diff --git a/.changeset/wet-laws-smoke.md b/.changeset/wet-laws-smoke.md
new file mode 100644
index 0000000000..fad3f205c1
--- /dev/null
+++ b/.changeset/wet-laws-smoke.md
@@ -0,0 +1,8 @@
+---
+"@effect/platform": patch
+"effect": patch
+"@effect/cli": patch
+"@effect/rpc": patch
+---
+
+Changed various function signatures to return `Array` instead of `ReadonlyArray`
diff --git a/packages/cli/src/internal/commandDescriptor.ts b/packages/cli/src/internal/commandDescriptor.ts
index 00ed9ace1f..49c1366801 100644
--- a/packages/cli/src/internal/commandDescriptor.ts
+++ b/packages/cli/src/internal/commandDescriptor.ts
@@ -512,7 +512,7 @@ const parseInternal = (
     case "Standard": {
       const parseCommandLine = (
         args: ReadonlyArray<string>
-      ): Effect.Effect<ReadonlyArray<string>, ValidationError.ValidationError> =>
+      ): Effect.Effect<Array<string>, ValidationError.ValidationError> =>
         Arr.matchLeft(args, {
           onEmpty: () => {
             const error = InternalHelpDoc.p(`Missing command name: '${self.name}'`)
diff --git a/packages/effect/src/ConfigProvider.ts b/packages/effect/src/ConfigProvider.ts
index 57c11d8541..001d6ac570 100644
--- a/packages/effect/src/ConfigProvider.ts
+++ b/packages/effect/src/ConfigProvider.ts
@@ -81,7 +81,7 @@ export declare namespace ConfigProvider {
       path: ReadonlyArray<string>,
       config: Config.Config.Primitive<A>,
       split?: boolean
-    ): Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+    ): Effect.Effect<Array<A>, ConfigError.ConfigError>
     enumerateChildren(
       path: ReadonlyArray<string>
     ): Effect.Effect<HashSet.HashSet<string>, ConfigError.ConfigError>
@@ -162,7 +162,7 @@ export const makeFlat: (options: {
     path: ReadonlyArray<string>,
     config: Config.Config.Primitive<A>,
     split: boolean
-  ) => Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+  ) => Effect.Effect<Array<A>, ConfigError.ConfigError>
   readonly enumerateChildren: (
     path: ReadonlyArray<string>
   ) => Effect.Effect<HashSet.HashSet<string>, ConfigError.ConfigError>
diff --git a/packages/effect/src/Metric.ts b/packages/effect/src/Metric.ts
index be6d1cb2d4..cd33096579 100644
--- a/packages/effect/src/Metric.ts
+++ b/packages/effect/src/Metric.ts
@@ -361,7 +361,7 @@ export const set: {
  * @since 2.0.0
  * @category getters
  */
-export const snapshot: Effect.Effect<ReadonlyArray<MetricPair.MetricPair.Untyped>> = internal.snapshot
+export const snapshot: Effect.Effect<Array<MetricPair.MetricPair.Untyped>> = internal.snapshot
 
