> For the complete documentation index, see [llms.txt](https://docs.megaeth.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.megaeth.com/mega-evme/configuration/block-environment.md).

# Block Environment

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

```bash
# 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](https://github.com/megaeth-labs/mega-evm/blob/main/docs/spec/evm/gas-detention.md) — the remaining compute gas is capped to reduce parallel execution conflicts. This is normal MegaETH behavior and is reflected in `mega-evme` execution.


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