diff --git a/framework/framework/api.ts b/framework/framework/api.ts
index 54b522f8b..231d3cc50 100644
--- a/framework/framework/api.ts
+++ b/framework/framework/api.ts
@@ -187,7 +187,7 @@ declare module 'cordis' {
     }
 }
 
-export class ApiHandler<C extends Context> extends Handler<C> {
+export class ApiHandler extends Handler {
     @param('op', Types.String)
     async all({ }, op: string) {
         if (!['get', 'post'].includes(this.request.method.toLowerCase())) {
@@ -219,7 +219,7 @@ export class ApiHandler<C extends Context> extends Handler<C> {
     }
 }
 
-export class ApiConnectionHandler<C extends Context> extends ConnectionHandler<C> {
+export class ApiConnectionHandler extends ConnectionHandler {
     dispose: () => Promise<void> | void;
     isRpc: boolean;
 
diff --git a/framework/framework/decorators.ts b/framework/framework/decorators.ts
index 1235bcf34..d7b92854a 100644
--- a/framework/framework/decorators.ts
+++ b/framework/framework/decorators.ts
@@ -1,4 +1,3 @@
-import { Context } from 'cordis';
 import Schema from 'schemastery';
 import { ValidationError } from './error';
 import type { Handler } from './server';
@@ -57,7 +56,7 @@ function _buildParam(name: string, source: 'get' | 'post' | 'all' | 'route', ...
 }
 
 function _descriptor(v: ParamOption<any>) {
-    return function desc<T extends Context>(this: Handler<T>, target: any, funcName: string, obj: any) {
+    return function desc(this: Handler, target: any, funcName: string, obj: any) {
         target.__param ||= {};
         target.__param[target.constructor.name] ||= {};
         if (!target.__param[target.constructor.name][funcName]) {
@@ -66,7 +65,7 @@ function _descriptor(v: ParamOption<any>) {
             const firstArg = val.split(')')[0]?.split(',')[0]?.split('(')[1]?.trim() || '';
             const domainIdStyle = firstArg.toLowerCase().startsWith('domainid');
             target.__param[target.constructor.name][funcName] = [];
-            obj.value = function validate(this: Handler<T>, rawArgs: any, ...extra: any[]) {
+            obj.value = function validate(this: Handler, rawArgs: any, ...extra: any[]) {
                 if (typeof rawArgs !== 'object' || extra.length) return originalMethod.call(this, rawArgs, ...extra);
                 const c = [];
                 const arglist: ParamOption<any>[] = target.__param[target.constructor.name][funcName];
diff --git a/framework/framework/interface.ts b/framework/framework/interface.ts
index 1aa0a5f94..358b31681 100644
--- a/framework/framework/interface.ts
+++ b/framework/framework/interface.ts
@@ -1,4 +1,3 @@
-import type { Context } from 'cordis';
 import type { ApiHandler } from './api';
 import type { ConnectionHandler, Handler, NotFoundHandler } from './server';
 
@@ -6,7 +5,7 @@ export interface KnownHandlers {
     NotFound: NotFoundHandler;
 }
 
-type MapHandlerEvents<N extends string, H extends Handler<any>> =
+type MapHandlerEvents<N extends string, H extends Handler> =
     Record<`handler/${HookType}/${N}`, (thisArg: H) => VoidReturn>
     & Record<`handler/${HookWithMethod}/${N}/${Methods}`, (thisArg: H) => VoidReturn>;
 
@@ -14,8 +13,8 @@ type KnownHandlerEvents = {
     [key in keyof KnownHandlers]: MapHandlerEvents<key, KnownHandlers[key]>
 }[keyof KnownHandlers];
 
-type HandlerEvents<C> =
-    Record<`handler/${HookType}`, (thisArg: Handler<C>) => VoidReturn>
+type HandlerEvents =
+    Record<`handler/${HookType}`, (thisArg: Handler) => VoidReturn>
     & Record<`connection/${'create' | 'active' | 'close'}`, (thisArg: any) => VoidReturn>;
 
 export type VoidReturn = Promise<any> | any;
@@ -23,23 +22,23 @@ export type HookType = 'before-prepare' | 'before' | 'before-operation' | 'after
 export type Methods = 'get' | 'post' | 'put' | 'delete' | 'patch';
 export type HookWithMethod = Exclude<HookType, 'before-operation'>;
 
