diff --git a/cannon/cmd/load_elf.go b/cannon/cmd/load_elf.go
index 5cfc3078e90..7c41fc3c0ef 100644
--- a/cannon/cmd/load_elf.go
+++ b/cannon/cmd/load_elf.go
@@ -7,6 +7,7 @@ import (
 	"github.com/urfave/cli/v2"
 
 	"github.com/ethereum-optimism/optimism/cannon/mipsevm"
+	"github.com/ethereum-optimism/optimism/op-service/jsonutil"
 )
 
 var (
@@ -66,10 +67,10 @@ func LoadELF(ctx *cli.Context) error {
 	if err != nil {
 		return fmt.Errorf("failed to compute program metadata: %w", err)
 	}
-	if err := writeJSON[*mipsevm.Metadata](ctx.Path(LoadELFMetaFlag.Name), meta); err != nil {
+	if err := jsonutil.WriteJSON[*mipsevm.Metadata](ctx.Path(LoadELFMetaFlag.Name), meta, OutFilePerm); err != nil {
 		return fmt.Errorf("failed to output metadata: %w", err)
 	}
-	return writeJSON[*mipsevm.State](ctx.Path(LoadELFOutFlag.Name), state)
+	return jsonutil.WriteJSON[*mipsevm.State](ctx.Path(LoadELFOutFlag.Name), state, OutFilePerm)
 }
 
 var LoadELFCommand = &cli.Command{
diff --git a/cannon/cmd/matcher.go b/cannon/cmd/matcher.go
index 2f0267c143b..b569ef6df6b 100644
--- a/cannon/cmd/matcher.go
+++ b/cannon/cmd/matcher.go
@@ -4,11 +4,13 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
-
-	"github.com/ethereum-optimism/optimism/cannon/mipsevm"
 )
 
-type StepMatcher func(st *mipsevm.State) bool
+type VMState interface {
+	GetStep() uint64
+}
+
+type StepMatcher func(st VMState) bool
 
 type StepMatcherFlag struct {
 	repr    string
@@ -26,11 +28,11 @@ func MustStepMatcherFlag(pattern string) *StepMatcherFlag {
 func (m *StepMatcherFlag) Set(value string) error {
 	m.repr = value
 	if value == "" || value == "never" {
-		m.matcher = func(st *mipsevm.State) bool {
+		m.matcher = func(st VMState) bool {
 			return false
 		}
 	} else if value == "always" {
-		m.matcher = func(st *mipsevm.State) bool {
+		m.matcher = func(st VMState) bool {
 			return true
 		}
 	} else if strings.HasPrefix(value, "=") {
@@ -38,16 +40,16 @@ func (m *StepMatcherFlag) Set(value string) error {
 		if err != nil {
 			return fmt.Errorf("failed to parse step number: %w", err)
 		}
-		m.matcher = func(st *mipsevm.State) bool {
-			return st.Step == when
+		m.matcher = func(st VMState) bool {
+			return st.GetStep() == when
 		}
 	} else if strings.HasPrefix(value, "%") {
 		when, err := strconv.ParseUint(value[1:], 0, 64)
 		if err != nil {
 			return fmt.Errorf("failed to parse step interval number: %w", err)
 		}
-		m.matcher = func(st *mipsevm.State) bool {
-			return st.Step%when == 0
+		m.matcher = func(st VMState) bool {
+			return st.GetStep()%when == 0
 		}
 	} else {
 		return fmt.Errorf("unrecognized step matcher: %q", value)
@@ -61,7 +63,7 @@ func (m *StepMatcherFlag) String() string {
 
 func (m *StepMatcherFlag) Matcher() StepMatcher {
 	if m.matcher == nil { // Set(value) is not called for omitted inputs, default to never matching.
-		return func(st *mipsevm.State) bool {
+		return func(st VMState) bool {
 			return false
 		}
 	}
diff --git a/cannon/cmd/run.go b/cannon/cmd/run.go
index 5b821cf0695..4f15ad95f18 100644
--- a/cannon/cmd/run.go
+++ b/cannon/cmd/run.go
@@ -16,6 +16,7 @@ import (
 
