diff --git a/docs/design/server_contracts/index.md b/docs/design/server_contracts/index.md
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+# Server Contracts
+
+FastVideo's typed public API (`fastvideo.api`) is consumed by three
+server-class integrations that must share one execution substrate so we
+don't grow three near-duplicate progress loops:
+
+| Consumer | Transport | Request shape | State model |
+| --- | --- | --- | --- |
+| [Stateless OpenAI](openai.md) | HTTP POST `/v1/videos` | `VideoGenerationsRequest` → `GenerationRequest` merged onto `ServeConfig.default_request` | Stateless; optional `ContinuationState` round-trip |
+| [Streaming WebSocket](streaming.md) | WebSocket JSON + binary fMP4 | `GenerationRequest` per segment | Server-held `SessionStore`, snapshot-on-demand |
+| [Dynamo native backend](dynamo.md) | Dynamo RPC | `NvCreateVideoRequest` → adapter → `GenerationRequest` | Aggregated today; disaggregated via `ContinuationState` later |
+
+All three consume the same underlying surface:
+
+```python
+from fastvideo import VideoGenerator
+from fastvideo.api import (
+    ContinuationState,
+    GenerationRequest,
+    InputConfig,
+    OutputConfig,
+    SamplingConfig,
+    ServeConfig,
+)
+
+# Sync today, async after PR 7.10 lands VideoGenerator.generate_async.
+result = generator.generate(request)
+```
+
+These docs lock down the request/response shapes so drift between
+FastVideo, the internal UI, and Dynamo can be caught at review time.
+PR 8 does not ship runtime code; it ships the contract reference and
+the contract tests that guard it.
+
+## Related
+
+- [API refactor design](../overview.md)
+- Parity inventory: [`inference_schema_parity_inventory.yaml`](../inference_schema_parity_inventory.yaml)
+- [Streaming server upstream plan](../../../.agents/exploration/streaming-server-upstream-plan.md)
+- Draft PR (closed) that establishes the Dynamo shape:
+  https://github.com/ai-dynamo/dynamo/pull/7544
diff --git a/docs/design/server_contracts/openai.md b/docs/design/server_contracts/openai.md
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+# OpenAI-compatible HTTP Contract
+
+The stateless FastVideo HTTP server lives at
+[`fastvideo/entrypoints/openai/`](https://github.com/hao-ai-lab/FastVideo/tree/main/fastvideo/entrypoints/openai).
+Launch: `fastvideo serve --config serve.yaml`.
+
+## Endpoints
+
+| Method | Path | Description |
+| --- | --- | --- |
+| `POST` | `/v1/videos/generations` | Synchronous video generation |
+| `GET` | `/v1/videos` | List prior jobs held in the in-memory store |
+| `GET` | `/v1/videos/{id}` | Job status / result |
+| `GET` | `/v1/videos/{id}/content` | Download the MP4 once ready |
+| `POST` | `/v1/images/generations` | Synchronous image generation |
+| `GET` | `/v1/models` | Enumerate registered models |
+| `GET` | `/health` | Liveness probe |
+
+## `VideoGenerationsRequest` shape
+
+Mirrors the OpenAI `POST /v1/videos/generations` shape:
+
+```json
+{
+  "prompt": "a fox running through snow",
+  "size": "1024x1536",
+  "seconds": 5,
+  "fps": 24,
+  "num_frames": 121,
+  "seed": 42,
+  "num_inference_steps": 8,
+  "guidance_scale": 1.0,
+  "negative_prompt": "blurry, low quality",
+  "input_reference": "/path/to/init.png"
+}
+```
+
+SGLang-compatible extensions carried today:
+`num_inference_steps`, `guidance_scale`, `guidance_scale_2`,
+`true_cfg_scale`, `negative_prompt`, `enable_teacache`, `output_path`.
+
+## Merge precedence
+
+The server builds a `GenerationRequest` each call using three layers,
+highest first:
+
+1. **Request body (client-explicit)** — only fields carried in
+   `request.model_fields_set` (Pydantic v2). Unset fields do not count,
+   even if the Pydantic model has a schema default for them.
+2. **`ServeConfig.default_request` (operator-explicit)** — projected via
+   [`explicit_request_updates()`](../../../fastvideo/api/compat.py);
+   only fields the operator actually wrote into the YAML count as
+   defaults. Every other field inherits the schema default rather than
+   being pinned.
+3. **Hardcoded fallback** — e.g. `fps = 24`.
+
+The gate matters: both surfaces carry schema defaults. Without
+`model_fields_set` / explicit-path tracking, schema defaults would
+masquerade as intent and silently shadow the other side.
+
+See [`video_api.py::_build_generation_kwargs`](../../../fastvideo/entrypoints/openai/video_api.py)
+for the canonical implementation; the per-request assembly lives there,
+not in pipeline code.
+
+## Continuation state
+
+The stateless surface accepts an opaque `ContinuationState` round-trip.
+Clients that want continuation pass the prior `state` blob back on the
+next request, and receive a new one on the response when
+`request.output.return_state = true`.
+
+Shape:
+
+```json
+{
+  "state": {
+    "kind": "ltx2.v1",
+    "payload": { "schema_version": 1, "segment_index": 3, ... }
+  }
+}
+```
+
+Payload is always JSON-serializable. Large tensors may live in an
+opaque blob-store reference the client simply round-trips; see
+[`LTX2ContinuationState`](../../../fastvideo/pipelines/basic/ltx2/continuation.py).
+
+Continuation is not yet wired all the way through to
+`generator.generate_video(...)` — PR 7.6 (GPU pool upstream) is the
+pipeline-level consumer. PR 7 locked the envelope so this surface is
+stable ahead of that plumbing.
+
+## Error codes
+
+| HTTP | Condition |
+| --- | --- |
+| `400 Bad Request` | Parse/validation failure (unknown field, type mismatch, incompatible preset/state) |
+| `404 Not Found` | `GET /v1/videos/{id}` for an unknown job |
+| `409 Conflict` | Job id already exists |
+| `500 Internal Server Error` | Pipeline raised; body mirrors upstream OpenAI error envelope |
+| `503 Service Unavailable` | No generator loaded, or shutdown in progress |
+
+Errors include a JSON body with
+`{"error": {"type": "...", "message": "..."}}` matching the OpenAI
+Python SDK's expectation.
+
+## What does not cross this boundary
+
+* Flat legacy kwargs (`ltx2_refine_enabled`, `torch_compile_kwargs`,
+  etc.) — these are init-time, configured via `ServeConfig.generator`,
+  never per-request.
+* Private Dreamverse-only fields — those live in a private adapter on
+  the Dreamverse side; the public FastVideo surface never promises
+  backward compatibility for them.
+* Raw tensor payloads (`ltx2_audio_clean_latent` et al.) — these are
+  derived by the pipeline from `ContinuationState`, never shipped as
+  request fields.