-export interface ServerEvents<C extends Context> extends KnownHandlerEvents, HandlerEvents<C> {
-    'handler/create': (thisArg: Handler<C> | ConnectionHandler<C>, type: 'ws' | 'http') => VoidReturn;
-    'handler/create/http': (thisArg: Handler<C>) => VoidReturn;
-    'handler/create/ws': (thisArg: ConnectionHandler<C>) => VoidReturn;
-    'handler/init': (thisArg: Handler<C>) => VoidReturn;
-    'handler/error': (thisArg: Handler<C> | ConnectionHandler<C>, e: Error) => VoidReturn;
-    'handler/api/before': (thisArg: ApiHandler<C>) => VoidReturn;
+export interface ServerEvents extends KnownHandlerEvents, HandlerEvents {
+    'handler/create': (thisArg: Handler | ConnectionHandler, type: 'ws' | 'http') => VoidReturn;
+    'handler/create/http': (thisArg: Handler) => VoidReturn;
+    'handler/create/ws': (thisArg: ConnectionHandler) => VoidReturn;
+    'handler/init': (thisArg: Handler) => VoidReturn;
+    'handler/error': (thisArg: Handler | ConnectionHandler, e: Error) => VoidReturn;
+    'handler/api/before': (thisArg: ApiHandler) => VoidReturn;
     'api/before': (args: any) => VoidReturn;
     [k: `handler/${HookType}/${string}`]: (thisArg: any) => VoidReturn;
     [k: `handler/${HookWithMethod}/${string}/${Methods}`]: (thisArg: any) => VoidReturn;
     [k: `handler/register/${string}`]: (HandlerClass: new (...args: any[]) => any) => VoidReturn;
-    [k: `handler/error/${string}`]: (thisArg: Handler<C>, e: Error) => VoidReturn;
-    [k: `handler/api/before/${string}`]: (thisArg: ApiHandler<C>) => VoidReturn;
+    [k: `handler/error/${string}`]: (thisArg: Handler, e: Error) => VoidReturn;
+    [k: `handler/api/before/${string}`]: (thisArg: ApiHandler) => VoidReturn;
     [k: `api/before/${string}`]: (args: any) => VoidReturn;
 }
 
 declare module 'cordis' {
-    interface Events<C> extends ServerEvents<C> {
+    interface Events extends ServerEvents {
     }
 }
diff --git a/framework/framework/serializer.ts b/framework/framework/serializer.ts
index affa84a5c..9dd63e4a5 100644
--- a/framework/framework/serializer.ts
+++ b/framework/framework/serializer.ts
@@ -1,6 +1,6 @@
 import type { HandlerCommon } from './server';
 
-export default function serializer<T>(ignoreSerializeFunction = false, h?: HandlerCommon<T>) {
+export default function serializer(ignoreSerializeFunction = false, h?: HandlerCommon) {
     return (k: string, v: any) => {
         if (k.startsWith('_') && k !== '_id') return undefined;
         if (typeof v === 'bigint') return `BigInt::${v.toString()}`;
diff --git a/framework/framework/server.ts b/framework/framework/server.ts
index cf2c2568f..2e17b282d 100644
--- a/framework/framework/server.ts
+++ b/framework/framework/server.ts
@@ -3,6 +3,7 @@ import http from 'http';
 import { tmpdir } from 'os';
 import { join } from 'path';
 import { PassThrough } from 'stream';
+import type { } from '@cordisjs/plugin-timer';
 import { Context as CordisContext, Service } from 'cordis';
 import type { Files } from 'formidable';
 import fs from 'fs-extra';
@@ -43,7 +44,7 @@ export function encodeRFC5987ValueChars(str: string) {
     );
 }
 
-async function forkContextWithScope<C extends CordisContext>(ctx: C) {
+async function forkContextWithScope(ctx: CordisContext) {
     const scope = ctx.plugin(() => { });
     await scope;
     const dispose = () => scope.dispose();
@@ -141,8 +142,8 @@ export interface UserModel {
     _id: number;
 }
 
