Agent skill
convex-backend-development
Develop and maintain Convex backend functions including queries, mutations, and actions. Use when working with database operations, authentication, game management, scoring logic, and real-time data updates in the dev-quiz-battle app.
Install this agent skill to your Project
npx add-skill https://github.com/violabg/dev-quiz-battle/tree/main/skills/convex-backend-development
Metadata
Additional technical details for this skill
- author
- dev-quiz-battle
- version
- 1.0
SKILL.md
Convex Backend Development
This skill covers building and maintaining Convex backend functions for the dev-quiz-battle application.
Step-by-step instructions
1. Understanding the Project Structure
The Convex backend is located in the convex/ directory with:
queries/- Read-only functions (games, users, answers, leaderboard)mutations/- Write operations (creating games, submitting answers, updating user scores)actions/- Long-running operations (AI question generation)schema.ts- Database schema definitionauth.ts- Authentication configuration
2. Creating Queries
Queries fetch data from the database without modifying it. Common patterns:
import { query } from "convex/server";
import { v } from "convex/values";
export const getGameData = query({
args: { gameCode: v.string() },
handler: async (ctx, args) => {
const game = await ctx.db
.query("games")
.filter((q) => q.eq(q.field("code"), args.gameCode))
.first();
return game;
},
});
3. Creating Mutations
Mutations modify the database state. Always validate input:
import { mutation } from "convex/server";
import { v } from "convex/values";
export const createGame = mutation({
args: { creatorId: v.id("users"), language: v.string() },
handler: async (ctx, args) => {
const gameId = await ctx.db.insert("games", {
creatorId: args.creatorId,
language: args.language,
code: generateUniqueCode(),
status: "waiting",
createdAt: Date.now(),
});
return gameId;
},
});
4. Creating Actions
Actions handle async operations like API calls:
import { action } from "convex/server";
import { v } from "convex/values";
export const generateQuestion = action({
args: { language: v.string(), difficulty: v.string() },
handler: async (ctx, args) => {
// Call external API or perform async work
const response = await fetch("https://api.example.com/questions");
return response.json();
},
});
5. Using Authentication
Access the authenticated user:
const identity = await ctx.auth.getUserIdentity();
if (!identity) {
throw new Error("Not authenticated");
}
const userId = identity.subject;
6. Validation Patterns
Always validate arguments using Convex validators:
args: {
email: v.string(),
password: v.string(),
language: v.string(),
}
Common Edge Cases
- Invalid game codes: Check if game exists before operations
- Concurrent submissions: Use game status to prevent duplicate answers
- User authentication: Always verify identity for sensitive mutations
- Score calculations: Account for time-based bonuses and difficulty multipliers
Key Files to Reference
See Convex Schema Reference for complete schema definition.
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