diff --git a/packages/devtools-rpc/src/client.ts b/packages/devtools-rpc/src/client.ts
index 15ad3ae4..fbe0fe7f 100644
--- a/packages/devtools-rpc/src/client.ts
+++ b/packages/devtools-rpc/src/client.ts
@@ -1,4 +1,4 @@
-import type { BirpcOptions } from 'birpc'
+import type { BirpcOptions, BirpcReturn } from 'birpc'
 import { createBirpc } from 'birpc'
 
 export function createRpcClient<
@@ -10,7 +10,7 @@ export function createRpcClient<
     preset: BirpcOptions<ServerFunctions>
     rpcOptions?: Partial<BirpcOptions<ServerFunctions>>
   },
-) {
+): BirpcReturn<ServerFunctions, ClientFunctions> {
   const { preset, rpcOptions = {} } = options
   return createBirpc<ServerFunctions, ClientFunctions>(functions, {
     ...preset,
diff --git a/packages/devtools-rpc/src/presets/ws/client.ts b/packages/devtools-rpc/src/presets/ws/client.ts
index 066b8733..a4640c5f 100644
--- a/packages/devtools-rpc/src/presets/ws/client.ts
+++ b/packages/devtools-rpc/src/presets/ws/client.ts
@@ -1,3 +1,4 @@
+import type { RpcClientPreset } from '..'
 import { parse, stringify } from 'structured-clone-es'
 import { defineRpcClientPreset } from '..'
 
@@ -10,7 +11,12 @@ export interface WebSocketRpcClientOptions {
 
 function NOOP() {}
 
-export const createWsRpcPreset = defineRpcClientPreset((options: WebSocketRpcClientOptions) => {
+export const createWsRpcPreset: RpcClientPreset<(options: WebSocketRpcClientOptions) => {
+  on: (handler: (data: string) => void) => void
+  post: (data: string) => void
+  serialize: (obj: any) => string
+  deserialize: (str: string) => unknown
+}> = defineRpcClientPreset((options: WebSocketRpcClientOptions) => {
   const ws = new WebSocket(options.url)
   const {
     onConnected = NOOP,
diff --git a/packages/devtools-rpc/src/presets/ws/server.ts b/packages/devtools-rpc/src/presets/ws/server.ts
index 1be309cc..26adcd50 100644
--- a/packages/devtools-rpc/src/presets/ws/server.ts
+++ b/packages/devtools-rpc/src/presets/ws/server.ts
@@ -1,5 +1,6 @@
 import type { BirpcGroup, BirpcOptions, ChannelOptions } from 'birpc'
 import type { WebSocket } from 'ws'
+import type { RpcServerPreset } from '..'
 import { parse, stringify } from 'structured-clone-es'
 import { WebSocketServer } from 'ws'
 import { defineRpcServerPreset } from '..'
@@ -12,7 +13,7 @@ export interface WebSocketRpcServerOptions {
 
 function NOOP() {}
 
-export const createWsRpcPreset = defineRpcServerPreset((options: WebSocketRpcServerOptions) => {
+export const createWsRpcPreset: RpcServerPreset<(options: WebSocketRpcServerOptions) => <ClientFunctions, ServerFunctions>(rpc: BirpcGroup<ClientFunctions, ServerFunctions>, options?: Pick<BirpcOptions<ClientFunctions>, 'serialize' | 'deserialize'>) => void> = defineRpcServerPreset((options: WebSocketRpcServerOptions) => {
   const {
     port,
     onConnected = NOOP,
diff --git a/packages/devtools-rpc/src/server.ts b/packages/devtools-rpc/src/server.ts
index 4c1c31a6..8db87a71 100644
--- a/packages/devtools-rpc/src/server.ts
+++ b/packages/devtools-rpc/src/server.ts
@@ -10,7 +10,7 @@ export function createRpcServer<
     preset: (rpc: BirpcGroup<ClientFunctions, ServerFunctions>) => void
     rpcOptions?: EventOptions<ClientFunctions>
   },
-) {
+): BirpcGroup<ClientFunctions, ServerFunctions> {
   const rpc = createBirpcGroup<ClientFunctions, ServerFunctions>(functions, [], options?.rpcOptions ?? {})
   options?.preset(rpc)
 
diff --git a/packages/devtools-rpc/tsdown.config.ts b/packages/devtools-rpc/tsdown.config.ts
index 34ed6d67..9aac4673 100644
--- a/packages/devtools-rpc/tsdown.config.ts
+++ b/packages/devtools-rpc/tsdown.config.ts
@@ -6,9 +6,11 @@ export default defineConfig([{
   ],
   clean: true,
   fixedExtension: true,
+  dts: { isolatedDeclarations: true },
 }, {
   entry: ['src/presets/ws/client.ts', 'src/presets/ws/server.ts', 'src/presets/index.ts'],
   clean: true,
   fixedExtension: true,
   outDir: 'dist/presets',
+  dts: { isolatedDeclarations: true },
 }])
diff --git a/packages/devtools/src/dirs.ts b/packages/devtools/src/dirs.ts
index c4e56e5a..4258d9c3 100644
--- a/packages/devtools/src/dirs.ts
+++ b/packages/devtools/src/dirs.ts
@@ -1,3 +1,3 @@
 import { fileURLToPath } from 'node:url'
 
-export const distDir = fileURLToPath(new URL('../dist/public', import.meta.url))
+export const distDir: string = fileURLToPath(new URL('../dist/public', import.meta.url))
diff --git a/packages/devtools/tsdown.config.ts b/packages/devtools/tsdown.config.ts
index dc375b49..69c8fa99 100644
--- a/packages/devtools/tsdown.config.ts
+++ b/packages/devtools/tsdown.config.ts
@@ -11,4 +11,5 @@ export default defineConfig({
   clean: false,
   target: 'esnext',
   fixedExtension: true,
+  dts: { isolatedDeclarations: true },
 })