-export interface HandlerCommon<C> { } // eslint-disable-line ts/no-unused-vars
-export class HandlerCommon<C> {
+export interface HandlerCommon { }
+export class HandlerCommon {
     static [kHandler]: string | boolean = 'HandlerCommon';
     session: Record<string, any>;
     args: Record<string, any>;
@@ -151,7 +152,7 @@ export class HandlerCommon<C> {
     UiContext: Record<string, any>;
     user: UserModel;
 
-    constructor(public context: KoaContext, public ctx: C) {
+    constructor(public context: KoaContext, public ctx: CordisContext) {
         this.renderHTML = this.renderHTML.bind(this);
         this.url = this.url.bind(this);
         this.session = context.session;
@@ -212,7 +213,7 @@ export class HandlerCommon<C> {
     }
 }
 
-export class Handler<C = CordisContext> extends HandlerCommon<C> {
+export class Handler extends HandlerCommon {
     static [kHandler] = 'Handler';
 
     loginMethods: any;
@@ -260,7 +261,7 @@ export class Handler<C = CordisContext> extends HandlerCommon<C> {
     }
 }
 
-export class ConnectionHandler<C> extends HandlerCommon<C> {
+export class ConnectionHandler extends HandlerCommon {
     static [kHandler] = 'ConnectionHandler';
 
     conn: WebSocket;
@@ -300,7 +301,7 @@ export class ConnectionHandler<C> extends HandlerCommon<C> {
     }
 }
 
-export class NotFoundHandler extends Handler<CordisContext> {
+export class NotFoundHandler extends Handler {
     prepare() { throw new NotFoundError(this.request.path); }
     all() { }
 }
@@ -328,7 +329,7 @@ function executeMiddlewareStack(context: any, middlewares: { name: string, func:
     return dispatch(0);
 }
 
-export class WebService<C extends CordisContext = CordisContext> extends Service<never, C> {
+export class WebService extends Service<never> {
     static Config = Schema.object({
         keys: Schema.array(Schema.string()),
         proxy: Schema.boolean(),
@@ -347,8 +348,8 @@ export class WebService<C extends CordisContext = CordisContext> extends Service
     private handlerLayers = [];
     private wsLayers = [];
     private captureAllRoutes = Object.create(null);
-    private customDefaultContext: C;
-    private activeHandlers: Map<Handler<C>, { start: number, name: string }> = new Map();
+    private customDefaultContext: CordisContext;
+    private activeHandlers: Map<Handler, { start: number, name: string }> = new Map();
 
     renderers: Record<string, Renderer> = Object.create(null);
     server = koa;
@@ -357,7 +358,7 @@ export class WebService<C extends CordisContext = CordisContext> extends Service
     Handler = Handler;
     ConnectionHandler = ConnectionHandler;
 
-    constructor(ctx: C, public config: ReturnType<typeof WebService.Config>) {
+    constructor(ctx: CordisContext, public config: ReturnType<typeof WebService.Config>) {
         super(ctx, 'server');
         ctx.mixin('server', ['Route', 'Connection', 'withHandlerClass']);
         this.server.keys = this.config.keys;
@@ -503,7 +504,7 @@ ${c.response.status} ${endTime - startTime}ms ${c.response.length}`);
         });
     }
 
-    private async handleHttp(ctx: KoaContext, HandlerClass, checker, savedContext: C) {
+    private async handleHttp(ctx: KoaContext, HandlerClass, checker, savedContext: CordisContext) {
         const { args } = ctx.HydroContext;
         Object.assign(args, ctx.params);
         await using sub = await forkContextWithScope(savedContext);
@@ -589,7 +590,7 @@ ${c.response.status} ${endTime - startTime}ms ${c.response.length}`);
         }
     }
 
-    private async handleWS(ctx: KoaContext, HandlerClass, checker, conn?, layer?, savedContext?) {
+    private async handleWS(ctx: KoaContext, HandlerClass, checker, conn?, layer?, savedContext?: CordisContext) {
         const { args } = ctx.HydroContext;
         const sub = await forkContextWithScope(savedContext);
         const h = new HandlerClass(ctx, sub.ctx);
@@ -731,7 +732,7 @@ ${c.response.status} ${endTime - startTime}ms ${c.response.length}`);
                     perm = item;
                 }
             }
-            return function check(this: Handler<C>) {
+            return function check(this: Handler) {
                 checker();
                 if (perm) this.checkPerm(perm);
                 if (priv) this.checkPriv(priv);
@@ -767,7 +768,7 @@ ${c.response.status} ${endTime - startTime}ms ${c.response.length}`);
         });
     }
 
