IDE Daemon Adapter Draft

Goal

Let the VS Code companion extension dogfood Mode B by connecting from the extension host to qwen serve through DaemonSessionClient.

The webview must not call the daemon directly. The extension host owns daemon URL, token, session id, and SSE replay state, then forwards sanitized app events to the webview.

Proposed Entry Point

VS Code settings:

json

{
  "qwen-code.experimentalDaemon.enabled": true,
  "qwen-code.experimentalDaemon.url": "http://127.0.0.1:4170",
  "qwen-code.experimentalDaemon.token": ""
}

Environment fallback for local dogfood:

bash

QWEN_IDE_DAEMON_URL=http://127.0.0.1:4170 code .

Minimal Flow

Extension host creates DaemonClient.
Fetch /capabilities and verify workspace compatibility.
Create or attach with DaemonSessionClient.createOrAttach().
Subscribe to session.events() in the extension host.
Translate daemon events into existing webview messages.
Send user prompts through session.prompt().
Route cancel/model switch through session.cancel() and session.setModel().
Route permission decisions through session.respondToPermission().

Relationship To Existing ACP Connection

The first implementation introduces a sibling connection path, not replace AcpConnection:

text

QwenAgentManager
  current default -> AcpConnection -> qwen --acp child
  experimental    -> DaemonIdeConnection -> qwen serve HTTP/SSE

Both paths should feed the same higher-level webview callbacks where practical. If an event cannot be faithfully mapped yet, the daemon path should surface a clear unsupported-state warning rather than silently pretending parity.

This PR adds DaemonIdeConnection as the locally verifiable extension-host adapter spike. It is not wired into the default QwenAgentManager path yet, so existing VS Code behavior remains ACP subprocess based.

Event Mapping Contract

Daemon event	IDE handling
`session_update` / `agent_message_chunk`	Existing assistant stream callback
`session_update` / `agent_thought_chunk`	Existing thinking stream callback
`session_update` / `tool_call`	Existing tool-call update callback
`permission_request`	Existing approval UI callback
`permission_resolved`	Close/update approval UI
`model_switched`	Existing model-state callback where possible
`session_died`	Disconnect UI + reconnect affordance

Unknown events must be ignored or logged as debug metadata.

Runtime Locality UX

The extension must make daemon locality visible:

workspace/files are daemon-host paths
MCP servers run on the daemon host
skills load from the daemon filesystem
provider credentials are resolved in the daemon process environment

Do not imply that local VS Code extensions, local browser profile, local localhost services, or local SSH/kube credentials are automatically available to the daemon.

Explicit Non-Goals

No default migration away from AcpConnection.
No webview direct-to-daemon transport.
No daemon-side file CRUD through the IDE until file service boundaries land.
No reverse RPC for editor/browser/clipboard yet.
No full remote-control integration.

Merge Safety

Default off behind setting/env.
Additive sibling connection path.
Existing VS Code ACP subprocess path unchanged.
Daemon token never crosses into webview JavaScript.

Validation Plan

Unit-test daemon session factory connection and SSE event consumption.
Unit-test daemon event to existing extension-host callback mapping.
Unit-test prompt, cancel, model switch, and permission response forwarding.
Unit-test settings/env resolution when the feature flag is wired.
Smoke-test local extension host against qwen serve:
- prompt streams into chat
- cancel works
- permission UI can resolve a request
- SSE reconnect uses tracked Last-Event-ID

Blockers Before Default Migration

Typed daemon event schema.
Daemon-stamped client identity.
Session-scoped permission route.
Read-only runtime diagnostics.
FileSystemService boundary and safe file read routes.
Output sink refactor for CLI/TUI parity.