convex-create-component

SKILL.md

Convex Create Component

Create reusable Convex components with clear boundaries and a small app-facing
API.

When to Use

Creating a new Convex component in an existing app

Extracting reusable backend logic into a component

Building a third-party integration that should own its own tables and
workflows

Packaging Convex functionality for reuse across multiple apps

When Not to Use

One-off business logic that belongs in the main app

Thin utilities that do not need Convex tables or functions

App-level orchestration that should stay in convex/

Cases where a normal TypeScript library is enough

Workflow

Ask the user what they are building and what the end goal is. If the repo
already makes the answer obvious, say so and confirm before proceeding.

Choose the shape using the decision tree below and read the matching
reference file.

Decide whether a component is justified. Prefer normal app code or a regular
library if the feature does not need isolated tables, backend functions, or
reusable persistent state.

Make a short plan for:

what tables the component owns

what public functions it exposes

what data must be passed in from the app (auth, env vars, parent IDs)

what stays in the app as wrappers or HTTP mounts

Create the component structure with convex.config.ts, schema.ts, and
function files.

Implement functions using the component's own ./_generated/server imports,
not the app's generated files.

Wire the component into the app with app.use(...). If the app does not
already have convex/convex.config.ts, create it.

Call the component from the app through components.<name> using
ctx.runQuery, ctx.runMutation, or ctx.runAction.

If React clients, HTTP callers, or public APIs need access, create wrapper
functions in the app instead of exposing component functions directly.

Run npx convex dev and fix codegen, type, or boundary issues before
finishing.

Choose the Shape

Ask the user, then pick one path:

Goal
Shape
Reference

Component for this app only
Local
references/local-components.md

Publish or share across apps
Packaged
references/packaged-components.md

User explicitly needs local + shared library code
Hybrid
references/hybrid-components.md

Not sure
Default to local
references/local-components.md

Read exactly one reference file before proceeding.

Default Approach

Unless the user explicitly wants an npm package, default to a local component:

Put it under convex/components/<componentName>/

Define it with defineComponent(...) in its own convex.config.ts

Install it from the app's convex/convex.config.ts with app.use(...)

Let npx convex dev generate the component's own _generated/ files

Component Skeleton

A minimal local component with a table and two functions, plus the app wiring.

// convex/components/notifications/convex.config.ts
import { defineComponent } from "convex/server";

export default defineComponent("notifications");

// convex/components/notifications/schema.ts
import { defineSchema, defineTable } from "convex/server";
import { v } from "convex/values";

export default defineSchema({
  notifications: defineTable({
    userId: v.string(),
    message: v.string(),
    read: v.boolean(),
  }).index("by_user", ["userId"]),
});

// convex/components/notifications/lib.ts
import { v } from "convex/values";
import { mutation, query } from "./_generated/server.js";

export const send = mutation({
  args: { userId: v.string(), message: v.string() },
  returns: v.id("notifications"),
  handler: async (ctx, args) => {
    return await ctx.db.insert("notifications", {
      userId: args.userId,
      message: args.message,
      read: false,
    });
  },
});

export const listUnread = query({
  args: { userId: v.string() },
  returns: v.array(
    v.object({
      _id: v.id("notifications"),
      _creationTime: v.number(),
      userId: v.string(),
      message: v.string(),
      read: v.boolean(),
    }),
  ),
  handler: async (ctx, args) => {
    return await ctx.db
      .query("notifications")
      .withIndex("by_user", (q) => q.eq("userId", args.userId))
      .filter((q) => q.eq(q.field("read"), false))
      .collect();
  },
});

// convex/convex.config.ts
import { defineApp } from "convex/server";
import notifications from "./components/notifications/convex.config.js";

const app = defineApp();
app.use(notifications);

export default app;

