Cosmos3 transfer fix (#5614)

Signed-off-by: Maciej Bala <mbala@nvidia.com>

docs/serving/videos_api.md

@@ -161,11 +161,21 @@ are not implemented yet. Models may expose additional V2V controls through
 `extra_params`. For example, Cosmos3 supports
 `condition_frame_indexes_vision` and `condition_video_keep` to select which
 decoded reference frames are used as clean conditioning. Cosmos3 transfer mode
-also accepts `edge`, `blur`, `depth`, `seg`, or `wsm` control hints plus
-transfer options such as `control_path`, `control_guidance`,
-`control_guidance_interval`, `num_video_frames_per_chunk`,
-`num_conditional_frames`, `show_control_condition`, and `show_input`; see the
-Cosmos3 recipe for complete examples.
+also accepts `edge`, `blur`, `depth`, `seg`, or `wsm` control hints. Each hint
+may specify its own `control_path` and `control_weight`. Request-level transfer
+options include
+`control_guidance`, `control_guidance_interval`,
+`emphasize_control_in_prompt`, `num_video_frames_per_chunk`,
+`num_conditional_frames`, `show_control_condition`, and `show_input`. Transfer
+uses its transfer-specific system prompt and, by default, appends a
+control-adherence directive to the positive prompt. It adds duration/FPS and
+resolution metadata to both CFG branches but does not add a negative prompt
+automatically. The Cosmos3 recipe includes an optional reference negative
+prompt and shows how to pass it. Set `emphasize_control_in_prompt`,
+`use_duration_template`, or `use_resolution_template` to `false` to disable the
+corresponding addition. `negative_metadata_mode` accepts `same`, `inverse`, or
+`none` and defaults to `same` for transfer. See the Cosmos3 recipe for complete
+examples.
 
 HTTP redirects for `image_reference.image_url` follow vLLM's
 `VLLM_MEDIA_URL_ALLOW_REDIRECTS` setting. Before starting the server, set it to