dsh-in-convo-mode-change

Readme

# dsh-in-convo-mode-change

Switch the **agent preset** of a conversation mid-session in the DeepSeek
Harness web UI. The presets are the "conversation modes" shipped with the
harness — **Standard mode**, **Code mode (PTC)**, **Minimal mode**, and
**Creator mode**, plus any custom presets you have authored.

By default the session header's preset icon is a read-only label: a session's
composition is fixed when it starts, and the built-in picker only exists on
the new-session hero screen. This plugin turns the header icon into a real
mode switcher that works on a conversation that has already started.

## How it works

- **Client half** (`lib/client.js`) replaces the built-in `agent-preset` cell
  in `conversation.session.header.actions` with a menu button. Picking a mode
  asks for confirmation, then POSTs `{ sessionId, agentPreset }` to the host
  route.
- **Host half** (`lib/index.js`) registers the `POST /change-convo-mode/switch`
  route on the web server. It uses the host's own
  `agentPresets.recompose()` — the same machinery the built-in blank-session
  picker uses — without the "no turn has ever run" restriction, and records
  the switch in the session log as an `agent-preset/selected` event so the
  transcript stays honest.
- Picking is disabled while the session is running a turn; the host refuses
  anyway (defense in depth), because re-parenting the agent's scope chain
  mid-call could strand an in-flight tool invocation.

## Caveats

Switching modes mid-conversation is deliberately *not* offered by the host,
and this plugin bypasses that gate on purpose:

- The switch applies from the **next turn**. The current transcript is
  untouched, but tool calls made under the previous mode may **render
  differently** in the chat afterwards, because the UI resolves tool views
  through the session's current preset.
- Don't switch while a turn is running — the menu is disabled during a run.

## Install

From a local checkout:

```sh
dsh plugin --profile web add /path/to/dsh-in-convo-mode-change
```

Or straight from GitHub (the `dsh.bundle.patch` manifest field makes the
dependency join the profile's plugin layers automatically):

```sh
dsh plugin --profile web add github:jiangr100/dsh-in-convo-mode-change
```

Then **restart the web server** (stop the `dsh web` process and run `dsh web`
again) so the loader picks up the new plugin row and the client bundle.

After restart, the header of any conversation shows the mode switcher where
the read-only preset label used to be.

## Uninstall

```sh
dsh plugin --profile web remove dsh-in-convo-mode-change
```

and restart `dsh web`. Sessions that already switched modes keep running on
the preset they switched to.

## Development notes

- The client bundle is a hand-written module-loader bundle (no build step),
  following the same pattern as `dsh-rewind`.
- The host row injects `webServer`, `agentPresets`, and `agents`; it imports
  error classes from `@deepseek-ai/dsh-agent-presets`, resolved by the
  harness loader at mount time.
- The client replaces the built-in label by registering the SAME id
  (`agent-preset`) in `conversation.session.header.actions` at a **lower
  `priority`** (the built-in sits at the default 0). The slots registry keys
  list cells by `(id, priority)`: a duplicate id at the same priority throws
  and fails the whole plugin entry at load; the lowest priority wins the
  cell. `test/slots.test.mjs` drives the real `SlotCore` to lock this in.
  Do not remove the `priority: -10` option.