op-challenger: Integrate challenging L2 block numbers (#10446)

* op-challenger: Make l2-eth-rpc required for all trace types.

Add rollupEndpoint to NewConfig signature since it was already always required.

* op-e2e: Remove rollup and l2-eth-rpc params from WithCannon and WithAlphabet

* op-challenger: Integrate challenging L2 block numbers

op-challenger/game/fault/agent.go

@@ -30,6 +30,7 @@ type Responder interface {
 
 type ClaimLoader interface {
 	GetAllClaims(ctx context.Context, block rpcblock.Block) ([]types.Claim, error)
+	IsL2BlockNumberChallenged(ctx context.Context, block rpcblock.Block) (bool, error)
 }
 
 type Agent struct {
@@ -84,6 +85,14 @@ func (a *Agent) Act(ctx context.Context) error {
 	defer func() {
 		a.metrics.RecordGameActTime(a.systemClock.Since(start).Seconds())
 	}()
+
+	if challenged, err := a.loader.IsL2BlockNumberChallenged(ctx, rpcblock.Latest); err != nil {
+		return fmt.Errorf("failed to check if L2 block number already challenged: %w", err)
+	} else if challenged {
+		a.log.Debug("Skipping game with already challenged L2 block number")
+		return nil
+	}
+
 	game, err := a.newGameFromContracts(ctx)
 	if err != nil {
 		return fmt.Errorf("create game from contracts: %w", err)
@@ -105,11 +114,13 @@ func (a *Agent) Act(ctx context.Context) error {
 
 func (a *Agent) performAction(ctx context.Context, wg *sync.WaitGroup, action types.Action) {
 	defer wg.Done()
-	actionLog := a.log.New("action", action.Type, "is_attack", action.IsAttack, "parent", action.ParentIdx)
+	actionLog := a.log.New("action", action.Type)
 	if action.Type == types.ActionTypeStep {
 		containsOracleData := action.OracleData != nil
 		isLocal := containsOracleData && action.OracleData.IsLocal
 		actionLog = actionLog.New(
+			"is_attack", action.IsAttack,
+			"parent", action.ParentIdx,
 			"prestate", common.Bytes2Hex(action.PreState),
 			"proof", common.Bytes2Hex(action.ProofData),
 			"containsOracleData", containsOracleData,
@@ -118,8 +129,8 @@ func (a *Agent) performAction(ctx context.Context, wg *sync.WaitGroup, action ty
 		if action.OracleData != nil {
 			actionLog = actionLog.New("oracleKey", common.Bytes2Hex(action.OracleData.OracleKey))
 		}
-	} else {
-		actionLog = actionLog.New("value", action.Value)
+	} else if action.Type == types.ActionTypeMove {
+		actionLog = actionLog.New("is_attack", action.IsAttack, "parent", action.ParentIdx, "value", action.Value)
 	}
 
 	switch action.Type {
@@ -127,6 +138,7 @@ func (a *Agent) performAction(ctx context.Context, wg *sync.WaitGroup, action ty
 		a.metrics.RecordGameMove()
 	case types.ActionTypeStep:
 		a.metrics.RecordGameStep()
+		// TODO(client-pod#852): Add metrics for L2 block number challenges
 	}
 	actionLog.Info("Performing action")
 	err := a.responder.PerformAction(ctx, action)

op-challenger/game/fault/agent_test.go

@@ -57,6 +57,18 @@ func TestDoNotMakeMovesWhenGameIsResolvable(t *testing.T) {
 	}
 }
 
+func TestDoNotMakeMovesWhenL2BlockNumberChallenged(t *testing.T) {
+	ctx := context.Background()
+
+	agent, claimLoader, responder := setupTestAgent(t)
+	claimLoader.blockNumChallenged = true
+
+	require.NoError(t, agent.Act(ctx))
+
+	require.Equal(t, 1, responder.callResolveCount, "should check if game is resolvable")
+	require.Equal(t, 1, claimLoader.callCount, "should fetch claims only once for resolveClaim")
+}
+
 func createClaimsWithClaimants(t *testing.T, d types.Depth) []types.Claim {
 	claimBuilder := test.NewClaimBuilder(t, d, alphabet.NewTraceProvider(big.NewInt(0), d))
 	rootClaim := claimBuilder.CreateRootClaim()
@@ -180,9 +192,14 @@ func setupTestAgent(t *testing.T) (*Agent, *stubClaimLoader, *stubResponder) {
 }
 
 type stubClaimLoader struct {
-	callCount int
-	maxLoads  int
-	claims    []types.Claim
+	callCount          int
+	maxLoads           int
+	claims             []types.Claim
+	blockNumChallenged bool
+}
+
+func (s *stubClaimLoader) IsL2BlockNumberChallenged(_ context.Context, _ rpcblock.Block) (bool, error) {
+	return s.blockNumChallenged, nil
 }
 
 func (s *stubClaimLoader) GetAllClaims(_ context.Context, _ rpcblock.Block) ([]types.Claim, error) {

op-challenger/game/fault/contracts/faultdisputegame.go

@@ -52,7 +52,10 @@ var (
 	methodWETH                = "weth"
 )
 
-var ErrSimulationFailed = errors.New("tx simulation failed")
+var (
+	ErrSimulationFailed             = errors.New("tx simulation failed")
+	ErrChallengeL2BlockNotSupported = errors.New("contract version does not support challenging L2 block number")
+)
 
 type FaultDisputeGameContractLatest struct {
 	metrics     metrics.ContractMetricer
@@ -410,6 +413,14 @@ func (f *FaultDisputeGameContractLatest) vm(ctx context.Context) (*VMContract, e
 	return NewVMContract(vmAddr, f.multiCaller), nil
 }
 