 	"github.com/ethereum-optimism/optimism/cannon/mipsevm"
 	preimage "github.com/ethereum-optimism/optimism/op-preimage"
+	"github.com/ethereum-optimism/optimism/op-service/jsonutil"
 )
 
 var (
@@ -90,6 +91,8 @@ var (
 		Name:  "pprof.cpu",
 		Usage: "enable pprof cpu profiling",
 	}
+
+	OutFilePerm = os.FileMode(0o755)
 )
 
 type Proof struct {
@@ -234,7 +237,7 @@ func Run(ctx *cli.Context) error {
 		defer profile.Start(profile.NoShutdownHook, profile.ProfilePath("."), profile.CPUProfile).Stop()
 	}
 
-	state, err := loadJSON[mipsevm.State](ctx.Path(RunInputFlag.Name))
+	state, err := jsonutil.LoadJSON[mipsevm.State](ctx.Path(RunInputFlag.Name))
 	if err != nil {
 		return err
 	}
@@ -284,7 +287,7 @@ func Run(ctx *cli.Context) error {
 		l.Info("no metadata file specified, defaulting to empty metadata")
 		meta = &mipsevm.Metadata{Symbols: nil} // provide empty metadata by default
 	} else {
-		if m, err := loadJSON[mipsevm.Metadata](metaPath); err != nil {
+		if m, err := jsonutil.LoadJSON[mipsevm.Metadata](metaPath); err != nil {
 			return fmt.Errorf("failed to load metadata: %w", err)
 		} else {
 			meta = m
@@ -337,7 +340,7 @@ func Run(ctx *cli.Context) error {
 		}
 
 		if snapshotAt(state) {
-			if err := writeJSON(fmt.Sprintf(snapshotFmt, step), state); err != nil {
+			if err := jsonutil.WriteJSON(fmt.Sprintf(snapshotFmt, step), state, OutFilePerm); err != nil {
 				return fmt.Errorf("failed to write state snapshot: %w", err)
 			}
 		}
@@ -369,7 +372,7 @@ func Run(ctx *cli.Context) error {
 				proof.OracleValue = witness.PreimageValue
 				proof.OracleOffset = witness.PreimageOffset
 			}
-			if err := writeJSON(fmt.Sprintf(proofFmt, step), proof); err != nil {
+			if err := jsonutil.WriteJSON(fmt.Sprintf(proofFmt, step), proof, OutFilePerm); err != nil {
 				return fmt.Errorf("failed to write proof data: %w", err)
 			}
 		} else {
@@ -398,7 +401,7 @@ func Run(ctx *cli.Context) error {
 		}
 	}
 
-	if err := writeJSON(ctx.Path(RunOutputFlag.Name), state); err != nil {
+	if err := jsonutil.WriteJSON(ctx.Path(RunOutputFlag.Name), state, OutFilePerm); err != nil {
 		return fmt.Errorf("failed to write state output: %w", err)
 	}
 	return nil
diff --git a/cannon/cmd/witness.go b/cannon/cmd/witness.go
index d92a2777918..c2f38daa362 100644
--- a/cannon/cmd/witness.go
+++ b/cannon/cmd/witness.go
@@ -5,6 +5,7 @@ import (
 	"os"
 
 	"github.com/ethereum-optimism/optimism/cannon/mipsevm"
+	"github.com/ethereum-optimism/optimism/op-service/jsonutil"
 	"github.com/urfave/cli/v2"
 )
 
