diff --git a/mainnet/2025-12-04-set-jovian-parameters/.env b/mainnet/2025-12-04-set-jovian-parameters/.env
new file mode 100644
index 00000000..8dfcfafc
--- /dev/null
+++ b/mainnet/2025-12-04-set-jovian-parameters/.env
@@ -0,0 +1,17 @@
+# Base Contracts commit
+BASE_CONTRACTS_COMMIT=51788f920e368e72c63cef24a5e1ea0f6562d9a5
+
+# Optimism commit (op-contracts/v5.0.0)
+OP_COMMIT=d09c836f818c73ae139f60b717654c4e53712743
+
+# Contract addresses
+SYSTEM_CONFIG=0x73a79Fab69143498Ed3712e519A88a918e1f4072
+OWNER_SAFE=0x14536667Cd30e52C0b458BaACcB9faDA7046E056
+
+# Jovian parameters
+DA_FOOTPRINT_GAS_SCALAR=312
+MIN_BASE_FEE=200000
+
+SENDER=0x1841CB3C2ce6870D0417844C817849da64E6e937
+
+RECORD_STATE_DIFF=true
diff --git a/mainnet/2025-12-04-set-jovian-parameters/FACILITATORS.md b/mainnet/2025-12-04-set-jovian-parameters/FACILITATORS.md
new file mode 100644
index 00000000..327dffca
--- /dev/null
+++ b/mainnet/2025-12-04-set-jovian-parameters/FACILITATORS.md
@@ -0,0 +1,44 @@
+#### Execute the transaction
+
+### 1. Update repo:
+
+```bash
+cd contract-deployments
+git pull
+cd mainnet/2025-12-04-set-jovian-parameters
+make deps
+```
+
+### 2. Execute
+
+1. Collect outputs from all participating signers.
+1. Concatenate all signatures and export it as the `SIGNATURES`
+   environment variable, i.e. `export
+SIGNATURES="[SIGNATURE1][SIGNATURE2]..."`.
+1. Run the `make execute` command as described below to execute the transaction.
+
+For example, if the quorum is 3 and you get the following outputs:
+
+```shell
+Data:  0xDEADBEEF
+Signer: 0xC0FFEE01
+Signature: AAAA
+```
+
+```shell
+Data:  0xDEADBEEF
+Signer: 0xC0FFEE02
+Signature: BBBB
+```
+
+```shell
+Data:  0xDEADBEEF
+Signer: 0xC0FFEE03
+Signature: CCCC
+```
+
+Execute the transaction:
+
+```bash
+SIGNATURES=AAAABBBBCCCC make execute
+```
diff --git a/mainnet/2025-12-04-set-jovian-parameters/Makefile b/mainnet/2025-12-04-set-jovian-parameters/Makefile
new file mode 100644
index 00000000..c25f9322
--- /dev/null
+++ b/mainnet/2025-12-04-set-jovian-parameters/Makefile
@@ -0,0 +1,27 @@
+include ../../Makefile
+include ../../Multisig.mk
+include ../.env
+include .env
+
+ifndef LEDGER_ACCOUNT
+override LEDGER_ACCOUNT = 0
+endif
+
+SCRIPT_NAME = SetJovianParametersScript
+
+RPC_URL = $(L1_RPC_URL)
+
+.PHONY: gen-validation
+gen-validation: checkout-signer-tool run-script
+
+.PHONY: run-script
+run-script:
+	cd $(SIGNER_TOOL_PATH); \
+	npm ci; \
+	bun run scripts/genValidationFile.ts --rpc-url $(RPC_URL) \
+	--workdir .. --forge-cmd 'forge script --rpc-url $(RPC_URL) \
+	$(SCRIPT_NAME) --sig "sign(address[])" [] --sender $(SENDER)' --out ../validations/base-signer.json;
+
+.PHONY: execute
+execute:
+	$(call MULTISIG_EXECUTE,$(SIGNATURES))
diff --git a/mainnet/2025-12-04-set-jovian-parameters/README.md b/mainnet/2025-12-04-set-jovian-parameters/README.md
new file mode 100644
index 00000000..128be5ef
--- /dev/null
+++ b/mainnet/2025-12-04-set-jovian-parameters/README.md
@@ -0,0 +1,58 @@
+# Set Jovian Parameters on Base Mainnet
+
+Status: READY TO SIGN
+
+## Description
+
+This task sets the Jovian hardfork parameters on Base Mainnet's SystemConfig contract. The parameters being set are:
+
+- `setDAFootprintGasScalar(312)` - Sets the data availability footprint gas scalar
+- `setMinBaseFee(200000)` - Sets the minimum base fee
+
+These parameters activate with the Jovian hardfork and affect data availability fee calculations and base fee management on the L2.