+func (f *FaultDisputeGameContractLatest) IsL2BlockNumberChallenged(ctx context.Context, block rpcblock.Block) (bool, error) {
+	return false, nil
+}
+
+func (f *FaultDisputeGameContractLatest) ChallengeL2BlockNumberTx(challenge *types.InvalidL2BlockNumberChallenge) (txmgr.TxCandidate, error) {
+	return txmgr.TxCandidate{}, ErrChallengeL2BlockNotSupported
+}
+
 func (f *FaultDisputeGameContractLatest) AttackTx(parentContractIndex uint64, pivot common.Hash) (txmgr.TxCandidate, error) {
 	call := f.contract.Call(methodAttack, new(big.Int).SetUint64(parentContractIndex), pivot)
 	return call.ToTxCandidate()
@@ -523,6 +534,8 @@ type FaultDisputeGameContract interface {
 	GetClaim(ctx context.Context, idx uint64) (types.Claim, error)
 	GetAllClaims(ctx context.Context, block rpcblock.Block) ([]types.Claim, error)
 	IsResolved(ctx context.Context, block rpcblock.Block, claims ...types.Claim) ([]bool, error)
+	IsL2BlockNumberChallenged(ctx context.Context, block rpcblock.Block) (bool, error)
+	ChallengeL2BlockNumberTx(challenge *types.InvalidL2BlockNumberChallenge) (txmgr.TxCandidate, error)
 	AttackTx(parentContractIndex uint64, pivot common.Hash) (txmgr.TxCandidate, error)
 	DefendTx(parentContractIndex uint64, pivot common.Hash) (txmgr.TxCandidate, error)
 	StepTx(claimIdx uint64, isAttack bool, stateData []byte, proof []byte) (txmgr.TxCandidate, error)

op-challenger/game/fault/contracts/faultdisputegame_test.go

@@ -652,6 +652,30 @@ func TestFaultDisputeGame_IsResolved(t *testing.T) {
 	}
 }
 
+func TestFaultDisputeGameContractLatest_IsL2BlockNumberChallenged(t *testing.T) {
+	for _, version := range versions {
+		version := version
+		t.Run(version.version, func(t *testing.T) {
+			_, game := setupFaultDisputeGameTest(t, version)
+			challenged, err := game.IsL2BlockNumberChallenged(context.Background(), rpcblock.Latest)
+			require.NoError(t, err)
+			require.False(t, challenged)
+		})
+	}
+}
+
+func TestFaultDisputeGameContractLatest_ChallengeL2BlockNumberTx(t *testing.T) {
+	for _, version := range versions {
+		version := version
+		t.Run(version.version, func(t *testing.T) {
+			_, game := setupFaultDisputeGameTest(t, version)
+			tx, err := game.ChallengeL2BlockNumberTx(&faultTypes.InvalidL2BlockNumberChallenge{})
+			require.ErrorIs(t, err, ErrChallengeL2BlockNotSupported)
+			require.Equal(t, txmgr.TxCandidate{}, tx)
+		})
+	}
+}
+
 func setupFaultDisputeGameTest(t *testing.T, version contractVersion) (*batchingTest.AbiBasedRpc, FaultDisputeGameContract) {
 	fdgAbi := version.loadAbi()
 

op-challenger/game/fault/register.go

@@ -67,15 +67,9 @@ func RegisterGameTypes(
 	selective bool,
 	claimants []common.Address,
 ) (CloseFunc, error) {
-	var closer CloseFunc
-	var l2Client *ethclient.Client
-	if cfg.TraceTypeEnabled(config.TraceTypeCannon) || cfg.TraceTypeEnabled(config.TraceTypePermissioned) || cfg.TraceTypeEnabled(config.TraceTypeAsterisc) {
-		l2, err := ethclient.DialContext(ctx, cfg.L2Rpc)
-		if err != nil {
-			return nil, fmt.Errorf("dial l2 client %v: %w", cfg.L2Rpc, err)
-		}
-		l2Client = l2
-		closer = l2Client.Close
+	l2Client, err := ethclient.DialContext(ctx, cfg.L2Rpc)
+	if err != nil {
+		return nil, fmt.Errorf("dial l2 client %v: %w", cfg.L2Rpc, err)
 	}
 	syncValidator := newSyncStatusValidator(rollupClient)
 
@@ -95,11 +89,11 @@ func RegisterGameTypes(
 		}
 	}
 	if cfg.TraceTypeEnabled(config.TraceTypeAlphabet) {
-		if err := registerAlphabet(registry, oracles, ctx, systemClock, l1Clock, logger, m, syncValidator, rollupClient, txSender, gameFactory, caller, l1HeaderSource, selective, claimants); err != nil {
+		if err := registerAlphabet(registry, oracles, ctx, systemClock, l1Clock, logger, m, syncValidator, rollupClient, l2Client, txSender, gameFactory, caller, l1HeaderSource, selective, claimants); err != nil {
 			return nil, fmt.Errorf("failed to register alphabet game type: %w", err)
 		}
 	}
-	return closer, nil
+	return l2Client.Close, nil
 }
 
 func registerAlphabet(
@@ -112,6 +106,7 @@ func registerAlphabet(
 	m metrics.Metricer,
 	syncValidator SyncValidator,
 	rollupClient RollupClient,
+	l2Client utils.L2HeaderSource,
 	txSender TxSender,
 	gameFactory *contracts.DisputeGameFactoryContract,
 	caller *batching.MultiCaller,
@@ -143,7 +138,7 @@ func registerAlphabet(
 		}
 		prestateProvider := outputs.NewPrestateProvider(rollupClient, prestateBlock)
 		creator := func(ctx context.Context, logger log.Logger, gameDepth faultTypes.Depth, dir string) (faultTypes.TraceAccessor, error) {
-			accessor, err := outputs.NewOutputAlphabetTraceAccessor(logger, m, prestateProvider, rollupClient, l1Head, splitDepth, prestateBlock, poststateBlock)
+			accessor, err := outputs.NewOutputAlphabetTraceAccessor(logger, m, prestateProvider, rollupClient, l2Client, l1Head, splitDepth, prestateBlock, poststateBlock)
 			if err != nil {
 				return nil, err
 			}

op-challenger/game/fault/responder/responder.go

@@ -11,7 +11,6 @@ import (
 	gameTypes "github.com/ethereum-optimism/optimism/op-challenger/game/types"
 	"github.com/ethereum-optimism/optimism/op-service/txmgr"
 	"github.com/ethereum/go-ethereum/common"
-
 	"github.com/ethereum/go-ethereum/log"
 )
 
@@ -23,6 +22,7 @@ type GameContract interface {
 	AttackTx(parentContractIndex uint64, pivot common.Hash) (txmgr.TxCandidate, error)
 	DefendTx(parentContractIndex uint64, pivot common.Hash) (txmgr.TxCandidate, error)
 	StepTx(claimIdx uint64, isAttack bool, stateData []byte, proof []byte) (txmgr.TxCandidate, error)
+	ChallengeL2BlockNumberTx(challenge *types.InvalidL2BlockNumberChallenge) (txmgr.TxCandidate, error)
 	GetRequiredBond(ctx context.Context, position types.Position) (*big.Int, error)
 }
 