-    public setDefaultContext(ctx: C) {
+    public setDefaultContext(ctx: CordisContext) {
         try {
             if (!ctx.server) throw new Error();
         } catch (e) {
@@ -783,7 +784,7 @@ ${c.response.status} ${endTime - startTime}ms ${c.response.length}`);
     }
 
     public withHandlerClass<T extends string>(
-        name: T, callback: (HandlerClass: T extends `${string}ConnectionHandler` ? typeof ConnectionHandler<C> : typeof Handler<C>) => any,
+        name: T, callback: (HandlerClass: T extends `${string}ConnectionHandler` ? typeof ConnectionHandler : typeof Handler) => any,
     ) {
         name = name.replace(/Handler$/, '') as any;
         if (this.registry[name]) callback(this.registry[name]);
@@ -792,7 +793,7 @@ ${c.response.status} ${endTime - startTime}ms ${c.response.length}`);
     }
 
     // eslint-disable-next-line ts/naming-convention
-    public Route(name: string, path: string, RouteHandler: typeof Handler<C>, ...permPrivChecker) {
+    public Route(name: string, path: string, RouteHandler: typeof Handler, ...permPrivChecker) {
         // if (name === 'contest_scoreboard') {
         //     console.log('+++', this.ctx);
         //     console.log(this.ctx.scoreboard);
@@ -801,7 +802,7 @@ ${c.response.status} ${endTime - startTime}ms ${c.response.length}`);
     }
 
     // eslint-disable-next-line ts/naming-convention
-    public Connection(name: string, path: string, RouteHandler: typeof ConnectionHandler<C>, ...permPrivChecker) {
+    public Connection(name: string, path: string, RouteHandler: typeof ConnectionHandler, ...permPrivChecker) {
         return this.register('conn', name, path, RouteHandler, ...permPrivChecker);
     }
 
@@ -866,15 +867,15 @@ ${c.response.status} ${endTime - startTime}ms ${c.response.length}`);
         });
     }
 
-    public handlerMixin(MixinClass: Partial<HandlerCommon<C>> | ((s: HandlerCommon<C>) => Partial<HandlerCommon<C>>)) {
+    public handlerMixin(MixinClass: Partial<HandlerCommon> | ((s: HandlerCommon) => Partial<HandlerCommon>)) {
         return this._applyMixin(HandlerCommon, MixinClass);
     }
 
-    public httpHandlerMixin(MixinClass: Partial<Handler<C>> | ((s: Handler<C>) => Partial<Handler<C>>)) {
+    public httpHandlerMixin(MixinClass: Partial<Handler> | ((s: Handler) => Partial<Handler>)) {
         return this._applyMixin(Handler, MixinClass);
     }
 
-    public wsHandlerMixin(MixinClass: Partial<ConnectionHandler<C>> | ((s: ConnectionHandler<C>) => Partial<ConnectionHandler<C>>)) {
+    public wsHandlerMixin(MixinClass: Partial<ConnectionHandler> | ((s: ConnectionHandler) => Partial<ConnectionHandler>)) {
         return this._applyMixin(ConnectionHandler, MixinClass);
     }
 
@@ -891,9 +892,9 @@ ${c.response.status} ${endTime - startTime}ms ${c.response.length}`);
 
