API key creation: long names return opaque 500

[fullheart]

Summary

Creating an API key fails with a generic toast "Failed to generate API key" when the Name exceeds better-auth’s allowed length. The UI does not show a max length.

Steps to reproduce

1. Settings → Profile → API/CLI Keys → Generate New Key
2. Use a long name (~30+ characters)
3. Prefix empty, rate limiting off → Generate

Actual

POST /api/trpc/user.createApiKey → 500 with message:

The name length is either too large or too small.

Wrapped as INTERNAL_SERVER_ERROR (generic toast).

Expected

• Validate name length in UI/Zod against the library limit
• Clear validation error instead of 500
• Show max length on the Name field

Workaround

Use a short name.

Notes

Server input currently looks like z.string().min(1) only; better-auth enforces a stricter length. Related but different: #4024 / #4026.

[tanaymishra]

Hey, can I take this one?

Dug into it a bit. The name is only validated with min(1) on the tRPC input, but the api-key plugin caps names at 32 chars by default (maximumNameLength in @better-auth/api-key). When you go over, better-auth actually throws a 400, but since we call auth.createApiKey() and don't map that error, tRPC just wraps it as a 500, hence the vague toast.

Plan is to add .max(32) on the name in both the form and server schema so it shows a proper "max 32 characters" error, and surface the limit on the field.