 /**
  * Creates a metric that ignores input and produces constant output.
diff --git a/packages/effect/src/MetricRegistry.ts b/packages/effect/src/MetricRegistry.ts
index 0d2c239602..e43d8519b5 100644
--- a/packages/effect/src/MetricRegistry.ts
+++ b/packages/effect/src/MetricRegistry.ts
@@ -25,7 +25,7 @@ export type MetricRegistryTypeId = typeof MetricRegistryTypeId
  */
 export interface MetricRegistry {
   readonly [MetricRegistryTypeId]: MetricRegistryTypeId
-  snapshot(): ReadonlyArray<MetricPair.MetricPair.Untyped>
+  snapshot(): Array<MetricPair.MetricPair.Untyped>
   get<Type extends MetricKeyType.MetricKeyType<any, any>>(
     key: MetricKey.MetricKey<Type>
   ): MetricHook.MetricHook<
diff --git a/packages/effect/src/internal/configProvider.ts b/packages/effect/src/internal/configProvider.ts
index e30a3cb010..fe8a0f9227 100644
--- a/packages/effect/src/internal/configProvider.ts
+++ b/packages/effect/src/internal/configProvider.ts
@@ -68,7 +68,7 @@ export const makeFlat = (
       path: ReadonlyArray<string>,
       config: Config.Config.Primitive<A>,
       split: boolean
-    ) => Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+    ) => Effect.Effect<Array<A>, ConfigError.ConfigError>
     readonly enumerateChildren: (
       path: ReadonlyArray<string>
     ) => Effect.Effect<HashSet.HashSet<string>, ConfigError.ConfigError>
@@ -114,7 +114,7 @@ export const fromEnv = (
     path: ReadonlyArray<string>,
     primitive: Config.Config.Primitive<A>,
     split = true
-  ): Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError> => {
+  ): Effect.Effect<Array<A>, ConfigError.ConfigError> => {
     const pathString = makePathString(path)
     const current = getEnv()
     const valueOpt = pathString in current ? Option.some(current[pathString]!) : Option.none()
@@ -165,7 +165,7 @@ export const fromMap = (
     path: ReadonlyArray<string>,
     primitive: Config.Config.Primitive<A>,
     split = true
-  ): Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError> => {
+  ): Effect.Effect<Array<A>, ConfigError.ConfigError> => {
     const pathString = makePathString(path)
     const valueOpt = mapWithIndexSplit.has(pathString) ?
       Option.some(mapWithIndexSplit.get(pathString)!) :
@@ -240,20 +240,20 @@ const fromFlatLoop = <A>(
   prefix: ReadonlyArray<string>,
   config: Config.Config<A>,
   split: boolean
-): Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError> => {
+): Effect.Effect<Array<A>, ConfigError.ConfigError> => {
   const op = config as _config.ConfigPrimitive
   switch (op._tag) {
     case OpCodes.OP_CONSTANT: {
-      return core.succeed(Arr.of(op.value)) as Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+      return core.succeed(Arr.of(op.value)) as Effect.Effect<Array<A>, ConfigError.ConfigError>
     }
     case OpCodes.OP_DESCRIBED: {
       return core.suspend(
         () => fromFlatLoop(flat, prefix, op.config, split)
-      ) as unknown as Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+      ) as unknown as Effect.Effect<Array<A>, ConfigError.ConfigError>
     }
     case OpCodes.OP_FAIL: {
       return core.fail(configError.MissingData(prefix, op.message)) as Effect.Effect<
-        ReadonlyArray<A>,
+        Array<A>,
         ConfigError.ConfigError
       >
     }
@@ -269,11 +269,11 @@ const fromFlatLoop = <A>(
           }
           return core.fail(error1)
         })
-      ) as unknown as Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+      ) as unknown as Effect.Effect<Array<A>, ConfigError.ConfigError>
     }
     case OpCodes.OP_LAZY: {
       return core.suspend(() => fromFlatLoop(flat, prefix, op.config(), split)) as Effect.Effect<
-        ReadonlyArray<A>,
+        Array<A>,
         ConfigError.ConfigError
       >
     }
@@ -290,7 +290,7 @@ const fromFlatLoop = <A>(
             )
           )
         )
-      ) as unknown as Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+      ) as unknown as Effect.Effect<Array<A>, ConfigError.ConfigError>
     }
     case OpCodes.OP_NESTED: {
       return core.suspend(() =>
@@ -300,7 +300,7 @@ const fromFlatLoop = <A>(
           op.config,
           split
         )
-      ) as unknown as Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+      ) as unknown as Effect.Effect<Array<A>, ConfigError.ConfigError>
     }
     case OpCodes.OP_PRIMITIVE: {
       return pipe(
@@ -317,7 +317,7 @@ const fromFlatLoop = <A>(
             })
           )
         )
-      ) as unknown as Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+      ) as unknown as Effect.Effect<Array<A>, ConfigError.ConfigError>
     }
     case OpCodes.OP_SEQUENCE: {
       return pipe(
@@ -330,7 +330,7 @@ const fromFlatLoop = <A>(
               if (indices.length === 0) {
                 return core.suspend(() =>
                   core.map(fromFlatLoop(flat, patchedPrefix, op.config, true), Arr.of)
-                ) as unknown as Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+                ) as unknown as Effect.Effect<Array<A>, ConfigError.ConfigError>
               }
               return pipe(
                 core.forEachSequential(
@@ -344,7 +344,7 @@ const fromFlatLoop = <A>(
                   }
                   return Arr.of(flattened)
                 })
-              ) as unknown as Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+              ) as unknown as Effect.Effect<Array<A>, ConfigError.ConfigError>
             })
           )
         )
@@ -382,7 +382,7 @@ const fromFlatLoop = <A>(
             )
           )
         )
-      ) as unknown as Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+      ) as unknown as Effect.Effect<Array<A>, ConfigError.ConfigError>
     }
     case OpCodes.OP_ZIP_WITH: {
       return core.suspend(() =>
@@ -430,7 +430,7 @@ const fromFlatLoop = <A>(
             )
           )
         )
-      ) as unknown as Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError>
+      ) as unknown as Effect.Effect<Array<A>, ConfigError.ConfigError>
     }
   }
 }
@@ -592,7 +592,7 @@ export const within = dual<
   return orElse(nest, () => self)
 })
 
