V8 MCP Server

mcp-v8 is a Model Context Protocol server, written in Rust, that lets an AI agent run JavaScript and TypeScript in a sandboxed V8 isolate. Instead of wiring up dozens of narrow tools, you give the agent one tool - run_js - and it writes code: looping, branching, transforming data, and calling other tools, often with far fewer tokens than equivalent tool-call chains.

People who need filesystem tools inside Claude, Cursor, VS Code, or another MCP client. The project is written in Rust.

VERIFIED ACTIVE

LAST COMMIT 2026-09-08 · ★ 57 · #25 OF 41 MAINTAINED FILESYSTEM · VERIFIED 2026-09-18

AGPL-3.0 · Rust servers · how we verify → /methodology

01 · Install V8

before you install - you'll need

MCP_V8_URL

Environment variables documented in the project's README - it lists which are required and which have defaults.

Docker

docker run -i --rm docker.io/wholelottahoopla/mcp-js:0.21.0-rc.2

Claude Desktop - add to config

{
  "mcpServers": {
    "r33drichards-mcp-js": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "docker.io/wholelottahoopla/mcp-js:0.21.0-rc.2"
      ]
    }
  }
}

Using another client? Same JSON, different key

Claude Desktop · mcpServers

Cursor · mcpServers

VS Code · servers

Windsurf · mcpServers

Zed · context_servers

Cline · mcpServers

Roo Code · mcpServers

Continue · mcpServers

LibreChat · mcpServers

Gemini CLI · mcpServers

Codex CLI · mcp_servers

Full setup guides: every client.

02 · Evidence

Security posture

What to check before giving this server access to your agent - from the registry, GitHub, and our own probes. We don't score safety; we show what's verifiable.

runs as container (OCI image) - can be sandboxed away from your filesystem

license AGPL-3.0 - declared in the repository

registry namespace io.github.r33drichards is GitHub-verified and matches the repo owner

03 · What V8 can do

Prose above is summarized from the project's README and registry record - no invented capabilities.

Limitations (from the README)

- setInterval is not available - use a loop with awaited setTimeout. - No DOM or browser APIs - there is no window/document. - TypeScript is type-stripped, not type-checked - invalid types are removed, not reported. JSX/TSX is not supported (it parses to a clear error).

Latest releases

v0.21.0-rc.2 · 2026-09-08

v0.20.1 · 2026-09-07

v0.20.0 · 2026-08-19

04 · Who maintains V8

mcp-v8 is maintained by r33drichards. It's the only MCP server we track from this author; the repo dates to Apr 2025.

05 · Facts

repository: github.com/r33drichards/mcp-js
category: filesystem - ranked #25 of 41 actively-maintained filesystem servers as of 2026-09-18.
release cadence: 7 releases in the last 90 days (latest 2026-09-08)
registry: io.github.r33drichards/mcp-js (active, first published 2026-09-07 · 3 versions)
packages: oci:docker.io/wholelottahoopla/mcp-js:0.21.0-rc.2

06 · V8 FAQ

What is V8?

Is V8 still maintained?

Yes - as of 2026-09-18, its last commit was 2026-09-08 and it shipped 7 releases in the last 90 days. We re-verify nightly.

How do I install V8?

Run `docker run -i --rm docker.io/wholelottahoopla/mcp-js:0.21.0-rc.2`. The README documents one environment variable (MCP_V8_URL) to set first. You can also paste the ready-made client config above.

07 · Alternatives to V8

Alternatives to V8

Maintained filesystem servers if V8 isn't the fit.

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