MiniMax H3 Checkpoint Manager

MiniMax H3 Checkpoint Manager is the browser for your chain's hard drive. The recursive loop saves a checkpoint for every accepted take, and across a long production with retries and rerolls that's a branching tree of saved scenes. This node lets you walk that tree, preview the media, and then hand a specific lineage to a deferred upscale - without rerendering anything.

It's not a rendering node at all. There's one required input, selection_json, which is a hidden serialized string the node's own browser UI maintains - you don't type into it. The optional plan input is there if you want "Load selected branch" to restore an editable H3 Chain Plan, but the tooltip is explicit that you don't need it for inspection, deletion, or deferred upscaling. So the shape of the node is: browse in the UI, act from the outputs.

What you can do here

• Preview saved media per scene and inspect the exact video/audio context dependencies and their storage - the chain is a DAG of continuations, and knowing what a checkpoint depends on matters before you touch it.
• Emit a selected lineage - the selected_manifest output is a verified H3_CHAIN_MANIFEST for the chosen branch. This is deliberately the only input the Checkpoint Upscale Adapter accepts. You pick a branch tip, and the manager validates the immutable lineage and embeds the recovery metadata (compatibility hashes, Source Timeline) so the upscale child graph needs no source Plan or decoded media.
• Load any branch into a connected Plan for further edits or re-renders.
• Delete inactive leaves, safely. Deleting is leaf-first, one revision at a time, and the manager shows you a complete deletion preview before anything is removed. The reasoning is documented in the pack's runs-and-recovery notes: no bulk deletion, because the leaf-first workflow makes the exact context consequences visible instead of silently orphaning later checkpoints.

The plan pass-through is nice in practice: you can leave Checkpoint Manager connected in a generation workflow, where it just passes the Plan through, and use it as a standalone browser when you need it.

Where it shines

The intended flow is: finish a branch, open Checkpoint Manager, select the final scene of the complete branch, and use its selected_manifest to feed either the Full-Chain Latent Video Adapter (whole-video SeedVR2 finishing) or the Checkpoint Upscale Adapter (per-scene LBH de-rope upscale). A partial generated lineage is a valid manifest even if the saved Plan contains later scenes - so you can upscale everything you've accepted so far and keep going.

Installing it

In ComfyUI-MiniMaxH3-Contex-Loop. ComfyUI Manager: search "MiniMax H3 Contex Loop". Or:

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

Restart ComfyUI. It appears under conditioning/minimax/contex_loop alongside the rest of the chain nodes. No extra Python deps beyond the pack itself; you still need the H3 weights and a ComfyUI build with native Add Guide (PR #15439).

Common issues

The main gotcha is wiring selected_manifest to the wrong thing. It's a verified manifest for the selected lineage - if you haven't selected a branch in the UI, you can end up feeding an empty or stale lineage to the upscaler. And since the manager defers the upscale graph entirely (no source Plan needed), don't expect the child graph to know your reference media - that's exactly why the upscale path uses cached reference descriptors. When a branch refuses to delete, it's almost always because later checkpoints depend on it; walk the leaves first.