MiniMax H3 Prompt Relay Preview / 时间线预检 (Advanced)

The most expensive way to find a timeline bug in a Prompt Relay workflow is to discover it twenty minutes into a render - overlapping events, a gap where the timeline isn't covered, an event whose range runs past the clip. MiniMaxH3PromptRelayPreviewT8Advanced exists to make that impossible: it validates an authenticated relay plan and shows you every event's frame and second range before any H3 model, CLIP, or VAE is loaded and before any sampling begins. You plug in a plan, hit run, and get the whole timeline back in seconds.

It's the relay system's answer to the pack's general preflight philosophy - check the cheap stuff first, then commit the expensive stuff. And it fits inline, not just as a one-off: the plan output is an unchanged pass-through, so you can drop a Preview between your Plan and your Conditioning node and keep it in the working graph permanently.

What it does

One required input - prompt_relay_plan - and five outputs:

• prompt_relay_plan - the same plan, passed through untouched.
• ready - a BOOLEAN. This is the gate: wire it somewhere that blocks the real render, or just read it.
• event_count - how many local events the plan carries.
• timeline_text - the human-readable rundown: each event, its frames, its seconds, whether it overlaps or leaves a gap.
• report_json - the machine-readable version for anyone who wants to parse it.

Validation isn't cosmetic. The plan's ranges have to obey the rules the Plan node enforces - sorted by start time, frames as integers with inclusive ends, percent within 0–100, no gaps or overlaps unless explicitly allowed, and the total must tile H3's frame grid. Preview catches all of that. It also gives you a zero-event plan the honest verdict: a global-only passthrough, which means "you built a relay plan that relays nothing - either add events or skip the relay entirely."

Why you'll want it in the graph

The README notes that the eleven generation templates in 14-prompt-relay each inline a Preview, plus there's a standalone plan/preview workflow (2026-08-20_H3_Prompt_Relay_Plan_Preview_Advanced_EXP.json). That's the tell: the author treats Preview as the normal first step of any relay run. When the relay mechanics fail you - an event never fires, an action starts mid-scene - the timeline report is the first thing to check, because if the ranges are right, the problem is the prompt or the model, not the plumbing. Cheap, deterministic, zero VRAM. There's no reason not to have one in line.

Install

Part of the MiniMax H3 Audio T8 pack:

cd ComfyUI/custom_nodes
git clone https://github.com/T8mars/comfyui-minimax-h3-audio-T8

or search "MiniMax H3 Audio T8" in ComfyUI Manager and restart. No pip deps, no model downloads - it's pure plan validation and runs on an empty machine. Preview first, patch later.