mcp-handlerSAFE
Easily spin up an MCP Server on Next.js, Nuxt, Svelte, and more
Overview
From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.
mcp-handler is a framework-agnostic HTTP adapter for hosting Model Context Protocol (MCP) servers in JavaScript and TypeScript applications. It turns an MCP server definition into a Web-standard (Request) => Promise handler that can be mounted in Next.js, Nuxt/Nitro, SvelteKit, Hono, and other Fetch-compatible frameworks.
Built on MCP SDK v2, it serves the 2026-07-28 MCP specification natively while transparently falling back to stateless Streamable HTTP for 2025-era clients — one handler, both protocol generations.
Installation
npm install mcp-handler@^2 @modelcontextprotocol/server@^2 zod@^4
Note:mcp-handler2.x requires the MCP SDK v2 packages (@modelcontextprotocol/server^2.0.0), zod ^4.2.0, and Node.js 20+. If you're on@modelcontextprotocol/sdk1.x, usemcp-handler1.x.
Framework Compatibility
createMcpHandler returns a Web-standard request handler, so the package is not tied to Vercel or any particular framework. It can be mounted in:
- Next.js Route Handlers
- Nuxt/Nitro server handlers using
fromWebHandler - SvelteKit server routes
- Hono
17e765065600OBSERVED · 2026-10-12Connect
Built from this server's own package name, version and transport as found in its source — not copied from anyone's documentation, so it cannot drift against a page we do not control.
claude mcp add mcp-handler -- npx -y [email protected]
{
"mcpServers": {
"mcp-handler": {
"command": "npx",
"args": [
"-y",
"[email protected]"
]
}
}
}Exposed tools (4)
4 read · 0 write · 0 destructive.
| Tool | Risk | Description |
|---|---|---|
echo | read | |
issue.created | read | New issues |
roll_dice | read | |
secret | read |
Trust audit
SAFEgrade B · trust 86/100 Nothing in the source contradicts what it says it does. Grade A is reserved for packages that have also passed the behavioural sandbox.
| Layer | What it checks | Result |
|---|---|---|
| L0 | Provenance & inventory | PASS |
| L1 | Static analysis of the code | PASS |
| L2 | Instruction surface (what it tells the agent) | PASS |
| L3 | Class-specific surface | WARN |
| L4 | Behavioural (sandbox) | SKIPPED |
What the source does
- Filesystem
- none-observed
- Network
- declared (1 observation(s))
- Shell
- declared (1 observation(s))
- Dependencies
- not all pinned
- Secrets in source
- none-found
Findings (8)
streamable-http
new Function("document", "navigator", "fetch", "console", script)(const handler = new Function(
new Function("navigator", "document", script)(new Function("navigator", "document", script)(undefined, undefined),const decoded = atob(encoded);
chalk, commander, @changesets/cli, @modelcontextprotocol/client, @modelcontextprotocol/server, @types/node, tsup, typescript
Gates applied: no_behavioural_pass, no_license.
17e765065600full audit observations/trust-audit/mcp-server/vercel__mcp-handler.json · Report an issue / request a re-scanAudit history
Every audit this server has had. A grade with a past is a grade somebody is still checking.
| Date | Source | Verdict | Grade | Score | Change |
|---|---|---|---|---|---|
| 2026-10-12 | 17e765065600 | SAFE | B | 86 | first audit |
Questions
What is the mcp-handler MCP server?
Easily spin up an MCP Server on Next.js, Nuxt, Svelte, and more
What tools does mcp-handler expose?
4 in total: 4 read-only, 0 that write, and 0 that can delete or overwrite. Every one is listed on this page with its risk.
Is mcp-handler safe to connect to an agent?
The audit found nothing in the source that contradicts what it says it does, and graded it B (86/100). Grade A is held back for packages that have also passed a sandboxed behavioural run, which is why a clean server reads B.
What credentials does mcp-handler need?
No credential environment variables were found in its source, so it appears to need none.
How does mcp-handler run?
It speaks streamable-http, so it runs as a service you connect to over the network. It is published on npm as mcp-handler at 2.3.0.
How current is this page?
The grade is for one exact copy of the source (17e765065600), read on 2026-10-12. The repository is watched and re-audited when it changes.