MiniMax H3 Contex Loop Start

MiniMax H3 Contex Loop Start is the entry point to the recursion that makes this pack different from a one-shot H3 render. It takes a validated Plan, kicks off scene 1, and - the part nobody else gives you for free - lets you resume an interrupted production from any contiguous scene without rerendering what you already approved.

The trick that makes the whole loop work: Loop Start is only fully executed once, at the top of the run. Inside the recursion, ComfyUI re-invokes it with the loop's internal state and it acts as a pass-through - the flow output is a raw link that defines the recursive body, and Loop End clones that body for later scenes. That's why the tooltip is so insistent: flow must connect directly to Loop End's flow input, not through other nodes. Break that and the recursion can't self-clone.

The inputs you'll set

• plan - the validated output from H3 Chain Plan. Nothing happens without it.
• start_clip - legacy/resume scene to render next. 1 starts a new chain. A value above 1 loads and validates the saved checkpoint for the preceding scene before resuming - this is the resume mechanism.
• scene_range (optional) - the modern way to pick your range. Leave blank to run from start_clip to the end; 3 runs only scene 3; 3:8 runs scenes 3 through 8. A start above 1 requires the preceding checkpoint, and disjoint comma selections are rejected because they'd break continuity.
• verify_resume_history (optional, default ON) - the safety rail. It requires every completed predecessor to match the current Plan's prompts, seeds, timing, source audio, model and reference fingerprint before it will resume. Turn it off only to deliberately reuse a saved predecessor after changing the Plan. The docs are blunt: even with it off, missing files, SHA-256 artifact integrity, checkpoint tensor shape and internal metadata consistency are still verified. Changes to a predecessor are never applied retroactively.
• external_context (optional) - the output of MiniMax H3 Existing Video Context, when scene 1 should continue imported footage.
• source_timeline / source_audio (optional) - the 0.5 and legacy media routes respectively. They're mutually exclusive; connect one. In 0.5, source_timeline from the Source Timeline node is the primary route and stays lazy across recursive scenes. source_audio is the old full-AUDIO route, saved once as a path-backed run asset.

The outputs

flow (to Loop End), state (to Current Shot and the recursive body), and status - a STRING reporting the starting scene, total count, and resume/padding status. That status line is genuinely informative: it'll tell you when a run resumed, when history verification was disabled, and when silent source audio is being padded.

Where it shines

The preflight. Before H3 loads, Loop Start validates timing, media, references, compatibility and resume state - you find out about a broken scene_range or a mismatched Plan before burning a 40-minute render, which is exactly the kind of forethought the rest of ComfyUI usually leaves to you.

Installing it

Part of ComfyUI-MiniMaxH3-Contex-Loop (ComfyUI Manager: "MiniMax H3 Contex Loop"), or:

cd ComfyUI/custom_nodes && git clone https://github.com/ethanfel/ComfyUI-MiniMaxH3-Contex-Loop.git

Restart ComfyUI. Requires H3 weights and a current ComfyUI with native Add Guide (PR #15439).

Common issues

The top resume gotcha is a changed Plan: you edited scene 2's prompt after scene 1 was accepted, and resume refuses because verify_resume_history catches the mismatch. That's a feature - the fix is either reverting the change or deliberately disabling verification. And if you connect both source_timeline and source_audio, Loop Start raises a clear error rather than guessing. Most "stuck at scene 1" reports trace back to a broken flow connection; recheck that raw link first.