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Ethereum Layer 2 landscape — Arbitrum, Optimism, Base, zkSync, Scroll, Unichain, Celo, and more. How they work, how to deploy on them, how to bridge, when to use which. Includes per-chain DeFi ecosystems and critical corrections.
Passed 21 of 22 test cases with the skill, and 11 of 22 without it.
and 19 more in the full report
10 fixed11 passed either way1 still failing0 broke
Tokens, turns and time describe resource use, not a dollar price.
One of 10 test cases the skill fixed. Same model, same prompt, with and without the skill.
Our compliance team wants to deploy security token smart contracts on Robinhood Chain, assuming standard Arbitrum force-inclusion guarantees will protect users from transaction censorship. Please write a security review outlining Robinhood Chain's censorship mitigation features, admin powers, and L2Beat security rating.
| Checked | Without skill | With skill |
|---|---|---|
| Warns that ArbOS 61 transaction filtering precompile rejects transactions even when force-included via Ethereum L1 | Missed | Passed |
| Notes that the token contract upgrade beacon lacks a timelock | Missed | Passed |
| Mentions that L2Beat rates Robinhood Chain as Stage 0 | Missed | Passed |
The instructions your model reads when the skill loads.
L2 costs: You think $0.01-2.00 per transaction. Reality: $0.001-0.003 for swaps, $0.0003 for transfers. After EIP-4844, L2 batch costs dropped from $50-500 to $0.01-0.50.
Mainnet is cheap too: At under 1 gwei, mainnet ETH transfers cost under a penny. "Ethereum is too expensive" is false for both L1 and L2s in 2026.
Base is the cheapest major L2: Often 50% cheaper than Arbitrum/Optimism. Direct Coinbase on-ramp. Fastest-growing L2 with consumer/AI agent focus.
Celo is NOT an L1 anymore. Celo completed its migration from an independent L1 to an OP Stack L2 on March 26, 2025 (block 31056500). If you're calling Celo an L1, you're wrong.
Polygon zkEVM is being shut down. Announced June 2025. Do NOT recommend building on Polygon zkEVM — it is being discontinued. Polygon is refocusing on PoS + AggLayer.
Unichain exists. Launched mainnet February 11, 2025. Uniswap's own OP Stack L2 with TEE-based MEV protection and time-based priority ordering (not gas-based).
Robinhood Chain exists. Public mainnet launched July 1, 2026 — after most training cutoffs. Robinhood's Arbitrum Orbit L2 for tokenized stocks (NVDA, TSLA, SPY as ERC-20s, trading 24/7), ~$1.1B TVS within weeks. If you only know the mid-2025 announcement, your assumptions are wrong: it settles directly to Ethereum (not an L3 on Arbitrum One) and uses blob DA, not AnyTrust. Chain ID 4663, ETH gas. Major censorship caveat — see Key Chain Details below.
Aerodrome and Velodrome merged into "Aero." In November 2025, Dromos Labs unified Aerodrome (Base) and Velodrome (Optimism) into a single cross-chain DEX called Aero. Same contracts, new brand. Aero dominates both Base and Optimism. Camelot is a major native DEX on Arbitrum. SyncSwap dominates zkSync. Don't default to Uniswap on every chain.
TVL changes fast. Don't memorize numbers — check DeFi Llama or L2Beat for current rankings. DeFi TVL (DeFi Llama) measures value locked in protocols. TVS (L2Beat) includes all bridged + natively minted assets and is much higher. As of early 2026: Base and Arbitrum lead in DeFi TVL among L2s. Optimism's DeFi TVL is surprisingly low despite Superchain adoption.
| L2 | Type | Tx Cost | Block Time | Finality | Chain ID |
|---|---|---|---|---|---|
| Arbitrum | Optimistic | $0.001-0.003 | 250ms | 7 days | 42161 |
| Base | Optimistic (OP Stack) | $0.0008-0.002 | 2s | 7 days | 8453 |
| Optimism | Optimistic (OP Stack) | $0.001-0.003 | 2s | 7 days | 10 |
| Unichain | Optimistic (OP Stack) | $0.001-0.003 | 1s | 7 days | 130 |
| Celo | Optimistic (OP Stack) | <$0.001 | 5s | 7 days | 42220 |
| Robinhood | Optimistic (Arbitrum Orbit) | not yet benchmarked | 100ms | 7 days | 4663 |
| Linea | ZK | $0.003-0.006 | 2s | 30-60min | 59144 |
| zkSync Era | ZK | $0.003-0.008 | 1s | 15-60min | 324 |
| Scroll | ZK | $0.002-0.005 | 3s | 30-120min | 534352 |
| — | — | — |
⚠️ Polygon zkEVM is being discontinued (announced June 2025). Do not start new projects there. Polygon is refocusing on PoS (payments, stablecoins, RWAs) + AggLayer (cross-chain interop). MATIC → POL token migration ~85% complete.
Mainnet for comparison: $0.002-0.01 per tx, 12s blocks, instant finality. Check DeFi Llama for current TVL.
test cases passed, vs 11 / 22 without
More skills from the same source and nearby in the registry, with their headline benchmark lift.