Unable to use /context or /usage commands in Claude Agent

Does this issue occur when all extensions are disabled?: Yes/No

Version: 1.130.0 (user setup)
Commit: 1b6a188127eeaf9194f945eb6eb89a657e93c54c
Date: 2026-07-22T14:55:04Z
Electron: 42.6.0
ElectronBuildId: 14623276
Chromium: 148.0.7778.280
Node.js: 24.18.0
V8: 14.8.178.38-electron.0
OS: Windows_NT x64 10.0.26200

with settings:
```
"chat.agentHost.enabled": true,
"chat.agents.claude.preferAgentHost": true,
"chat.editor.claude.preferAgentHost": true,
```

and host settings:
```
"claudeUseCopilotProxy": false
```

Steps to Reproduce:

1. Configure settings as above (have not tested _which_ settings impact it)
2. Open Agents View
3. Type a claude slash command like `/context` or `/usage` - note the autocomplete

Expected Result:
The command is run and the output is shown

Actual Result:
The message cannot be sent - nothing happens after pressing enter or manually clicking send - the input remains untouched (does not clear). No obvious error is emitted.