io.github.mrfentmen/open5e-mcp

open5e-mcp

Is the io.github.mrfentmen/open5e-mcp MCP server down? No. It answered initialize and tools/list in the probe of 2026-11-09.

Open5e reference for D&D 5e: spells, monsters and magic items from the open SRD, with stats and text

alive probed 2026-11-14 · unchanged since 2026-11-09

4tools

755tokens in Claude Opus 5.5

0.4 %of Claude's 200k window

0.3×the median server

308 msto initialize

32 msto list tools

Run it: npx -y @mrfentmen/open5e-mcp@1.0.2 (stdio, probed in a container with the network off)
Host: npmjs.com
Reports itself as: open5e-mcp 1.0.1
Capabilities: tools
Instructions: none
Of a 1M window: <0.1 % of a 1M context window
Count: 755 tokens in Claude Opus 5.5, exact, measured 2026-10-31. With the Claude Code prefix mcp__…__ on each tool name: 803. The o200k_base estimate is 428. Counted again when the tool definitions change. Method.
Repository: https://github.com/mrfentmen/awesome-servers
Registry: active, updated 2026-11-08 · registry entry
Changes: 2 recorded, reachable in 2 of them. A row is added when the result, the tool count or the cost changes.

Most expensive tools

The Claude column scales the o200k estimate of each tool by this server's ratio of exact to estimate, 1.76×.

Tool	≈ Claude tokens	o200k estimate	Share of this server
search_spells	250	142	33 %
search_monsters	198	112	26 %
monster_detail	159	90	21 %
spell_detail	148	84	20 %

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

Servers that mention reference or monsters.

We add a row when the result changes. A server with no change keeps its last row.

Probed	Result	Init	Tools	Claude	o200k
2026-10-31 07:37	alive	315 ms	4	755	428
2026-10-17 06:18	alive	308 ms	2	254	136

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.