From ea4b01d22c5329072bf2dea2be6e18a77aa8c60f Mon Sep 17 00:00:00 2001
From: pdobacz <5735525+pdobacz@users.noreply.github.com>
Date: Wed, 19 Aug 2026 15:58:59 +0000
Subject: [PATCH 1/2] feat(monad_next): adopt EIP-7981 increase access list
 cost

MONAD_NEXT charges access list bytes at its own floor token rate, ordered after Amsterdam by succession, and releases as the monad_eip7981 feature.

Co-Authored-By: Claude <claude-opus-5>
---
 .github/configs/feature.yaml                  |  4 +++
 .../pytest_commands/plugins/forks/forks.py    |  4 ++-
 .../src/execution_testing/forks/base_fork.py  | 20 +++++++++--
 .../execution_testing/forks/forks/forks.py    | 23 ++++++++----
 src/ethereum/forks/monad_next/transactions.py | 36 ++++++++++++++++---
 .../conftest.py                               | 10 ++++++
 .../eip7708_eth_transfer_logs/conftest.py     | 10 ++++++
 .../conftest.py                               | 10 ++++++
 tests/amsterdam/eip7843_slotnum/conftest.py   | 10 ++++++
 .../conftest.py                               | 10 ++++++
 .../conftest.py                               |  7 ++++
 .../test_access_list_cost.py                  |  5 +--
 .../test_fork_transition.py                   | 16 +++++----
 .../conftest.py                               | 10 ++++++
 .../eip8024_dupn_swapn_exchange/conftest.py   | 10 ++++++
 .../conftest.py                               | 10 ++++++
 .../conftest.py                               | 10 ++++++
 .../eip8070_sparse_blobpool/conftest.py       |  7 ++++
 .../eip8246_selfdestruct_no_burn/conftest.py  | 10 ++++++
 .../conftest.py                               |  9 +++++
 20 files changed, 208 insertions(+), 23 deletions(-)
 create mode 100644 tests/amsterdam/eip2780_reduce_intrinsic_tx_gas/conftest.py
 create mode 100644 tests/amsterdam/eip7708_eth_transfer_logs/conftest.py
 create mode 100644 tests/amsterdam/eip7778_block_gas_accounting_without_refunds/conftest.py
 create mode 100644 tests/amsterdam/eip7843_slotnum/conftest.py
 create mode 100644 tests/amsterdam/eip7928_block_level_access_lists/conftest.py
 create mode 100644 tests/amsterdam/eip7997_deterministic_factory_predeploy/conftest.py
 create mode 100644 tests/amsterdam/eip8024_dupn_swapn_exchange/conftest.py
 create mode 100644 tests/amsterdam/eip8037_state_creation_gas_cost_increase/conftest.py
 create mode 100644 tests/amsterdam/eip8038_state_access_gas_cost_increase/conftest.py
 create mode 100644 tests/amsterdam/eip8246_selfdestruct_no_burn/conftest.py

diff --git a/.github/configs/feature.yaml b/.github/configs/feature.yaml
index 7fca18fd9ef..7849a5e116a 100644
--- a/.github/configs/feature.yaml
+++ b/.github/configs/feature.yaml
@@ -11,3 +11,7 @@ monad_runloop:
   evm-type: eels
   # Like `monad`, but `--monad-runloop` and eestnet chain id `30143`
   fill-params: -m blockchain_test --from=MONAD_EIGHT --until=MONAD_TEN --chain-id=30143 --monad-runloop -k "not invalid_header"
+
+monad_eip7981:
+  evm-type: eels
+  fill-params: -m blockchain_test --fork=MONAD_NEXT --chain-id=143 -k "not invalid_header"
diff --git a/packages/testing/src/execution_testing/cli/pytest_commands/plugins/forks/forks.py b/packages/testing/src/execution_testing/cli/pytest_commands/plugins/forks/forks.py
index 6075481806c..29ef4dc86e3 100644
--- a/packages/testing/src/execution_testing/cli/pytest_commands/plugins/forks/forks.py
+++ b/packages/testing/src/execution_testing/cli/pytest_commands/plugins/forks/forks.py
@@ -1265,7 +1265,9 @@ def _process_with_marker_args(
                 "Missing fork argument with 'valid_at_transition_to' marker."
             )
 
