### Preflight Checklist - [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet - [x] This is a single bug report (please file separate reports for different bugs) - [x] I am using the latest version of Claude Code ### What's Wrong? Summary After upgrading the VS Code Claude Code extension to 2.1.141, the chat stream began stalling and dying on large conversations. Downgrading to

2.1.141 regression: streaming stalls → sdk_stream_ended_no_result had_error:true on large conversations; 2.1.140 unaffected

Resolved 💬 5 comments Opened May 14, 2026 by gedikeakos Closed May 15, 2026

Preflight Checklist

[x] I have searched existing issues and this hasn't been reported yet
[x] This is a single bug report (please file separate reports for different bugs)
[x] I am using the latest version of Claude Code

What's Wrong?

Summary

After upgrading the VS Code Claude Code extension to 2.1.141, the chat stream began stalling and dying on large
conversations. Downgrading to 2.1.140 resolved it. This is a clean before/after on the same resumed conversation —
same machine, same network, same conversation depth — so the extension version is the deciding variable.

Environment

Windows 10 Pro, Version 10.0.19045.7184
VS Code + Claude Code extension (native binary claude.exe)
Affected: 2.1.141 — Working: 2.1.140
No proxy, no VPN. Network verified clean (ping to api.anthropic.com 4–14ms, 0% loss over 90 packets; HTTPS TTFB

33–52ms across 5 trials).

Symptom

On a long conversation (~370–380 messages), the stream stalls repeatedly (stream_idle_partial, Slow first byte: no
stream chunk 30.0s) and the session ends with sdk_stream_ended_no_result / had_error:true. The extension host does
not crash — clean exit.

Reproduction / evidence

All three log sessions below resumed the same conversation (resume: 2d840057-bca1-4702-9a66-b8671e0d0802).

FAILING — v2.1.141, session 20260514T142746:
14:33:48 [WARN] [Stall] stream_idle_partial lastChunkAgeMs=15007 bytesTotal=0 idleDeadlineMs=300000
14:34:00 [WARN] Slow first byte: no stream chunk 30.0s after request sent (attempt 1)
14:34:00 [DEBUG] Stream started - received first chunk
14:34:15 [WARN] [Stall] stream_idle_partial lastChunkAgeMs=15006 bytesTotal=701 idleDeadlineMs=300000
14:36:52 [WARN] [Stall] stream_idle_partial lastChunkAgeMs=15008 bytesTotal=0 idleDeadlineMs=300000
14:37:04 [WARN] Slow first byte: no stream chunk 30.0s after request sent (attempt 1)
14:37:20 [WARN] [Stall] stream_idle_partial lastChunkAgeMs=14999 bytesTotal=710 idleDeadlineMs=300000
14:37:35 log_event sdk_stream_ended_no_result had_error:true message_count:374

FAILING — v2.1.141, session 20260514T145058:
14:53:05 [WARN] [Stall] stream_idle_partial lastChunkAgeMs=15017 bytesTotal=0 idleDeadlineMs=300000
14:53:16 [WARN] Slow first byte: no stream chunk 30.0s after request sent (attempt 1)
14:53:32 [WARN] [Stall] stream_idle_partial lastChunkAgeMs=15011 bytesTotal=697 idleDeadlineMs=300000
14:53:47 [WARN] [Stall] stream_idle_partial lastChunkAgeMs=30009 bytesTotal=697 idleDeadlineMs=300000
14:53:47 log_event sdk_stream_ended_no_result had_error:true message_count:380

WORKING — v2.1.140, session 20260514T150641 (same conversation, ≥380 messages):
15:07:41 [DEBUG] Stream started - received first chunk
15:07:56 [WARN] [Stall] stream_idle_partial lastChunkAgeMs=15014 bytesTotal=758 idleDeadlineMs=300000
15:08:10 [INFO] [Stall] tool_dispatch_start tool=Read permissionDecisionMs=7
15:08:20 [DEBUG] Stream started - received first chunk
15:08:32 [INFO] [Stall] tool_dispatch_start tool=Edit permissionDecisionMs=9
15:08:36 [DEBUG] Stream started - received first chunk
15:08:44 [INFO] [Stall] tool_dispatch_start tool=Edit permissionDecisionMs=5
15:08:56 [DEBUG] Stream started - received first chunk
→ No sdk_stream_ended_no_result. Each ~15s idle recovered and dispatched a tool. Subsequent long multi-hour
sessions on 2.1.140 have also been stall-free.

Expected vs actual

Expected: large conversations stream normally (as they do on 2.1.140).
Actual on 2.1.141: repeated stalls culminating in had_error:true session death at ~370+ messages.

Log file location

C:\Users\<user>\AppData\Roaming\Code\logs\<session>\window1\exthost\Anthropic.claude-code\Claude VSCode.log

---

What Should Happen?

Downgrading to 2.1.140 resolved it.

Error Messages/Logs

Steps to Reproduce

Reproduction / evidence

All three log sessions below resumed the same conversation (resume: 2d840057-bca1-4702-9a66-b8671e0d0802).

Expected vs actual

Expected: large conversations stream normally (as they do on 2.1.140).
Actual on 2.1.141: repeated stalls culminating in had_error:true session death at ~370+ messages.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.1.141

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_

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