Open in Editor fails to display Agent conversation despite successful session discovery

Bing copilot helped debug and wrote this bug report.

- Copilot Chat Extension Version:
- Bundled Copilot extension shipped with the VS Code build referenced below
- Exact extension version not visible in attached logs

- VS Code Version:
- VS Code Stable
- Commit: 110a328ea54b42367b803ec53ee0bf52ef26b419

- About box copy:
Version: 1.134.0 (system setup)
Commit: 110a328ea54b42367b803ec53ee0bf52ef26b419
Date: 2026-08-18T18:24:44Z
Electron: 42.8.1
ElectronBuildId: 14906494
Chromium: 148.0.7778.280
Node.js: 24.18.1
V8: 14.8.178.38-electron.0
@github/copilot: 1.0.81-0
@github/copilot-sdk: 1.0.11
OS: 110a328ea54b42367b803ec53ee0bf52ef26b419

- OS Version:
- Client: Windows
- Remote Host: Ubuntu 22.04 (via VS Code Tunnel)

- Feature (e.g. agent/edit/ask mode):
- Agent Mode
- Open in Editor

- Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet):
- Claude Opus 5

- Logs:

[window2/renderer.log](https://github.com/user-attachments/files/31323460/renderer.log)
[window2/views.log](https://github.com/user-attachments/files/31323494/views.log)
[window2/output_20260821T143930/agentSessionsOutput.log](https://github.com/user-attachments/files/31323498/agentSessionsOutput.log)
[window2/network.log](https://github.com/user-attachments/files/31323492/network.log)

[ptyhost.log](https://github.com/user-attachments/files/31323474/ptyhost.log)
[remoteTunnelService.log](https://github.com/user-attachments/files/31323469/remoteTunnelService.log)
[sharedprocess.log](https://github.com/user-attachments/files/31323468/sharedprocess.log)
[telemetry.log](https://github.com/user-attachments/files/31323472/telemetry.log)
[terminal.log](https://github.com/user-attachments/files/31323464/terminal.log)
[tunnelHostService.log](https://github.com/user-attachments/files/31323466/tunnelHostService.log)
[userDataSync.log](https://github.com/user-attachments/files/31323475/userDataSync.log)
[agenthost.log](https://github.com/user-attachments/files/31323465/agenthost.log)
[editSessions.log](https://github.com/user-attachments/files/31323467/editSessions.log)
[main.log](https://github.com/user-attachments/files/31323473/main.log)
[mcpGateway.log](https://github.com/user-attachments/files/31323471/mcpGateway.log)
[network-shared.log](https://github.com/user-attachments/files/31323470/network-shared.log)

Description:

Selecting "Open in Editor" from the Agents UI does not display the selected conversation.

The issue occurs even though the Agent Host appears to discover an existing session. Diagnostic logs indicate that a session is found and classified, but ultimately no discoverable chats are emitted.

The renderer log also reports a missing chat-related service during initialization.

I investigated several environmental differences and have not identified a clear correlation:

- Reproduces in a workspace rooted above multiple Git repositories.
- Reproduces in a workspace rooted directly in an Azure DevOps Git repository.
- Does not reproduce in at least one cloud-agent environment.

Because the issue reproduces in both repository layouts, I do not currently believe repository topology alone explains the problem.

Observed behavior:

- Agent conversations are visible in the Agents UI.
- Selecting "Open in Editor" does not display the conversation in an editor tab.
- Session-related commands are present in the Command Palette.
- Tunnel connectivity appears healthy when the issue reproduces.

Relevant log excerpts:

Agent Host:

[Copilot] Listed 1 SDK session(s) for discoverable chats

[Copilot] Chat discovery:
1 SDK session(s) ->
...
1 outside the import window
...

[Copilot] Chat discovery: emitting 0 of 0 discovered chat(s)

Renderer:

Unable to create workbench contribution 'chat.contextContributions'.

[createInstance] _St depends on UNKNOWN service
chatSessionRoutingProviderService

Additional renderer output included repeated:
- Extension host (Remote) is unresponsive
- Extension host (Remote) is responsive
- "An unknown error occurred. Please consult the log for more details."

Expected Result:

Selecting "Open in Editor" should open the selected Agent conversation in an editor tab.

Actual Result:

The conversation does not appear in an editor tab.

Steps to Reproduce:

1. Connect to a remote machine using VS Code Tunnel.
2. Open a workspace.
3. Start or resume an Agent Mode conversation.
4. Verify the conversation is visible in the Agents UI.
5. Select "Open in Editor".
6. Observe that no conversation is displayed in an editor tab.