Vercel Policy Guardrails

Prerequisites

• ESLint configured in project
• Pre-commit hooks infrastructure
• CI/CD pipeline with policy checks
• TypeScript for type enforcement

Instructions

Policy guardrails for Vercel deployments protect against the most common failure modes: accidental secret exposure in client bundles, deployment to wrong environments, incompatible edge runtime API usage, and runaway serverless function costs. Implementing guardrails at multiple enforcement points (lint, pre-commit, CI, and runtime) ensures that issues are caught as early as possible in the development lifecycle rather than discovered in production.

Step 1: Create ESLint Rules

Implement custom lint rules that flag Vercel-specific anti-patterns: using process.env variables prefixed with NEXT_PUBLIC_ for secrets (which exposes them in the client bundle), importing Node.js-only modules in files with export const runtime = 'edge', and omitting explicit region configuration for latency-sensitive edge functions. Rules should provide error messages that clearly state what is wrong and suggest the correct approach.

Step 2: Configure Pre-Commit Hooks

Set up pre-commit hooks that scan staged files for Vercel project IDs, deployment tokens, or other credentials that should not enter version control. Pair with a .env.example file that documents required variables without values so contributors know what to configure without copying secrets.

Step 3: Add CI Policy Checks

Implement CI checks that validate the Vercel configuration file (vercel.json) schema, confirm that all environment variables referenced in code are declared in your deployment configuration, and run bundle size analysis to alert when the JavaScript bundle crosses your performance budget thresholds.

Step 4: Enable Runtime Guardrails

Add middleware that enforces authentication on all routes matching your protected path patterns, with a fallback to a clear error page for unauthenticated requests rather than a broken UI state.

Output

• ESLint rules detecting secret exposure and edge runtime incompatibilities
• Pre-commit hooks preventing credentials from entering version control
• CI checks validating configuration schema and bundle size budgets
• Middleware enforcing authentication on all protected routes

Error Handling

See ${CLAUDE_SKILL_DIR}/references/errors.md for comprehensive error handling.

Examples

See ${CLAUDE_SKILL_DIR}/references/examples.md for detailed examples.

Resources

• ESLint Plugin Development
• Pre-commit Framework
• Open Policy Agent

Overview

Implement Vercel lint rules, policy enforcement, and automated guardrails.