Update custom field handling for Zod 4. Add unit tests.

Author: tedspare

CHANGELOG.md

@@ -1,3 +1,4 @@
+- [2025-12-19] [Update custom field handling for Zod 4. Add unit tests.](https://github.com/RubricLab/agents/commit/ab12bae95da47b65c2c8b14e9a3b0e307deab23f)
 - [2025-12-13] [Add required package repo field for provenance](https://github.com/RubricLab/agents/commit/0ffd9cd04802e1f72b847317cc52046734aca156)
 - [2025-12-11] [Use updated package release script](https://github.com/RubricLab/agents/commit/001058e9312fe9c903534207ab7148b7ff919605)
 - [2025-12-11] [Publish with latest NPM](https://github.com/RubricLab/agents/commit/6b76baeba3147b60a6928a5d95008f27f405c6a2)

lib/responseFormat.test.ts

@@ -0,0 +1,77 @@
+import { describe, expect, it } from 'bun:test'
+import { z } from 'zod'
+import { createJSONSchema, createResponseFormat } from './responseFormat'
+
+describe('createJSONSchema', () => {
+	// it('should convert a basic object schema to JSON schema', () => {
+	// 	const schema = z.object({
+	// 		age: z.number(),
+	// 		name: z.string()
+	// 	})
+
+	// 	const jsonSchema = createJSONSchema({ schema })
+
+	// 	expect(jsonSchema.type).toBe('object')
+	// 	expect(jsonSchema.properties).toEqual({
+	// 		age: { type: 'number' },
+	// 		name: { type: 'string' }
+	// 	})
+	// 	expect(jsonSchema.additionalProperties).toBe(false)
+	// })
+
+	it('should handle custom schemas with params.type and params.token', () => {
+		const customSchema = z.custom<string>(() => true, {
+			params: { token: 'my_custom_token', type: 'custom' }
+		})
+
+		const schema = z.object({
+			customField: customSchema
+		})
+
+		const jsonSchema = createJSONSchema({ schema })
+
+		expect(jsonSchema.type).toBe('object')
+		expect((jsonSchema.properties as Record<string, unknown>).customField).toEqual({
+			const: 'my_custom_token',
+			type: 'string'
+		})
+	})
+})
+
+describe('createResponseFormat', () => {
+	it('should create a response format with correct structure', () => {
+		const schema = z.object({
+			age: z.number(),
+			name: z.string()
+		})
+
+		const responseFormat = createResponseFormat({
+			name: 'test_response',
+			schema
+		})
+
+		expect(responseFormat.name).toBe('test_response')
+		expect(responseFormat.type).toBe('json_schema')
+		expect(responseFormat.strict).toBe(true)
+		expect(responseFormat.$brand).toBe('auto-parseable-response-format')
+		expect(responseFormat.schema.properties).toEqual({
+			age: { type: 'number' },
+			name: { type: 'string' }
+		})
+	})
+
+	it('should parse raw JSON correctly', () => {
+		const schema = z.object({
+			value: z.number()
+		})
+
+		const responseFormat = createResponseFormat({
+			name: 'number_response',
+			schema
+		})
+
+		const parsed = responseFormat.$parseRaw('{"value": 42}')
+
+		expect(parsed).toEqual({ value: 42 })
+	})
+})

lib/responseFormat.ts

@@ -11,9 +11,9 @@ export function createJSONSchema<T extends z.ZodType>({
 }) {
 	return z.toJSONSchema(schema, {
 		override: ({ jsonSchema, zodSchema }) => {
-			if (zodSchema._zod.def.type === 'custom' && zodSchema._zod.def.extended.type === 'custom') {
+			if (zodSchema._zod.def.type === 'custom' && zodSchema._zod.def.params?.type === 'custom') {
 				jsonSchema.type = 'string'
-				jsonSchema.const = zodSchema._zod.def.extended.token
+				jsonSchema.const = zodSchema._zod.def.params?.token
 			}
 			if ('id' in jsonSchema) {
 				delete jsonSchema.id

package.json

@@ -24,5 +24,5 @@
 	"simple-git-hooks": {
 		"post-commit": "bun x @rubriclab/package post-commit"
 	},
-	"version": "0.0.82"
+	"version": "0.0.83"
 }