morph-altfee

Morph Alt-Fee — AI Agent Skill

Pay gas with alternative tokens (tx type 0x7f) on Morph Mainnet (Chain ID: 2818). All commands output JSON. Morph-exclusive feature not available on other L2s.

Activation Triggers

Use this skill when the user wants to: list fee tokens, check fee token info, estimate gas cost in an alternative token, or send a transaction paying gas with a non-ETH token on Morph.

Quick Start

pip install requests eth_account

# Run from repository root
python3 scripts/morph_api.py <command> [options]

No API keys required. Queries the on-chain TokenRegistry at 0x5300000000000000000000000000000000000021.

BGW Routing Note

Decide the mode once via the root SKILL.md and docs/social-wallet-integration.md.

• Altfee is a Morph transaction mechanism, not a Social Login Wallet product feature.
• altfee-send requires --private-key (local signing only).
• Social Login Wallet users cannot use altfee through this skill. BGW's swap flow has its own gas handling (including gasless no_gas mode).

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Commands

altfee-tokens

List all supported fee tokens from the on-chain TokenRegistry.

python3 scripts/morph_api.py altfee-tokens

altfee-token-info

Get details for a specific fee token: contract address, scale, feeRate, decimals, active status.

python3 scripts/morph_api.py altfee-token-info --id 5

altfee-estimate

Estimate the minimum feeLimit needed to pay gas with a fee token. Includes a 10% safety margin.

# Estimate for a simple ETH transfer (21000 gas)
python3 scripts/morph_api.py altfee-estimate --id 5

# Estimate for an ERC20 transfer (200000 gas)
python3 scripts/morph_api.py altfee-estimate --id 5 --gas-limit 200000

altfee-send

Sign and broadcast a transaction paying gas with an alternative fee token (tx type 0x7f). --fee-limit defaults to 0 (no limit — uses available balance, unused portion is refunded).

# Simple ETH transfer, pay gas with USDT (token ID 5)
python3 scripts/morph_api.py altfee-send --to 0xRecipient --value 0.01 --fee-token-id 5 --private-key 0xKey

# Contract call with explicit fee limit and gas limit
python3 scripts/morph_api.py altfee-send --to 0xContract --data 0xCalldata... --fee-token-id 5 --fee-limit 500000 --gas-limit 200000 --private-key 0xKey

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Safety Rules

1. Always confirm with the user before executing altfee-send — show the recipient, amount, fee token, and fee limit before signing.
2. Private keys are used locally for signing only — never sent to any API.
3. Default feeLimit=0 means no limit — unused portion is refunded, but confirm this with the user.

Domain Knowledge

• Morph supports paying gas with alternative tokens via custom transaction type 0x7f
• Fee tokens are managed by the on-chain TokenRegistry (IDs 1-6)
• Current fee tokens: 1=USDT.e, 2=USDC.e, 3=BGB (old), 4=BGB, 5=USDT, 6=USDC
• Formula: feeLimit >= (gasFeeCap × gasLimit + L1DataFee) × tokenScale / feeRate
• feeLimit = 0 means "no limit" — uses entire balance, unused portion is refunded
• Fee token 5 = USDT (0xe7cd86e13AC4309349F30B3435a9d337750fC82D)
• Alt-fee and EIP-7702 are mutually exclusive — cannot use both in one transaction
• L1 Data Fee depends on calldata size and L1 gas price; not estimable upfront

Common Workflows

Pay gas with alternative token:

altfee-tokens (list available) → altfee-estimate (calculate cost) → altfee-send (sign & broadcast)

DEX swap with alt-fee gas payment:

dex-quote --recipient 0xAddr (morph-dex skill) → altfee-send --data 0xCalldata... --fee-token-id 5

Which Commands Support Altfee

Command	--fee-token-id support
altfee-send	Yes (required) — standalone altfee transaction
agent-register	Yes (optional) — inline altfee gas payment
agent-feedback	Yes (optional) — inline altfee gas payment
transfer	No — use altfee-send --to ... --value ... instead
transfer-token	No — use altfee-send --to ... --data ... instead
dex-send	No — use altfee-send --to ... --data ... instead

Cross-Skill Integration

• Use dex-quote (morph-dex) to get swap calldata, then pass to altfee-send for gas payment with alt tokens.
• Use token-balance (morph-wallet) to check fee token balance before sending.
• Use balance (morph-wallet) to check if user has ETH — if not, suggest alt-fee.
• If the user is actually asking for a Social Login Wallet or TEE signing flow, route to BGW skills instead — BGW's swap flow has its own gas handling (including gasless no_gas mode).