2: false }));
+
 // Have to run this above the other imports because they are importing clack that
 // has the problematic imports.
 if (!satisfies(process.version, NODE_VERSION_RANGE)) {
diff --git a/package.json b/package.json
index cdb312cf1..4ec58c5e2 100644
--- a/package.json
+++ b/package.json
@@ -60,6 +60,7 @@
     "recast": "^0.23.3",
     "semver": "^7.5.3",
     "typebox": "1.1.38",
+    "undici": "8.5.0",
     "uuid": "^11.1.0",
     "xcode": "3.0.1",
     "xml-js": "^1.6.11",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index e0fab1552..7c2d2ae30 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -92,6 +92,9 @@ importers:
       typebox:
         specifier: 1.1.38
         version: 1.1.38
+      undici:
+        specifier: 8.5.0
+        version: 8.5.0
       uuid:
         specifier: ^11.1.0
         version: 11.1.0