diff --git a/Sources/tart/Commands/IP.swift b/Sources/tart/Commands/IP.swift
index beca08b..131ba19 100644
--- a/Sources/tart/Commands/IP.swift
+++ b/Sources/tart/Commands/IP.swift
@@ -19,7 +19,7 @@ struct IP: AsyncParsableCommand {
     let vmMACAddress = MACAddress(fromString: vmConfig.macAddress.string)!
 
     guard let ipViaDHCP = try await IP.resolveIP(vmMACAddress, secondsToWait: wait) else {
-      throw RuntimeError("no IP address found, is your VM running?")
+      throw RuntimeError.NoIPAddressFound("no IP address found, is your VM running?")
     }
 
     let arpCache = try ARPCache()
diff --git a/Sources/tart/Commands/Login.swift b/Sources/tart/Commands/Login.swift
index f68777b..8c98f43 100644
--- a/Sources/tart/Commands/Login.swift
+++ b/Sources/tart/Commands/Login.swift
@@ -47,7 +47,7 @@ struct Login: AsyncParsableCommand {
                                   credentialsProviders: [credentialsProvider])
       try await registry.ping()
     } catch {
-      throw RuntimeError("invalid credentials: \(error)")
+      throw RuntimeError.InvalidCredentials("invalid credentials: \(error)")
     }
 
     try KeychainCredentialsProvider().store(host: host, user: user, password: password)
diff --git a/Sources/tart/Commands/Run.swift b/Sources/tart/Commands/Run.swift
index 6a80ca8..f7bbedb 100644
--- a/Sources/tart/Commands/Run.swift
+++ b/Sources/tart/Commands/Run.swift
@@ -117,7 +117,7 @@ struct Run: AsyncParsableCommand {
       }
 
       if try !FileLock(lockURL: additionalDiskAttachment.url).trylock() {
-        throw RuntimeError("disk \(additionalDiskAttachment.url.path) seems to be already in use, "
+        throw RuntimeError.DiskAlreadyInUse("disk \(additionalDiskAttachment.url.path) seems to be already in use, "
           + "unmount it first in Finder")
       }
     }
@@ -154,7 +154,7 @@ struct Run: AsyncParsableCommand {
     // [1]: https://man.openbsd.org/fcntl
     let lock = try PIDLock(lockURL: vmDir.configURL)
     if try !lock.trylock() {
-      throw RuntimeError("Virtual machine \"\(name)\" is already running!", exitCode: 2)
+      throw RuntimeError.VMAlreadyRunning("VM \"\(name)\" is already running!")
     }
 
     let task = Task {
diff --git a/Sources/tart/Commands/Stop.swift b/Sources/tart/Commands/Stop.swift
index 7e7306f..1ecc0d0 100644
--- a/Sources/tart/Commands/Stop.swift
+++ b/Sources/tart/Commands/Stop.swift
@@ -19,7 +19,7 @@ struct Stop: AsyncParsableCommand {
     // Find the VM's PID
     var pid = try lock.pid()
     if pid == 0 {
-      throw RuntimeError("VM \(name) is not running", exitCode: 2)
+      throw RuntimeError.VMNotRunning("VM \"\(name)\" is not running")
     }
 
     // Try to gracefully terminate the VM
@@ -54,7 +54,7 @@ struct Stop: AsyncParsableCommand {
     if ret != 0 {
       let details = Errno(rawValue: CInt(errno))
 
-      throw RuntimeError("failed to forcefully terminate the VM \(name): \(details)")
+      throw RuntimeError.VMTerminationFailed("failed to forcefully terminate the VM \"\(name)\": \(details)")
     }
   }
 }
diff --git a/Sources/tart/OCI/RemoteName.swift b/Sources/tart/OCI/RemoteName.swift
index 2ddb35e..3fbf2ea 100644
--- a/Sources/tart/OCI/RemoteName.swift
+++ b/Sources/tart/OCI/RemoteName.swift
@@ -106,7 +106,7 @@ struct RemoteName: Comparable, Hashable, CustomStringConvertible {
     try ParseTreeWalker().walk(referenceCollector, try parser.root())
 
     if let error = errorCollector.error {
-      throw RuntimeError("failed to parse remote name: \(error)")
+      throw RuntimeError.FailedToParseRemoteName("\(error)")
     }
 
     host = referenceCollector.host!
@@ -120,7 +120,7 @@ struct RemoteName: Comparable, Hashable, CustomStringConvertible {
       } else if reference.starts(with: ":") {
         self.reference = Reference(tag: String(reference.dropFirst(1)))
       } else {
-        throw RuntimeError("failed to parse remote name: unknown reference format")
+        throw RuntimeError.FailedToParseRemoteName("unknown reference format")
       }
     } else {
       self.reference = Reference(tag: "latest")
diff --git a/Sources/tart/PIDLock.swift b/Sources/tart/PIDLock.swift
index 7800059..f65c417 100644
--- a/Sources/tart/PIDLock.swift
+++ b/Sources/tart/PIDLock.swift
@@ -44,7 +44,7 @@ class PIDLock {
 
       let details = Errno(rawValue: CInt(errno))
 
-      throw RuntimeError("\(message): \(details)")
+      throw RuntimeError.PIDLockFailed("\(message): \(details)")
     }
 
     return (true, result)
diff --git a/Sources/tart/Root.swift b/Sources/tart/Root.swift
index c7ee3e9..5becce5 100644
--- a/Sources/tart/Root.swift
+++ b/Sources/tart/Root.swift
@@ -106,8 +106,8 @@ struct Root: AsyncParsableCommand {
 
       print(error)
 
