Extend Music · V6_MINI

What it is

Suno tracks like to stop when they feel like it. KIE_Next_V6_MINI_9dbf733f is the node that says "keep going" - it continues a track by its Suno audio_id rather than by uploading a file, which is the important structural difference from the Upload And Extend nodes beside it in the menu.

That distinction is the whole reason this node exists in a ComfyUI graph. If the track you want more of came out of Generate Music, you don't have it as a file yet - you have a task result. This node takes the identifier and asks KIE to carry on from a point you choose, using the fast V6_MINI tier. Two extensions in sequence is how you get from a 90-second sketch to something that can hold a three-minute edit.

How it works

The node submits an extend job to KIE's task API and polls for completion on its own - 2.5 seconds initially, backing off toward 15 - inside a timeout_seconds window that defaults to 1200 seconds and can go to 7200. Success means the result gets downloaded and decoded into ComfyUI's AUDIO type, so whatever comes next in the graph treats it as ordinary audio. The V6_MINI model string is sent inside the request; the outer job envelope carries KIE's market name for the extend endpoint. Cost lands on your KIE credits and is reported back to the node.

There's no local model here and no VRAM cost. What there is: your prompts and ids go to KIE, and the audio you get back is streamed to you from their storage.

Inputs that matter

• audio_id - required, and the one field you have to go find. It's the track id from a previous Suno generation, not the task id: open the earlier node's raw_json output (or all_urls_json context) and copy the track's id. Getting the task id instead is the classic wrong-value mistake.
• prompt - lyrics for the extended section when you're extending a vocal track. It's a required widget, though the docs treat the source id as enough on its own.
• continue_at - required-ish in practice, defaulting to 60 seconds. This is where the extension starts, and it must sit inside the original track - greater than 0 and less than the track's total length. Set it at the exact end and you're inviting a seam; set it a little before the end and the model has material to blend with.
• instrumental - optional, and here it defaults to false, the opposite of the Upload And Extend nodes. If you're extending an instrumental track, turn it on deliberately; when it's true the docs say not to pass lyrics, prompt or vocal_gender at all.
• style - optionally steer the new section, though the docs note it should usually match the original for the seam to sell.
• title, negative_tags, lyrics, variety - labelling, exclusion, explicit lyrics (which override prompt), and stylistic spread from 0 to 4.
• style_weight, weirdness_constraint, audio_weight - all defaulting to 0.65. For extension work, audio_weight and a restrained weirdness_constraint are what keep the new section sounding like the same band.
• persona_id + persona_model - carry a saved style or voice persona into the extension.

Outputs

audio is the extended track, ready for Save Audio or a video mux. url is the primary result URL. all_urls_json is every URL the provider returned - worth reading, since these endpoints return more than one take and the socket only carries the first. task_id matters more here than on most nodes: it's the handle for chaining another extension or editing the result further. raw_json is the full response, and credits_consumed / credits_left report the spend.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/felipederosilva/ComfyUI-KIE-Nodes-Next
cd ComfyUI-KIE-Nodes-Next && pip install -r requirements.txt

Restart ComfyUI. The dependency list is requests, Pillow, numpy, PyYAML - no models to download, nothing to fit in VRAM. Windows users can run the one-click installer from the repo's dist/ folder instead. ComfyUI Manager listing is the pack's stated direction (it ships registry metadata under publisher felipeosilva), but the clone is the route that works today.

Set the key once in Settings → KIE.ai Nodes Next → Connection; it's validated before replacing anything saved, and KIE_API_KEY wins if you're on a headless server.

Where it goes wrong

Wrong id. Task id instead of track id, or an id from a different account - you'll get a failed job, not a helpful message.

continue_at past the end. Documented as needing to be inside the track's duration.

Timing out mid-flight. The provider often finishes after your patience does. Re-poll task_id with KIE • Wait for Task before spending credits on a resubmit.

Seams. Not an error, just the physics of it: overlap the extension point slightly rather than starting at the last sample of the original.