# Design Documents

This section contains design documents and architecture specifications for
vLLM-Omni. The sidebar groups documents by the system concern they describe;
retired module pages are preserved in the legacy archive instead of remaining
in the active navigation.

## Architecture Documents

- [Architecture Overview](architecture_overview.md)

## Feature Design Documents

For user-facing configuration and current compatibility, see the
[Features overview](../features/README.md). A design document defines an
implementation contract; it is not, by itself, a general support claim.

### Runtime and stage execution

- [Full-Duplex Runtime (MiniCPM-o 4.5)](fullduplex.md)
- [Full-Duplex Runtime (PersonaPlex)](fullduplex-personaplex.md)
- [Disaggregated Inference](feature/disaggregated_inference.md)
- [Host Weight Runtime](feature/host_weight_runtime.md)
- [Async Chunk](feature/async_chunk.md)
- [Async Diffusion Output](feature/async_diffusion_output.md)
- [Async Omni Output Materialization](feature/omni_async_output_materialization.md)
- [Runner-to-model Prefill/Decode Phase Contract](feature/preprocess_phase_contract.md)
- [Automatic Prefix Caching in Omni Models](feature/prefix_caching.md)
- [Model-local KV Caches](feature/model_local_kv_caches.md)
- [Realtime AR-Diffusion Sessions](feature/realtime_ar_diffusion.md)

### Communication

#### OmniConnector implementations

- [Mooncake Store Connector](feature/omni_connectors/mooncake_store_connector.md)
- [Mooncake Transfer Engine Connector](feature/omni_connectors/mooncake_transfer_engine_connector.md)
- [Mori Transfer Engine Connector](feature/omni_connectors/mori_transfer_engine_connector.md)
- [NIXL Connector](feature/omni_connectors/nixl_connector.md)
- [Shared Memory Connector](feature/omni_connectors/shared_memory_connector.md)
- [Yuanrong Store Connector](feature/omni_connectors/yuanrong_connector.md)
- [Yuanrong Transfer Engine Connector](feature/omni_connectors/yuanrong_transfer_engine_connector.md)

### Quantization

- [Quantization](feature/quantization.md)

### Diffusion acceleration

#### Parallelism

- [CFG-Parallel](feature/cfg_parallel.md)
- [Expert Parallel](feature/expert_parallel.md)
- [Hybrid Sharded Data Parallel (HSDP)](feature/hsdp.md)
- [Pipeline Parallel](feature/pipeline_parallel.md)
- [Sequence Parallel](feature/sequence_parallel.md)
- [Tensor Parallel](feature/tensor_parallel.md)
- [VAE Patch Parallelism](feature/vae_parallel.md)

#### Attention optimization

The [Diffusion Attention Backends](../user_guide/diffusion/attention_backends.md)
guides list selectable backends, platform defaults, installation, and tuning.
The design contracts separate selection mechanics from backend algorithms:

- [Attention Backend Selection](feature/attention_backend_selection.md)
- [Skip-Softmax](feature/skip_softmax.md)

#### CPU offloading

- [Overview and Shared Contracts](feature/offloader/README.md)
- [Model-Level Offload](feature/offloader/module_offload.md)
- [Layerwise Offload](feature/offloader/layerwise_offload.md)
- [Distributed Layerwise Offload](feature/offloader/distributed_layerwise_offload.md)

- [Cache-DiT](feature/cache_dit.md)
- [TeaCache](feature/teacache.md)
- [Diffusion Continuous Batching](feature/diffusion_continuous_batching.md)

## Infrastructure and Performance

- [Prometheus Metrics](metrics.md)
- [Speech Generation Performance Optimizations](qwen3_omni_tts_performance_optimization.md)

## Module Design Documents

- [Entrypoints and Serving Boundaries](module/entrypoints.md)
- [vLLM-Omni Configuration](module/vllm_omni_config.md)
- [Input, Output, and Modality Contracts](module/input_output_modality_contracts.md)
- [Error Classification, Propagation, and Rendering](module/error_contracts.md)
- [Engine Orchestration](module/engine_orchestration.md)
- [Stage Runtime and Replica Lifecycle](module/stage_runtime.md)
- [OmniConnector](module/omni_connector.md)
- [Model Integration](module/model_integration.md)
- [Autoregressive Runtime](module/ar_runtime.md)
- Diffusion
    - [Overview](module/diffusion/index.md)
    - [Runtime](module/diffusion/diffusion_runtime.md)
    - [Model Integration](module/diffusion/diffusion_model_integration.md)
    - [Continuous Batching](module/diffusion/continuous_batching.md)
    - [Parallelism](module/diffusion/parallelism.md)
    - [Offloader](module/diffusion/offloader.md)
- [Execution Platforms](module/execution_platforms.md)
- [Cache Management](module/cache_management.md)
- [Host Weight Runtime](module/host_weight_runtime.md)
- [Quantization](module/quantization.md)
- [Observability](module/observability.md)
- [Profiling](module/profiling.md)
- [Benchmarking](module/benchmarking.md)

The pre-#5137 pages are preserved in the
[legacy module archive](module/archive/README.md) for historical reference and
are not active design contracts.