// convex/notifications.ts  (app-side wrapper)
import { v } from "convex/values";
import { mutation, query } from "./_generated/server";
import { components } from "./_generated/api";
import { getAuthUserId } from "@convex-dev/auth/server";

export const sendNotification = mutation({
  args: { message: v.string() },
  returns: v.null(),
  handler: async (ctx, args) => {
    const userId = await getAuthUserId(ctx);
    if (!userId) throw new Error("Not authenticated");

    await ctx.runMutation(components.notifications.lib.send, {
      userId,
      message: args.message,
    });
    return null;
  },
});

export const myUnread = query({
  args: {},
  handler: async (ctx) => {
    const userId = await getAuthUserId(ctx);
    if (!userId) throw new Error("Not authenticated");

    return await ctx.runQuery(components.notifications.lib.listUnread, {
      userId,
    });
  },
});

Note the reference path shape: a function in
convex/components/notifications/lib.ts is called as
components.notifications.lib.send from the app.

Critical Rules

Keep authentication in the app, because ctx.auth is not available inside
components.

Keep environment access in the app, because component functions cannot read
process.env.

Pass parent app IDs across the boundary as strings, because Id types become
plain strings in the app-facing ComponentApi.

Do not use v.id("parentTable") for app-owned tables inside component args or
schema, because the component has no access to the app's table namespace.

Import query, mutation, and action from the component's own
./_generated/server, not the app's generated files.

Do not expose component functions directly to clients. Create app wrappers
when client access is needed, because components are internal and need
auth/env wiring the app provides.

If the component defines HTTP handlers, mount the routes in the app's
convex/http.ts, because components cannot register their own HTTP routes.

If the component needs pagination, use paginator from convex-helpers
instead of built-in .paginate(), because .paginate() does not work across
the component boundary.

Add args and returns validators to all public component functions, because
the component boundary requires explicit type contracts.

Patterns

Authentication and environment access

// Bad: component code cannot rely on app auth or env
const identity = await ctx.auth.getUserIdentity();
const apiKey = process.env.OPENAI_API_KEY;

// Good: the app resolves auth and env, then passes explicit values
const userId = await getAuthUserId(ctx);
if (!userId) throw new Error("Not authenticated");

await ctx.runAction(components.translator.translate, {
  userId,
  apiKey: process.env.OPENAI_API_KEY,
  text: args.text,
});

Client-facing API

// Bad: assuming a component function is directly callable by clients
export const send = components.notifications.send;

// Good: re-export through an app mutation or query
export const sendNotification = mutation({
  args: { message: v.string() },
  returns: v.null(),
  handler: async (ctx, args) => {
    const userId = await getAuthUserId(ctx);
    if (!userId) throw new Error("Not authenticated");

    await ctx.runMutation(components.notifications.lib.send, {
      userId,
      message: args.message,
    });
    return null;
  },
});

IDs across the boundary

// Bad: parent app table IDs are not valid component validators
args: {
  userId: v.id("users");
}

// Good: treat parent-owned IDs as strings at the boundary
args: {
  userId: v.string();
}

Advanced Patterns

For additional patterns including function handles for callbacks, deriving
validators from schema, static configuration with a globals table, and
class-based client wrappers, see references/advanced-patterns.md.

Validation

Try validation in this order:

npx convex codegen --component-dir convex/components/<name>

npx convex codegen

npx convex dev

Important:

Fresh repos may fail these commands until CONVEX_DEPLOYMENT is configured.

Until codegen runs, component-local ./_generated/* imports and app-side
components.<name>... references will not typecheck.

If validation blocks on Convex login or deployment setup, stop and ask the
user for that exact step instead of guessing.

Reference Files

Read exactly one of these after the user confirms the goal:

references/local-components.md

references/packaged-components.md

references/hybrid-components.md

Official docs:
Authoring Components

Checklist

 Asked the user what they want to build and confirmed the shape

 Read the matching reference file

 Confirmed a component is the right abstraction

 Planned tables, public API, boundaries, and app wrappers

 Component lives under convex/components/<name>/ (or package layout if
publishing)

 Component imports from its own ./_generated/server

 Auth, env access, and HTTP routes stay in the app

 Parent app IDs cross the boundary as v.string()

 Public functions have args and returns validators

 Ran npx convex dev and fixed codegen or type issues