Mellos Mapping MCP Server

Mellos Mapping

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A live, terminal-native map of bottom-up development for Claude Code and Codex CLI.

While Claude builds your system, a split pane beside the conversation shows the system's layered dependency map: primitive layers at the bottom, dependency edges that may only point downward, ghost nodes for what is designed, a spinner on what is being built right now, and solid green for what is built and verified.

  Mellos Mapping · the plugin itself

━━━━━━━━━━━━━━━━━━━━━━━━━━ orchestration

  ╭╌╌╌╌╌╌╌╌╌╌╌╌╌╌╮
  ╎ · MCP Server ╎
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       │ │  │
       └─┼──┼─────────────┐
         │  └──────┐      │
         │         │      │
━━━━━━━━━┿━━━━━━━━━┿━━━━━━┿━━━ contracts
         │         │      │
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  ┃ ■ State Store ┃│ ╎ · Watcher ╎
  ┗━━━━━┯━━━━━━━━━┛│ ╰╌╌╌╌╌┬╌╌╌╌╌╯
        │          │       │
        │ ┌────────┘       │
        │ │                │
━━━━━━━━┿━┿━━━━━━━━━━━━━━━━┿━ primitives
        │ │                │
  ┏━━━━━┷━┷━━━━━━┓  ╭──────┴───────────╮
  ┃ ■ Map Domain ┃  │ ⠋ ASCII Renderer │
  ┗━━━━━━━━━━━━━━┛  ╰──────────────────╯

  · planned   ⠋ in-progress   ■ done   ✗ regressed

In a real terminal the wiring and band bars render FAINT while node boxes glow in their status colors with bold labels — a dark circuit board where the components are the bright things. Skip-level edges thread through gaps between boxes (watch the line dive between State Store and Watcher above); non-overlapping wire segments share track rows to keep the bands close.

(This is the plugin's own map, mid-development. The spinner really spins.)

Why

Most progress reporting is a task list — a top-down worldview. A Mellos map grows the other way: an upper node can only stand on nodes below it, and the picture makes the discipline visible:

• The ghost design appears before any code. Claude declares the whole intended structure as dashed ghost nodes first; you can veto a bad design while it is still only a picture.
• The spinner is where Claude's attention is. One glance answers "what is it doing right now, and on top of what?"
• Done means verified. A node turns solid green only with evidence (a passing test run). If later work cracks a foundation, the node turns red — a cracked foundation under a spinning upper floor is the most honest status report there is.
• The map is a ledger, not a judge. The tools refuse only structural corruption (an edge pointing upward, a duplicate rank). Workflow is Claude's discipline, defined in the bundled skill; violations are made visible, never silently blocked.

Install

Two lines inside any Claude Code conversation:

/plugin marketplace add GuangminJu/mellos-mapping
/plugin install mellos-mapping@mellos-mapping

Or one line in a terminal:

claude plugin marketplace add GuangminJu/mellos-mapping && claude plugin install mellos-mapping@mellos-mapping

Requires Node.js 18+ on PATH (Claude Code itself requires Node, so you already have it). No build step: the MCP server and watcher ship pre-bundled.

Update

claude plugin marketplace update mellos-mapping && claude plugin update mellos-mapping@mellos-mapping

Two steps because plugin update compares against the locally cached marketplace clone — the first command is what actually pulls this repo. Restart Claude Code to apply. Releases are version bumps on master. (In-app, /plugin opens the same management UI.)

Codex CLI

The same repo doubles as a Codex plugin (codex-cli 0.147+). Three lines:

codex plugin marketplace add GuangminJu/mellos-mapping
codex plugin add mellos-mapping@mellos-mapping
node ~/.codex/plugins/cache/mellos-mapping/mellos-mapping/<version>/scripts/codex-register.mjs

The first two install the skill (the map discipline) as a Codex plugin. The third registers the MCP server at user level — needed because Codex spawns plugin-bundled MCP servers inside the plugin cache with no way to see your workspace, so a bundled server would write the map into the cache. A user-level codex mcp add entry (which the script writes) inherits each session's working directory instead: the state file lands in your project, same as under Claude Code. The registered path is version-specific — re-run the script after updating the plugin.

