diff --git a/src/main/kotlin/slack/cli/sarif/MergeSarifReports.kt b/src/main/kotlin/slack/cli/sarif/MergeSarifReports.kt
index 18495bf..2e44691 100644
--- a/src/main/kotlin/slack/cli/sarif/MergeSarifReports.kt
+++ b/src/main/kotlin/slack/cli/sarif/MergeSarifReports.kt
@@ -16,15 +16,23 @@
 package slack.cli.sarif
 
 import com.github.ajalt.clikt.core.CliktCommand
+import com.github.ajalt.clikt.parameters.arguments.argument
+import com.github.ajalt.clikt.parameters.arguments.multiple
 import com.github.ajalt.clikt.parameters.options.flag
 import com.github.ajalt.clikt.parameters.options.option
 import com.github.ajalt.clikt.parameters.options.required
-import com.github.ajalt.clikt.parameters.types.file
+import com.github.ajalt.clikt.parameters.types.path
 import com.google.auto.service.AutoService
 import io.github.detekt.sarif4k.SarifSchema210
 import io.github.detekt.sarif4k.SarifSerializer
-import java.io.File
+import java.nio.file.Path
 import kotlin.io.path.absolutePathString
+import kotlin.io.path.createParentDirectories
+import kotlin.io.path.deleteIfExists
+import kotlin.io.path.exists
+import kotlin.io.path.readText
+import kotlin.io.path.relativeTo
+import kotlin.io.path.writeText
 import kotlin.system.exitProcess
 import slack.cli.CommandFactory
 import slack.cli.projectDirOption
@@ -41,8 +49,10 @@ public class MergeSarifReports : CliktCommand(help = DESCRIPTION) {
   }
 
   private val projectDir by projectDirOption()
-  private val outputFile: File by option("--output-file").file().required()
-  private val filePrefix by option("--file-prefix").required()
+  private val outputFile by option("--output-file").path().required()
+  private val filePrefix by option("--file-prefix")
+  private val argFiles by
+    argument("--files").path(mustExist = true, canBeDir = false, mustBeReadable = true).multiple()
   private val verbose by option("--verbose", "-v").flag()
   private val remapSrcRoots by
     option(
@@ -75,13 +85,11 @@ public class MergeSarifReports : CliktCommand(help = DESCRIPTION) {
   }
 
   private fun prepareOutput() {
-    if (outputFile.exists()) {
-      outputFile.delete()
-    }
-    outputFile.parentFile?.mkdirs()
+    outputFile.deleteIfExists()
+    outputFile.createParentDirectories()
   }
 
-  private fun findBuildFiles(): List<File> {
+  private fun findBuildFiles(): List<Path> {
     log("Finding build files in ${projectDir.toFile().canonicalFile}")
     val buildFiles =
       projectDir
@@ -90,6 +98,7 @@ public class MergeSarifReports : CliktCommand(help = DESCRIPTION) {
         .walkTopDown()
         .skipBuildAndCacheDirs()
         .filter { it.name == "build.gradle.kts" }
+        .map { it.toPath() }
         .toList()
     log("${buildFiles.size} build files found")
     return buildFiles
@@ -97,25 +106,41 @@ public class MergeSarifReports : CliktCommand(help = DESCRIPTION) {
 
   private fun String.prefixPathWith(prefix: String) = "$prefix/$this"
 
-  private fun findSarifFiles(): List<File> {
-    // Find build files first, this gives us an easy hook to then go looking in build/reports dirs.
-    // Otherwise we don't have a way to easily exclude populated build dirs that would take forever.
-    val buildFiles = findBuildFiles()
+  private fun findSarifFiles(): List<Path> {
+    require(filePrefix != null || argFiles.isNotEmpty()) {
+      "Must specify either --file-prefix or pass files as arguments"
+    }
 
-    log("Finding sarif files")
-    return buildFiles
-      .asSequence()
-      .flatMap { buildFile ->
-        val reportsDir = File(buildFile.parentFile, "build/reports")
-        if (reportsDir.exists()) {
-          reportsDir.walkTopDown().filter {
-            it.isFile && it.extension == "sarif" && it.nameWithoutExtension.startsWith(filePrefix)
+    val files = mutableListOf<Path>()
+
+    files += argFiles
+
+    filePrefix?.let { prefix ->
+      // Find build files first, this gives us an easy hook to then go looking in build/reports
+      // dirs.
+      // Otherwise we don't have a way to easily exclude populated build dirs that would take
+      // forever.
+      val buildFiles = findBuildFiles()
+
+      log("Finding sarif files")
+      files +=
+        buildFiles.asSequence().flatMap { buildFile ->
+          val reportsDir = buildFile.parent.resolve("build/reports")
+          if (reportsDir.exists()) {
+            reportsDir
+              .toFile()
+              .walkTopDown()
+              .filter {
+                it.isFile && it.extension == "sarif" && it.nameWithoutExtension.startsWith(prefix)
+              }
+              .map { it.toPath() }
+          } else {
+            emptySequence()
           }
-        } else {
-          emptySequence()
         }
-      }
-      .toList()
+    }
+
+    return files
   }
 
   /**
@@ -150,16 +175,16 @@ public class MergeSarifReports : CliktCommand(help = DESCRIPTION) {
    * libraries/lib/src/main/java/com/example/app/LibActivity.kt
    * ```
    */
-  private fun SarifSchema210.remapSrcRoots(sarifFile: File): SarifSchema210 {
-    //   <module>/─────────────────────────────────┐
-    //       build/─────────────────────┐          │
-    //          reports/──────┐         │          │
-    //                        ▼         ▼          ▼
-    val module = sarifFile.parentFile.parentFile.parentFile
-    check(File(module, "build.gradle.kts").exists()) {
+  private fun SarifSchema210.remapSrcRoots(sarifFile: Path): SarifSchema210 {
+    //   <module>/─────────────────────────┐
+    //       build/─────────────────┐      │
+    //          reports/──────┐     │      │
+    //                        ▼     ▼      ▼
+    val module = sarifFile.parent.parent.parent
+    check(module.resolve("build.gradle.kts").exists()) {
       "Expected to find build.gradle.kts in $module"
     }
-    val modulePrefix = module.toRelativeString(projectDir.toFile())
+    val modulePrefix = module.relativeTo(projectDir).toString()
     return copy(
       runs =
         runs.map { run ->
@@ -239,7 +264,7 @@ public class MergeSarifReports : CliktCommand(help = DESCRIPTION) {
     )
   }
 
-  private fun loadSarifs(inputs: List<File>): List<SarifSchema210> {
+  private fun loadSarifs(inputs: List<Path>): List<SarifSchema210> {
     return inputs.map { sarifFile ->
       log("Parsing $sarifFile")
       val parsed = SarifSerializer.fromJson(sarifFile.readText())
@@ -256,7 +281,7 @@ public class MergeSarifReports : CliktCommand(help = DESCRIPTION) {
     }
   }
 
-  private fun merge(inputs: List<File>) {
+  private fun merge(inputs: List<Path>) {
     log("Parsing ${inputs.size} sarif files")
     val sarifs = loadSarifs(inputs)