-        if len(forks) > 1:
+        # A single EIP argument expands to one fork per enabling fork, so
+        # the limit is on the arguments rather than on the resolved forks.
+        if len(fork_args) > 1:
             raise Exception(
                 "Too many forks specified to 'valid_at_transition_to' marker."
             )
diff --git a/packages/testing/src/execution_testing/forks/base_fork.py b/packages/testing/src/execution_testing/forks/base_fork.py
index f842878c42f..808d94b6045 100644
--- a/packages/testing/src/execution_testing/forks/base_fork.py
+++ b/packages/testing/src/execution_testing/forks/base_fork.py
@@ -333,12 +333,23 @@ def _maybe_transitioned(fork_cls: "BaseForkMeta") -> "BaseForkMeta":
     @staticmethod
     def _is_subclass_of(a: "BaseForkMeta", b: "BaseForkMeta") -> bool:
         """
-        Check if `a` is a subclass of `b`, taking fork transitions into
-        account.
+        Check if `a` is a subclass of `b`, taking fork transitions and
+        declared succession into account.
+
+        A fork can follow another fork it does not inherit from, which
+        places it after that fork (and after everything that fork comes
+        after) in the fork order without adopting its behavior.
         """
         a = BaseForkMeta._maybe_transitioned(a)
         b = BaseForkMeta._maybe_transitioned(b)
-        return issubclass(a, b)
+        if issubclass(a, b):
+            return True
+        followed = getattr(a, "_follows", None)
+        while followed is not None:
+            if issubclass(followed, b):
+                return True
+            followed = followed._follows
+        return False
 
     def __gt__(cls, other: "BaseForkMeta") -> bool:
         """Compare if a fork is newer than some other fork (cls > other)."""
@@ -381,6 +392,7 @@ class BaseFork(ForkOpcodeInterface, metaclass=BaseForkMeta):
     _fork_by_timestamp: ClassVar[bool] = False
     _blob_constants: ClassVar[Dict[str, int]] = {}
     _deployed: ClassVar[bool] = True
+    _follows: ClassVar[Optional[Type["BaseFork"]]] = None
     _enabled_eips: ClassVar[Set[int]] = set()
     _enabling_forks: ClassVar[Set[Type["BaseFork"]]] = set()
 
@@ -396,6 +408,7 @@ def __init_subclass__(
         transition_tool_name: Optional[str] = None,
         ignore: bool = False,
         bpo_fork: bool = False,
+        follows: Optional[Type["BaseFork"]] = None,
         ruleset_name: Optional[str] = None,
         fork_by_timestamp: Optional[bool] = None,
         deployed: Optional[bool] = None,
@@ -410,6 +423,7 @@ def __init_subclass__(
         forks.
         """
         cls._transition_tool_name = transition_tool_name
+        cls._follows = follows
         cls._ignore = ignore
         cls._bpo_fork = bpo_fork
         cls._ruleset_name = ruleset_name
diff --git a/packages/testing/src/execution_testing/forks/forks/forks.py b/packages/testing/src/execution_testing/forks/forks/forks.py
index ecf3b02f3ae..04fde59cc0c 100644
--- a/packages/testing/src/execution_testing/forks/forks/forks.py
+++ b/packages/testing/src/execution_testing/forks/forks/forks.py
@@ -1805,12 +1805,6 @@ def _calculate_sstore_gas_mip8(
         return gas_cost
 
 
-class MONAD_NEXT(MONAD_TEN):  # noqa: N801
-    """MONAD_NEXT fork, a placeholder identical to MONAD_TEN."""
-
-    pass
-
-
 class BPO1(
     Osaka,
     bpo_fork=True,
@@ -1904,3 +1898,20 @@ def engine_payload_attribute_target_gas_limit(cls) -> bool:
         limit.
         """
         return True
+
+
+class MONAD_NEXT(  # noqa: N801
+    eips.EIP7981,
+    MONAD_TEN,
+    follows=Amsterdam,
+):
+    """
+    MONAD_NEXT fork.
+
+    Amsterdam-based successor to MONAD_TEN, adopting the EIP-7981
+    changes. The Amsterdam changes it does not adopt stay out of the
+    fork by not being inherited at all; the fork order still places
+    MONAD_NEXT after Amsterdam through `follows`.
+    """
+
+    pass
diff --git a/src/ethereum/forks/monad_next/transactions.py b/src/ethereum/forks/monad_next/transactions.py
index 24bb4880a74..71bce9409f3 100644
--- a/src/ethereum/forks/monad_next/transactions.py
+++ b/src/ethereum/forks/monad_next/transactions.py
@@ -30,6 +30,22 @@
 
 TX_MAX_GAS_LIMIT = Uint(30_000_000)
 
