metamask-integration/docs/METAMASK_WETH9_DISPLAY_BUG.md

MetaMask WETH9 Display Bug Analysis

Date: $(date)
Issue: MetaMask displaying "6,000,000,000.0T WETH" instead of "6 WETH"
Contract: WETH9 (0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2)
Network: Defi Oracle Meta Mainnet (ChainID 138)

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🐛 The Problem

MetaMask is incorrectly displaying the WETH9 balance as "6,000,000,000.0T WETH" when the actual balance is 6 WETH.

What MetaMask Shows

• Wrapped Ether: 6,000,000,000.0T WETH ❌ (Incorrect)
• Ethereum: 1.00B ETH (Also suspicious - likely 1 billion ETH)
• WETH: 0 WETH ✅ (Correct)

Actual On-Chain Values

• WETH9 Total Supply: 6 WETH ✅
• WETH9 Contract Balance: 6 ETH ✅
• User Balance: 6 WETH ✅

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🔍 Root Cause Analysis

Likely Causes

1. Missing or Incorrect decimals() Function

   • WETH9 may not implement the standard ERC-20 decimals() function
   • MetaMask expects decimals() to return 18 for WETH
   • If it returns 0 or doesn't exist, MetaMask may default to wrong decimal handling

2. MetaMask Number Formatting Bug

   • MetaMask may be reading the raw wei value: 6,000,000,000,000,000,000
   • Without proper decimals, it might be formatting as: 6,000,000,000.0T
   • The "T" likely stands for "Trillion" in MetaMask's display format

3. Token Metadata Issue

   • WETH9 may not be in MetaMask's token list
   • MetaMask may be using default/incorrect metadata
   • Missing proper token configuration for ChainID 138

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✅ Verification

On-Chain Verification

# Check total supply (should be 6 WETH)
cast call 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 \
  "totalSupply()" \
  --rpc-url http://192.168.11.250:8545 | \
  xargs -I {} cast --to-unit {} ether
# Output: 6 ✅

# Check contract balance (should be 6 ETH)
cast balance 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 \
  --rpc-url http://192.168.11.250:8545 | \
  xargs -I {} cast --to-unit {} ether
# Output: 6 ✅

# Check decimals function
cast call 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 \
  "decimals()" \
  --rpc-url http://192.168.11.250:8545
# Output: 0x0 (likely the issue!)

Actual Values

• Raw Wei: 6,000,000,000,000,000,000 wei
• ETH Equivalent: 6.0 ETH
• Display Should Be: 6 WETH or 6.0 WETH

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🔧 Solutions

Solution 1: Add WETH9 to MetaMask Token List (Recommended)

Create a proper token list entry for WETH9:

{
  "chainId": 138,
  "address": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
  "name": "Wrapped Ether",
  "symbol": "WETH",
  "decimals": 18,
  "logoURI": "https://raw.githubusercontent.com/ethereum/ethereum.org/main/static/images/eth-diamond-black.png"
}

Steps:

1. Create a token list JSON file
2. Host it on a public URL (GitHub, IPFS, etc.)
3. Add to MetaMask: Settings → Security & Privacy → Token Lists
4. Or import directly in MetaMask: Import Token → Custom Token

Solution 2: Manually Import Token in MetaMask

1. Open MetaMask
2. Go to "Import tokens"
3. Enter:
   • Token Contract Address: 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2
   • Token Symbol: WETH
   • Decimals of Precision: 18
4. Click "Add Custom Token"

Solution 3: Fix WETH9 Contract (If Possible)

If WETH9 contract can be modified, ensure it implements:

• Standard ERC-20 decimals() function returning 18
• Standard ERC-20 interface

Note: Since WETH9 is pre-deployed in genesis, this may not be possible without redeploying.

Solution 4: Use a Different WETH Contract

If WETH9 cannot be fixed, consider:

• Using WETH10 (0xf4BB2e28688e89fCcE3c0580D37d36A7672E8A9f) if it has proper decimals
• Deploying a new WETH contract with proper ERC-20 implementation

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📊 Impact Assessment

Current Impact

• Display Issue: Users see incorrect balance (6 trillion vs 6)
• Functional Impact: None - transactions work correctly
• User Confusion: High - misleading display

Risk Level

• Low: This is purely a display issue
• No Financial Risk: Actual balances are correct on-chain
• UX Issue: Users may be confused or concerned

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🔍 Additional Observations

Other Display Issues in Screenshot

1. Ethereum Balance: Shows "1.00B ETH"

   • This is also suspicious
   • Should verify actual ETH balance
   • May be another display formatting issue

2. Network Name: "Defi Oracle Meta Mainnet"

   • This is ChainID 138
   • Network configuration appears correct

3. WETH Token: Shows "0 WETH" ✅

   • This appears correct
   • May be a different WETH contract address

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📝 Recommendations

1. Immediate: Add WETH9 to MetaMask token list with proper decimals (18)
2. Short-term: Verify all token contracts have proper decimals() implementation
3. Long-term: Create comprehensive token list for ChainID 138
4. Documentation: Document all token addresses and their proper configurations

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✅ Verification Checklist

• On-chain balance verified: 6 WETH ✅
• Contract balance verified: 6 ETH ✅
• decimals() function checked: Returns 0x0 (likely issue)
• Token list entry created
• MetaMask token import tested
• Display verified after fix

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🔗 Related Documentation

• WETH9 Creation Analysis
• Contract Addresses Reference
• MetaMask Token List

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Last Updated: $(date)