@@ -25,7 +26,7 @@ var (
 func Witness(ctx *cli.Context) error {
 	input := ctx.Path(WitnessInputFlag.Name)
 	output := ctx.Path(WitnessOutputFlag.Name)
-	state, err := loadJSON[mipsevm.State](input)
+	state, err := jsonutil.LoadJSON[mipsevm.State](input)
 	if err != nil {
 		return fmt.Errorf("invalid input state (%v): %w", input, err)
 	}
diff --git a/cannon/mipsevm/state.go b/cannon/mipsevm/state.go
index ba95f1938df..fea495218a5 100644
--- a/cannon/mipsevm/state.go
+++ b/cannon/mipsevm/state.go
@@ -42,6 +42,8 @@ type State struct {
 	LastHint hexutil.Bytes `json:"lastHint,omitempty"`
 }
 
+func (s *State) GetStep() uint64 { return s.Step }
+
 func (s *State) VMStatus() uint8 {
 	return vmStatus(s.Exited, s.ExitCode)
 }
diff --git a/op-chain-ops/cmd/op-upgrade/main.go b/op-chain-ops/cmd/op-upgrade/main.go
index 87fcb9f8f54..7c5cf87f261 100644
--- a/op-chain-ops/cmd/op-upgrade/main.go
+++ b/op-chain-ops/cmd/op-upgrade/main.go
@@ -208,7 +208,7 @@ func entrypoint(ctx *cli.Context) error {
 
 	// Write the batch to disk or stdout
 	if outfile := ctx.Path("outfile"); outfile != "" {
-		if err := jsonutil.WriteJSON(outfile, batch); err != nil {
+		if err := jsonutil.WriteJSON(outfile, batch, 0o666); err != nil {
 			return err
 		}
 	} else {
diff --git a/op-chain-ops/cmd/op-version-check/main.go b/op-chain-ops/cmd/op-version-check/main.go
index 202084df3da..36144f9cacf 100644
--- a/op-chain-ops/cmd/op-version-check/main.go
+++ b/op-chain-ops/cmd/op-version-check/main.go
@@ -152,7 +152,7 @@ func entrypoint(ctx *cli.Context) error {
 	}
 	// Write contract versions to disk or stdout
 	if outfile := ctx.Path("outfile"); outfile != "" {
-		if err := jsonutil.WriteJSON(outfile, output); err != nil {
+		if err := jsonutil.WriteJSON(outfile, output, 0o666); err != nil {
 			return err
 		}
 	} else {
diff --git a/op-node/cmd/genesis/cmd.go b/op-node/cmd/genesis/cmd.go
index 67ea3e078f6..d94c7556f18 100644
--- a/op-node/cmd/genesis/cmd.go
+++ b/op-node/cmd/genesis/cmd.go
@@ -127,7 +127,7 @@ var Subcommands = cli.Commands{
 				return err
 			}
 
-			return jsonutil.WriteJSON(ctx.String("outfile.l1"), l1Genesis)
+			return jsonutil.WriteJSON(ctx.String("outfile.l1"), l1Genesis, 0o666)
 		},
 	},
 	{
@@ -250,10 +250,10 @@ var Subcommands = cli.Commands{
 				return fmt.Errorf("generated rollup config does not pass validation: %w", err)
 			}
 
-			if err := jsonutil.WriteJSON(ctx.String("outfile.l2"), l2Genesis); err != nil {
+			if err := jsonutil.WriteJSON(ctx.String("outfile.l2"), l2Genesis, 0o666); err != nil {
 				return err
 			}
-			return jsonutil.WriteJSON(ctx.String("outfile.rollup"), rollupConfig)
+			return jsonutil.WriteJSON(ctx.String("outfile.rollup"), rollupConfig, 0o666)
 		},
 	},
 }
diff --git a/cannon/cmd/json.go b/op-service/jsonutil/json.go
similarity index 85%
rename from cannon/cmd/json.go
rename to op-service/jsonutil/json.go
index 615bacedc86..a7918d6d4a6 100644
--- a/cannon/cmd/json.go
+++ b/op-service/jsonutil/json.go
@@ -1,4 +1,4 @@
-package cmd
+package jsonutil
 
 import (
 	"encoding/json"
@@ -10,7 +10,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-service/ioutil"
 )
 
