mcpcost

io.github.lu-zhengda/virtual-fs

Virtual Filesystem

Is the Virtual Filesystem MCP server down? No. It answered initialize and tools/list in the probe of 2026-10-31.

PostgreSQL-backed virtual filesystem for agents: session isolation, shared stores, POSIX ops, RLS.

alive probed 2026-11-14 · unchanged since 2026-10-31

11tools
3.0ktokens in Claude Opus 5.5
1.5 %of Claude's 200k window
1.2×the median server
279 msto initialize
10 msto list tools
Run it
npx -y mcp-virtual-fs@0.2.2 (stdio, probed in a container with the network off)
Host
npmjs.com
Reports itself as
mcp-virtual-fs 1.0.0
Capabilities
tools
Instructions
none
Of a 1M window
0.3 % of a 1M context window
Count
3.0k tokens in Claude Opus 5.5, exact, measured 2026-10-17. With the Claude Code prefix mcp__…__ on each tool name: 3.1k. The o200k_base estimate is 1.7k. Counted again when the tool definitions change. Method.
Repository
https://github.com/lu-zhengda/mcp-virtual-fs
Website
https://github.com/lu-zhengda/mcp-virtual-fs#readme
Registry
active, updated 2026-02-11 · registry entry

Most expensive tools

The Claude column scales the o200k estimate of each tool by this server's ratio of exact to estimate, 1.71×.

Tool≈ Claude tokenso200k estimateShare of this server
append34220012 %
write32418911 %
grep30818010 %
mv30017510 %
ls28416610 %

Compare this server with others.

More servers

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

Servers that mention virtual.

Badge for the README

mcpcost: alive

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

Atom feed

A mail when this server changes

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

For the publisher