[Bugfix] Fix Nemotron VoiceChat duplex nightly handshake (#7884)

Signed-off-by: Sy03 <1370724210@qq.com>

docs/design/fullduplex.md

@@ -242,10 +242,12 @@ vllm_omni/
 │           └── overlap_policy.py / commit_policy.py / playback_ledger.py
 ├── config/stage_config.py           PipelineConfig.duplex_plugin; DuplexSessionRuntimeConfig
 ├── model_executor/models/minicpmo_4_5/duplex/plugin.py   MiniCPMO45DuplexPlugin (+ data_plane, input, policy, ...)
+├── model_executor/models/nemotron_voicechat/duplex/plugin.py   NemotronVoiceChatDuplexPlugin (+ data_plane, input, capabilities)
 └── clients/
     ├── duplex.py                    DuplexClientBase (ABC), DuplexClient (websocket), client-side events
     ├── inline_duplex.py             InlineDuplexClient (in-process, over DuplexOmni)
     ├── minicpmo_4_5.py              MiniCPM-o 4.5 session preset
+    ├── nemotron_voicechat.py        Nemotron VoiceChat session preset
     └── personaplex.py               PersonaPlex session preset
 ```
 
@@ -388,7 +390,7 @@ policy that used to be two separately configured objects:
 | Half | Members |
 | --- | --- |
 | engine policy | `configure_sampling_params(runtime_config, defaults)`, `plan_append(...) -> DuplexAppendPlan` (the resumable Stage0 prompt for one unit), `decide_output(...) -> DuplexOutputDecision \| None` (e.g. the listen decision on a finished Stage0 segment) |
-| session policy | `capabilities(max_sessions)`, `validate_client_extra_body`, `prepare_runtime_config(config, model_config)` (server-owned runtime keys, reference audio resolution), `runtime_config_for_update`, `runtime_config_for_function_output`, `create_session_state() -> DuplexModelSessionState`, `data_plane: DuplexDataPlane` (projects raw stage outputs into internal events), `data_plane_context(...)` |
+| session policy | `capabilities(max_sessions)`, `validate_client_extra_body`, `prepare_runtime_config(config, model_config)` (server-owned runtime keys, reference audio resolution), `runtime_config_for_update`, `runtime_config_for_function_output`, `runtime_config_after_model_output` (consumption acknowledgement), `create_session_state() -> DuplexModelSessionState`, `data_plane: DuplexDataPlane` (projects raw stage outputs into internal events), `data_plane_context(...)` |
 
 `DuplexOmniEngine._validate_deployment` loads the plugin before any stage
 starts; `DuplexSessionManager.__init__` validates it against the stage
@@ -396,12 +398,12 @@ sampling defaults once the stage pools exist. Plugin hooks that may block
 (`prepare_runtime_config` fetching `ref_audio`) are awaited in `open()` and
 offloaded from the loop.
 
-The MiniCPM-o 4.5 plugin (`model_executor/models/minicpmo_4_5/duplex/plugin.py`)
-is the only integration in this framework version. PersonaPlex and Nemotron
-VoiceChat still carry their pre-framework duplex code (runtime extension plus
-serving adapter) and are therefore not served over this framework yet: their
-pipelines declare no `duplex_plugin`, so they run turn-based until the
-follow-up PRs port them (RFC vllm-omni#7181, PR 2/3).
+Frame-based plugins use `engine/duplex/intermediate.py::build_duplex_append_prompt`
+for the shared request identity, sequencing and config snapshots. Token budgets,
+PCM framing and model-specific worker fields remain in the plugins.
+
+See [supported models and deployments](../serving/full_duplex_api.md#enable-full-duplex)
+for the current plugin integrations and deployment configurations.
 
 ## Serving
 

docs/serving/full_duplex_api.md

@@ -72,12 +72,21 @@ does not switch engines. The Python `Omni` / `AsyncOmni` APIs are unchanged.
     `session.created.session.capabilities` is present before treating the
     connection as full duplex.
 
-**MiniCPM-o 4.5** (`vllm_omni/deploy/minicpmo_4_5.yaml`) is the only model
-served over this endpoint today. PersonaPlex and Nemotron VoiceChat still carry
-their pre-framework duplex code: their pipelines declare no `duplex_plugin`, so
-they run turn-based until the follow-up PRs port them to the plugin contract
+**MiniCPM-o 4.5** (`vllm_omni/deploy/minicpmo_4_5.yaml`), **Qwen3-Omni**
+(`vllm_omni/deploy/qwen3_omni_duplex.yaml`), and **Nemotron VoiceChat**
+(`vllm_omni/deploy/nemotron_labs_voicechat_duplex.yaml`) are served
+over this endpoint today. PersonaPlex still carries its pre-framework duplex
+code: its pipeline declares no `duplex_plugin`, so it runs turn-based until the
+follow-up PR ports it to the plugin contract
 (RFC [vllm-omni#7181](https://github.com/vllm-project/vllm-omni/issues/7181)).
 
+For Nemotron VoiceChat Python clients, use
+`vllm_omni.clients.nemotron_voicechat.create_duplex_session_config()` with
+`DuplexClient`. The preset selects 16 kHz float32 input, 22.05 kHz PCM16 output,
+and automatic responses. Append 1,280-sample (80 ms) input frames; when using
+`stream_pcm`, set `chunk_ms=80`. Pass `instructions` and optional `tools` to
+the preset before opening the session.
+
 JoyVL is a separate HTTP interaction orchestrator and does not use these
 WebSocket endpoints. See [Standalone Experimental Servers](standalone_servers.md).
 

docs/serving/realtime_duplex_api.md

@@ -8,11 +8,9 @@ history stays honest, and a dropped connection can resume the same session.
 This page covers how to run a duplex deployment, how to drive it from Python
 with `vllm_omni.clients.duplex.DuplexClient`, and the complete wire contract.
 
-The endpoint is served for models that ship a duplex plugin — including
-MiniCPM-o 4.5 and Qwen3-Omni — and just for deploy configurations that declare
-`session_mode: duplex`. PersonaPlex and Nemotron VoiceChat are ported to the
-plugin contract in follow-up PRs and are not served over this endpoint yet. The runtime architecture
-is described in [Full-Duplex Runtime (MiniCPM-o 4.5)](../design/fullduplex.md).
+The endpoint requires a duplex plugin and a deployment with `session_mode: duplex`.
+See [supported models and deployments](full_duplex_api.md#enable-full-duplex)
+and the [runtime architecture](../design/fullduplex.md).
 
 ## Qwen3-Omni conversation history
 
@@ -1340,9 +1338,6 @@ them out into typed events before they reach a client.
 
 ## Known Limitations
 
-- Only MiniCPM-o 4.5 is served over this endpoint today; PersonaPlex and
-  Nemotron VoiceChat arrive with the follow-up PRs that port them to the
-  plugin contract.
 - Several surfaces are capability-gated per model (see *Capability
   negotiation by model* above): PersonaPlex does not support session resume,
   barge-in, or audio truncation; Nemotron VoiceChat does not support barge-in