@@ -130,6 +130,8 @@ func (r *FaultResponder) PerformAction(ctx context.Context, action types.Action)
 		candidate.Value = bondValue
 	case types.ActionTypeStep:
 		candidate, err = r.contract.StepTx(uint64(action.ParentIdx), action.IsAttack, action.PreState, action.ProofData)
+	case types.ActionTypeChallengeL2BlockNumber:
+		candidate, err = r.contract.ChallengeL2BlockNumberTx(action.InvalidL2BlockNumberChallenge)
 	}
 	if err != nil {
 		return err

op-challenger/game/fault/responder/responder_test.go

@@ -284,6 +284,19 @@ func TestPerformAction(t *testing.T) {
 		require.Equal(t, 0, uploader.updates)
 		require.Equal(t, 1, oracle.existCalls)
 	})
+
+	t.Run("challengeL2Block", func(t *testing.T) {
+		responder, mockTxMgr, contract, _, _ := newTestFaultResponder(t)
+		challenge := &types.InvalidL2BlockNumberChallenge{}
+		action := types.Action{
+			Type:                          types.ActionTypeChallengeL2BlockNumber,
+			InvalidL2BlockNumberChallenge: challenge,
+		}
+		err := responder.PerformAction(context.Background(), action)
+		require.NoError(t, err)
+		require.Len(t, mockTxMgr.sent, 1)
+		require.Equal(t, []interface{}{challenge}, contract.challengeArgs)
+	})
 }
 
 func newTestFaultResponder(t *testing.T) (*FaultResponder, *mockTxManager, *mockContract, *mockPreimageUploader, *mockOracle) {
@@ -359,6 +372,7 @@ type mockContract struct {
 	attackArgs           []interface{}
 	defendArgs           []interface{}
 	stepArgs             []interface{}
+	challengeArgs        []interface{}
 	updateOracleClaimIdx uint64
 	updateOracleArgs     *types.PreimageOracleData
 }
@@ -387,6 +401,11 @@ func (m *mockContract) ResolveClaimTx(_ uint64) (txmgr.TxCandidate, error) {
 	return txmgr.TxCandidate{}, nil
 }
 
+func (m *mockContract) ChallengeL2BlockNumberTx(challenge *types.InvalidL2BlockNumberChallenge) (txmgr.TxCandidate, error) {
+	m.challengeArgs = []interface{}{challenge}
+	return txmgr.TxCandidate{TxData: ([]byte)("challenge")}, nil
+}
+
 func (m *mockContract) AttackTx(parentClaimId uint64, claim common.Hash) (txmgr.TxCandidate, error) {
 	m.attackArgs = []interface{}{parentClaimId, claim}
 	return txmgr.TxCandidate{TxData: ([]byte)("attack")}, nil

op-challenger/game/fault/solver/game_solver.go

@@ -2,6 +2,7 @@ package solver
 
 import (
 	"context"
+	"errors"
 	"fmt"
 
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/types"
@@ -27,6 +28,25 @@ func (s *GameSolver) CalculateNextActions(ctx context.Context, game types.Game)
 	if err != nil {
 		return nil, fmt.Errorf("failed to determine if root claim is correct: %w", err)
 	}
+
+	// Challenging the L2 block number will only work if we have the same output root as the claim
+	// Otherwise our output root preimage won't match. We can just proceed and invalidate the output root by disputing claims instead.
+	if agreeWithRootClaim {
+		if challenge, err := s.claimSolver.trace.GetL2BlockNumberChallenge(ctx, game); errors.Is(err, types.ErrL2BlockNumberValid) {
+			// We agree with the L2 block number, proceed to processing claims
+		} else if err != nil {
+			// Failed to check L2 block validity
+			return nil, fmt.Errorf("failed to determine L2 block validity: %w", err)
+		} else {
+			return []types.Action{
+				{
+					Type:                          types.ActionTypeChallengeL2BlockNumber,
+					InvalidL2BlockNumberChallenge: challenge,
+				},
+			}, nil
+		}
+	}
+
 	var actions []types.Action
 	agreedClaims := newHonestClaimTracker()
 	if agreeWithRootClaim {

op-challenger/game/fault/solver/game_solver_test.go

@@ -10,10 +10,36 @@ import (
 	faulttest "github.com/ethereum-optimism/optimism/op-challenger/game/fault/test"
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/trace"
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/types"
+	"github.com/ethereum-optimism/optimism/op-service/eth"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/stretchr/testify/require"
 )
 
+func TestCalculateNextActions_ChallengeL2BlockNumber(t *testing.T) {
+	startingBlock := big.NewInt(5)
+	maxDepth := types.Depth(6)
+	challenge := &types.InvalidL2BlockNumberChallenge{
+		Output: &eth.OutputResponse{OutputRoot: eth.Bytes32{0xbb}},
+	}
+	claimBuilder := faulttest.NewAlphabetClaimBuilder(t, startingBlock, maxDepth)
+	traceProvider := faulttest.NewAlphabetWithProofProvider(t, startingBlock, maxDepth, nil)
+	solver := NewGameSolver(maxDepth, trace.NewSimpleTraceAccessor(traceProvider))
+
+	// Do not challenge when provider returns error indicating l2 block is valid
+	actions, err := solver.CalculateNextActions(context.Background(), claimBuilder.GameBuilder().Game)
+	require.NoError(t, err)
+	require.Len(t, actions, 0)
+
+	// Do challenge when the provider returns a challenge
+	traceProvider.L2BlockChallenge = challenge
+	actions, err = solver.CalculateNextActions(context.Background(), claimBuilder.GameBuilder().Game)
+	require.NoError(t, err)
+	require.Len(t, actions, 1)
+	action := actions[0]
+	require.Equal(t, types.ActionTypeChallengeL2BlockNumber, action.Type)
+	require.Equal(t, challenge, action.InvalidL2BlockNumberChallenge)
+}
+
 func TestCalculateNextActions(t *testing.T) {
 	maxDepth := types.Depth(6)
 	startingL2BlockNumber := big.NewInt(0)
@@ -31,8 +57,6 @@ func TestCalculateNextActions(t *testing.T) {
 			},
 		},
 		{
-			// Note: The fault dispute game contract should prevent a correct root claim from actually being posted
-			// But for completeness, test we ignore it so we don't get sucked into playing an unwinnable game.
 			name:             "DoNotAttackCorrectRootClaim_AgreeWithOutputRoot",
 			rootClaimCorrect: true,
 			setupGame:        func(builder *faulttest.GameBuilder) {},

op-challenger/game/fault/test/alphabet.go

@@ -9,11 +9,12 @@ import (
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/types"
 )
 
-func NewAlphabetWithProofProvider(t *testing.T, startingL2BlockNumber *big.Int, maxDepth types.Depth, oracleError error) *alphabetWithProofProvider {
-	return &alphabetWithProofProvider{
+func NewAlphabetWithProofProvider(t *testing.T, startingL2BlockNumber *big.Int, maxDepth types.Depth, oracleError error) *AlphabetWithProofProvider {
+	return &AlphabetWithProofProvider{
 		alphabet.NewTraceProvider(startingL2BlockNumber, maxDepth),
 		maxDepth,
 		oracleError,
+		nil,
 	}
 }
 
