Grow the Mellos map: set the title and diagram kind, add layer bands, lanes and groups (labeled subsystems within a band — the zoomed-out view renders groups, so declare them for any map beyond a handful of nodes), add nodes, add dependency edges. Declare the whole ghost design up front, then grow it as understanding deepens. Edges must point strictly downward (a node may only use nodes on lower layers); the batch is all-or-nothing.

Update node status/label/evidence. Set in-progress when starting a node (the pane spins), done with evidence when its verification passes, regressed with evidence when a done node breaks. The map is a ledger: report honestly, it never blocks you.

Remove edges, nodes, groups and empty layer bands (in that order, all-or-nothing). Removing a node also removes every edge touching it; removing a group merely ungroups its members. Use when the ghost design turns out wrong — the map is a hypothesis, revising it is honest work.

Render the current Mellos map as monochrome text — the same picture the split-pane watcher shows live. Use it to check the map state or to show it inline in conversation.