flins: Skill for Claude Code

Convex Security Check

A quick security audit checklist for Convex applications covering authentication, function exposure, argument validation, row-level access control, and environment variable handling.

Documentation Sources

Before implementing, do not assume; fetch the latest documentation:

• Primary: https://docs.convex.dev/auth
• Production Security: https://docs.convex.dev/production
• Functions Auth: https://docs.convex.dev/auth/functions-auth
• For broader context: https://docs.convex.dev/llms.txt

Instructions

Security Checklist

Use this checklist to quickly audit your Convex application's security:

1. Authentication

• Authentication provider configured (Clerk, Auth0, etc.)
• All sensitive queries check ctx.auth.getUserIdentity()
• Unauthenticated access explicitly allowed where intended
• Session tokens properly validated

2. Function Exposure

• Public functions (query, mutation, action) reviewed
• Internal functions use internalQuery, internalMutation, internalAction
• No sensitive operations exposed as public functions
• HTTP actions validate origin/authentication

3. Argument Validation

• All functions have explicit args validators
• All functions have explicit returns validators
• No v.any() used for sensitive data
• ID validators use correct table names

4. Row-Level Access Control

• Users can only access their own data
• Admin functions check user roles
• Shared resources have proper access checks
• Deletion functions verify ownership

5. Environment Variables

• API keys stored in environment variables
• No secrets in code or schema
• Different keys for dev/prod environments
• Environment variables accessed only in actions

Authentication Check

// convex/auth.ts
import { query, mutation } from "./_generated/server";
import { v } from "convex/values";
import { ConvexError } from "convex/values";

// Helper to require authentication
async function requireAuth(ctx: QueryCtx | MutationCtx) {
  const identity = await ctx.auth.getUserIdentity();
  if (!identity) {
    throw new ConvexError("Authentication required");
  }
  return identity;
}

// Secure query pattern
export const getMyProfile = query({
  args: {},
  returns: v.union(v.object({
    _id: v.id("users"),
    name: v.string(),
    email: v.string(),
  }), v.null()),
  handler: async (ctx) => {
    const identity = await requireAuth(ctx);
    
    return await ctx.db
      .query("users")
      .withIndex("by_tokenIdentifier", (q) => 
        q.eq("tokenIdentifier", identity.tokenIdentifier)
      )
      .unique();
  },
});