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Troublor merged 4 commits into from
Jun 11, 2026
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docs(dev): Rex5 KeylessDeploy gas billing and SequencerRegistry note #53

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0c8e558
docs(dev): update KeylessDeploy guidance and add SequencerRegistry no…
Troublor Jun 11, 2026
266380e
style: format Markdown tables with prettier
Troublor Jun 11, 2026
cc415d9
docs(dev): clarify signer materialization charge is one-time per signer
Troublor Jun 11, 2026
8c3646f
address review feedback: add SequencerRegistry to system contract table
mega-putin[bot] Jun 11, 2026
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28 changes: 14 additions & 14 deletions docs/AGENTS.md
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Expand Up @@ -59,20 +59,20 @@ When in doubt: top-level pages prioritize readability, layer pages prioritize de

Use these exact forms consistently. Do not alternate between variants.

| Term | Correct | Incorrect |
| --------------------- | -------------------------------------------------------- | ----------------------------------------------------------- |
| Project name | MegaETH | megaETH, Mega ETH, megaeth, MEGAETH |
| EVM implementation | MegaEVM | MegaEvm, mega-evm, Mega EVM |
| Mainnet (proper noun) | MegaETH Mainnet | MegaETH mainnet, main net, main-net |
| Testnet (proper noun) | MegaETH Testnet | MegaETH testnet, test net, test-net |
| Currency ticker | ETH | eth, Eth |
| Currency name | ether | Ether, ETH (when referring to the currency, not the ticker) |
| Block type | mini-block | miniblock, mini block, MiniBlock |
| Onchain / offchain | onchain, offchain | on-chain, off-chain, on chain |
| Smart contract | smart contract | Smart Contract, smartcontract |
| Gas dimensions | compute gas, storage gas | Compute Gas, Storage Gas, Compute gas |
| Spec names | MiniRex, MiniRex1, MiniRex2, Rex, Rex1, Rex2, Rex3, Rex4 | minirex, MINIREX, mini-rex, rex-3 |
| State trie | SALT | Salt, salt |
| Term | Correct | Incorrect |
| --------------------- | -------------------------------------------------------------- | ----------------------------------------------------------- |
| Project name | MegaETH | megaETH, Mega ETH, megaeth, MEGAETH |
| EVM implementation | MegaEVM | MegaEvm, mega-evm, Mega EVM |
| Mainnet (proper noun) | MegaETH Mainnet | MegaETH mainnet, main net, main-net |
| Testnet (proper noun) | MegaETH Testnet | MegaETH testnet, test net, test-net |
| Currency ticker | ETH | eth, Eth |
| Currency name | ether | Ether, ETH (when referring to the currency, not the ticker) |
| Block type | mini-block | miniblock, mini block, MiniBlock |
| Onchain / offchain | onchain, offchain | on-chain, off-chain, on chain |
| Smart contract | smart contract | Smart Contract, smartcontract |
| Gas dimensions | compute gas, storage gas | Compute Gas, Storage Gas, Compute gas |
| Spec names | MiniRex, MiniRex1, MiniRex2, Rex, Rex1, Rex2, Rex3, Rex4, Rex5 | minirex, MINIREX, mini-rex, rex-3 |
| State trie | SALT | Salt, salt |

**Capitalization rules:**

Expand Down
42 changes: 39 additions & 3 deletions docs/dev/execution/system-contracts.md
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Expand Up @@ -12,6 +12,17 @@ MegaETH provides system contracts that give transactions access to functionality
| [KeylessDeploy](#keyless-deployment) | [`0x6342000000000000000000000000000000000003`](https://megaeth.blockscout.com/address/0x6342000000000000000000000000000000000003) | Deterministic cross-chain deployment (Nick's Method) |
| [MegaAccessControl](#mega-access-control) | [`0x6342000000000000000000000000000000000004`](https://megaeth.blockscout.com/address/0x6342000000000000000000000000000000000004) | Opt out of volatile data access detection |
| [MegaLimitControl](#mega-limit-control) | [`0x6342000000000000000000000000000000000005`](https://megaeth.blockscout.com/address/0x6342000000000000000000000000000000000005) | Query remaining compute gas budget |
| [SequencerRegistry](#sequencer-registry) | [`0x6342000000000000000000000000000000000006`](https://megaeth.blockscout.com/address/0x6342000000000000000000000000000000000006) | System address and sequencer role registry |

## Sequencer Registry

Tracks the current system address (Oracle and system-transaction authority) and the current sequencer (mini-block signing key).
Rex5 introduces this contract.
Most dapp code does not call it directly, but contracts and tools can read it when they need the canonical onchain source for either role.

**Address:** `0x6342000000000000000000000000000000000006`

For the formal specification, see [SequencerRegistry (spec)](https://docs.megaeth.com/spec/system-contracts/sequencer-registry).

