Using Drizzle Schemas

Drizzle’s createSelectSchema and createInsertSchema helpers (from drizzle-zod) produce Zod schemas that work directly in Covenant declarations.

Installation

bun add drizzle-zod

Basic usage

db/schema.ts

import { pgTable, text, timestamp } from "drizzle-orm/pg-core";
import { createSelectSchema, createInsertSchema } from "drizzle-zod";

export const todos = pgTable("todos", {
  id: text("id").primaryKey(),
  text: text("text").notNull(),
  createdAt: timestamp("created_at").notNull().defaultNow(),
});

export const todoSelectSchema = createSelectSchema(todos);
export const todoInsertSchema = createInsertSchema(todos, {
  // Exclude auto-generated fields from inserts
  id: (s) => s.optional(),
  createdAt: (s) => s.optional(),
});

Then import the schemas into your covenant:

covenant.ts

import { declareCovenant, query, mutation } from "@covenant-rpc/core";
import { z } from "zod";
import { todoSelectSchema, todoInsertSchema } from "@/db/schema";

export const covenant = declareCovenant({
  procedures: {
    getTodos: query({
      input: z.null(),
      output: z.array(todoSelectSchema),
    }),
    createTodo: mutation({
      input: todoInsertSchema,
      output: todoSelectSchema,
    }),
  },
  channels: {},
});

Handling dates

Drizzle timestamps come back as Date objects. Covenant’s ION serialization handles Date natively, so they round-trip correctly between server and client without any manual parsing.

Excluding sensitive columns

If your table has columns you don’t want to expose to the client (password hashes, internal flags), exclude them from the schema:

export const publicTodoSchema = createSelectSchema(todos).omit({
  internalFlag: true,
});

Use publicTodoSchema as the output schema instead of the full todoSelectSchema.