-func loadJSON[X any](inputPath string) (*X, error) {
+func LoadJSON[X any](inputPath string) (*X, error) {
 	if inputPath == "" {
 		return nil, errors.New("no path specified")
 	}
@@ -27,14 +27,14 @@ func loadJSON[X any](inputPath string) (*X, error) {
 	return &state, nil
 }
 
-func writeJSON[X any](outputPath string, value X) error {
+func WriteJSON[X any](outputPath string, value X, perm os.FileMode) error {
 	if outputPath == "" {
 		return nil
 	}
 	var out io.Writer
 	finish := func() error { return nil }
 	if outputPath != "-" {
-		f, err := ioutil.NewAtomicWriterCompressed(outputPath, 0755)
+		f, err := ioutil.NewAtomicWriterCompressed(outputPath, perm)
 		if err != nil {
 			return fmt.Errorf("failed to open output file: %w", err)
 		}
@@ -48,6 +48,7 @@ func writeJSON[X any](outputPath string, value X) error {
 		out = os.Stdout
 	}
 	enc := json.NewEncoder(out)
+	enc.SetIndent("", "  ")
 	if err := enc.Encode(value); err != nil {
 		return fmt.Errorf("failed to encode to JSON: %w", err)
 	}
diff --git a/cannon/cmd/json_test.go b/op-service/jsonutil/json_test.go
similarity index 86%
rename from cannon/cmd/json_test.go
rename to op-service/jsonutil/json_test.go
index 63d4636b7d9..16eb91992f8 100644
--- a/cannon/cmd/json_test.go
+++ b/op-service/jsonutil/json_test.go
@@ -1,4 +1,4 @@
-package cmd
+package jsonutil
 
 import (
 	"encoding/json"
@@ -13,7 +13,7 @@ func TestRoundTripJSON(t *testing.T) {
 	dir := t.TempDir()
 	file := filepath.Join(dir, "test.json")
 	data := &jsonTestData{A: "yay", B: 3}
-	err := writeJSON(file, data)
+	err := WriteJSON(file, data, 0o755)
 	require.NoError(t, err)
 
 	// Confirm the file is uncompressed
@@ -23,7 +23,7 @@ func TestRoundTripJSON(t *testing.T) {
 	require.NoError(t, err)
 
 	var result *jsonTestData
-	result, err = loadJSON[jsonTestData](file)
+	result, err = LoadJSON[jsonTestData](file)
 	require.NoError(t, err)
 	require.EqualValues(t, data, result)
 }
@@ -32,7 +32,7 @@ func TestRoundTripJSONWithGzip(t *testing.T) {
 	dir := t.TempDir()
 	file := filepath.Join(dir, "test.json.gz")
 	data := &jsonTestData{A: "yay", B: 3}
-	err := writeJSON(file, data)
+	err := WriteJSON(file, data, 0o755)
 	require.NoError(t, err)
 
 	// Confirm the file isn't raw JSON
@@ -42,7 +42,7 @@ func TestRoundTripJSONWithGzip(t *testing.T) {
 	require.Error(t, err, "should not be able to decode without decompressing")
 
 	var result *jsonTestData
-	result, err = loadJSON[jsonTestData](file)
+	result, err = LoadJSON[jsonTestData](file)
 	require.NoError(t, err)
 	require.EqualValues(t, data, result)
 }
diff --git a/op-service/jsonutil/write.go b/op-service/jsonutil/write.go
deleted file mode 100644
index 8b0a295f971..00000000000
--- a/op-service/jsonutil/write.go
+++ /dev/null
@@ -1,18 +0,0 @@
-package jsonutil
-
-import (
-	"encoding/json"
-	"os"
-)
-
-func WriteJSON(outfile string, input interface{}) error {
-	f, err := os.OpenFile(outfile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0o666)
-	if err != nil {
-		return err
-	}
-	defer f.Close()
-
-	enc := json.NewEncoder(f)
-	enc.SetIndent("", "  ")
-	return enc.Encode(input)
-}