## High-Precision Timestamp

Expand Down Expand Up @@ -93,20 +104,43 @@ bytes memory originalTx = hex"f8a58085174876e800830186a08080b853604580600e...";

**Preconditions:**

- `keylessDeploymentTransaction` must be a valid RLP-encoded Nick's Method deployment transaction: pre-EIP-155, contract creation (`to` = null), nonce = 0.
- `keylessDeploymentTransaction` must be a valid RLP-encoded Nick's Method deployment transaction: pre-EIP-155, contract creation (`to` = null), nonce = 0, with no trailing bytes after the signed payload.
- `gasLimitOverride` must be ≥ the original transaction's gas limit.
- The deployment address must not already contain code.
- The call must carry zero ETH value.
- The signer's balance must cover the inner transaction's `value` (zero for typical deployments) — the sandbox runs fee-free, so the signer needs no balance for gas.

**Outcome:**

- On success: returns `gasUsed`, `deployedAddress` (the deterministic address), and empty `errorData`.
- On deployment failure (e.g., out of gas): the call **does not revert**. It returns `gasUsed`, `deployedAddress = 0x0`, and `errorData` describing the failure. State changes from the attempted deployment (including gas charges) are still applied.
- On deployment failure (e.g., out of gas): the call **does not revert**. It returns `gasUsed`, `deployedAddress = 0x0`, and `errorData` describing the failure. State changes from the attempted deployment are still applied, and the gas it consumed is charged to the outer call.

### Gas billing

The outer transaction pays for everything the sandboxed deployment does:

| Charge | Amount | When |
| ---------------------- | -------------------------------------------- | --------------------------------------------------------------------------- |
| Dispatch overhead | 100,000 compute gas | Always — retained even if the deployment is rejected |
| Sandbox gas | Exact gas used by the re-executed deployment | On every completed deployment attempt, success or failure |
| Signer materialization | New-account storage gas for the inner signer | Only if the signer account does not exist yet (one-time per signer address) |

Size the outer transaction's gas limit for `100,000 + sandbox gas used + signer materialization`, not just the inner deployment's own cost.
`gasLimitOverride` is capped to the outer call's remaining gas, so the sandbox can never spend more than the outer transaction provides.
The sandbox's resource usage (compute gas, data size, KV updates, and state growth) also counts toward the outer transaction's [resource limits](resource-limits.md).

The inner signer pays no gas: the sandbox runs fee-free, so the signer address needs no ETH beyond the inner transaction's `value` (zero for typical Nick's Method deployments).
A consequence is that the `GASPRICE` opcode reads `0` inside the deployed contract's constructor.

{% hint style="danger" %}
**Migration note (Rex5):** before Rex5, the outer call was charged only the 100,000 gas dispatch overhead.
Rex5 charges the full sandbox gas to the outer transaction — for storage-heavy deployments this raises the relayer-side gas budget by 10–100×.
{% endhint %}

{% hint style="warning" %}
Code deposit costs 10,000 storage gas per byte on MegaETH.
A 24 KB contract costs roughly 240M storage gas.
If `gasLimitOverride` is too low for this cost, the inner deployment will fail (out of gas) but the outer call still succeeds — check `errorData` and `deployedAddress`.
If `gasLimitOverride` is too low for this cost, the inner deployment will fail (out of gas) but the outer call still succeeds — check `errorData` and `deployedAddress`, and note the outer call is still charged the gas the failed attempt consumed.
Simulate the transaction with [`mega-evme`](../send-tx/debugging.md#simulating-a-new-transaction) to find the required gas — it has no gas cap and fully implements MegaETH's gas model.
Alternatively, use `eth_estimateGas` on a MegaETH endpoint (subject to the [RPC compute gas cap](../send-tx/gas-estimation.md#the-rpc-compute-gas-cap)).
{% endhint %}
Expand Down Expand Up @@ -203,3 +237,5 @@ uint64 remaining = limitControl.remainingComputeGas();
- [KeylessDeploy (spec)](https://docs.megaeth.com/spec/system-contracts/keyless-deploy) — keyless deployment sandbox and validation rules
- [MegaAccessControl (spec)](https://docs.megaeth.com/spec/system-contracts/mega-access-control) — volatile data access restriction mechanism
- [MegaLimitControl (spec)](https://docs.megaeth.com/spec/system-contracts/mega-limit-control) — remaining compute gas query
- [SequencerRegistry (spec)](https://docs.megaeth.com/spec/system-contracts/sequencer-registry) — system address and sequencer role registry
- [Rex5 Upgrade (spec)](https://docs.megaeth.com/spec/upgrades/rex5) — full list of Rex5 behavior changes
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