-const splitPathString = (text: string, delim: string): ReadonlyArray<string> => {
+const splitPathString = (text: string, delim: string): Array<string> => {
   const split = text.split(new RegExp(`\\s*${regexp.escape(delim)}\\s*`))
   return split
 }
@@ -603,7 +603,7 @@ const parsePrimitive = <A>(
   primitive: Config.Config.Primitive<A>,
   delimiter: string,
   split: boolean
-): Effect.Effect<ReadonlyArray<A>, ConfigError.ConfigError> => {
+): Effect.Effect<Array<A>, ConfigError.ConfigError> => {
   if (!split) {
     return pipe(
       primitive.parse(text),
@@ -620,11 +620,11 @@ const parsePrimitive = <A>(
   )
 }
 
-const transpose = <A>(array: ReadonlyArray<ReadonlyArray<A>>): ReadonlyArray<ReadonlyArray<A>> => {
+const transpose = <A>(array: ReadonlyArray<ReadonlyArray<A>>): Array<Array<A>> => {
   return Object.keys(array[0]).map((column) => array.map((row) => row[column as any]))
 }
 
-const indicesFrom = (quotedIndices: HashSet.HashSet<string>): Effect.Effect<ReadonlyArray<number>> =>
+const indicesFrom = (quotedIndices: HashSet.HashSet<string>): Effect.Effect<Array<number>> =>
   pipe(
     core.forEachSequential(quotedIndices, parseQuotedIndex),
     core.mapBoth({
diff --git a/packages/effect/src/internal/metric.ts b/packages/effect/src/internal/metric.ts
index 43f0b2d9f9..3830e78338 100644
--- a/packages/effect/src/internal/metric.ts
+++ b/packages/effect/src/internal/metric.ts
@@ -525,9 +525,9 @@ export const zip = dual<
 )
 
 /** @internal */
-export const unsafeSnapshot = (): ReadonlyArray<MetricPair.MetricPair.Untyped> => globalMetricRegistry.snapshot()
+export const unsafeSnapshot = (): Array<MetricPair.MetricPair.Untyped> => globalMetricRegistry.snapshot()
 
 /** @internal */
-export const snapshot: Effect.Effect<ReadonlyArray<MetricPair.MetricPair.Untyped>> = core.sync(
+export const snapshot: Effect.Effect<Array<MetricPair.MetricPair.Untyped>> = core.sync(
   unsafeSnapshot
 )
diff --git a/packages/effect/src/internal/metric/registry.ts b/packages/effect/src/internal/metric/registry.ts
index beef571737..4417acafbc 100644
--- a/packages/effect/src/internal/metric/registry.ts
+++ b/packages/effect/src/internal/metric/registry.ts
@@ -27,7 +27,7 @@ class MetricRegistryImpl implements MetricRegistry.MetricRegistry {
     MetricHook.MetricHook.Root
   >()
 