-      if let runtimeError = error as? RuntimeError {
-        Foundation.exit(runtimeError.exitCode)
+      if let errorWithExitCode = error as? HasExitCode {
+        Foundation.exit(errorWithExitCode.exitCode)
       }
 
       Foundation.exit(1)
diff --git a/Sources/tart/URL+AccessDate.swift b/Sources/tart/URL+AccessDate.swift
index 0e62398..3d43d20 100644
--- a/Sources/tart/URL+AccessDate.swift
+++ b/Sources/tart/URL+AccessDate.swift
@@ -13,7 +13,7 @@ extension URL {
     let times = [accessDate.asTimeval(), modificationDate.asTimeval()]
     let ret = utimes(path, times)
     if ret != 0 {
-      throw RuntimeError("utimes(2) failed: \(ret.explanation())")
+      throw RuntimeError.FailedToUpdateAccessDate("utimes(2) failed: \(ret.explanation())")
     }
   }
 }
diff --git a/Sources/tart/VMDirectory.swift b/Sources/tart/VMDirectory.swift
index 8ce8bce..617f72d 100644
--- a/Sources/tart/VMDirectory.swift
+++ b/Sources/tart/VMDirectory.swift
@@ -41,7 +41,7 @@ struct VMDirectory: Prunable {
 
   func initialize(overwrite: Bool = false) throws {
     if !overwrite && initialized {
-      throw RuntimeError("VM directory is already initialized, preventing overwrite")
+      throw RuntimeError.VMDirectoryAlreadyInitialized("VM directory is already initialized, preventing overwrite")
     }
 
     try FileManager.default.createDirectory(at: baseURL, withIntermediateDirectories: true, attributes: nil)
@@ -53,11 +53,11 @@ struct VMDirectory: Prunable {
 
   func validate() throws {
     if !FileManager.default.fileExists(atPath: baseURL.path) {
-      throw RuntimeError("the specified VM does not exist")
+      throw RuntimeError.VMDoesNotExist(name: baseURL.lastPathComponent)
     }
 
     if !initialized {
-      throw RuntimeError("VM is missing some of its files (\(configURL.lastPathComponent),"
+      throw RuntimeError.VMMissingFiles("VM is missing some of its files (\(configURL.lastPathComponent),"
         + " \(diskURL.lastPathComponent) or \(nvramURL.lastPathComponent))")
     }
   }
diff --git a/Sources/tart/VMStorageHelper.swift b/Sources/tart/VMStorageHelper.swift
index a214c69..2dde162 100644
--- a/Sources/tart/VMStorageHelper.swift
+++ b/Sources/tart/VMStorageHelper.swift
@@ -26,7 +26,7 @@ class VMStorageHelper {
       return try closure()
     } catch {
       if error.isFileNotFound() {
-        throw RuntimeError("source VM \"\(name)\" not found, is it listed in \"tart list\"?")
+        throw RuntimeError.VMDoesNotExist(name: name)
       }
 
       throw error
@@ -40,17 +40,66 @@ extension Error {
   }
 }
 
-class RuntimeError: Error, CustomStringConvertible {
-  let message: String
-  let exitCode: Int32
+enum RuntimeError : Error {
+  case VMDoesNotExist(name: String)
+  case VMMissingFiles(_ message: String)
+  case VMNotRunning(_ message: String)
+  case VMAlreadyRunning(_ message: String)
+  case NoIPAddressFound(_ message: String)
+  case DiskAlreadyInUse(_ message: String)
+  case FailedToUpdateAccessDate(_ message: String)
+  case PIDLockFailed(_ message: String)
+  case FailedToParseRemoteName(_ message: String)
+  case VMTerminationFailed(_ message: String)
+  case InvalidCredentials(_ message: String)
+  case VMDirectoryAlreadyInitialized(_ message: String)
+}
 
-  init(_ message: String, exitCode: Int32 = 1) {
-    self.message = message
-    self.exitCode = exitCode
+protocol HasExitCode {
+  var exitCode: Int32 { get }
+}
+
+extension RuntimeError : CustomStringConvertible {
+  public var description: String {
+    switch self {
+    case .VMDoesNotExist(let name):
+      return "the specified VM \"\(name)\" does not exist"
+    case .VMMissingFiles(let message):
+      return message
+    case .VMNotRunning(let message):
+      return message
+    case .VMAlreadyRunning(let message):
+      return message
+    case .NoIPAddressFound(let message):
+      return message
+    case .DiskAlreadyInUse(let message):
+      return message
+    case .FailedToUpdateAccessDate(let message):
+      return message
+    case .PIDLockFailed(let message):
+      return message
+    case .FailedToParseRemoteName(let cause):
+      return "failed to parse remote name: \(cause)"
+    case .VMTerminationFailed(let message):
+      return message
+    case .InvalidCredentials(let message):
+      return message
+    case .VMDirectoryAlreadyInitialized(let message):
+      return message
+    }
   }
+}
 
-  var description: String {
-    message
+extension RuntimeError : HasExitCode {
+  var exitCode: Int32 {
+    switch self {
+    case .VMNotRunning:
+      return 2
+    case .VMAlreadyRunning:
+      return 2
+    default:
+      return 1
+    }
   }
 }
 
@@ -60,7 +109,7 @@ class RuntimeError: Error, CustomStringConvertible {
 extension RuntimeError : CustomNSError {
   var errorUserInfo: [String : Any] {
     [
-      NSDebugDescriptionErrorKey: message,
+      NSDebugDescriptionErrorKey: description,
     ]
   }
 }