 declare module 'cordis' {
     interface Context {
-        server: WebService<this>;
-        Route: WebService<this>['Route'];
-        Connection: WebService<this>['Connection'];
-        withHandlerClass: WebService<this>['withHandlerClass'];
+        server: WebService;
+        Route: WebService['Route'];
+        Connection: WebService['Connection'];
+        withHandlerClass: WebService['withHandlerClass'];
     }
 }
diff --git a/packages/hydrooj/package.json b/packages/hydrooj/package.json
index 27414f2e2..baed2d7d7 100644
--- a/packages/hydrooj/package.json
+++ b/packages/hydrooj/package.json
@@ -28,7 +28,7 @@
         "@zip.js/zip.js": "^2.8.26",
         "adm-zip": "0.5.16",
         "cac": "^7.0.0",
-        "cordis": "4.0.0-rc.0",
+        "cordis": "4.0.0-rc.2",
         "csv-stringify": "^6.7.0",
         "emoji-regex": "^10.6.0",
         "emojis-list": "2.1.0",
diff --git a/packages/hydrooj/src/context.ts b/packages/hydrooj/src/context.ts
index 54f674e12..26ad97d7a 100644
--- a/packages/hydrooj/src/context.ts
+++ b/packages/hydrooj/src/context.ts
@@ -1,7 +1,6 @@
-/* eslint-disable ts/no-unsafe-declaration-merging */
-import LoggerService from '@cordisjs/plugin-logger';
-import { TimerService } from '@cordisjs/plugin-timer';
-import * as cordis from 'cordis';
+import type { } from '@cordisjs/plugin-logger';
+import type { } from '@cordisjs/plugin-timer';
+import { Service } from 'cordis';
 import Schema from 'schemastery';
 import type { DomainDoc, GeoIP, ModuleInterfaces } from './interface';
 import { inject } from './lib/ui';
@@ -12,6 +11,21 @@ import type { } from './service/migration';
 
 export { EventMap as Events };
 
+declare module 'cordis' {
+    export interface Events extends EventMap { }
+    interface Context {
+        domain?: DomainDoc;
+        loader: Loader;
+        check: CheckService;
+        setImmediate: typeof setImmediate;
+        addScript: typeof addScript;
+        provideModule: typeof provideModule;
+        injectUI: typeof inject;
+        broadcast: Context['emit'];
+        geoip?: GeoIP;
+    }
+}
+
 function addScript<K>(name: string, description: string, validate: Schema<K>, run: (args: K, report: any) => boolean | Promise<boolean>) {
     if (global.Hydro.script[name]) throw new Error(`duplicate script ${name} registered.`);
     global.Hydro.script[name] = { description, validate, run };
@@ -24,28 +38,10 @@ function provideModule<T extends keyof ModuleInterfaces>(type: T, id: string, mo
     return () => delete global.Hydro.module[type][id];
 }
 
-export type Fiber = cordis.Fiber<Context>;
-export const Fiber = cordis.Fiber;
-
-export { Disposable, FiberState, Plugin } from 'cordis';
-
-export interface Context extends cordis.Context {
-    [Context.events]: EventMap & cordis.Events<Context>;
-    loader: Loader;
-    check: CheckService;
-    setImmediate: typeof setImmediate;
-    addScript: typeof addScript;
-    provideModule: typeof provideModule;
-    injectUI: typeof inject;
-    broadcast: Context['emit'];
-    geoip?: GeoIP;
-}
-
-export abstract class Service<T = never> extends cordis.Service<T, Context> {
-}
+export { Context, Disposable, Fiber, FiberState, Plugin, Service } from 'cordis';
 
 const T = <F extends (...args: any[]) => any>(origFunc: F, disposeFunc?) =>
-    function method(this: cordis.Service, ...args: Parameters<F>) {
+    function method(this: Service, ...args: Parameters<F>) {
         this.ctx.effect(() => {
             const res = origFunc(...args);
             return () => (disposeFunc ? disposeFunc(res) : res());
@@ -65,25 +61,3 @@ export class ApiMixin extends Service {
         ctx.mixin('$api', ['addScript', 'setImmediate', 'provideModule', 'injectUI', 'broadcast']);
     }
 }
-
-export class Context extends cordis.Context {
-    domain?: DomainDoc;
-
-    constructor() {
-        super();
-        this.plugin(ApiMixin);
-        this.plugin(TimerService);
-        this.plugin(LoggerService, {
-            console: {
-                showDiff: false,
-                showTime: 'dd hh:mm:ss',
-                label: {
-                    align: 'right',
-                    width: 9,
-                    margin: 1,
-                },
-                levels: { default: process.env.DEV ? 3 : 2 },
-            },
-        });
-    }
-}
diff --git a/packages/hydrooj/src/handler/contest.ts b/packages/hydrooj/src/handler/contest.ts
index 72b4c4da2..141e25725 100644
--- a/packages/hydrooj/src/handler/contest.ts
+++ b/packages/hydrooj/src/handler/contest.ts
@@ -876,7 +876,7 @@ class ScoreboardService extends Service {
     }
 }
 
