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Vercel AdapterSAFE

mcp/vercel/vercel-adapter-2
MCP server by vercel · Audited 2026-10-02
⚑ Report / re-scanSource ↗

Easily spin up an MCP Server on Next.js, Nuxt, Svelte, and more

Verdict
SAFE
Grade
B
Trust score
87 /100
Exposed tools
3 3r · 0w · 0d
Transport
streamable-http
License
—
Stars
678
01

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-handler 2.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/sdk 1.x, use mcp-handler 1.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
Read from source at commit 97ec27c26031OBSERVED · 2026-10-02
02

Connect

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-code
claude mcp add mcp-handler -- npx -y [email protected]
claude-desktop
{
  "mcpServers": {
    "mcp-handler": {
      "command": "npx",
      "args": [
        "-y",
        "[email protected]"
      ]
    }
  }
}
03

Exposed tools (3)

3 read · 0 write · 0 destructive.

ToolRiskDescription
echoread
roll_diceread
secretread
04

Trust audit

SAFEgrade B · trust 87/100 Nothing in the source contradicts what it says it does. Grade A is reserved for packages that have also passed the behavioural sandbox.

LayerWhat it checksResult
L0Provenance & inventoryPASS
L1Static analysis of the codePASS
L2Instruction surface (what it tells the agent)PASS
L3Class-specific surfaceWARN
L4Behavioural (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 (7)

MEDIUMAuth / authz · mcp.remote_no_auth · CWE-287, CWE-862
streamable-http
Why it matters. a network transport with no auth environment variable found
Fix. require a token
LOWInventory / provenance · inv.no_license · CWE-1104
Why it matters. no LICENSE file and no repo licence
Fix. add a licence
LOWCode injection · code.eval_exec · CWE-78, CWE-94, CWE-95
tests/webmcp-script.test.ts:62
new Function("document", "navigator", "fetch", "console", script)(
Why it matters. evaluates text as code
Fix. remove; use a parser or a dispatch table
LOWCode injection · code.eval_exec · CWE-78, CWE-94, CWE-95
tests/webmcp-script.test.ts:236
const handler = new Function(
Why it matters. evaluates text as code
Fix. remove; use a parser or a dispatch table
LOWCode injection · code.eval_exec · CWE-78, CWE-94, CWE-95
tests/webmcp.test.ts:123
new Function("navigator", "document", script)(
Why it matters. evaluates text as code
Fix. remove; use a parser or a dispatch table
LOWCode injection · code.eval_exec · CWE-78, CWE-94, CWE-95
tests/webmcp.test.ts:159
new Function("navigator", "document", script)(undefined, undefined),
Why it matters. evaluates text as code
Fix. remove; use a parser or a dispatch table
LOWSupply chain · supply.unpinned · CWE-829, CWE-1357
package.json
chalk, commander, @changesets/cli, @modelcontextprotocol/client, @modelcontextprotocol/server, @types/node, tsup, typescript
Why it matters. 10 dependency range(s) float
Fix. pin exact versions or ship a lockfile

Gates applied: no_behavioural_pass, no_license.

Audited 2026-10-02 · audit v0.4.1 · source sha 97ec27c26031full audit observations/trust-audit/mcp-server/vercel__vercel-adapter-2.json · Report an issue / request a re-scan
05

Audit history

Every audit this server has had. A grade with a past is a grade somebody is still checking.

DateSourceVerdictGradeScoreChange
2026-10-0297ec27c26031SAFEB87first audit
06

Questions

What is the Vercel Adapter MCP server?

Easily spin up an MCP Server on Next.js, Nuxt, Svelte, and more

What tools does Vercel Adapter expose?

3 in total: 3 read-only, 0 that write, and 0 that can delete or overwrite. Every one is listed on this page with its risk.

Is Vercel Adapter safe to connect to an agent?

The audit found nothing in the source that contradicts what it says it does, and graded it B (87/100). 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 Vercel Adapter need?

No credential environment variables were found in its source, so it appears to need none.

How does Vercel Adapter 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 2.2.0.

How current is this page?

The grade is for one exact copy of the source (97ec27c26031), read on 2026-10-02. The repository is watched and re-audited when it changes.

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