@@ -22,13 +23,14 @@ func NewAlphabetClaimBuilder(t *testing.T, startingL2BlockNumber *big.Int, maxDe
 	return NewClaimBuilder(t, maxDepth, alphabetProvider)
 }
 
-type alphabetWithProofProvider struct {
+type AlphabetWithProofProvider struct {
 	*alphabet.AlphabetTraceProvider
-	depth       types.Depth
-	OracleError error
+	depth            types.Depth
+	OracleError      error
+	L2BlockChallenge *types.InvalidL2BlockNumberChallenge
 }
 
-func (a *alphabetWithProofProvider) GetStepData(ctx context.Context, i types.Position) ([]byte, []byte, *types.PreimageOracleData, error) {
+func (a *AlphabetWithProofProvider) GetStepData(ctx context.Context, i types.Position) ([]byte, []byte, *types.PreimageOracleData, error) {
 	preimage, _, _, err := a.AlphabetTraceProvider.GetStepData(ctx, i)
 	if err != nil {
 		return nil, nil, nil, err
@@ -37,3 +39,11 @@ func (a *alphabetWithProofProvider) GetStepData(ctx context.Context, i types.Pos
 	data := types.NewPreimageOracleData([]byte{byte(traceIndex)}, []byte{byte(traceIndex - 1)}, uint32(traceIndex-1))
 	return preimage, []byte{byte(traceIndex - 1)}, data, nil
 }
+
+func (c *AlphabetWithProofProvider) GetL2BlockNumberChallenge(_ context.Context) (*types.InvalidL2BlockNumberChallenge, error) {
+	if c.L2BlockChallenge != nil {
+		return c.L2BlockChallenge, nil
+	} else {
+		return nil, types.ErrL2BlockNumberValid
+	}
+}

op-challenger/game/fault/trace/access.go

@@ -40,4 +40,12 @@ func (t *Accessor) GetStepData(ctx context.Context, game types.Game, ref types.C
 	return provider.GetStepData(ctx, pos)
 }
 
+func (t *Accessor) GetL2BlockNumberChallenge(ctx context.Context, game types.Game) (*types.InvalidL2BlockNumberChallenge, error) {
+	provider, err := t.selector(ctx, game, game.Claims()[0], types.RootPosition)
+	if err != nil {
+		return nil, err
+	}
+	return provider.GetL2BlockNumberChallenge(ctx)
+}
+
 var _ types.TraceAccessor = (*Accessor)(nil)

op-challenger/game/fault/trace/access_test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/test"
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/trace/alphabet"
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/types"
+	"github.com/ethereum-optimism/optimism/op-service/eth"
 	"github.com/stretchr/testify/require"
 )
 
@@ -67,4 +68,32 @@ func TestAccessor_UsesSelector(t *testing.T) {
 		require.Equal(t, expectedProofData, actualProofData)
 		require.Equal(t, expectedPreimageData, actualPreimageData)
 	})
+
+	t.Run("GetL2BlockNumberChallenge", func(t *testing.T) {
+		provider := &ChallengeTraceProvider{
+			TraceProvider: provider1,
+		}
+		accessor := &Accessor{
+			selector: func(ctx context.Context, actualGame types.Game, ref types.Claim, pos types.Position) (types.TraceProvider, error) {
+				require.Equal(t, game, actualGame)
+				require.Equal(t, game.Claims()[0], ref)
+				require.Equal(t, types.RootPosition, pos)
+				return provider, nil
+			},
+		}
+		challenge, err := accessor.GetL2BlockNumberChallenge(ctx, game)
+		require.NoError(t, err)
+		require.NotNil(t, challenge)
+		require.Equal(t, eth.Bytes32{0xaa, 0xbb}, challenge.Output.OutputRoot)
+	})
+}
+
+type ChallengeTraceProvider struct {
+	types.TraceProvider
+}
+
+func (c *ChallengeTraceProvider) GetL2BlockNumberChallenge(_ context.Context) (*types.InvalidL2BlockNumberChallenge, error) {
+	return &types.InvalidL2BlockNumberChallenge{
+		Output: &eth.OutputResponse{OutputRoot: eth.Bytes32{0xaa, 0xbb}},
+	}, nil
 }

op-challenger/game/fault/trace/alphabet/provider.go

@@ -75,6 +75,10 @@ func (ap *AlphabetTraceProvider) Get(ctx context.Context, i types.Position) (com
 	return alphabetStateHash(claimBytes), nil
 }
 
+func (ap *AlphabetTraceProvider) GetL2BlockNumberChallenge(_ context.Context) (*types.InvalidL2BlockNumberChallenge, error) {
+	return nil, types.ErrL2BlockNumberValid
+}
+
 // BuildAlphabetPreimage constructs the claim bytes for the index and claim.
 func BuildAlphabetPreimage(traceIndex *big.Int, claim *big.Int) []byte {
 	return append(traceIndex.FillBytes(make([]byte, 32)), claim.FillBytes(make([]byte, 32))...)

op-challenger/game/fault/trace/asterisc/provider.go

@@ -96,6 +96,10 @@ func (p *AsteriscTraceProvider) GetStepData(ctx context.Context, pos types.Posit
 	return value, data, oracleData, nil
 }
 
+func (p *AsteriscTraceProvider) GetL2BlockNumberChallenge(_ context.Context) (*types.InvalidL2BlockNumberChallenge, error) {
+	return nil, types.ErrL2BlockNumberValid
+}
+
 // loadProof will attempt to load or generate the proof data at the specified index
 // If the requested index is beyond the end of the actual trace it is extended with no-op instructions.
 func (p *AsteriscTraceProvider) loadProof(ctx context.Context, i uint64) (*utils.ProofData, error) {

op-challenger/game/fault/trace/cannon/provider.go

@@ -94,6 +94,10 @@ func (p *CannonTraceProvider) GetStepData(ctx context.Context, pos types.Positio
 	return value, data, oracleData, nil
 }
 
