Block Environment

Configure block number, timestamp, coinbase, base fee, and other block-level fields.

These options configure the block context for EVM execution. They are available in the run and tx commands. The replay command fetches block environment from the RPC automatically.

Options

Flag	Default	Aliases	Description
--block.number <NUM>	1	—	Block number
--block.coinbase <ADDR>	0x0…0	--block.beneficiary	Block coinbase / beneficiary address
--block.timestamp <TS>	1	—	Block timestamp (Unix seconds)
--block.gaslimit <GAS>	10000000000	--block.gas-limit, --block.gas	Block gas limit
--block.basefee <FEE>	0	--block.base-fee	EIP-1559 base fee
--block.difficulty <DIFF>	0	—	Block difficulty
--block.prevrandao <HASH>	0x0…0	--block.random	Previous randao value (post-merge)
--block.blobexcessgas <GAS>	0	--block.blob-excess-gas	EIP-4844 blob excess gas

Examples

# Simulate a specific block context — call WETH.name() at a fixed block
mega-evme tx \
  --receiver 0x4200000000000000000000000000000000000006 \
  --input 0x06fdde03 \
  --sender.balance 1ether \
  --block.number 1000 \
  --block.timestamp 1234567890 \
  --block.basefee 1000000000 \
  --basefee 1000000000

# Test COINBASE opcode — pushes the beneficiary address onto the stack
mega-evme run 0x41 --block.coinbase 0x1111111111111111111111111111111111111111

Notes

The block environment affects opcodes like NUMBER, TIMESTAMP, COINBASE, BASEFEE, DIFFICULTY / PREVRANDAO, and BLOBBASEFEE.

In MegaETH specs (MiniRex and above), accessing block environment fields triggers gas detention — the remaining compute gas is capped to reduce parallel execution conflicts. This is normal MegaETH behavior and is reflected in mega-evme execution.