Grow the Mellos map: set the title and diagram kind, add layer bands, lanes and groups (labeled subsystems within ONE band — declare them when a single band grows crowded, roughly five or more nodes in that band; a group must be a strict subset of its band, and a map spread thin across many bands needs none), add nodes, add dependency edges. Declare the missing design after reading existing pages with mmap_read; reuse verified nodes. Edges must point strictly downward (a node may only use nodes on lower layers); the batch is all-or-nothing. Title and kind can also be changed with mmap_update; this legacy form remains supported. Revising what already exists (moving, renaming, relabeling, clearing) is mmap_update.

The revision tool, all-or-nothing. Record progress on nodes: in-progress when starting a node (the pane spins), done with evidence when its verification passes, regressed with evidence when a done node breaks. Revise what the ghost design got wrong: move a node to another band, join or leave a group or lane, rename a band (or re-rank it, which reorders the whole map), relabel a group or a lane. Every clearable field takes null to empty it — that is how a field is cleared, never an empty string. Bands, groups and lanes are applied before the node updates, and within one node update layer moves the node before its other fields. The map is a ledger: report honestly, it never blocks you.

Read existing pages before creating a map. Returns structured IDs, revisions and bounded results. pages lists summaries; map reads page metadata/context; nodes/edges/layers/groups/lanes read editable records; neighborhood reads related nodes; changes compares saved source hashes with local files. New conversations and compacted context should resume the existing effort. mmap_view remains the picture.

Atomically combine additions, updates and removals on ONE page. Checks the final graph, so a coordinated move or edge replacement needs no intermediate saves. Read IDs and revision with mmap_read first. Cross-page deletion is excluded.

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. pages is the other scale: it DELETES whole page files, so a finished effort can be cleaned up instead of accumulating tabs forever. A bare {pages: ["slug"]} with no other field is the normal form; combined with map edits, the edits are applied first and the pages are deleted after. The deletion is permanent and cannot be undone, so delete only pages whose effort is over — and only ever with the user behind it. An unknown slug is refused with the project's real page list (naming a page that does not exist is a typo, not a request). The default page has no slug and is not deletable here. A node elsewhere still pointing at a deleted page with submap stays legal — a submap reference has no existence invariant — but it has nowhere to dive until the page comes back.

Get or set the mapping policy — WHEN the assistant opens a Mellos map. Call with no arguments to read it: the reply names the policy chosen for the USER (every project), the one this PROJECT overrides it with if any, and which of them is in effect. If it reports "not set", ask the USER to choose (never pick for them): always = map every structured task — workflows, designs, architecture, technical dependencies; complex = map only medium or complex tasks — several modules, a new subsystem, roughly an hour or more; on-request = map only when the user explicitly asks. Then call again with their choice to persist it. It defaults to user scope, which is the normal one — the question is about how someone works, so it is asked once ever, not once per repository. Pass scope: "project" only when the user wants THIS project to differ from that habit. The policy guides you; it never blocks the tools, and an explicit user request for a map always wins.

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. Every response ends with a pages: line naming the pages this project actually has and which one you are looking at, so this is also how you discover whether a map exists at all and under which slugs — never probe the files.

For automatic display beside the current ChatGPT desktop conversation in Codex mode, use surface: "web-terminal", then call open_in_codex with the returned browser hostOpen object. No paste or Computer Use is needed. For the native host terminal, use surface: "codex-terminal": prepare absolute watcher commands for the current project, then ask the host to open its right terminal. This does not launch the watcher or type into that terminal. Agent exec PTYs cannot be attached using their numeric session ids. For a document panel, use surface: "markdown": generate MD + SVG files, enable automatic preview updates after successful map writes, then use the HOST file-opening tool to display the returned absolute Markdown path on the right of the current conversation. Generated does not mean visible: this server cannot open or observe the desktop side panel. For interactive maps, choose surface: "web": start or reuse a project-local web viewer and pass the returned URL to the host browser-opening tool. Markdown and terminal remain available. The default surface is "terminal", preserving the terminal workflow. Put the live map on the user's screen: a terminal pane beside this conversation that redraws on every write. Call it whenever a result says pane: CLOSED — and do NOT ask permission first, because a user who has set a mapping policy has already said they want to see the map. With a pane already open this RETARGETS it to page instead of opening a second one, so it is also how you show the user a particular page when they ask for one. It never closes a pane: taking the map off the screen belongs to the user (the q key in the pane, or typing mmap in a terminal). The reply says whether a pane actually reported itself in afterwards, not merely that a command was run. Automatic terminal opening supports Windows Terminal, tmux on Linux/macOS, and Pebrel, which splits the conversation's own pane. omp (Oh My Pi) has no side panel of its own: there the routes are this same terminal pane (a Windows Terminal split, or a tmux split on Linux/macOS) and the web viewer, whose URL the session opens with its own browser tool. If opening fails, relay the reason and copyable command; retry only after the environment changes or the user asks.