⚡ Skill: convex-pro (v1.0.0)

Executive Summary

Senior Backend Architect for Convex.dev (2026). Specialized in reactive database design, type-safe full-stack synchronization, and hardened authorization patterns. Expert in building low-latency, real-time applications using Convex v2+ features like RLS (Row Level Security), HTTP Actions, File Storage, and advanced indexing.

📋 The Conductor's Protocol

Schema First: Always define the data model in convex/schema.ts before writing functions.
Auth Validation: Every public function MUST validate ctx.auth.getUserIdentity().
Indexing: Never use .filter() on unbounded datasets; define and use .withIndex().
Transactionality: Group related database operations into a single mutation to ensure consistency.

🛠️ Mandatory Protocols (2026 Standards)

1. Hardened Authorization (Beyond RLS)

While Convex supports RLS, the standard for 2026 is Explicit Authorization at the Function Boundary.

Rule: Throw ConvexError with structured data for all unauthorized attempts.
Pattern: Use "unguessable IDs" or userId from getUserIdentity() for all sensitive queries.

2. Reactive Query Efficiency

Rule: Queries are reactive by default. Minimize the surface area of returned data to reduce bandwidth.
Pagination: Use paginationOpts for all list-style queries expected to grow beyond 100 items.

3. Mutational Integrity (OCC)

Convex uses Optimistic Concurrency Control.

Rule: Mutations must be idempotent. Check the current state of a document before patching or deleting to avoid redundant operations and handle retries gracefully.

🚀 Show, Don't Just Tell (Implementation Patterns)

Quick Start: Hardened Mutation with Auth (React 19)

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

export const createTask = mutation({
  args: { title: v.string() },
  handler: async (ctx, args) => {
    const identity = await ctx.auth.getUserIdentity();
    if (!identity) {
      throw new ConvexError({ code: "UNAUTHORIZED", message: "Login required" });
    }

    const taskId = await ctx.db.insert("tasks", {
      title: args.title,
      userId: identity.subject, // Unique provider ID (e.g. Clerk ID)
      completed: false,
    });
    
    return taskId;
  },
});

Advanced Pattern: Transactional Internal Logic

// convex/users.ts
import { internalMutation } from "./_generated/server";

export const _onboardUser = internalMutation({
  args: { userId: v.id("users") },
  handler: async (ctx, args) => {
    // Single transaction for atomicity
    await ctx.db.patch(args.userId, { status: "active" });
    await ctx.db.insert("logs", { type: "ONBOARDING_COMPLETE", userId: args.userId });
  }
});

🛡️ The Do Not List (Anti-Patterns)

DO NOT use npx convex deploy unless specifically asked; use npx convex dev for local development.
DO NOT use Array.filter() inside a query handler for large datasets. Use ctx.db.query(...).withIndex(...).
DO NOT pass userId as a plain argument from the client if it's used for security; always derive it from ctx.auth.getUserIdentity().
DO NOT use ctx.runQuery or ctx.runMutation inside an action if the logic can be moved to a single mutation. It breaks transactionality.
DO NOT ignore return validators. Always specify returns: v.any() or a strict object schema.

📂 Progressive Disclosure (Deep Dives)

Auth & RLS Strategies: Integrating Clerk/Auth.js and enforcing access control.
Advanced Indexing: Search indexes, vector indexes (AI), and performance optimization.
HTTP Actions & Webhooks: External API integration and Hono on Convex.
File Storage Mastery: Large file uploads, transformations, and access URLs.

🛠️ Specialized Tools & Scripts

scripts/sync-schema.ts: Automatically generates Zod schemas from your Convex data model.
scripts/audit-indexes.py: Scans your functions to find queries without proper indexing.

🎓 Learning Resources

Updated: January 23, 2026 - 16:15

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