+ACCESS_LIST_ADDRESS_FLOOR_TOKENS = Uint(80)
+"""
+Floor data tokens contributed by a single access list address per
+[EIP-7981].
+
+[EIP-7981]: https://eips.ethereum.org/EIPS/eip-7981
+"""
+
+ACCESS_LIST_STORAGE_KEY_FLOOR_TOKENS = Uint(128)
+"""
+Floor data tokens contributed by a single access list storage key per
+[EIP-7981].
+
+[EIP-7981]: https://eips.ethereum.org/EIPS/eip-7981
+"""
+
 
 @final
 @slotted_freezable
@@ -587,10 +603,6 @@ def calculate_intrinsic_cost(tx: Transaction) -> Tuple[Uint, Uint]:
     num_non_zeros = ulen(tx.data) - num_zeros
 
     tokens_in_calldata = num_zeros + num_non_zeros * Uint(4)
-    # EIP-7623 floor price (note: no EVM costs)
-    calldata_floor_gas_cost = (
-        tokens_in_calldata * GasCosts.TX_DATA_TOKEN_FLOOR + GasCosts.TX_BASE
-    )
 
     data_cost = tokens_in_calldata * GasCosts.TX_DATA_TOKEN_STANDARD
 
@@ -600,12 +612,28 @@ def calculate_intrinsic_cost(tx: Transaction) -> Tuple[Uint, Uint]:
         create_cost = Uint(0)
 
     access_list_cost = Uint(0)
+    tokens_in_access_list = Uint(0)
     if has_access_list(tx):
         for access in tx.access_list:
             access_list_cost += GasCosts.TX_ACCESS_LIST_ADDRESS
             access_list_cost += (
                 ulen(access.slots) * GasCosts.TX_ACCESS_LIST_STORAGE_KEY
             )
+            tokens_in_access_list += ACCESS_LIST_ADDRESS_FLOOR_TOKENS
+            tokens_in_access_list += (
+                ulen(access.slots) * ACCESS_LIST_STORAGE_KEY_FLOOR_TOKENS
+            )
+
+    # Data token floor cost for access list bytes.
+    access_list_cost += tokens_in_access_list * GasCosts.TX_DATA_TOKEN_FLOOR
+
+    # Total floor tokens.
+    total_floor_tokens = tokens_in_calldata + tokens_in_access_list
+
+    # EIP-7623 floor price (note: no EVM costs)
+    calldata_floor_gas_cost = (
+        total_floor_tokens * GasCosts.TX_DATA_TOKEN_FLOOR + GasCosts.TX_BASE
+    )
 