+func (p *CannonTraceProvider) GetL2BlockNumberChallenge(_ context.Context) (*types.InvalidL2BlockNumberChallenge, error) {
+	return nil, types.ErrL2BlockNumberValid
+}
+
 // loadProof will attempt to load or generate the proof data at the specified index
 // If the requested index is beyond the end of the actual trace it is extended with no-op instructions.
 func (p *CannonTraceProvider) loadProof(ctx context.Context, i uint64) (*utils.ProofData, error) {

op-challenger/game/fault/trace/outputs/output_alphabet.go

@@ -7,6 +7,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/trace"
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/trace/alphabet"
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/trace/split"
+	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/trace/utils"
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/types"
 	"github.com/ethereum-optimism/optimism/op-challenger/metrics"
 	"github.com/ethereum-optimism/optimism/op-service/eth"
@@ -19,12 +20,13 @@ func NewOutputAlphabetTraceAccessor(
 	m metrics.Metricer,
 	prestateProvider types.PrestateProvider,
 	rollupClient OutputRollupClient,
+	l2Client utils.L2HeaderSource,
 	l1Head eth.BlockID,
 	splitDepth types.Depth,
 	prestateBlock uint64,
 	poststateBlock uint64,
 ) (*trace.Accessor, error) {
-	outputProvider := NewTraceProvider(logger, prestateProvider, rollupClient, l1Head, splitDepth, prestateBlock, poststateBlock)
+	outputProvider := NewTraceProvider(logger, prestateProvider, rollupClient, l2Client, l1Head, splitDepth, prestateBlock, poststateBlock)
 	alphabetCreator := func(ctx context.Context, localContext common.Hash, depth types.Depth, agreed contracts.Proposal, claimed contracts.Proposal) (types.TraceProvider, error) {
 		provider := alphabet.NewTraceProvider(agreed.L2BlockNumber, depth)
 		return provider, nil

op-challenger/game/fault/trace/outputs/output_asterisc.go

@@ -31,7 +31,7 @@ func NewOutputAsteriscTraceAccessor(
 	prestateBlock uint64,
 	poststateBlock uint64,
 ) (*trace.Accessor, error) {
-	outputProvider := NewTraceProvider(logger, prestateProvider, rollupClient, l1Head, splitDepth, prestateBlock, poststateBlock)
+	outputProvider := NewTraceProvider(logger, prestateProvider, rollupClient, l2Client, l1Head, splitDepth, prestateBlock, poststateBlock)
 	asteriscCreator := func(ctx context.Context, localContext common.Hash, depth types.Depth, agreed contracts.Proposal, claimed contracts.Proposal) (types.TraceProvider, error) {
 		logger := logger.New("pre", agreed.OutputRoot, "post", claimed.OutputRoot, "localContext", localContext)
 		subdir := filepath.Join(dir, localContext.Hex())

op-challenger/game/fault/trace/outputs/output_cannon.go

@@ -31,7 +31,7 @@ func NewOutputCannonTraceAccessor(
 	prestateBlock uint64,
 	poststateBlock uint64,
 ) (*trace.Accessor, error) {
-	outputProvider := NewTraceProvider(logger, prestateProvider, rollupClient, l1Head, splitDepth, prestateBlock, poststateBlock)
+	outputProvider := NewTraceProvider(logger, prestateProvider, rollupClient, l2Client, l1Head, splitDepth, prestateBlock, poststateBlock)
 	cannonCreator := func(ctx context.Context, localContext common.Hash, depth types.Depth, agreed contracts.Proposal, claimed contracts.Proposal) (types.TraceProvider, error) {
 		logger := logger.New("pre", agreed.OutputRoot, "post", claimed.OutputRoot, "localContext", localContext)
 		subdir := filepath.Join(dir, localContext.Hex())

op-challenger/game/fault/trace/outputs/provider.go

@@ -4,7 +4,9 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"math/big"
 
+	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/trace/utils"
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/types"
 	"github.com/ethereum-optimism/optimism/op-service/eth"
 	"github.com/ethereum/go-ethereum/common"
@@ -29,17 +31,19 @@ type OutputTraceProvider struct {
 	types.PrestateProvider
 	logger         log.Logger
 	rollupProvider OutputRollupClient
+	l2Client       utils.L2HeaderSource
 	prestateBlock  uint64
 	poststateBlock uint64
 	l1Head         eth.BlockID
 	gameDepth      types.Depth
 }
 
-func NewTraceProvider(logger log.Logger, prestateProvider types.PrestateProvider, rollupProvider OutputRollupClient, l1Head eth.BlockID, gameDepth types.Depth, prestateBlock, poststateBlock uint64) *OutputTraceProvider {
+func NewTraceProvider(logger log.Logger, prestateProvider types.PrestateProvider, rollupProvider OutputRollupClient, l2Client utils.L2HeaderSource, l1Head eth.BlockID, gameDepth types.Depth, prestateBlock, poststateBlock uint64) *OutputTraceProvider {
 	return &OutputTraceProvider{
 		PrestateProvider: prestateProvider,
 		logger:           logger,
 		rollupProvider:   rollupProvider,
+		l2Client:         l2Client,
 		prestateBlock:    prestateBlock,
 		poststateBlock:   poststateBlock,
 		l1Head:           l1Head,
@@ -94,6 +98,29 @@ func (o *OutputTraceProvider) GetStepData(_ context.Context, _ types.Position) (
 	return nil, nil, nil, ErrGetStepData
 }
 
+func (o *OutputTraceProvider) GetL2BlockNumberChallenge(ctx context.Context) (*types.InvalidL2BlockNumberChallenge, error) {
+	outputBlock, err := o.HonestBlockNumber(ctx, types.RootPosition)
+	if err != nil {
+		return nil, err
+	}
+	claimedBlock, err := o.ClaimedBlockNumber(types.RootPosition)
+	if err != nil {
+		return nil, err
+	}
+	if claimedBlock == outputBlock {
+		return nil, types.ErrL2BlockNumberValid
+	}
+	output, err := o.rollupProvider.OutputAtBlock(ctx, outputBlock)
+	if err != nil {
+		return nil, err
+	}
+	header, err := o.l2Client.HeaderByNumber(ctx, new(big.Int).SetUint64(outputBlock))
+	if err != nil {
+		return nil, fmt.Errorf("failed to retrieve L2 block header %v: %w", outputBlock, err)
+	}
+	return types.NewInvalidL2BlockNumberProof(output, header), nil
+}
+
 func (o *OutputTraceProvider) outputAtBlock(ctx context.Context, block uint64) (common.Hash, error) {
 	output, err := o.rollupProvider.OutputAtBlock(ctx, block)
 	if err != nil {

op-challenger/game/fault/trace/outputs/provider_test.go

@@ -11,7 +11,9 @@ import (
 	"github.com/ethereum-optimism/optimism/op-challenger/game/fault/types"
 	"github.com/ethereum-optimism/optimism/op-service/eth"
 	"github.com/ethereum-optimism/optimism/op-service/testlog"
+	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
+	ethTypes "github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/stretchr/testify/require"
 )
@@ -29,34 +31,34 @@ var (
 func TestGet(t *testing.T) {
 	t.Run("ErrorsTraceIndexOutOfBounds", func(t *testing.T) {
 		deepGame := types.Depth(164)
-		provider, _ := setupWithTestData(t, prestateBlock, poststateBlock, deepGame)
+		provider, _, _ := setupWithTestData(t, prestateBlock, poststateBlock, deepGame)
 		pos := types.NewPosition(0, big.NewInt(0))
 		_, err := provider.Get(context.Background(), pos)
 		require.ErrorIs(t, err, ErrIndexTooBig)
 	})
 