+
+## Procedure
+
+## 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 (NOTE: do not enter the task directory. Run this command from the project's root).
+
+```bash
+make sign-task
+```
+
+### 3. Open the UI at [http://localhost:3000](http://localhost:3000)
+
+Be sure to select the correct task user from the list of available users to sign.
+After completion, the signer tool can be closed by using Ctrl + c
+
+### 4. Send signature to facilitator
diff --git a/mainnet/2025-12-04-set-jovian-parameters/foundry.toml b/mainnet/2025-12-04-set-jovian-parameters/foundry.toml
new file mode 100644
index 00000000..14499ab0
--- /dev/null
+++ b/mainnet/2025-12-04-set-jovian-parameters/foundry.toml
@@ -0,0 +1,20 @@
+[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
diff --git a/mainnet/2025-12-04-set-jovian-parameters/script/SetJovianParameters.s.sol b/mainnet/2025-12-04-set-jovian-parameters/script/SetJovianParameters.s.sol
new file mode 100644
index 00000000..21059cca
--- /dev/null
+++ b/mainnet/2025-12-04-set-jovian-parameters/script/SetJovianParameters.s.sol
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.15;
+
+import {Vm} from "forge-std/Vm.sol";
+import {console} from "forge-std/console.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 daFootprintGasScalar() external view returns (uint16);
+    function minBaseFee() external view returns (uint64);
+    function setDAFootprintGasScalar(uint16 _daFootprintGasScalar) external;
+    function setMinBaseFee(uint64 _minBaseFee) external;
+}
+
+contract SetJovianParametersScript is MultisigScript {
+    address internal immutable OWNER_SAFE;
+    address internal immutable SYSTEM_CONFIG;
+
+    uint16 internal immutable DA_FOOTPRINT_GAS_SCALAR;
+    uint64 internal immutable MIN_BASE_FEE;
+
+    constructor() {
+        OWNER_SAFE = vm.envAddress("OWNER_SAFE");
+        SYSTEM_CONFIG = vm.envAddress("SYSTEM_CONFIG");
+        DA_FOOTPRINT_GAS_SCALAR = uint16(vm.envUint("DA_FOOTPRINT_GAS_SCALAR"));
+        MIN_BASE_FEE = uint64(vm.envUint("MIN_BASE_FEE"));
+    }
+
+    function setUp() external view {
+        // Log current values for reference
+        console.log("Current DA Footprint Gas Scalar:", ISystemConfig(SYSTEM_CONFIG).daFootprintGasScalar());
+        console.log("Current Min Base Fee:", ISystemConfig(SYSTEM_CONFIG).minBaseFee());
+        console.log("New DA Footprint Gas Scalar:", DA_FOOTPRINT_GAS_SCALAR);
+        console.log("New Min Base Fee:", MIN_BASE_FEE);
+    }
+
+    function _postCheck(Vm.AccountAccess[] memory, Simulation.Payload memory) internal view override {
+        vm.assertEq(
+            ISystemConfig(SYSTEM_CONFIG).daFootprintGasScalar(),
+            DA_FOOTPRINT_GAS_SCALAR,
+            "DA Footprint Gas Scalar mismatch"
+        );
+        vm.assertEq(ISystemConfig(SYSTEM_CONFIG).minBaseFee(), MIN_BASE_FEE, "Min Base Fee mismatch");
+    }
+
+    function _buildCalls() internal view override returns (IMulticall3.Call3Value[] memory) {
+        IMulticall3.Call3Value[] memory calls = new IMulticall3.Call3Value[](2);
+
+        calls[0] = IMulticall3.Call3Value({
+            target: SYSTEM_CONFIG,
+            allowFailure: false,
+            callData: abi.encodeCall(ISystemConfig.setDAFootprintGasScalar, (DA_FOOTPRINT_GAS_SCALAR)),