-declare module '../context' {
+declare module 'cordis' {
     interface Context {
         scoreboard: ScoreboardService;
     }
diff --git a/packages/hydrooj/src/lib/i18n.ts b/packages/hydrooj/src/lib/i18n.ts
index 15e6c4953..da68c0c07 100644
--- a/packages/hydrooj/src/lib/i18n.ts
+++ b/packages/hydrooj/src/lib/i18n.ts
@@ -2,7 +2,7 @@ import { Context, Service } from '../context';
 
 const translations: Record<string, Record<string, string>[]> = {};
 
-declare module '../context' {
+declare module 'cordis' {
     interface Context {
         i18n: I18nService;
     }
diff --git a/packages/hydrooj/src/loader.ts b/packages/hydrooj/src/loader.ts
index 4f9c1735b..9b8a64750 100644
--- a/packages/hydrooj/src/loader.ts
+++ b/packages/hydrooj/src/loader.ts
@@ -12,12 +12,14 @@ import { I18nService } from './lib/i18n';
 
 import { Logger } from './logger';
 import {
-    Context, Service, FiberState, Fiber,
+    Context, Service, FiberState, Fiber, ApiMixin,
 } from './context';
 // eslint-disable-next-line import/no-duplicates
 import { sleep, unwrapExports } from './utils';
 import { PRIV } from './model/builtin';
 import { getAddons } from './options';
+import { TimerService } from '@cordisjs/plugin-timer';
+import LoggerService from '@cordisjs/plugin-logger';
 import Schema from 'schemastery';
 import { isEqual } from 'lodash';
 
@@ -162,6 +164,20 @@ export class Loader extends Service {
     }
 }
 
+app.plugin(ApiMixin);
+app.plugin(TimerService);
+app.plugin(LoggerService, {
+    console: {
+        showDiff: false,
+        showTime: 'dd hh:mm:ss',
+        label: {
+            align: 'right',
+            width: 9,
+            margin: 1,
+        },
+        levels: { default: process.env.DEV ? 3 : 2 },
+    },
+});
 app.plugin(I18nService);
 app.plugin(Loader);
 
diff --git a/packages/hydrooj/src/model/oauth.ts b/packages/hydrooj/src/model/oauth.ts
index ac1e35225..1201bf740 100644
--- a/packages/hydrooj/src/model/oauth.ts
+++ b/packages/hydrooj/src/model/oauth.ts
@@ -10,7 +10,7 @@ export interface OauthMap {
     uid: number;
 }
 
-declare module '../context' {
+declare module 'cordis' {
     interface Context {
         oauth: OauthModel;
     }
diff --git a/packages/hydrooj/src/service/bus.ts b/packages/hydrooj/src/service/bus.ts
index 14aacd7ba..ddf2bbca3 100644
--- a/packages/hydrooj/src/service/bus.ts
+++ b/packages/hydrooj/src/service/bus.ts
@@ -22,10 +22,10 @@ export interface EventMap {
     'app/before-reload': (entries: Set<string>) => VoidReturn;
     'app/reload': (entries: Set<string>) => VoidReturn;
 
-    'subscription/init': (h: ConnectionHandler<Context>, privileged: boolean) => VoidReturn;
+    'subscription/init': (h: ConnectionHandler, privileged: boolean) => VoidReturn;
     'subscription/subscribe': (channel: string, user: User, metadata: Record<string, string>) => VoidReturn;
     'subscription/enable': (
-        channel: string, h: ConnectionHandler<Context>, privileged: boolean, onDispose: (disposable: () => void) => void,
+        channel: string, h: ConnectionHandler, privileged: boolean, onDispose: (disposable: () => void) => void,
     ) => VoidReturn;
 
     'app/watch/change': (path: string) => VoidReturn;
@@ -91,7 +91,7 @@ export interface EventMap {
     'contest/balloon': (domainId: string, tid: ObjectId, bdoc: ContestBalloonDoc) => VoidReturn;
     'contest/del': (domainId: string, tid: ObjectId) => VoidReturn;
 