-  snapshot(): ReadonlyArray<MetricPair.MetricPair.Untyped> {
+  snapshot(): Array<MetricPair.MetricPair.Untyped> {
     const result: Array<MetricPair.MetricPair.Untyped> = []
     for (const [key, hook] of this.map) {
       result.push(metricPair.unsafeMake(key, hook.get()))
diff --git a/packages/platform/README.md b/packages/platform/README.md
index 41c7e27c0b..1234cad7bf 100644
--- a/packages/platform/README.md
+++ b/packages/platform/README.md
@@ -295,7 +295,7 @@ Here's a list of operations that can be performed using the `FileSystem` tag:
 | **makeTempFile**            | `options?: MakeTempFileOptions`                                  | `Effect<string, PlatformError>`                | Create a temporary file. The directory creation is functionally equivalent to `makeTempDirectory`. The file name will be a randomly generated string.                  |
 | **makeTempFileScoped**      | `options?: MakeTempFileOptions`                                  | `Effect<string, PlatformError, Scope>`         | Create a temporary file inside a scope. Functionally equivalent to `makeTempFile`, but the file will be automatically deleted when the scope is closed.                |
 | **open**                    | `path: string`, `options?: OpenFileOptions`                      | `Effect<File, PlatformError, Scope>`           | Open a file at `path` with the specified `options`. The file handle will be automatically closed when the scope is closed.                                             |
-| **readDirectory**           | `path: string`, `options?: ReadDirectoryOptions`                 | `Effect<ReadonlyArray<string>, PlatformError>` | List the contents of a directory. You can recursively list the contents of nested directories by setting the `recursive` option.                                       |
+| **readDirectory**           | `path: string`, `options?: ReadDirectoryOptions`                 | `Effect<Array<string>, PlatformError>` | List the contents of a directory. You can recursively list the contents of nested directories by setting the `recursive` option.                                       |
 | **readFile**                | `path: string`                                                   | `Effect<Uint8Array, PlatformError>`            | Read the contents of a file.                                                                                                                                           |
 | **readFileString**          | `path: string`, `encoding?: string`                              | `Effect<string, PlatformError>`                | Read the contents of a file as a string.                                                                                                                               |
 | **readLink**                | `path: string`                                                   | `Effect<string, PlatformError>`                | Read the destination of a symbolic link.                                                                                                                               |
diff --git a/packages/platform/src/Command.ts b/packages/platform/src/Command.ts
index f224fd4e97..d9eb48c751 100644
--- a/packages/platform/src/Command.ts
+++ b/packages/platform/src/Command.ts
@@ -172,7 +172,7 @@ export const flatten: (self: Command) => NonEmptyReadonlyArray<StandardCommand>
 export const lines: (
   command: Command,
   encoding?: string
-) => Effect<ReadonlyArray<string>, PlatformError, CommandExecutor> = internal.lines
+) => Effect<Array<string>, PlatformError, CommandExecutor> = internal.lines
 
