---
name: convex-backend-31215cd5f501
description: Convex backend development guidelines. Use when writing Convex functions, schemas, queries, mutations, actions, or any backend code in a Convex project. Triggers on tasks involving Convex database operations, real-time subscriptions, file storage, or serverless functions.
---

# Convex Backend Guidelines

### When to Load

- **Trigger**: Convex-specific development, writing Convex functions, schemas, queries, mutations, actions, or real-time subscriptions
- **Skip**: Project does not use Convex as its backend

Comprehensive guide for building Convex backends with TypeScript. Covers function syntax, validators, schemas, queries, mutations, actions, scheduling, and file storage.

## When to Apply

Reference these guidelines when:

- Writing new Convex functions (queries, mutations, actions)
- Defining database schemas and validators
- Implementing real-time data fetching
- Setting up cron jobs or scheduled functions
- Working with file storage
- Designing API structure

## Rule Categories

| Category          | Impact   | Description                                   |
| ----------------- | -------- | --------------------------------------------- |
| Function Syntax   | CRITICAL | New function syntax with args/returns/handler |
| Validators        | CRITICAL | Type-safe argument and return validation      |
| Schema Design     | HIGH     | Table definitions, indexes, system fields     |
| Query Patterns    | HIGH     | Efficient data fetching with indexes          |
| Mutation Patterns | MEDIUM   | Database writes, patch vs replace             |
| Action Patterns   | MEDIUM   | External API calls, Node.js runtime           |
| Scheduling        | MEDIUM   | Crons and delayed function execution          |
| File Storage      | LOW      | Blob storage and metadata                     |

## Quick Reference

### Function Registration

```typescript
// Public functions (exposed to clients)
import { query, mutation, action } from "./_generated/server";

// Internal functions (only callable from other Convex functions)
import {
  internalQuery,
  internalMutation,
  internalAction,
} from "./_generated/server";
```

### Function Syntax (Always Use This)

```typescript
export const myFunction = query({
  args: { name: v.string() },
  returns: v.string(),
  handler: async (ctx, args) => {
    return "Hello " + args.name;
  },
});
```

### Common Validators

| Type     | Validator                         | Example       |
| -------- | --------------------------------- | ------------- |
| String   | `v.string()`                      | `"hello"`     |
| Number   | `v.number()`                      | `3.14`        |
| Boolean  | `v.boolean()`                     | `true`        |
| ID       | `v.id("tableName")`               | `doc._id`     |
| Array    | `v.array(v.string())`             | `["a", "b"]`  |
| Object   | `v.object({...})`                 | `{name: "x"}` |
| Optional | `v.optional(v.string())`          | `undefined`   |
| Union    | `v.union(v.string(), v.number())` | `"x"` or `1`  |
| Literal  | `v.literal("status")`             | `"status"`    |
| Null     | `v.null()`                        | `null`        |

### Function References

```typescript
// Public functions
import { api } from "./_generated/api";
api.example.myQuery; // convex/example.ts → myQuery

// Internal functions
import { internal } from "./_generated/api";
internal.example.myInternalMutation;
```

### Query with Index

```typescript
// Schema
messages: defineTable({...}).index("by_channel", ["channelId"])

// Query
await ctx.db
  .query("messages")
  .withIndex("by_channel", (q) => q.eq("channelId", channelId))
  .order("desc")
  .take(10);
```

### Key Rules

1. **Always include `args` and `returns` validators** on all functions
2. **Use `v.null()` for void returns** - never omit return validator
3. **Use `withIndex()` not `filter()`** - define indexes in schema
4. **Use `internalQuery/Mutation/Action`** for private functions
5. **Actions cannot access `ctx.db`** - use runQuery/runMutation instead
6. **Include type annotations** when calling functions in same file

## Full Compiled Document

For the complete guide with all rules and detailed code examples, see [AGENTS.md](AGENTS.md).


---
Source attribution: CloudAI-X
Original project: https://github.com/CloudAI-X/claude-workflow-v2
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Mega AI Hub.

## Upstream license notice

MIT License

Copyright (c) 2026 Gabriel Moreira

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Mega AI Hub resource metadata

Creator / publisher: CloudAI-X
Original project: https://github.com/CloudAI-X/claude-workflow-v2
Attribution basis: Upstream repository explicitly recorded in package mirror path

Fields of work: Development & Engineering, Product Management
Roles: Backend Developer, Full-Stack Developer, Product Manager
Specialties: API, Backend, Database, Design, Word Documents, Frontend
Tools: Convex
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: 1fa362a9a1a041b9507a011ac627522f46ec501ed9d8c8a4da7039a7ac894724