 	t.Run("FirstBlockAfterPrestate", func(t *testing.T) {
-		provider, _ := setupWithTestData(t, prestateBlock, poststateBlock)
+		provider, _, _ := setupWithTestData(t, prestateBlock, poststateBlock)
 		value, err := provider.Get(context.Background(), types.NewPosition(gameDepth, big.NewInt(0)))
 		require.NoError(t, err)
 		require.Equal(t, firstOutputRoot, value)
 	})
 
 	t.Run("MissingOutputAtBlock", func(t *testing.T) {
-		provider, _ := setupWithTestData(t, prestateBlock, poststateBlock)
+		provider, _, _ := setupWithTestData(t, prestateBlock, poststateBlock)
 		_, err := provider.Get(context.Background(), types.NewPosition(gameDepth, big.NewInt(1)))
 		require.ErrorIs(t, err, errNoOutputAtBlock)
 	})
 
 	t.Run("PostStateBlock", func(t *testing.T) {
-		provider, _ := setupWithTestData(t, prestateBlock, poststateBlock)
+		provider, _, _ := setupWithTestData(t, prestateBlock, poststateBlock)
 		value, err := provider.Get(context.Background(), types.NewPositionFromGIndex(big.NewInt(228)))
 		require.NoError(t, err)
 		require.Equal(t, value, poststateOutputRoot)
 	})
 
 	t.Run("AfterPostStateBlock", func(t *testing.T) {
-		provider, _ := setupWithTestData(t, prestateBlock, poststateBlock)
+		provider, _, _ := setupWithTestData(t, prestateBlock, poststateBlock)
 		value, err := provider.Get(context.Background(), types.NewPositionFromGIndex(big.NewInt(229)))
 		require.NoError(t, err)
 		require.Equal(t, value, poststateOutputRoot)
@@ -87,7 +89,7 @@ func TestHonestBlockNumber(t *testing.T) {
 	for _, test := range tests {
 		test := test
 		t.Run(test.name, func(t *testing.T) {
-			provider, stubRollupClient := setupWithTestData(t, prestateBlock, poststateBlock)
+			provider, stubRollupClient, _ := setupWithTestData(t, prestateBlock, poststateBlock)
 			stubRollupClient.maxSafeHead = test.maxSafeHead
 			actual, err := provider.HonestBlockNumber(context.Background(), test.pos)
 			require.NoError(t, err)
@@ -97,13 +99,55 @@ func TestHonestBlockNumber(t *testing.T) {
 
 	t.Run("ErrorsTraceIndexOutOfBounds", func(t *testing.T) {
 		deepGame := types.Depth(164)
-		provider, _ := setupWithTestData(t, prestateBlock, poststateBlock, deepGame)
+		provider, _, _ := setupWithTestData(t, prestateBlock, poststateBlock, deepGame)
 		pos := types.NewPosition(0, big.NewInt(0))
 		_, err := provider.HonestBlockNumber(context.Background(), pos)
 		require.ErrorIs(t, err, ErrIndexTooBig)
 	})
 }
 
+func TestGetL2BlockNumberChallenge(t *testing.T) {
+	tests := []struct {
+		name            string
+		maxSafeHead     uint64
+		expectChallenge bool
+	}{
+		{"NoChallengeWhenMaxHeadNotLimited", math.MaxUint64, false},
+		{"NoChallengeWhenBeforeMaxHead", poststateBlock + 1, false},
+		{"NoChallengeWhenAtMaxHead", poststateBlock, false},
+		{"ChallengeWhenBeforeMaxHead", poststateBlock - 1, true},
+	}
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			provider, stubRollupClient, stubL2Client := setupWithTestData(t, prestateBlock, poststateBlock)
+			stubRollupClient.maxSafeHead = test.maxSafeHead
+			if test.expectChallenge {
+				stubRollupClient.outputs[test.maxSafeHead] = &eth.OutputResponse{
+					OutputRoot: eth.Bytes32{0xaa},
+					BlockRef: eth.L2BlockRef{
+						Number: test.maxSafeHead,
+					},
+				}
+				stubL2Client.headers[test.maxSafeHead] = &ethTypes.Header{
+					Number: new(big.Int).SetUint64(test.maxSafeHead),
+					Root:   common.Hash{0xcc},
+				}
+			}
+			actual, err := provider.GetL2BlockNumberChallenge(context.Background())
+			if test.expectChallenge {
+				require.NoError(t, err)
+				require.Equal(t, &types.InvalidL2BlockNumberChallenge{
+					Output: stubRollupClient.outputs[test.maxSafeHead],
+					Header: stubL2Client.headers[test.maxSafeHead],
+				}, actual)
+			} else {
+				require.ErrorIs(t, err, types.ErrL2BlockNumberValid)
+			}
+		})
+	}
+}
+
 func TestClaimedBlockNumber(t *testing.T) {
 	tests := []struct {
 		name        string
@@ -128,7 +172,7 @@ func TestClaimedBlockNumber(t *testing.T) {
 	for _, test := range tests {
 		test := test
 		t.Run(test.name, func(t *testing.T) {
-			provider, stubRollupClient := setupWithTestData(t, prestateBlock, poststateBlock)
+			provider, stubRollupClient, _ := setupWithTestData(t, prestateBlock, poststateBlock)
 			stubRollupClient.maxSafeHead = test.maxSafeHead
 			actual, err := provider.ClaimedBlockNumber(test.pos)
 			require.NoError(t, err)
@@ -138,7 +182,7 @@ func TestClaimedBlockNumber(t *testing.T) {
 
 	t.Run("ErrorsTraceIndexOutOfBounds", func(t *testing.T) {
 		deepGame := types.Depth(164)
-		provider, _ := setupWithTestData(t, prestateBlock, poststateBlock, deepGame)
+		provider, _, _ := setupWithTestData(t, prestateBlock, poststateBlock, deepGame)
 		pos := types.NewPosition(0, big.NewInt(0))
 		_, err := provider.ClaimedBlockNumber(pos)
 		require.ErrorIs(t, err, ErrIndexTooBig)
@@ -146,12 +190,12 @@ func TestClaimedBlockNumber(t *testing.T) {
 }
 
 func TestGetStepData(t *testing.T) {
-	provider, _ := setupWithTestData(t, prestateBlock, poststateBlock)
+	provider, _, _ := setupWithTestData(t, prestateBlock, poststateBlock)
 	_, _, _, err := provider.GetStepData(context.Background(), types.NewPosition(1, common.Big0))
 	require.ErrorIs(t, err, ErrGetStepData)
 }
 
