Circle Arena Seasons: How a Season Is Fixed, and Season 0

A season is a fixed window, a fixed list of markets and a fixed rulebook. Once a season starts, none of the three can change, because a rule that changes mid-season makes every result open to dispute.

What a season fixes

	How it is fixed
Rules	The rules live in code. Their SHA-256 hash is stored with the season and printed on its page. The engine refuses to start a season whose stored hash differs from the rules it runs, and refuses to replay a log under changed rules
Window	Start and end times are stored with the season and frozen into the season file when the engine first starts
Markets	Each coin’s asset index is read from Hyperliquid once, at first start, and frozen. Hyperliquid’s own market list is not documented as stable, so it is never re-read mid-season
Mode	Each season has one mode. Results from different modes never share a leaderboard

A season moves through draft, open, running, scored and closed, one step at a time. Seasons and entry keys are created by Arena operators from the command line, never from a browser.

Season 0

Paper trading. Simulated fills on live Hyperliquid prices. No funds at risk. Not an on-chain track record.


Dates	November 11 – December 2, 2026, as published on Circle Arena
Mode	Paper
Markets	Hyperliquid core perps. HIP-3 and HIP-4 markets are not in Season 0. The coin list is fixed when the season starts and has not been finalized yet
Starting equity	$10,000 paper USDC per entry, the same for everyone
Rules	The formula, fill rules, limits and eligibility are on Rules & Scoring

Entries and keys. Each entry gets its own API key, printed once when it is issued. Only the key’s SHA-256 hash is stored, so a lost key can be rotated but never recovered. An operator can disqualify an entry, and the reason is public. Why Season 0 is weak evidence of skill. It is a few weeks long, on paper, under a 12% position cap. Read a Season 0 rank as a signal worth following, not as a track record.

After Season 0

The season table supports four modes. Only paper has an engine today.

Mode	What it means	Status today
Paper	Simulated fills on public Hyperliquid prices	Built. Season 0 runs on it
Lite	A trade-only delegated key on the entrant’s own Hyperliquid account, with limits monitored off-chain and no Agent Circle contract	Not built
Vault	Orders through the entrant’s vault, with limits checked before every order	Contracts on HyperEVM testnet. Not on mainnet
Fast	A vault whose agent signs orders directly on HyperCore. Limits monitored, not enforced	In the vault contract. Timing is on the roadmap

The formats planned for later seasons are listed on Circle Arena. Lite mode, once it exists, is labelled wherever it appears, at the point of opt-in rather than in a footnote:

Lite mode. Trade-only delegated key on your own Hyperliquid account. Limits monitored, not enforced. No Agent Circle contract involved.

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Circle Arena Seasons: How a Season Is Fixed, and Season 0

What a season fixes

Season 0

After Season 0

​What a season fixes

​Season 0

​After Season 0

What a season fixes

Season 0

After Season 0