     auth_cost = Uint(0)
     if isinstance(tx, SetCodeTransaction):
diff --git a/tests/amsterdam/eip2780_reduce_intrinsic_tx_gas/conftest.py b/tests/amsterdam/eip2780_reduce_intrinsic_tx_gas/conftest.py
new file mode 100644
index 00000000000..de52075d396
--- /dev/null
+++ b/tests/amsterdam/eip2780_reduce_intrinsic_tx_gas/conftest.py
@@ -0,0 +1,10 @@
+"""Pytest (plugin) definitions local to EIP-2780 tests."""
+
+import pytest
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip7708_eth_transfer_logs/conftest.py b/tests/amsterdam/eip7708_eth_transfer_logs/conftest.py
new file mode 100644
index 00000000000..fb1d9465b3e
--- /dev/null
+++ b/tests/amsterdam/eip7708_eth_transfer_logs/conftest.py
@@ -0,0 +1,10 @@
+"""Pytest (plugin) definitions local to EIP-7708 tests."""
+
+import pytest
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip7778_block_gas_accounting_without_refunds/conftest.py b/tests/amsterdam/eip7778_block_gas_accounting_without_refunds/conftest.py
new file mode 100644
index 00000000000..5cbdebdc9ef
--- /dev/null
+++ b/tests/amsterdam/eip7778_block_gas_accounting_without_refunds/conftest.py
@@ -0,0 +1,10 @@
+"""Pytest (plugin) definitions local to EIP-7778 tests."""
+
+import pytest
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip7843_slotnum/conftest.py b/tests/amsterdam/eip7843_slotnum/conftest.py
new file mode 100644
index 00000000000..6e43f18fb35
--- /dev/null
+++ b/tests/amsterdam/eip7843_slotnum/conftest.py
@@ -0,0 +1,10 @@
+"""Pytest (plugin) definitions local to EIP-7843 tests."""
+
+import pytest
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip7928_block_level_access_lists/conftest.py b/tests/amsterdam/eip7928_block_level_access_lists/conftest.py
new file mode 100644
index 00000000000..3bedcfe2651
--- /dev/null
+++ b/tests/amsterdam/eip7928_block_level_access_lists/conftest.py
@@ -0,0 +1,10 @@
+"""Pytest (plugin) definitions local to EIP-7928 tests."""
+
+import pytest
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip7976_increase_calldata_floor_cost/conftest.py b/tests/amsterdam/eip7976_increase_calldata_floor_cost/conftest.py
index f92a0e003a0..9a252257297 100644
--- a/tests/amsterdam/eip7976_increase_calldata_floor_cost/conftest.py
+++ b/tests/amsterdam/eip7976_increase_calldata_floor_cost/conftest.py
@@ -370,3 +370,10 @@ def tx(
         blob_versioned_hashes=blob_versioned_hashes,
         error=tx_error,
     )
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip7981_increase_access_list_cost/test_access_list_cost.py b/tests/amsterdam/eip7981_increase_access_list_cost/test_access_list_cost.py
index 2d093e6d0bb..981617c0ec0 100644
--- a/tests/amsterdam/eip7981_increase_access_list_cost/test_access_list_cost.py
+++ b/tests/amsterdam/eip7981_increase_access_list_cost/test_access_list_cost.py
@@ -124,10 +124,11 @@ def test_access_list_token_calculation(
     expected_floor_cost = (
         expected_floor_tokens * gas_costs.TX_DATA_TOKEN_FLOOR
         + gas_costs.TX_BASE
+    )
+    if fork.is_eip_enabled(2780):
         # EIP-2780 anchors the floor on the decomposed intrinsic base; the
         # tx targets a non-self account, adding the recipient-access charge.
-        + gas_costs.COLD_ACCOUNT_ACCESS
-    )
+        expected_floor_cost += gas_costs.COLD_ACCOUNT_ACCESS
     actual_floor_cost = fork.transaction_data_floor_cost_calculator()(
         data=b"", access_list=access_list
     )
diff --git a/tests/amsterdam/eip7981_increase_access_list_cost/test_fork_transition.py b/tests/amsterdam/eip7981_increase_access_list_cost/test_fork_transition.py
index 62a899b346a..92b02d7def7 100644
--- a/tests/amsterdam/eip7981_increase_access_list_cost/test_fork_transition.py
+++ b/tests/amsterdam/eip7981_increase_access_list_cost/test_fork_transition.py
@@ -7,12 +7,13 @@
 transition timestamp) and pin the per-transaction gas paid on each side,
 plus the validity flip for gas limits inside the uplift gap.
 
-The post-fork intrinsic composes three repricings; the hand-derived
+The post-fork intrinsic composes up to three repricings; the hand-derived
 expectations below keep each term explicit so the EIP-7981 surcharge is
 individually visible:
 
-- EIP-2780 decomposes the flat pre-fork `TX_BASE` into the lowered base
-  plus the `COLD_ACCOUNT_ACCESS` recipient charge.
+- EIP-2780, on the forks that enable it, decomposes the flat pre-fork
+  `TX_BASE` into the lowered base plus the `COLD_ACCOUNT_ACCESS`
+  recipient charge.
 - EIP-8038 reprices the per-address and per-storage-key access list
   charges to the fork's cold access costs.
 - EIP-7981 adds four floor tokens per access list byte, charged at
@@ -116,11 +117,12 @@ def test_access_list_intrinsic_across_amsterdam_transition(
     )
     expected_post = (
         post_costs.TX_BASE
-        + post_costs.COLD_ACCOUNT_ACCESS
         + addresses * post_costs.TX_ACCESS_LIST_ADDRESS
         + total_keys * post_costs.TX_ACCESS_LIST_STORAGE_KEY
         + surcharge
     )
+    if post_fork.is_eip_enabled(2780):
+        expected_post += post_costs.COLD_ACCOUNT_ACCESS
 
     timestamps = [PRE_FORK_TIMESTAMP, POST_FORK_TIMESTAMP]
     expected_intrinsics = [expected_pre, expected_post]
@@ -322,10 +324,10 @@ def test_access_list_floor_across_amsterdam_transition(
         post_costs.TX_DATA_TOKEN_STANDARD
     ) + calculate_access_list_floor_tokens(access_list)
     expected_post = int(
-        post_costs.TX_BASE
-        + post_costs.COLD_ACCOUNT_ACCESS
-        + post_tokens * post_costs.TX_DATA_TOKEN_FLOOR
+        post_costs.TX_BASE + post_tokens * post_costs.TX_DATA_TOKEN_FLOOR
     )
+    if post_fork.is_eip_enabled(2780):
+        expected_post += int(post_costs.COLD_ACCOUNT_ACCESS)
 
