io.github.hudsonkit/arc

Arc

Is the Arc MCP server down? No. It answered initialize and tools/list in the probe of 2026-10-26.

Author, validate, lay out, render, and diff architecture diagrams as code.

alive probed 2026-11-14 · unchanged since 2026-10-26

10tools

4.1ktokens in Claude Opus 5.5

2.0 %of Claude's 200k window

1.6×the median server

286 msto initialize

11 msto list tools

Run it: npx -y @hudsonkit/arc-mcp@0.14.1 (stdio, probed in a container with the network off)
Host: npmjs.com
Reports itself as: arc 0.14.1
Capabilities: resources, tools
Instructions: none
Of a 1M window: 0.4 % of a 1M context window
Count: 4.1k tokens in Claude Opus 5.5, exact, measured 2026-10-26. With the Claude Code prefix mcp__…__ on each tool name: 4.1k. The o200k_base estimate is 2.2k. Counted again when the tool definitions change. Method.
Repository: https://github.com/hudsonkit/arc
Website: https://hudsonkit.com/arc
Registry: active, updated 2026-10-25 · registry entry

Most expensive tools

The Claude column scales the o200k estimate of each tool by this server's ratio of exact to estimate, 1.83×.

Tool	≈ Claude tokens	o200k estimate	Share of this server
render_html	871	476	21 %
render_animation	711	389	17 %
render_png	547	299	13 %
render_svg	505	276	12 %
diff_diagram	311	170	8 %

Other registry entries on npmjs.com, the ones next to this name; all of them.

Servers that mention architecture or diagrams.

The result of the latest probe, the tool count and the token cost. The feed has an entry for every probe that changed them.

Stops answering, comes back, tool set or cost changes. One confirmation mail first, a stop link in every mail.