To watch the live pane beside a Codex session on Windows, run node <plugin root>/scripts/open-pane.mjs <project dir> — it splits the terminal window hosting the session (or falls back to a dedicated "mellos-mapping" window; --window picks that on purpose). Elsewhere run node <plugin root>/dist/watch.mjs from the project directory in a second terminal (or any terminal split).

Any MCP client

The server ships on npm, so any MCP client (Cursor, Windsurf, Zed, Gemini CLI, …) can run it with a standard stdio entry:

npx -y mellos-mapping

The map file lands in the client session's working directory (.claude/mellos-mapping.json). Open the live pane from the same project:

npx -y -p mellos-mapping mellos-mapping-watch

The skill/discipline layer is Claude Code + Codex specific; other clients get the four mmap_* tools and the pane, and bring their own prompting.

Use

1. Ask Claude to build something non-trivial. The bundled skill has Claude declare the ghost design and keep the map current as it works.
2. Run /mellos-mapping:mmap to open the live pane (Windows Terminal split on Windows, tmux split inside tmux, or a printed command to run in any second terminal). On Windows the pane opens in the terminal window hosting YOUR session, even with several windows open; pass --window to put the map in its own dedicated window instead. Prefer --ascii if your font lacks box-drawing glyphs.
3. Watch nodes light up from the bottom. Interrupt when the picture worries you — that is what it is for.

The pane is mouse-aware (xterm SGR any-event tracking — the same protocol htop and tmux speak):

Zooming scales the picture first and switches display mode only at the ends of the ladder, so every level still shows meaningful data:

detail ← 100% ← 85% ← 70% ← 55% ← overview

• zoom in past 100% — evidence and design notes unfold inside the boxes;
• 85–55% — whitespace tightens and labels truncate proportionally, boxes stay boxes;
• below 55% — labels would stop meaning anything, so the map AGGREGATES: each declared group (a labeled subsystem within a band) becomes one box named foundation subsystem 1/2 with its status derived from the members, edges collapse onto the groups, ungrouped nodes stay themselves. Like a real map, zooming out shows province names — not anonymous dots. (A map with no groups falls back to a pure glyph constellation with per-band counts.) The footer always names the level.

The two detail rows live at a fixed spot between map and hint line, showing the focused node's status, layer, evidence and both wire directions (uses → … · used by ← …) — nothing ever floats over the map.

--no-mouse disables mouse reporting if your terminal multiplexer wants the mouse for itself.

Pages

A project can keep several maps side by side — one effort = one page. Claude targets a page by passing page to any mmap_* tool; the pane grows a tab bar as soon as a second page exists. The active tab is bold in its map's aggregate status color; when a background page's file changes, its tab lights up in status color instead of stealing your view. Each page remembers its own pan, zoom and pinned node. Because every page is its own file, two Claude sessions writing two pages can never clobber each other — this is also the answer to running several Claude sessions in one project.

State lives in .claude/mellos-mapping.json (the default page) plus .claude/mellos-mapping.pages/<page>.json for named pages — plain JSON, safe to commit if you want the maps' history in git.

Diagram kinds

The default kind, dev, is the living progress ledger described above. The same layered-DAG machinery also draws documentation diagrams: pass kind in mmap_declare and the page renders neutrally — plain solid boxes, no ghosts, no spinners, no progress counts.

Node kinds and edge labels work on dev maps too. State machines are out of scope on purpose: transitions cycle, and edges here only point downward.

Sub-maps

A node can link a child page with submap: <page-slug> — the pane badges it ⊞; double-click dives into the child map, Backspace climbs back out. A map of maps, built entirely from pages: no new storage, no new invariants. Whether a node deserves a sub-map is the AI's judgment call — most don't.

Sub-maps are interior detail, not siblings: a page referenced as a submap never occupies a tab. Inside a dive the tab row becomes a breadcrumb — ⌫ parent map ▸ node — and clicking it (or Backspace) climbs back out. When a hidden sub-map changes in the background, the footer says so.

MCP tools

Structural invariants enforced by the tools: layers form a total order by rank; every node lives in exactly one layer; edges point strictly downward — which makes the graph acyclic by construction; nodes may not depend on same-layer siblings (if A needs sibling B, either B is really a lower concept or A and B are one node).

Development

npm install
npm run verify   # typecheck + tests + bundle

The repo is itself layered bottom-up, and each layer has its spec:

dist/ is committed deliberately: plugin installation clones this repo and runs nothing, so entry points ship bundled.

License

MIT