feat(mainnet): Add task to increase EIP-1559 denominator

mainnet/2026-02-03-eip1559-denominator-increase/.env

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+# Required: Git commit hash for https://github.com/ethereum-optimism/optimism
+OP_COMMIT=d09c836f818c73ae139f60b717654c4e53712743
+
+# Required: Git commit hash for https://github.com/base/contracts
+BASE_CONTRACTS_COMMIT=9526d38b63be2ee10fc905dee60f0b2a0a17e89e
+
+# Required: L1 SystemConfig proxy contract address
+SYSTEM_CONFIG=0x73a79Fab69143498Ed3712e519A88a918e1f4072
+
+# Required: Address of the Gnosis Safe that owns SystemConfig
+OWNER_SAFE=0x14536667Cd30e52C0b458BaACcB9faDA7046E056
+
+# Required: Address of a signer on OWNER_SAFE (used for simulation)
+SENDER=0x1841CB3C2ce6870D0417844C817849da64E6e937
+
+# Enable state diff recording for validation
+RECORD_STATE_DIFF=true
+
+# EIP-1559 Denominator: 50 -> 125 (2.5x increase)
+FROM_DENOMINATOR=50
+TO_DENOMINATOR=125

mainnet/2026-02-03-eip1559-denominator-increase/FACILITATORS.md

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+# Facilitator Guide
+
+Guide for facilitators after collecting signatures from signers.
+
+### 1. Update repo:
+
+```bash
+cd contract-deployments
+git pull
+cd mainnet/2026-02-03-eip1559-denominator-increase
+make deps
+```
+
+### 2. Execute upgrade
+
+```bash
+SIGNATURES=AAABBBCCC make execute
+```
+
+### 3. (**ONLY** if needed) Execute upgrade rollback
+
+> [!IMPORTANT]
+> 
+> THIS SHOULD ONLY BE PERFORMED IN THE EVENT THAT WE NEED TO ROLLBACK
+
+```bash
+SIGNATURES=AAABBBCCC make execute-rollback
+```

mainnet/2026-02-03-eip1559-denominator-increase/Makefile

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+include ../../Makefile
+include ../../Multisig.mk
+include ../.env
+include .env
+
+ifndef LEDGER_ACCOUNT
+override LEDGER_ACCOUNT = 0
+endif
+
+ifndef ROLLBACK_NONCE_OFFSET
+override ROLLBACK_NONCE_OFFSET = 1
+endif
+
+RPC_URL = $(L1_RPC_URL)
+SCRIPT_NAME = IncreaseEip1559DenominatorScript
+
+# Validate required configuration before execution
+.PHONY: validate-config
+validate-config:
+	@test -n "$(OP_COMMIT)" -a "$(OP_COMMIT)" != "TODO" || (echo "OP_COMMIT required" && exit 1)
+	@test -n "$(BASE_CONTRACTS_COMMIT)" -a "$(BASE_CONTRACTS_COMMIT)" != "TODO" || (echo "BASE_CONTRACTS_COMMIT required" && exit 1)
+	@test -n "$(OWNER_SAFE)" || (echo "OWNER_SAFE required" && exit 1)
+	@test -n "$(SYSTEM_CONFIG)" || (echo "SYSTEM_CONFIG required" && exit 1)
+	@test -n "$(SENDER)" || (echo "SENDER required" && exit 1)
+	@test -n "$(FROM_DENOMINATOR)" -a "$(FROM_DENOMINATOR)" != "TODO" || (echo "FROM_DENOMINATOR required" && exit 1)
+	@test -n "$(TO_DENOMINATOR)" -a "$(TO_DENOMINATOR)" != "TODO" || (echo "TO_DENOMINATOR required" && exit 1)
+	@echo "Configuration validated successfully"
+
+.PHONY: gen-validation
+gen-validation: validate-config checkout-signer-tool run-script
+
+.PHONY: run-script
+run-script:
+	mkdir -p validations; \
+	cd $(SIGNER_TOOL_PATH); \
+	npm ci; \
+	bun run scripts/genValidationFile.ts --rpc-url $(RPC_URL) \
+	--workdir .. --forge-cmd 'NEW_DENOMINATOR=$(TO_DENOMINATOR) \
+	OLD_DENOMINATOR=$(FROM_DENOMINATOR) \
+	forge script --rpc-url $(RPC_URL) \
+	$(SCRIPT_NAME) --sig "sign(address[])" [] --sender $(SENDER)' --out ../validations/base-signer.json;
+
+.PHONY: execute
+execute: validate-config
+	NEW_DENOMINATOR=$(TO_DENOMINATOR) \
+	OLD_DENOMINATOR=$(FROM_DENOMINATOR) \
+	$(call MULTISIG_EXECUTE,$(SIGNATURES))
+
+.PHONY: gen-validation-rollback
+gen-validation-rollback: validate-config checkout-signer-tool run-script-rollback
+
+.PHONY: run-script-rollback
+run-script-rollback:
+	cd $(SIGNER_TOOL_PATH); \
+	npm ci; \
+	bun run scripts/genValidationFile.ts --rpc-url $(RPC_URL) \
+	--workdir .. --forge-cmd 'OLD_DENOMINATOR=$(TO_DENOMINATOR) \
+	NEW_DENOMINATOR=$(FROM_DENOMINATOR) \
+	SAFE_NONCE=$(shell expr $$(cast call $(OWNER_SAFE) "nonce()" --rpc-url $(RPC_URL) | cast to-dec) + $(ROLLBACK_NONCE_OFFSET)) \
+	forge script --rpc-url $(RPC_URL) \
+	$(SCRIPT_NAME) --sig "sign(address[])" [] --sender $(SENDER)' --out ../validations/base-signer-rollback.json;
+
+.PHONY: execute-rollback
+execute-rollback: validate-config
+	OLD_DENOMINATOR=$(TO_DENOMINATOR) \
+	NEW_DENOMINATOR=$(FROM_DENOMINATOR) \
+	SAFE_NONCE=$(shell expr $$(cast call $(OWNER_SAFE) "nonce()" --rpc-url $(RPC_URL) | cast to-dec) + $(ROLLBACK_NONCE_OFFSET)) \
+	forge script --rpc-url $(RPC_URL) $(SCRIPT_NAME) \
+	--sig "run(bytes)" $(SIGNATURES) --ledger --hd-paths "m/44'/60'/$(LEDGER_ACCOUNT)'/0/0" --broadcast