-func setupWithTestData(t *testing.T, prestateBlock, poststateBlock uint64, customGameDepth ...types.Depth) (*OutputTraceProvider, *stubRollupClient) {
+func setupWithTestData(t *testing.T, prestateBlock, poststateBlock uint64, customGameDepth ...types.Depth) (*OutputTraceProvider, *stubRollupClient, *stubL2HeaderSource) {
 	rollupClient := &stubRollupClient{
 		outputs: map[uint64]*eth.OutputResponse{
 			prestateBlock: {
@@ -166,6 +210,9 @@ func setupWithTestData(t *testing.T, prestateBlock, poststateBlock uint64, custo
 		},
 		maxSafeHead: math.MaxUint64,
 	}
+	l2Client := &stubL2HeaderSource{
+		headers: make(map[uint64]*ethTypes.Header),
+	}
 	inputGameDepth := gameDepth
 	if len(customGameDepth) > 0 {
 		inputGameDepth = customGameDepth[0]
@@ -173,10 +220,11 @@ func setupWithTestData(t *testing.T, prestateBlock, poststateBlock uint64, custo
 	return &OutputTraceProvider{
 		logger:         testlog.Logger(t, log.LevelInfo),
 		rollupProvider: rollupClient,
+		l2Client:       l2Client,
 		prestateBlock:  prestateBlock,
 		poststateBlock: poststateBlock,
 		gameDepth:      inputGameDepth,
-	}, rollupClient
+	}, rollupClient, l2Client
 }
 
 type stubRollupClient struct {
@@ -201,3 +249,15 @@ func (s *stubRollupClient) SafeHeadAtL1Block(_ context.Context, l1BlockNum uint6
 		},
 	}, nil
 }
+
+type stubL2HeaderSource struct {
+	headers map[uint64]*ethTypes.Header
+}
+
+func (s *stubL2HeaderSource) HeaderByNumber(_ context.Context, num *big.Int) (*ethTypes.Header, error) {
+	header, ok := s.headers[num.Uint64()]
+	if !ok {
+		return nil, ethereum.NotFound
+	}
+	return header, nil
+}

op-challenger/game/fault/trace/outputs/split_adapter_test.go

@@ -139,7 +139,7 @@ func setupAdapterTest(t *testing.T, topDepth types.Depth) (split.ProviderCreator
 	prestateProvider := &stubPrestateProvider{
 		absolutePrestate: prestateOutputRoot,
 	}
-	topProvider := NewTraceProvider(testlog.Logger(t, log.LevelInfo), prestateProvider, rollupClient, l1Head, topDepth, prestateBlock, poststateBlock)
+	topProvider := NewTraceProvider(testlog.Logger(t, log.LevelInfo), prestateProvider, rollupClient, nil, l1Head, topDepth, prestateBlock, poststateBlock)
 	adapter := OutputRootSplitAdapter(topProvider, creator.Create)
 	return adapter, creator
 }

op-challenger/game/fault/trace/translate.go

@@ -46,4 +46,8 @@ func (p *TranslatingProvider) AbsolutePreStateCommitment(ctx context.Context) (h
 	return p.provider.AbsolutePreStateCommitment(ctx)
 }
 
+func (p *TranslatingProvider) GetL2BlockNumberChallenge(ctx context.Context) (*types.InvalidL2BlockNumberChallenge, error) {
+	return p.provider.GetL2BlockNumberChallenge(ctx)
+}
+
 var _ types.TraceProvider = (*TranslatingProvider)(nil)

op-challenger/game/fault/types/actions.go

@@ -9,12 +9,15 @@ func (a ActionType) String() string {
 }
 
 const (
-	ActionTypeMove ActionType = "move"
-	ActionTypeStep ActionType = "step"
+	ActionTypeMove                   ActionType = "move"
+	ActionTypeStep                   ActionType = "step"
+	ActionTypeChallengeL2BlockNumber ActionType = "challenge-l2-block-number"
 )
 
 type Action struct {
-	Type           ActionType
+	Type ActionType
+
+	// Moves and Steps
 	ParentIdx      int
 	ParentPosition Position
 	IsAttack       bool
@@ -26,4 +29,7 @@ type Action struct {
 	PreState   []byte
 	ProofData  []byte
 	OracleData *PreimageOracleData
+
+	// Challenge L2 Block Number
+	InvalidL2BlockNumberChallenge *InvalidL2BlockNumberChallenge
 }

op-challenger/game/fault/types/position.go

@@ -10,6 +10,8 @@ import (
 
 var (
 	ErrPositionDepthTooSmall = errors.New("position depth is too small")
+
+	RootPosition = NewPositionFromGIndex(big.NewInt(1))
 )
 
 // Depth is the depth of a position in a game tree where the root level has

op-challenger/game/fault/types/position_test.go

@@ -13,6 +13,10 @@ func bi(i int) *big.Int {
 	return big.NewInt(int64(i))
 }
 
+func TestRootPosition(t *testing.T) {
+	require.True(t, RootPosition.IsRootPosition())
+}
+
 func TestBigMSB(t *testing.T) {
 	large, ok := new(big.Int).SetString("18446744073709551615", 10)
 	require.True(t, ok)

op-challenger/game/fault/types/types.go

@@ -7,12 +7,15 @@ import (
 	"time"
 
 	preimage "github.com/ethereum-optimism/optimism/op-preimage"
+	"github.com/ethereum-optimism/optimism/op-service/eth"
 	"github.com/ethereum/go-ethereum/common"
+	ethTypes "github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
 )
 
 var (
-	ErrGameDepthReached = errors.New("game depth reached")
+	ErrGameDepthReached   = errors.New("game depth reached")
+	ErrL2BlockNumberValid = errors.New("l2 block number is valid")
 )
 
 const (
@@ -103,6 +106,10 @@ type TraceAccessor interface {
 	// GetStepData returns the data required to execute the step at the specified position,
 	// evaluated in the context of the specified claim (ref).
 	GetStepData(ctx context.Context, game Game, ref Claim, pos Position) (prestate []byte, proofData []byte, preimageData *PreimageOracleData, err error)
+
+	// GetL2BlockNumberChallenge returns the data required to prove the correct L2 block number of the root claim.
+	// Returns ErrL2BlockNumberValid if the root claim is known to come from the same block as the claimed L2 block.
+	GetL2BlockNumberChallenge(ctx context.Context, game Game) (*InvalidL2BlockNumberChallenge, error)
 }
 
