MCP-JS
MCP server that exposes a V8 JavaScript runtime as a tool for AI agents. Sandboxed JS execution for one-off computation, parsing, and transformation. 43 GitHub stars and 45 commits on main in the last 30 days. 0BSD license.
“MCP server that exposes a V8 JavaScript runtime as a tool for AI agents. Sandboxed JS execution for one-off computation, parsing, and transformation. 43 stars and 45 commits on main in the last 30 days.”
INSTALL THIS SERVER
{
"mcpServers": {
"mcp-js": {
"command": "npx",
"args": [
"-y",
"mcp-js"
]
}
}
}
{
"mcpServers": {
"mcp-js": {
"command": "npx",
"args": [
"-y",
"mcp-js"
]
}
}
}
{
"mcpServers": {
"mcp-js": {
"command": "npx",
"args": [
"-y",
"mcp-js"
]
}
}
}
{
"mcpServers": {
"mcp-js": {
"command": "npx",
"args": [
"-y",
"mcp-js"
]
}
}
}
{
"mcpServers": {
"mcp-js": {
"command": "npx",
"args": [
"-y",
"mcp-js"
]
}
}
}
4 TOOLS AVAILABLE
OUR ASSESSMENT
- 45 commits on main in the last 30 days. Top-tier cadence.
- 0BSD license, the most permissive option available.
- V8-based sandbox runs JavaScript inside the MCP process.
- Sandbox-reset tool prevents state bleeding between agent invocations.
- No authentication required; ready immediately after install.
- Arbitrary code execution inside the agent loop; review the agent prompt path before mounting in production.
- 43 stars indicates early adoption.
- Community-maintained; no vendor support.
V8 sandbox isolates from the host process via the V8 isolate boundary. Operators decide which globals to expose. Treat the agent flow as having capability to compute anything expressible in JavaScript: regex DoS, infinite loops, and crypto-mining patterns are within scope. Prefer a CPU and memory budget on the host process for production agent flows.
Agents that need ad-hoc JS computation without leaving the agent loop; data transformation flows where a custom MCP is overkill; debugging agents that want to evaluate snippets against runtime state.
TECHNICAL DETAILS
ADOPTION METRICS
// Reading this43 stars on r33drichards/mcp-js. 45 commits on main in the last 30 days, top-tier cadence.
// Reading thisPairs with Chrome DevTools, Claude Code, OpenSpec, MCP Inspector for dev-tools developer infrastructure. V8 sandbox surface is unique.
SOURCES & VERIFICATION
We don't take any single directory's word for it. Before scoring, we cross-reference 3 public MCP sources, install the server ourselves against the clients we cover, and record when we last re-verified.
The same server, 3 different lenses. We reconcile these signals into our editorial score, which is why our number sometimes diverges from a directory-aggregate star count.
| Source | Their rating | Their star count | Their downloads | Last synced |
|---|---|---|---|---|
| AutomationSwitch This page | 4.2editorial | 43 | — | MAY 6, 2026 |
| PulseMCP | — unrated | unavailable | unavailable | MAY 6, 2026 |
| MCP.so | — unrated | unavailable | unavailable | MAY 6, 2026 |
| Glama | — unrated | unavailable | unavailable | MAY 6, 2026 |
// Counts are directory-reported; we don't adjust them. Discrepancies usually come from different snapshot times or star-caching.
OTHER DEV TOOLS MCP SERVERS
GitHub
Official GitHub MCP server. 29,469 stars, MIT, 33 commits on main in the last 30 days. Repo, issue, PR, action, and code search tools backed by the GitHub REST + GraphQL APIs.
Playwright
Official Microsoft Playwright MCP server. Browser automation tools (navigate, click, fill, screenshot, evaluate JS, network capture) backed by Playwright. 31,942 stars, 35 commits/30d, Apache-2.0.
MCP Inspector
The official MCP debugging and testing tool maintained by the Model Context Protocol project. Visual inspector for MCP servers: invoke tools, inspect transports, validate protocol behaviour during development. 9,647 GitHub stars and 32 commits on main in the last 30 days.
GitLab MCP
GitLab MCP with 60+ tools covering merge requests, repositories, issues, branches, commits, files, discussions, draft notes, approvals, pipelines, and OAuth multi-user support. 54 commits on main in the last 30 days.
OpenSpec
The leading spec-driven development workflow for AI agents. Implements the /opsx:propose → /opsx:apply → /opsx:archive cycle that scaffolds proposals, specs, design docs, and task checklists, then applies them and archives once shipped.
Chrome DevTools for Agents
Vendor-official Chrome DevTools MCP server from the Chrome DevTools team at Google. Lets agents control and inspect a live Chrome browser for automation, debugging, and performance analysis.
DISCUSS YOUR
MCP REQUIREMENTS.
Evaluating a server, scoping an internal deployment, or working out whether MCP is the right fit at all. Start the conversation and we will point you at the right piece of the ecosystem.