mainnet/2026-02-03-eip1559-denominator-increase/README.md

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+# Increase EIP-1559 Denominator in L1 `SystemConfig`
+
+Status: READY TO SIGN
+
+## Executed Transactions
+
+PENDING
+
+## Description
+
+We are increaseing the EIP-1559 Denominator to reduce the maximum rate of change for the base fee, and thus limit overall fee volatility.
+
+This runbook invokes the following script which allows our signers to sign the same call with two different sets of parameters for our Incident Multisig, defined in the [base-org/contracts](https://github.com/base/contracts) repository:
+
+`IncreaseEip1559Denominator` -- This script will update the EIP-1559 denominator to 125 if invoked as part of the "upgrade" process, or revert to the old denominator of 50 if invoked as part of the "rollback" process.
+
+The values we are sending are statically defined in the `.env` file.
+
+> [!IMPORTANT]
+>
+> We have two transactions to sign. Please follow
+> the flow for both "Approving the Update transaction" and
+> "Approving the Rollback transaction". Hopefully we only need
+> the former, but will have the latter available if needed.
+
+## Install dependencies
+
+### 1. Update foundry
+
+```bash
+foundryup
+```
+
+### 2. Install Node.js if needed
+
+First, check if you have node installed
+
+```bash
+node --version
+```
+
+If you see a version output from the above command, you can move on. Otherwise, install node
+
+```bash
+brew install node
+```
+
+## Approving the Update transaction
+
+### 1. Update repo:
+
+```bash
+cd contract-deployments
+git pull
+```
+
+### 2. Run the signing tool
+
+```bash
+make sign-task
+```
+
+### 3. Open the UI at [http://localhost:3000](http://localhost:3000)
+
+Be sure to select the correct task from the list of available tasks to sign (**not** the "Base Signer Rollback" task). Copy the resulting signature and save it.
+
+### 4. Rollback signing
+
+Now, click on the "Base Signer" selection and switch over to the rollback task (called "Base Signer Rollback"). Copy the resulting signature and save it.
+
+### 5. Send signatures to facilitator
+
+Send the two signatures to the facilitator and make sure to clearly note which one is the primary one and which one is the rollback.
+
+You may now kill the Signer Tool process in your terminal window by running `Ctrl + C`.

