diff --git a/src/BotApiError.ts b/src/BotApiError.ts
index d5757ea..b0a0561 100644
--- a/src/BotApiError.ts
+++ b/src/BotApiError.ts
@@ -9,7 +9,7 @@ import * as Predicate from 'effect/Predicate'
 import * as Dialog from './Dialog.ts'
 import * as internal from './internal/botApiError.ts'
 
-export const TypeId = '@grom.js/effect-tg/BotApiError'
+export const TypeId: unique symbol = Symbol.for('@grom.js/effect-tg/BotApiError')
 
 export type TypeId = typeof TypeId
 
@@ -32,7 +32,7 @@ export class TransportError extends Data.TaggedError('TransportError')<{
 }> {
   readonly [TypeId]: TypeId = TypeId
 
-  override get message() {
+  override get message(): string {
     return Match.value(this.cause).pipe(
       Match.tagsExhaustive({
         RequestError: e => e.message,
diff --git a/src/Content.ts b/src/Content.ts
index 5c941ef..8e5bc7d 100644
--- a/src/Content.ts
+++ b/src/Content.ts
@@ -214,7 +214,7 @@ export const text = (
   options?: {
     linkPreview?: LinkPreview.LinkPreview
   },
-) => new Text({
+): Text => new Text({
   text,
   linkPreview: Option.fromNullable(options?.linkPreview),
 })
diff --git a/src/Dialog.ts b/src/Dialog.ts
index 0ab4846..48b3d52 100644
--- a/src/Dialog.ts
+++ b/src/Dialog.ts
@@ -93,19 +93,19 @@ export class Supergroup extends Data.TaggedClass('Supergroup')<{
  * @see {@link https://core.telegram.org/api/bots/ids Telegram API • Bot API dialog IDs}
  */
 export type DialogId = number & Brand.Brand<'@grom.js/effect-tg/DialogId'>
-export const DialogId = Brand.refined<DialogId>(
+export const DialogId: Brand.Brand.Constructor<DialogId> = Brand.refined<DialogId>(
   n => Option.isSome(internal.decodeDialogId(n)),
   n => Brand.error(`Invalid dialog ID: ${n}`),
 )
 
 export type UserId = number & Brand.Brand<'@grom.js/effect-tg/UserId'>
-export const UserId = Brand.refined<UserId>(
+export const UserId: Brand.Brand.Constructor<UserId> = Brand.refined<UserId>(
   n => Option.isSome(internal.encodePeerId('user', n)),
   n => Brand.error(`Invalid user ID: ${n}`),
 )
 
 export type GroupId = number & Brand.Brand<'@grom.js/effect-tg/GroupId'>
-export const GroupId = Brand.refined<GroupId>(
+export const GroupId: Brand.Brand.Constructor<GroupId> = Brand.refined<GroupId>(
   n => Option.isSome(internal.encodePeerId('group', n)),
   n => Brand.error(`Invalid group ID: ${n}`),
 )
@@ -116,7 +116,7 @@ export const GroupId = Brand.refined<GroupId>(
  * @see {@link https://core.telegram.org/api/bots/ids Telegram API • Bot API dialog IDs}
  */
 export type ChannelId = number & Brand.Brand<'@grom.js/effect-tg/ChannelId'>
-export const ChannelId = Brand.refined<ChannelId>(
+export const ChannelId: Brand.Brand.Constructor<ChannelId> = Brand.refined<ChannelId>(
   n => Option.isSome(internal.encodePeerId('channel', n)),
   n => Brand.error(`Invalid channel or supergroup ID: ${n}`),
 )
@@ -125,7 +125,7 @@ export const ChannelId = Brand.refined<ChannelId>(
 export type SupergroupId = ChannelId
 
 /** @alias ChannelId */
-export const SupergroupId = ChannelId
+export const SupergroupId: Brand.Brand.Constructor<ChannelId> = ChannelId
 
 // =============================================================================
 // Dialog ID <-> Peer ID
diff --git a/src/File.ts b/src/File.ts
index 8cf39d6..1332757 100644
--- a/src/File.ts
+++ b/src/File.ts
@@ -11,10 +11,10 @@ import * as Data from 'effect/Data'
 import * as internal from './internal/file.ts'
 
 export type FileId = string & Brand.Brand<'FileId'>
-export const FileId = Brand.nominal<FileId>()
+export const FileId: Brand.Brand.Constructor<FileId> = Brand.nominal<FileId>()
 
 export type External = URL & Brand.Brand<'External'>
-export const External = Brand.nominal<External>()
+export const External: Brand.Brand.Constructor<External> = Brand.nominal<External>()
 
 export class InputFile extends Data.TaggedClass('InputFile')<{
   stream: Stream.Stream<Uint8Array>
diff --git a/src/Runner.ts b/src/Runner.ts
index 7d1b84e..0399f1b 100644
--- a/src/Runner.ts
+++ b/src/Runner.ts
@@ -1,5 +1,7 @@
 import type * as Effect from 'effect/Effect'
 import type * as Bot from './Bot.ts'
+import type * as BotApi from './BotApi.ts'
+import type * as BotApiError from './BotApiError.ts'
 import * as internal from './internal/runner.ts'
 
