Everything you need to know about Evolution Arena — how it works, what it costs, and how your data is handled.
Product
It's an AI prompt optimizer. You give it your system prompt and some test questions. It runs variants against each other in structured battles, judges the winner, and evolves a stronger version. You get back a better prompt without the guesswork.
Two variants of your prompt are created with different emphases (one prioritizes clarity, one prioritizes depth). They each answer your test questions. A judge scores both on 5 criteria: accuracy, clarity, reasoning, practical utility, and intellectual honesty. The winner's traits are preserved and mutated into an offspring. This repeats for N rounds.
Real demos show 5–8 point average improvement per round. The quality depends on your test questions — the more specific and challenging, the better the evolution pressure.
Yes. In your dashboard Settings, paste your key. When set, your key is used for all optimizations (AES-256 encrypted at rest). You pay Anthropic directly; we just charge the platform fee.
Pricing
3 runs/day, Haiku model only, up to 10 runs/month. No credit card required.
Free: Haiku only. Starter: Haiku + Sonnet. Pro: all models including Opus. With BYOK, you can use any model you have access to.
No. Daily and monthly limits reset at midnight UTC and the 1st of each month.
No subscription. Pay per run: Haiku $0.10, Sonnet $0.50, Opus $2.00.
Account & Security
AES-256 encrypted at rest using a server-side encryption key. The raw key is never logged or stored in plaintext.
Email [email protected] and we'll delete everything within 48 hours.
No. Your prompts are used only for the optimization run you submitted. We don't store them long-term or use them for training.
Still have questions?
Reach out — we're a small team and we actually respond.