mainnet/2026-02-03-eip1559-denominator-increase/foundry.toml

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+[profile.default]
+src = 'src'
+out = 'out'
+libs = ['lib']
+broadcast = 'records'
+fs_permissions = [{ access = "read-write", path = "./" }]
+optimizer = true
+optimizer_runs = 999999
+solc_version = "0.8.15"
+via-ir = false
+remappings = [
+    '@eth-optimism-bedrock/=lib/optimism/packages/contracts-bedrock/',
+    '@openzeppelin/contracts/=lib/openzeppelin-contracts/contracts',
+    '@openzeppelin/contracts-upgradeable/=lib/openzeppelin-contracts-upgradeable/contracts',
+    '@rari-capital/solmate/=lib/solmate/',
+    '@base-contracts/=lib/base-contracts',
+    'solady/=lib/solady/src/',
+]
+
+# See more config options https://github.com/foundry-rs/foundry/tree/master/config

mainnet/2026-02-03-eip1559-denominator-increase/script/IncreaseEip1559Denominator.s.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.15;
+
+import {Vm} from "forge-std/Vm.sol";
+import {Simulation} from "@base-contracts/script/universal/Simulation.sol";
+import {IMulticall3} from "forge-std/interfaces/IMulticall3.sol";
+
+import {MultisigScript} from "@base-contracts/script/universal/MultisigScript.sol";
+
+interface ISystemConfig {
+    function eip1559Elasticity() external view returns (uint32);
+    function eip1559Denominator() external view returns (uint32);
+    function setEIP1559Params(uint32 _denominator, uint32 _elasticity) external;
+}
+
+contract IncreaseEip1559DenominatorScript is MultisigScript {
+    address internal immutable OWNER_SAFE;
+    address internal immutable SYSTEM_CONFIG;
+
+    uint32 internal immutable DENOMINATOR;
+    uint32 internal immutable NEW_DENOMINATOR;
+    uint32 internal immutable ELASTICITY;
+
+    constructor() {
+        OWNER_SAFE = vm.envAddress("OWNER_SAFE");
+        SYSTEM_CONFIG = vm.envAddress("SYSTEM_CONFIG");
+
+        DENOMINATOR = uint32(vm.envUint("OLD_DENOMINATOR"));
+        NEW_DENOMINATOR = uint32(vm.envUint("NEW_DENOMINATOR"));
+
+        ELASTICITY = ISystemConfig(SYSTEM_CONFIG).eip1559Elasticity();
+    }
+
+    function _postCheck(Vm.AccountAccess[] memory, Simulation.Payload memory) internal view override {
+        vm.assertEq(ISystemConfig(SYSTEM_CONFIG).eip1559Denominator(), NEW_DENOMINATOR, "Denominator mismatch");
+        vm.assertEq(ISystemConfig(SYSTEM_CONFIG).eip1559Elasticity(), ELASTICITY, "Elasticity mismatch");
+    }
+
+    function _simulationOverrides() internal view override returns (Simulation.StateOverride[] memory _stateOverrides) {
+        if (DENOMINATOR != ISystemConfig(SYSTEM_CONFIG).eip1559Denominator()) {
+            // Override SystemConfig state to the expected "from" values so simulations succeeds even
+            // when the chain already reflects the post-change values (during rollback simulation).
+
+            // Prepare one storage override for SystemConfig
+            Simulation.StateOverride[] memory stateOverrides = new Simulation.StateOverride[](1);
+            Simulation.StorageOverride[] memory storageOverrides = new Simulation.StorageOverride[](1);
+
+            // Load current packed EIP-1559 params (slot 0x6a) and replace only the lower 32 bits with DENOMINATOR
+            bytes32 eip1559SlotKey = bytes32(uint256(0x6a));
+            uint256 existingEip1559Word = uint256(vm.load(SYSTEM_CONFIG, eip1559SlotKey));
+            uint256 updatedEip1559Word = (existingEip1559Word & ~uint256(0xffffffff)) | uint256(DENOMINATOR);
+            storageOverrides[0] = Simulation.StorageOverride({key: eip1559SlotKey, value: bytes32(updatedEip1559Word)});
+
+            stateOverrides[0] = Simulation.StateOverride({contractAddress: SYSTEM_CONFIG, overrides: storageOverrides});
+            return stateOverrides;
+        }
+    }
+
+    function _buildCalls() internal view override returns (IMulticall3.Call3Value[] memory) {
+        IMulticall3.Call3Value[] memory calls = new IMulticall3.Call3Value[](1);
+
+        calls[0] = IMulticall3.Call3Value({
+            target: SYSTEM_CONFIG,
+            allowFailure: false,
+            callData: abi.encodeCall(ISystemConfig.setEIP1559Params, (NEW_DENOMINATOR, ELASTICITY)),
+            value: 0
+        });
+
+        return calls;
+    }
+
+    function _ownerSafe() internal view override returns (address) {
+        return OWNER_SAFE;
+    }
+}

