I Built the Same App with Fable 5, Opus 4.8, and Sonnet 5…The Results Weren’t Even Close

Member-only story

Anthropic now has three models that can code:

• Fable 5 at the top
• Opus 4.8 in the middle
• And Sonnet 5 as the new free default.

I built the same app on all three.

I used the same spec, the same stack, and the same judgment criteria. The prompt counts tell the whole story.

My Spec #

I used a real client spec.

An expense tracker with five features:

• Auth via email/password with protected routes
• Dashboard with total spending, category breakdown chart, and monthly trend line
• Add expense form with description, amount, category dropdown, and date picker
• Expenses table with category filter and CSV export
• Mobile responsive throughout

The spec(Remember to add your Supabase project URL and anon key):

Build a team expense tracker app.Stack: React, Vite, TypeScript, Tailwind CSS, Supabase.Supabase project URL and anon key are in .env as VITE_SUPABASE_URL and VITE_SUPABASE_ANON_KEY.The database…