 // PrestateProvider defines an interface to request the absolute prestate.
@@ -124,6 +131,10 @@ type TraceProvider interface {
 	// and any pre-image data that needs to be loaded into the oracle prior to execution (may be nil)
 	// The prestate returned from GetStepData for trace 10 should be the pre-image of the claim from trace 9
 	GetStepData(ctx context.Context, i Position) (prestate []byte, proofData []byte, preimageData *PreimageOracleData, err error)
+
+	// GetL2BlockNumberChallenge returns the data required to prove the correct L2 block number of the root claim.
+	// Returns ErrL2BlockNumberValid if the root claim is known to come from the same block as the claimed L2 block.
+	GetL2BlockNumberChallenge(ctx context.Context) (*InvalidL2BlockNumberChallenge, error)
 }
 
 // ClaimData is the core of a claim. It must be unique inside a specific game.
@@ -201,3 +212,15 @@ func NewClock(duration time.Duration, timestamp time.Time) Clock {
 		Timestamp: timestamp,
 	}
 }
+
+type InvalidL2BlockNumberChallenge struct {
+	Output *eth.OutputResponse
+	Header *ethTypes.Header
+}
+
+func NewInvalidL2BlockNumberProof(output *eth.OutputResponse, header *ethTypes.Header) *InvalidL2BlockNumberChallenge {
+	return &InvalidL2BlockNumberChallenge{
+		Output: output,
+		Header: header,
+	}
+}

op-e2e/e2eutils/disputegame/helper.go

@@ -172,6 +172,7 @@ func (h *FactoryHelper) StartOutputCannonGame(ctx context.Context, l2Node string
 	cfg := NewGameCfg(opts...)
 	logger := testlog.Logger(h.T, log.LevelInfo).New("role", "OutputCannonGameHelper")
 	rollupClient := h.System.RollupClient(l2Node)
+	l2Client := h.System.NodeClient(l2Node)
 
 	extraData := h.CreateBisectionGameExtraData(l2Node, l2BlockNumber, cfg)
 
@@ -200,7 +201,7 @@ func (h *FactoryHelper) StartOutputCannonGame(ctx context.Context, l2Node string
 	l1Head := h.GetL1Head(ctx, game)
 
 	prestateProvider := outputs.NewPrestateProvider(rollupClient, prestateBlock.Uint64())
-	provider := outputs.NewTraceProvider(logger, prestateProvider, rollupClient, l1Head, faultTypes.Depth(splitDepth.Uint64()), prestateBlock.Uint64(), poststateBlock.Uint64())
+	provider := outputs.NewTraceProvider(logger, prestateProvider, rollupClient, l2Client, l1Head, faultTypes.Depth(splitDepth.Uint64()), prestateBlock.Uint64(), poststateBlock.Uint64())
 
 	return &OutputCannonGameHelper{
 		OutputGameHelper: *NewOutputGameHelper(h.T, h.Require, h.Client, h.Opts, game, h.FactoryAddr, createdEvent.DisputeProxy, provider, h.System),
@@ -228,6 +229,7 @@ func (h *FactoryHelper) StartOutputAlphabetGame(ctx context.Context, l2Node stri
 	cfg := NewGameCfg(opts...)
 	logger := testlog.Logger(h.T, log.LevelInfo).New("role", "OutputAlphabetGameHelper")
 	rollupClient := h.System.RollupClient(l2Node)
+	l2Client := h.System.NodeClient(l2Node)
 
 	extraData := h.CreateBisectionGameExtraData(l2Node, l2BlockNumber, cfg)
 
@@ -256,7 +258,7 @@ func (h *FactoryHelper) StartOutputAlphabetGame(ctx context.Context, l2Node stri
 	l1Head := h.GetL1Head(ctx, game)
 	prestateProvider := outputs.NewPrestateProvider(rollupClient, prestateBlock.Uint64())
 
-	provider := outputs.NewTraceProvider(logger, prestateProvider, rollupClient, l1Head, faultTypes.Depth(splitDepth.Uint64()), prestateBlock.Uint64(), poststateBlock.Uint64())
+	provider := outputs.NewTraceProvider(logger, prestateProvider, rollupClient, l2Client, l1Head, faultTypes.Depth(splitDepth.Uint64()), prestateBlock.Uint64(), poststateBlock.Uint64())
 
 	return &OutputAlphabetGameHelper{
 		OutputGameHelper: *NewOutputGameHelper(h.T, h.Require, h.Client, h.Opts, game, h.FactoryAddr, createdEvent.DisputeProxy, provider, h.System),

op-e2e/e2eutils/disputegame/output_alphabet_helper.go

@@ -46,8 +46,9 @@ func (g *OutputAlphabetGameHelper) CreateHonestActor(ctx context.Context, l2Node
 	splitDepth := g.SplitDepth(ctx)
 	l1Head := g.GetL1Head(ctx)
 	rollupClient := g.System.RollupClient(l2Node)
+	l2Client := g.System.NodeClient(l2Node)
 	prestateProvider := outputs.NewPrestateProvider(rollupClient, prestateBlock)
-	correctTrace, err := outputs.NewOutputAlphabetTraceAccessor(logger, metrics.NoopMetrics, prestateProvider, rollupClient, l1Head, splitDepth, prestateBlock, poststateBlock)
+	correctTrace, err := outputs.NewOutputAlphabetTraceAccessor(logger, metrics.NoopMetrics, prestateProvider, rollupClient, l2Client, l1Head, splitDepth, prestateBlock, poststateBlock)
 	g.Require.NoError(err, "Create trace accessor")
 	return NewOutputHonestHelper(g.T, g.Require, &g.OutputGameHelper, contract, correctTrace)
 }

op-e2e/e2eutils/disputegame/output_cannon_helper.go

@@ -290,7 +290,7 @@ func (g *OutputCannonGameHelper) createCannonTraceProvider(ctx context.Context,
 	rollupClient := g.System.RollupClient(l2Node)
 	prestateProvider := outputs.NewPrestateProvider(rollupClient, prestateBlock)
 	l1Head := g.GetL1Head(ctx)
-	outputProvider := outputs.NewTraceProvider(logger, prestateProvider, rollupClient, l1Head, splitDepth, prestateBlock, poststateBlock)
+	outputProvider := outputs.NewTraceProvider(logger, prestateProvider, rollupClient, l2Client, l1Head, splitDepth, prestateBlock, poststateBlock)
 
 	var localContext common.Hash
 	selector := split.NewSplitProviderSelector(outputProvider, splitDepth, func(ctx context.Context, depth types.Depth, pre types.Claim, post types.Claim) (types.TraceProvider, error) {