Claude Mythos: Coding Arena Debut?

Platform comparison

Active sub-markets

Market context

Anthropic will release a Claude model branded as "Mythos" and submit it to Arena.ai's Coding Leaderboard, where it must achieve a specified performance threshold within 24 hours of first appearing. The leaderboard tracks model performance across coding tasks, with scores updated dynamically as new submissions arrive. Settlement hinges on both the model's debut and its measured performance meeting the predefined benchmark at a precise timestamp.

The 99% crowd probability reflects Anthropic's established pattern of releasing new Claude variants into public benchmarking systems. Claude 3.5 Sonnet entered Arena.ai's leaderboard in October 2024 and maintained competitive rankings across multiple coding evaluation sets. Anthropic has consistently named model families (Opus, Sonnet, Haiku) and recently introduced "Thinking" variants, establishing precedent for branded model releases. The Mythos designation—if deployed—would follow this naming convention, though Anthropic hasn't formally announced such a model as of late 2024.

Traders monitoring this market should track Anthropic's official announcements and Arena.ai's leaderboard update logs, which typically post new model entries within hours of release. The settlement window extends through end-2026, providing substantial time for a release, though the probability's height suggests market participants expect deployment within months rather than years. Programmatically, automated monitoring of Arena.ai's API endpoints and Anthropic's press releases would flag qualifying entries; the critical variable becomes whether the model's score meets the threshold rather than whether it appears at all.

Methodology

This page is a comparison snapshot: one live quote (Polymarket), four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket Review UK, which mirrors the Polymarket order book directly.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket Review UK, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket Review UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket Review UK triggers a quick verification flow that finishes in minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.