     timestamps = [PRE_FORK_TIMESTAMP, POST_FORK_TIMESTAMP]
     expected_floors = [expected_pre, expected_post]
diff --git a/tests/amsterdam/eip7997_deterministic_factory_predeploy/conftest.py b/tests/amsterdam/eip7997_deterministic_factory_predeploy/conftest.py
new file mode 100644
index 00000000000..de93abfcfef
--- /dev/null
+++ b/tests/amsterdam/eip7997_deterministic_factory_predeploy/conftest.py
@@ -0,0 +1,10 @@
+"""Pytest (plugin) definitions local to EIP-7997 tests."""
+
+import pytest
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip8024_dupn_swapn_exchange/conftest.py b/tests/amsterdam/eip8024_dupn_swapn_exchange/conftest.py
new file mode 100644
index 00000000000..d8c781bb489
--- /dev/null
+++ b/tests/amsterdam/eip8024_dupn_swapn_exchange/conftest.py
@@ -0,0 +1,10 @@
+"""Pytest (plugin) definitions local to EIP-8024 tests."""
+
+import pytest
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip8037_state_creation_gas_cost_increase/conftest.py b/tests/amsterdam/eip8037_state_creation_gas_cost_increase/conftest.py
new file mode 100644
index 00000000000..2d16c275db4
--- /dev/null
+++ b/tests/amsterdam/eip8037_state_creation_gas_cost_increase/conftest.py
@@ -0,0 +1,10 @@
+"""Pytest (plugin) definitions local to EIP-8037 tests."""
+
+import pytest
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip8038_state_access_gas_cost_increase/conftest.py b/tests/amsterdam/eip8038_state_access_gas_cost_increase/conftest.py
new file mode 100644
index 00000000000..cd29eb50dcb
--- /dev/null
+++ b/tests/amsterdam/eip8038_state_access_gas_cost_increase/conftest.py
@@ -0,0 +1,10 @@
+"""Pytest (plugin) definitions local to EIP-8038 tests."""
+
+import pytest
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip8070_sparse_blobpool/conftest.py b/tests/amsterdam/eip8070_sparse_blobpool/conftest.py
index cb2a757494c..dc3ee7c3ecd 100644
--- a/tests/amsterdam/eip8070_sparse_blobpool/conftest.py
+++ b/tests/amsterdam/eip8070_sparse_blobpool/conftest.py
@@ -148,3 +148,10 @@ def txs(
         )
         txs.append(network_wrapped_tx)
     return txs
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip8246_selfdestruct_no_burn/conftest.py b/tests/amsterdam/eip8246_selfdestruct_no_burn/conftest.py
new file mode 100644
index 00000000000..4fb53dba402
--- /dev/null
+++ b/tests/amsterdam/eip8246_selfdestruct_no_burn/conftest.py
@@ -0,0 +1,10 @@
+"""Pytest (plugin) definitions local to EIP-8246 tests."""
+
+import pytest
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )
diff --git a/tests/amsterdam/eip8282_builder_execution_requests/conftest.py b/tests/amsterdam/eip8282_builder_execution_requests/conftest.py
index e17cee467fc..7a42ba76785 100644
--- a/tests/amsterdam/eip8282_builder_execution_requests/conftest.py
+++ b/tests/amsterdam/eip8282_builder_execution_requests/conftest.py
@@ -1,8 +1,17 @@
 """Fixtures for the EIP-8282 builder execution request tests."""
 
+import pytest
+
 from ...common.system_contract_request_fixtures import (
     blocks,  # noqa: F401
     included_requests,  # noqa: F401
     system_contract_interactions_per_block_copy,  # noqa: F401
     timestamp,  # noqa: F401
 )
+
+
+def pytest_generate_tests(metafunc: pytest.Metafunc) -> None:
+    """Mark all tests in this subdir as not valid for Monad forks."""
+    metafunc.definition.add_marker(
+        pytest.mark.not_valid_for("MONAD_EIGHT", subsequent_forks=True)
+    )

From 1faef38e4baab1bd12fc049f4334962c7fba4b41 Mon Sep 17 00:00:00 2001
From: pdobacz <5735525+pdobacz@users.noreply.github.com>
Date: Tue, 25 Aug 2026 10:51:08 +0000
Subject: [PATCH 2/2] refactor(forks): declare fork succession as a trait, not
 a keyword

`follows()` sits with the other fork traits, so `__init_subclass__` is untouched and a successor fork inherits the order without restating it.

