Cannot connect to remote agent host

[kieferrm]

Description

Connecting to a remote agent host fails with:

2026-09-11 17:40:45.054 [warning] [RemoteAgentHostProtocol] Request 1 failed: {"code":-32601,"message":"Method not found: initialize"}
2026-09-11 17:40:45.054 [warning] [RemoteAgentHost] Connection closed: ssh:mac-studio-tailscale

According to Agents:Update Remote Agent Host Server the agent host server is up-to-date.

Issue Details

Item	Value
Issue Category	Bug
Target	Agents Window
VS Code Version	Code - Insiders 1.138.0-insider (60ac69b, 2026-09-11T07:31:23Z)
OS Version	Darwin arm64 25.6.0

System Info

Item	Value
VS Code Version	Code - Insiders 1.138.0-insider (60ac69b, 2026-09-11T07:31:23Z)
OS Version	Darwin arm64 25.6.0
CPUs	Apple M4 (10 x 2400)
GPU Status	2d_canvas: enabled GPU0: VENDOR= 0x106b [Google Inc. (Apple)], DEVICE=0x0000 [ANGLE (Apple, ANGLE Metal Renderer: Apple M4, Version 26.6.2 (Build 25G83))], DRIVER_VENDOR=Apple, DRIVER_VERSION=26.6.2 ACTIVE Machine model name: Mac Machine model version: 16.12 direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: enabled_on trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgpu: enabled webnn: disabled_off
Load (avg)	2, 2, 2
Memory (System)	32.00GB (0.72GB free)
Process Argv	--enable-proposed-api lszomoru.lszomoru-proposed-api-sample --enable-proposed-api donjayamanne.kusto --crash-reporter-id ef10dfea-3602-4c74-ba1a-109ce7da7825
Screen Reader	no
VM	0%
User Agent	Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Code-Insiders/1.138.0-insider Chrome/148.0.7778.280 Electron/42.10.0 Safari/537.36
Installation pure	true

[roblourens]

Repro steps for what Kai and I saw:

1. connect to ssh remote- it works
2. use the folder picker on that remote a second time- get the error above

It looks like this is is fallout from #333655

---

The merged quick fix in #336315 narrowly unblocks the reported repeated SSH picker flow: it avoids reconnecting when that picker already has a connected SSH Agent Host. That guard prevents the immediate second initialize, but it intentionally leaves the underlying transport/client ownership contract unchanged.

The more complete architectural fix is in draft PR #336330. It enforces the invariant at the remote connection factory boundary: every newly constructed protocol client receives a fresh, uninitialized transport, while an already-live transport retains its existing protocol client. It also makes ordinary ensure/open operations distinct from explicit recovery reconnects, carries that contract through SSH and WSL IPC, audits desktop/browser/web tunnels, preserves immediate preferred-location changes and metadata refresh, and adds race/regression coverage across those transports.

Reopening this issue to track the architectural follow-up through #336330.

/cc Connor Peet (@connor4312)

(Written by Copilot)