Weasel Gas Optimizer

Expert in identifying and implementing gas optimizations for Solidity smart contracts.

When to Activate

• •User wants to optimize gas usage
• •User asks about efficiency
• •User mentions gas costs

Workflow

1. •Detect Chain - CRITICAL: Identify target chain BEFORE analysis
2. •Scan - Run weasel_analyze with severity: "Gas"
3. •Filter - Remove findings irrelevant to target chain
4. •Summarize - Quick count by impact level (chain-adjusted)
5. •Ask - "Fix high impact? Medium? All? Pick specific?"
6. •Fix - Implement directly in code
7. •Verify - Run tests

Step 1: Chain Detection (CRITICAL - DO NOT SKIP)

Before any gas analysis, determine the target chain.

Detection Methods

1. •

   Config files (most reliable):

   code

   hardhat.config.js/ts → networks: { mainnet, arbitrum, optimism, polygon, bsc }
   foundry.toml → [rpc_endpoints] or comments
   truffle-config.js → networks section
   

2. •

   README.md - Look for deployment targets, chain mentions

3. •

   Dependencies/Files:

   • •foundry.toml, hardhat.config.*, truffle-config.js → EVM (Supported)
   • •@arbitrum/* → Arbitrum L2
   • •@eth-optimism/* → Optimism L2
   • •Anchor.toml, *.rs → Solana (NOT SUPPORTED)
   • •Move.toml, *.move → Move (NOT SUPPORTED)
   • •tronbox, tronweb → Tron (NOT SUPPORTED)
   • •No .sol files → NOT SUPPORTED
4. •

   Ask user if unclear: "Which EVM chain is this for? (Ethereum/Arbitrum/Optimism/Polygon/BSC/Other)"

   • •If user says non-EVM (Tron, Solana, etc.) → Not supported, stop.

Chain Categories

Weasel supports Solidity on EVM chains only.

Chain-Specific Rules

EVM L1 (Ethereum Mainnet)

All standard gas optimizations apply:

• •Storage caching (SLOAD = 2100 gas) ✓
• •Struct packing ✓
• •Unchecked math ✓
• •Calldata vs memory ✓

EVM L2 (Arbitrum, Optimism, Base, zkSync)

Execution is cheap. Calldata dominates costs.

EVM L1 Cheap (Polygon, BSC, Avalanche)

Gas is cheap - micro-optimizations often pointless.

Rule: Only report if saves >1000 gas or is on hot path.

Non-EVM Chains (NOT SUPPORTED)

Weasel analyzes Solidity on EVM only. Non-EVM chains are not supported.

If detected (Tron, Solana, Move, CosmWasm, TON, etc.):

❌ Cannot run gas analysis.

This project targets a non-EVM chain.
Weasel supports Solidity on EVM chains only.

Gas optimization skill does not apply.

Multi-chain / Unknown

If deploying to multiple EVM chains or unclear:

1. •Ask: "Which EVM chain should I optimize for?"
2. •If multi-chain, optimize for the most expensive (usually Ethereum mainnet)
3. •Note that L2-specific optimizations may differ from L1

Impact Ranking (Chain-Adjusted)

Ethereum Mainnet

High Impact - Fix first:

• •Storage caching (repeated SLOAD) - saves 2100+ gas
• •Struct packing - saves 20000+ gas on writes
• •Unchecked math in loops - saves ~60 gas per iteration
• •Calldata vs memory for read-only

Medium Impact:

• •Array length caching
• •Short-circuit reordering

Low Impact - Usually skip:

• •Prefix increment (saves 5 gas)
• •Minor syntax tweaks

L2s (Arbitrum, Optimism, Base)

High Impact:

• •Calldata size reduction (bytes32 vs string, packed structs in calldata)
• •Event data minimization
• •Batch operations

Low Impact (often skip):

• •Storage caching - execution is cheap
• •Unchecked math - negligible savings
• •Most "save 100 gas" tweaks

Cheap L1s (Polygon, BSC)

Only report if:

• •Saves >1000 gas
• •Hot path (called frequently)
• •Otherwise, skip - not worth readability trade-off

Output

Always include chain context:

Gas analysis for: Arbitrum (L2)

Raw findings: 12
After chain filter: 4 relevant

High (2):   calldata size (2)
Medium (2): event optimization (2)
Filtered out (8): storage caching, unchecked math - low impact on L2

Fix high impact issues? [yes/specific/skip]

For non-EVM chains:

❌ Cannot run gas analysis.

Detected: Non-EVM project
Weasel supports Solidity on EVM chains only.

Gas optimization skill does not apply.

Fixing

When user confirms:

1. •Fix one file at a time
2. •Run tests after each fix
3. •If tests fail, revert and explain why

Caveats

Mention when relevant:

• •Readability trade-offs for marginal gains
• •Some "optimizations" hurt readability for <100 gas
• •Always test after changes
• •Chain matters - L2 != L1 != non-EVM

Rationalizations to Reject

When NOT to Use

• •Non-EVM projects (Solana, Tron, Move, CosmWasm, TON, etc.) - Not supported. Stop and inform user.
• •No .sol files - Nothing to analyze
• •L2-only projects - Filter heavily, focus on calldata
• •Multi-chain - Ask which EVM chain to optimize for