mainnet/2026-02-03-eip1559-denominator-increase/validations/base-signer-rollback.json

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+{
+  "cmd": "OLD_DENOMINATOR=125 NEW_DENOMINATOR=50 SAFE_NONCE=103 forge script --rpc-url https://eth-mainnet.public.blastapi.io IncreaseEip1559DenominatorScript --sig sign(address[]) [] --sender 0x1841CB3C2ce6870D0417844C817849da64E6e937",
+  "ledgerId": 0,
+  "rpcUrl": "https://eth-mainnet.public.blastapi.io",
+  "expectedDomainAndMessageHashes": {
+    "address": "0x14536667Cd30e52C0b458BaACcB9faDA7046E056",
+    "domainHash": "0xf3474c66ee08325b410c3f442c878d01ec97dd55a415a307e9d7d2ea24336289",
+    "messageHash": "0x96f9aabc336c8752c76a513c4de4f28886f7d8757f132fc375edb6005a3a0876"
+  },
+  "stateOverrides": [
+    {
+      "name": "Incident Safe - Mainnet",
+      "address": "0x14536667cd30e52c0b458baaccb9fada7046e056",
+      "overrides": [
+        {
+          "key": "0x0000000000000000000000000000000000000000000000000000000000000004",
+          "value": "0x0000000000000000000000000000000000000000000000000000000000000001",
+          "description": "Override the threshold to 1 so the transaction simulation can occur.",
+          "allowDifference": false
+        },
+        {
+          "key": "0x0000000000000000000000000000000000000000000000000000000000000005",
+          "value": "0x0000000000000000000000000000000000000000000000000000000000000067",
+          "description": "Override the nonce to be our expected value after initial execution.",
+          "allowDifference": false
+        },
+        {
+          "key": "0x46a08474ac712a822d2c6035d1899c5d8c6e0032d6fb14e842f146f6083e44a9",
+          "value": "0x0000000000000000000000000000000000000000000000000000000000000001",
+          "description": "Simulates an approval from msg.sender in order for the task simulation to succeed.",
+          "allowDifference": false
+        }
+      ]
+    },
+    {
+      "name": "System Config - Mainnet",
+      "address": "0x73a79fab69143498ed3712e519a88a918e1f4072",
+      "overrides": [
+        {
+          "key": "0x000000000000000000000000000000000000000000000000000000000000006a",
+          "value": "0x00000000000000000000008b000000000000000000000000000000060000007d",
+          "description": "Override EIP-1559 denominator to 125 (post-upgrade value) for rollback simulation",
+          "allowDifference": false
+        }
+      ]
+    }
+  ],
+  "stateChanges": [
+    {
+      "name": "Incident Safe - Mainnet",
+      "address": "0x14536667cd30e52c0b458baaccb9fada7046e056",
+      "changes": [
+        {
+          "key": "0x0000000000000000000000000000000000000000000000000000000000000005",
+          "before": "0x0000000000000000000000000000000000000000000000000000000000000067",
+          "after": "0x0000000000000000000000000000000000000000000000000000000000000068",
+          "description": "Increments the nonce",
+          "allowDifference": false
+        }
+      ]
+    },
+    {
+      "name": "System Config - Mainnet",
+      "address": "0x73a79fab69143498ed3712e519a88a918e1f4072",
+      "changes": [
+        {
+          "key": "0x000000000000000000000000000000000000000000000000000000000000006a",
+          "before": "0x00000000000000000000008b000000000000000000000000000000060000007d",
+          "after": "0x00000000000000000000008b0000000000000000000000000000000600000032",
+          "description": "Updates EIP-1559 denominator from 125 to 50 (rollback)",
+          "allowDifference": false
+        }
+      ]
+    }
+  ],
+  "balanceChanges": []
+}