+            value: 0
+        });
+
+        calls[1] = IMulticall3.Call3Value({
+            target: SYSTEM_CONFIG,
+            allowFailure: false,
+            callData: abi.encodeCall(ISystemConfig.setMinBaseFee, (MIN_BASE_FEE)),
+            value: 0
+        });
+
+        return calls;
+    }
+
+    function _ownerSafe() internal view override returns (address) {
+        return OWNER_SAFE;
+    }
+}
diff --git a/mainnet/2025-12-04-set-jovian-parameters/validations/base-signer.json b/mainnet/2025-12-04-set-jovian-parameters/validations/base-signer.json
new file mode 100644
index 00000000..a3e047c7
--- /dev/null
+++ b/mainnet/2025-12-04-set-jovian-parameters/validations/base-signer.json
@@ -0,0 +1,66 @@
+{
+  "cmd": "forge script --rpc-url https://eth-mainnet.public.blastapi.io SetJovianParametersScript --sig sign(address[]) [] --sender 0x1841CB3C2ce6870D0417844C817849da64E6e937",
+  "ledgerId": 0,
+  "rpcUrl": "https://eth-mainnet.public.blastapi.io",
+  "expectedDomainAndMessageHashes": {
+    "address": "0x14536667Cd30e52C0b458BaACcB9faDA7046E056",
+    "domainHash": "0xf3474c66ee08325b410c3f442c878d01ec97dd55a415a307e9d7d2ea24336289",
+    "messageHash": "0xabbc13082dc0c978a0d67092bf4da43670451de5604d69434dc7f7ab594785b5"
+  },
+  "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": "0xc3011018e301845703e8f147902e20fa435a206bf02aa8a392467aa139cf4049",
+          "value": "0x0000000000000000000000000000000000000000000000000000000000000001",
+          "description": "Simulates an approval from msg.sender in order for the task simulation to succeed.",
+          "allowDifference": false
+        }
+      ]
+    }
+  ],
+  "stateChanges": [
+    {
+      "name": "Incident Safe - Mainnet",
+      "address": "0x14536667cd30e52c0b458baaccb9fada7046e056",
+      "changes": [
+        {
+          "key": "0x0000000000000000000000000000000000000000000000000000000000000005",
+          "before": "0x0000000000000000000000000000000000000000000000000000000000000061",
+          "after": "0x0000000000000000000000000000000000000000000000000000000000000062",
+          "description": "Increments the nonce",
+          "allowDifference": false
+        }
+      ]
+    },
+    {
+      "name": "System Config - Mainnet",
+      "address": "0x73a79fab69143498ed3712e519a88a918e1f4072",
+      "changes": [
+        {
+          "key": "0x000000000000000000000000000000000000000000000000000000000000006a",
+          "before": "0x0000000000000000000000000000000000000000000000000000000500000032",
+          "after": "0x0000000000000000000001380000000000000000000000000000000500000032",
+          "description": "Sets the DA Footprint Gas Scalar to 312 (0x0138)",
+          "allowDifference": false
+        },
+        {
+          "key": "0x000000000000000000000000000000000000000000000000000000000000006c",
+          "before": "0x00000000000000000000000095703e0982140d16f8eba6d158fccede42f04a4c",
+          "after": "0x000000000000000000030d4095703e0982140d16f8eba6d158fccede42f04a4c",
+          "description": "Sets the Min Base Fee to 200000 (0x030d40)",
+          "allowDifference": false
+        }
+      ]
+    }
+  ],
+  "balanceChanges": []
+}