 /**
@@ -19,4 +21,6 @@ export interface Runner<E = never, R = never> {
  * Creates a simple runner that fetches updates by calling `BotApi.getUpdates`
  * method and handles them one by one.
  */
-export const makeSimple = internal.makeSimple
+export const makeSimple: (options?: {
+  allowedUpdates?: string[]
+}) => Runner<BotApiError.BotApiError, BotApi.BotApi> = internal.makeSimple
diff --git a/src/internal/file.ts b/src/internal/file.ts
index 96f6b8b..aaefa8c 100644
--- a/src/internal/file.ts
+++ b/src/internal/file.ts
@@ -1,11 +1,18 @@
-import type { FileId } from '../File.ts'
+import type * as HttpClientError from '@effect/platform/HttpClientError'
+import type * as HttpClientResponse from '@effect/platform/HttpClientResponse'
+import type * as BotApiError from '../BotApiError.ts'
+import type * as File from '../File.ts'
 import * as HttpClient from '@effect/platform/HttpClient'
 import * as Effect from 'effect/Effect'
 import * as BotApi from '../BotApi.ts'
 import * as BotApiUrl from '../BotApiUrl.ts'
 
-export const download = Effect.fnUntraced(
-  function* (fileId: FileId) {
+export const download: (fileId: File.FileId) => Effect.Effect<
+  HttpClientResponse.HttpClientResponse,
+  BotApiError.BotApiError | HttpClientError.HttpClientError,
+  BotApi.BotApi | BotApiUrl.BotApiUrl | HttpClient.HttpClient
+> = Effect.fnUntraced(
+  function* (fileId) {
     const file = yield* BotApi.callMethod('getFile', { file_id: fileId })
     if (file.file_path == null) {
       return yield* Effect.die(new Error(`Bot API returned no file path for file "${fileId}".`))
diff --git a/src/internal/send.ts b/src/internal/send.ts
index e1986a3..7d613b5 100644
--- a/src/internal/send.ts
+++ b/src/internal/send.ts
@@ -1,3 +1,5 @@
+import type * as Effect from 'effect/Effect'
+import type * as BotApiError from '../BotApiError.ts'
 import type * as Content from '../Content.ts'
 import type * as Dialog from '../Dialog.ts'
 import type * as Markup from '../Markup.ts'
@@ -7,7 +9,6 @@ import type * as Text from '../Text.ts'
 import type { Types } from './botApi.gen.ts'
 import * as Tgx from '@grom.js/tgx'
 import * as Duration from 'effect/Duration'
-import * as Effect from 'effect/Effect'
 import * as Match from 'effect/Match'
 import * as Option from 'effect/Option'
 import * as BotApi from '../BotApi.ts'
@@ -491,21 +492,29 @@ const paramsOptions = (options: Send.Options): ParamsOptions => {
 // Send Methods
 // =============================================================================
 
-export const sendMessage = Effect.fnUntraced(function* (params: {
+export const sendMessage: (params: {
   content: Content.Content
   dialog: Dialog.Dialog | Dialog.DialogId
   markup?: Markup.Markup
   reply?: Reply.Reply
   options?: Send.Options
-}) {
-  return yield* BotApi.callMethod(
-    methodByContent[params.content._tag],
-    {
-      ...paramsContent(params.content),
-      ...paramsDialog(params.dialog),
-      ...(params.markup ? paramsMarkup(params.markup) : {}),
-      ...(params.reply ? paramsReply(params.reply) : {}),
-      ...(params.options ? paramsOptions(params.options) : {}),
-    },
-  )
-})
+}) => Effect.Effect<
+  Types.Message,
+  BotApiError.BotApiError,
+  BotApi.BotApi
+> = ({
+  content,
+  dialog,
+  markup,
+  reply,
+  options,
+}) => BotApi.callMethod(
+  methodByContent[content._tag],
+  {
+    ...paramsContent(content),
+    ...paramsDialog(dialog),
+    ...(markup ? paramsMarkup(markup) : {}),
+    ...(reply ? paramsReply(reply) : {}),
+    ...(options ? paramsOptions(options) : {}),
+  },
+)
diff --git a/tsconfig.lib.json b/tsconfig.lib.json
index 6608030..1a34992 100644
--- a/tsconfig.lib.json
+++ b/tsconfig.lib.json
@@ -50,6 +50,7 @@
     "outDir": "dist",
     "sourceMap": true,
     "forceConsistentCasingInFileNames": true,
+    "isolatedDeclarations": true,
     "verbatimModuleSyntax": true,
     "skipLibCheck": true
   },