Zod dependency configuration does not follow official best practices for library authors

[Areo-Joe]

Zod dependency configuration does not follow official best practices for library authors

Summary

The current Zod usage in AG-UI TypeScript SDK does not follow the official Zod best practices for library authors. This may cause version conflicts for users and lacks Zod 4 compatibility.

Current State

1. Dependency Configuration Issues

Zod is currently in dependencies instead of peerDependencies:

Package	Current Config	Issue
@ag-ui/core	dependencies: "zod": "^3.22.4"	❌ Should be peerDependencies
@ag-ui/client	dependencies: "zod": "^3.22.4"	❌ Should be peerDependencies
@ag-ui/vercel-ai-sdk	dependencies: "zod": "^3.22.4"	❌ Should be peerDependencies

According to official docs:

Any library built on top of Zod should include "zod" in "peerDependencies". This lets your users "bring their own Zod".

2. Outdated Version Range

Current version ^3.22.4 is outdated and doesn't support Zod 4.

Recommended version range:

{
  "peerDependencies": {
    "zod": "^3.25.0 || ^4.0.0"
  }
}

3. Import Path Not Using Permalinks

All files currently import Zod like this:

import { z } from "zod";  // ❌ Not recommended

Official recommendation:

Import from these subpaths only. Think of them like "permalinks" to their respective Zod versions.

• "zod/v3" for Zod 3 ✅
• "zod/v4/core" for the Zod 4 Core package ✅

import * as z3 from "zod/v3";  // ✅ Recommended

References

• Zod: For library authors
• Versioning in Zod 4 - GitHub Issue #4371

[NathanTarbert]

Hi @Areo-Joe, flagging this for engineering review.

Thank you!

[TheComputerM]

Any updates, using zod v4 would be much better for performance also: https://zod.dev/v4?id=benchmarks

[ranst91]

As mentioned in the associated PR, we're moving away from zod.
Can be followed here: #1637