Vercel Security Basics

What it does

When your agent uses it

• Securing API keys
• Configuring security headers
• Auditing Vercel security configuration
• With phrases like vercel security

Example prompts

• “vercel security”
• “vercel secrets”
• “secure vercel”
• “/vercel-security-basics”

Requirements

• A credential in API_SECRET
• A credential in VERCEL_TOKEN
• Compatibility (from SKILL.md): Designed for Claude Code
• Pre-approved tools (allowed-tools): Read, Write, Edit, Bash(vercel:*), Grep

Workflow steps

6 steps, taken from the step headings in SKILL.md.

1. 1Secret Management with Environment Variables
2. 2Security Headers via vercel.json
3. 3Security Headers via Edge Middleware
4. 4Deployment Protection
5. 5Access Token Best Practices
6. 6API Route Authentication

What it can do on your machine

Read from SKILL.md and the folder at commit cfae287. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Write
  • Edit
  • Bash(vercel:*)
  • Grep

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • vercel
  • curl

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Hosts in commands or code, which the agent is likely to contact:

  • api.vercel.com

  Also links to:

  • vercel.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names these keys or tokens, usually read from environment variables:

  • API_SECRET
  • VERCEL_TOKEN
  • INTERNAL_API_KEY

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

• Compatibility

  Designed for Claude Code

  From compatibility in the SKILL.md frontmatter.

Context cost

Vercel Security Basics loads about 1.9k tokens when it runs, and up to ~2.6k if it reads all its reference files. Until then it costs about 79 tokens; SKILL.md has 402 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~79

When it runs · the whole SKILL.md, loaded when a task matches

~1.9k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~2.6k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• NoteMentions a .env fileSKILL.md:161

  1. Never commit tokens to git — use `.env.local` or CI secrets

• NoteMentions a .env fileSKILL.md:202

  | `.env.local` in `.gitignore` | Required |

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from jeremylongshore/tons-of-skills-marketplace at commit cfae287, republished under its MIT licence (© jeremylongshore). 402 words, ~1,894 tokens.

name

vercel-security-basics

description

Apply Vercel security best practices for secrets, headers, and access control. Use when securing API keys, configuring security headers, or auditing Vercel security configuration. Trigger with phrases like "vercel security", "vercel secrets", "secure vercel", "vercel headers", "vercel CSP".

allowed-tools

Read, Write, Edit, Bash(vercel:*), Grep

compatibility

Designed for Claude Code

version

1.18.0

license

MIT

author

Jeremy Longshore <jeremy@intentsolutions.io>

tags

saas, vercel, security, headers, secrets

# Add secrets scoped to specific environments
vercel env add DATABASE_URL production
vercel env add DATABASE_URL preview
vercel env add DATABASE_URL development

# Use 'sensitive' type — values hidden in dashboard and logs
vercel env add API_SECRET production --sensitive

# Via REST API
curl -X POST "https://api.vercel.com/v9/projects/my-app/env" \
  -H "Authorization: Bearer $VERCEL_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "key": "API_SECRET",
    "value": "sk-secret-value",
    "type": "sensitive",
    "target": ["production"]
  }'

{
  "headers": [
    {
      "source": "/(.*)",
      "headers": [
        { "key": "X-Content-Type-Options", "value": "nosniff" },
        { "key": "X-Frame-Options", "value": "DENY" },
        { "key": "X-XSS-Protection", "value": "1; mode=block" },
        { "key": "Referrer-Policy", "value": "strict-origin-when-cross-origin" },
        { "key": "Permissions-Policy", "value": "camera=(), microphone=(), geolocation=()" },
        {
          "key": "Strict-Transport-Security",
          "value": "max-age=63072000; includeSubDomains; preload"
        },
        {
          "key": "Content-Security-Policy",
          "value": "default-src 'self'; script-src 'self' 'unsafe-inline' https://vercel.live; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; font-src 'self' https://fonts.gstatic.com; connect-src 'self' https://api.vercel.com"
        }
      ]
    }
  ]
}

// middleware.ts
import { NextResponse } from 'next/server';
import type { NextRequest } from 'next/server';

export function middleware(request: NextRequest) {
  const response = NextResponse.next();

  // Security headers
  response.headers.set('X-Content-Type-Options', 'nosniff');
  response.headers.set('X-Frame-Options', 'DENY');
  response.headers.set('Referrer-Policy', 'strict-origin-when-cross-origin');
  response.headers.set(
    'Strict-Transport-Security',
    'max-age=63072000; includeSubDomains; preload'
  );

  // Remove server version headers
  response.headers.delete('X-Powered-By');

  return response;
}

// vercel.json
{
  "deploymentProtection": {
    "preview": "vercel-authentication",
    "optedOutFrom": []
  }
}

# Generate a bypass secret in Vercel dashboard > Settings > Deployment Protection
# Use in CI with:
curl -H "x-vercel-protection-bypass: your-bypass-secret" \
  https://my-app-preview.vercel.app/api/health

# Create scoped tokens — restrict to one team and project
# Settings > Tokens > Create Token:
# - Scope: Team → your-team
# - Expiration: 90 days (for CI)
# - Permissions: Deployment-only (no team admin)

# Rotate tokens on a schedule
# In CI (GitHub Actions):
# Store as GitHub Secret: VERCEL_TOKEN
# Set expiry alerts in your calendar

// api/protected.ts
import type { VercelRequest, VercelResponse } from '@vercel/node';

export default function handler(req: VercelRequest, res: VercelResponse) {
  // Verify API key from header
  const apiKey = req.headers['x-api-key'];
  if (!apiKey || apiKey !== process.env.INTERNAL_API_KEY) {
    return res.status(401).json({ error: 'Unauthorized' });
  }

  // Verify origin for CORS
  const origin = req.headers.origin;
  const allowedOrigins = (process.env.ALLOWED_ORIGINS ?? '').split(',');
  if (origin && !allowedOrigins.includes(origin)) {
    return res.status(403).json({ error: 'Forbidden origin' });
  }

  res.json({ data: 'protected content' });
}

© jeremylongshore, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 3 other files (references) in skills/.curated/vercel-security-basics of jeremylongshore/tons-of-skills-marketplace.

• SKILL.md
• references/errors.md
• references/examples.md
• references/implementation.md

Open the folder on GitHubat commit cfae287