Co-Authored-By: Claude <claude-opus-5>
---
 .../src/execution_testing/forks/base_fork.py  | 20 ++++++++++++++-----
 .../execution_testing/forks/forks/forks.py    |  6 +++++-
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/packages/testing/src/execution_testing/forks/base_fork.py b/packages/testing/src/execution_testing/forks/base_fork.py
index 808d94b6045..38dea7ca65c 100644
--- a/packages/testing/src/execution_testing/forks/base_fork.py
+++ b/packages/testing/src/execution_testing/forks/base_fork.py
@@ -344,11 +344,13 @@ def _is_subclass_of(a: "BaseForkMeta", b: "BaseForkMeta") -> bool:
         b = BaseForkMeta._maybe_transitioned(b)
         if issubclass(a, b):
             return True
-        followed = getattr(a, "_follows", None)
+        # The metaclass sees its instances as plain classes, so the
+        # trait is reached through a cast, as elsewhere in this class.
+        followed = cast(Type["BaseFork"], a).follows()
         while followed is not None:
             if issubclass(followed, b):
                 return True
-            followed = followed._follows
+            followed = followed.follows()
         return False
 
     def __gt__(cls, other: "BaseForkMeta") -> bool:
@@ -392,7 +394,6 @@ class BaseFork(ForkOpcodeInterface, metaclass=BaseForkMeta):
     _fork_by_timestamp: ClassVar[bool] = False
     _blob_constants: ClassVar[Dict[str, int]] = {}
     _deployed: ClassVar[bool] = True
-    _follows: ClassVar[Optional[Type["BaseFork"]]] = None
     _enabled_eips: ClassVar[Set[int]] = set()
     _enabling_forks: ClassVar[Set[Type["BaseFork"]]] = set()
 
@@ -408,7 +409,6 @@ def __init_subclass__(
         transition_tool_name: Optional[str] = None,
         ignore: bool = False,
         bpo_fork: bool = False,
-        follows: Optional[Type["BaseFork"]] = None,
         ruleset_name: Optional[str] = None,
         fork_by_timestamp: Optional[bool] = None,
         deployed: Optional[bool] = None,
@@ -423,7 +423,6 @@ def __init_subclass__(
         forks.
         """
         cls._transition_tool_name = transition_tool_name
-        cls._follows = follows
         cls._ignore = ignore
         cls._bpo_fork = bpo_fork
         cls._ruleset_name = ruleset_name
@@ -1421,6 +1420,17 @@ def enabling_forks(cls) -> Set[Type["BaseFork"]]:
             raise Exception(f"Class {cls.__name__} is not an EIP.")
         return cls._enabling_forks
 
+    @classmethod
+    def follows(cls) -> Type["BaseFork"] | None:
+        """
+        Return the fork this one comes after without inheriting it.
+
+        A fork that reuses another lineage's ordering overrides this;
+        comparisons then place it after that fork, and after everything
+        that fork comes after, while its behavior stays its own.
+        """
+        return None
+
     @classmethod
     def parent(cls) -> Type["BaseFork"] | None:
         """Return the parent fork."""
diff --git a/packages/testing/src/execution_testing/forks/forks/forks.py b/packages/testing/src/execution_testing/forks/forks/forks.py
index 04fde59cc0c..a4a8218052b 100644
--- a/packages/testing/src/execution_testing/forks/forks/forks.py
+++ b/packages/testing/src/execution_testing/forks/forks/forks.py
@@ -1903,7 +1903,6 @@ def engine_payload_attribute_target_gas_limit(cls) -> bool:
 class MONAD_NEXT(  # noqa: N801
     eips.EIP7981,
     MONAD_TEN,
-    follows=Amsterdam,
 ):
     """
     MONAD_NEXT fork.
@@ -1914,4 +1913,9 @@ class MONAD_NEXT(  # noqa: N801
     MONAD_NEXT after Amsterdam through `follows`.
     """
 
+    @classmethod
+    def follows(cls) -> type[BaseFork] | None:
+        """MONAD_NEXT comes after Amsterdam without inheriting it."""
+        return Amsterdam
+
     pass