 /**
  * Create a command with the specified process name and an optional list of
diff --git a/packages/platform/src/CommandExecutor.ts b/packages/platform/src/CommandExecutor.ts
index bea7f74053..85ff4ae63b 100644
--- a/packages/platform/src/CommandExecutor.ts
+++ b/packages/platform/src/CommandExecutor.ts
@@ -52,7 +52,7 @@ export interface CommandExecutor {
    *
    * If an encoding is not specified, the encoding will default to `utf-8`.
    */
-  readonly lines: (command: Command, encoding?: string) => Effect<ReadonlyArray<string>, PlatformError>
+  readonly lines: (command: Command, encoding?: string) => Effect<Array<string>, PlatformError>
   /**
    * Runs the command returning the output as a `Stream`.
    */
diff --git a/packages/platform/src/FileSystem.ts b/packages/platform/src/FileSystem.ts
index fb1babaf72..db9ed8f589 100644
--- a/packages/platform/src/FileSystem.ts
+++ b/packages/platform/src/FileSystem.ts
@@ -137,7 +137,7 @@ export interface FileSystem {
   readonly readDirectory: (
     path: string,
     options?: ReadDirectoryOptions
-  ) => Effect.Effect<ReadonlyArray<string>, PlatformError>
+  ) => Effect.Effect<Array<string>, PlatformError>
   /**
    * Read the contents of a file.
    */
diff --git a/packages/platform/src/Transferable.ts b/packages/platform/src/Transferable.ts
index b7cb9e3cd4..13f4d31466 100644
--- a/packages/platform/src/Transferable.ts
+++ b/packages/platform/src/Transferable.ts
@@ -15,8 +15,8 @@ import * as Option from "effect/Option"
 export interface CollectorService {
   readonly addAll: (_: Iterable<globalThis.Transferable>) => Effect.Effect<void>
   readonly unsafeAddAll: (_: Iterable<globalThis.Transferable>) => void
-  readonly read: Effect.Effect<ReadonlyArray<globalThis.Transferable>>
-  readonly unsafeRead: () => ReadonlyArray<globalThis.Transferable>
+  readonly read: Effect.Effect<Array<globalThis.Transferable>>
+  readonly unsafeRead: () => Array<globalThis.Transferable>
   readonly unsafeClear: () => void
   readonly clear: Effect.Effect<void>
 }
@@ -41,7 +41,7 @@ export const unsafeMakeCollector = (): CollectorService => {
       tranferables.push(transfer)
     }
   }
-  const unsafeRead = (): ReadonlyArray<globalThis.Transferable> => tranferables
+  const unsafeRead = (): Array<globalThis.Transferable> => tranferables
   const unsafeClear = (): void => {
     tranferables.length = 0
   }
diff --git a/packages/platform/src/internal/command.ts b/packages/platform/src/internal/command.ts
index b8ef6ec47b..3dad65929e 100644
--- a/packages/platform/src/internal/command.ts
+++ b/packages/platform/src/internal/command.ts
@@ -98,7 +98,7 @@ export const runInShell = dual<
 export const lines = (
   command: Command.Command,
   encoding = "utf-8"
-): Effect.Effect<ReadonlyArray<string>, PlatformError, CommandExecutor.CommandExecutor> =>
+): Effect.Effect<Array<string>, PlatformError, CommandExecutor.CommandExecutor> =>
   Effect.flatMap(commandExecutor.CommandExecutor, (executor) => executor.lines(command, encoding))
 
 const Proto = {
diff --git a/packages/platform/src/internal/commandExecutor.ts b/packages/platform/src/internal/commandExecutor.ts
index f56979a4b4..1ae82c8497 100644
--- a/packages/platform/src/internal/commandExecutor.ts
+++ b/packages/platform/src/internal/commandExecutor.ts
@@ -52,7 +52,7 @@ export const makeExecutor = (start: _CommandExecutor.CommandExecutor["start"]):
       return pipe(
         streamLines(command, encoding),
         Stream.runCollect,
-        Effect.map(Chunk.toReadonlyArray)
+        Effect.map(Chunk.toArray)
       )
     },
     streamLines
diff --git a/packages/rpc/src/Router.ts b/packages/rpc/src/Router.ts
index 2b2b49c97e..786007341e 100644
--- a/packages/rpc/src/Router.ts
+++ b/packages/rpc/src/Router.ts
@@ -317,7 +317,7 @@ export const toHandlerEffect = <R extends Router<any, any>>(router: R, options?:
   const getEncode = withRequestTag((req) => Schema.encode(Serializable.exitSchema(req)))
   const getEncodeChunk = withRequestTag((req) => Schema.encode(Schema.Chunk(Serializable.exitSchema(req))))
 
-  return (u: unknown): Effect.Effect<ReadonlyArray<Router.ResponseEffect>, ParseError, Router.Context<R>> =>
+  return (u: unknown): Effect.Effect<Array<Router.ResponseEffect>, ParseError, Router.Context<R>> =>
     Effect.flatMap(
       decode(u),
       Effect.forEach((req): Effect.Effect<Router.ResponseEffect, ParseError, any> => {