-    'oplog/log': (type: string, handler: Handler<Context> | ConnectionHandler<Context>, args: any, data: any) => VoidReturn;
+    'oplog/log': (type: string, handler: Handler | ConnectionHandler, args: any, data: any) => VoidReturn;
 
     'training/list': (query: Filter<TrainingDoc>, handler: any) => VoidReturn;
     'training/get': (tdoc: TrainingDoc, handler: any) => VoidReturn;
diff --git a/packages/hydrooj/src/service/db.ts b/packages/hydrooj/src/service/db.ts
index a1dac420e..af0c1d1ae 100644
--- a/packages/hydrooj/src/service/db.ts
+++ b/packages/hydrooj/src/service/db.ts
@@ -26,7 +26,7 @@ interface MongoConfig {
     collectionMap?: Record<string, string>;
 }
 
-declare module '../context' {
+declare module 'cordis' {
     interface Context {
         db: MongoService;
     }
diff --git a/packages/hydrooj/src/service/hmr.ts b/packages/hydrooj/src/service/hmr.ts
index 1673ef395..28718f46d 100644
--- a/packages/hydrooj/src/service/hmr.ts
+++ b/packages/hydrooj/src/service/hmr.ts
@@ -9,9 +9,9 @@ import { Context, Plugin, Service } from '../context';
 import { Logger } from '../logger';
 import { unwrapExports } from '../utils';
 
-declare module '../context' {
+declare module 'cordis' {
     interface Events {
-        'hmr/reload': (reloads: Map<Plugin, { filename: string, runtime: Plugin.Runtime<Context> }>) => void;
+        'hmr/reload': (reloads: Map<Plugin, { filename: string, runtime: Plugin.Runtime }>) => void;
     }
     interface Context {
         hmr: HMR;
@@ -150,7 +150,7 @@ export default class HMR extends Service {
         const pending = new Map<string, Plugin>();
 
         /** plugins that should be reloaded */
-        const reloads = new Map<Plugin, { filename: string, runtime: Plugin.Runtime<Context> }>();
+        const reloads = new Map<Plugin, { filename: string, runtime: Plugin.Runtime }>();
 
         // we assume that plugin entry files are "atomic"
         // that is, reloading them will not cause any other reloads
diff --git a/packages/hydrooj/src/service/migration.ts b/packages/hydrooj/src/service/migration.ts
index c6ac42fec..87d275f23 100644
--- a/packages/hydrooj/src/service/migration.ts
+++ b/packages/hydrooj/src/service/migration.ts
@@ -9,7 +9,7 @@ const argv = cac().parse();
 export type MigrationScript = null | ((ctx: Context) => Promise<boolean | void>);
 const logger = new Logger('migration');
 
-declare module '../context' {
+declare module 'cordis' {
     interface Context {
         migration: MigrationService;
     }
diff --git a/packages/hydrooj/src/service/server.ts b/packages/hydrooj/src/service/server.ts
index 33f8a67ea..298b74b03 100644
--- a/packages/hydrooj/src/service/server.ts
+++ b/packages/hydrooj/src/service/server.ts
@@ -28,7 +28,7 @@ const ignoredLimit = `,${argv.options.ignoredLimit},`;
 const logger = new Logger('server');
 
 declare module '@hydrooj/framework' {
-    export interface HandlerCommon<C> { // eslint-disable-line ts/no-unused-vars
+    export interface HandlerCommon {
         domain: DomainDoc;
 
         paginate<T>(cursor: FindCursor<T>, page: number, key: string): Promise<[docs: T[], numPages: number, count: number]>;
@@ -72,10 +72,10 @@ export function requireSudo(target: any, funcName: string, obj: any) {
     return obj;
 }
 
-export class Handler extends HandlerOriginal<Context> {
+export class Handler extends HandlerOriginal {
     domain: DomainDoc;
 }
-export class ConnectionHandler extends ConnectionHandlerOriginal<Context> {
+export class ConnectionHandler extends ConnectionHandlerOriginal {
     domain: DomainDoc;
 }
 
diff --git a/packages/hydrooj/src/service/storage.ts b/packages/hydrooj/src/service/storage.ts
index 118f58a20..e3c2318b6 100644
--- a/packages/hydrooj/src/service/storage.ts
+++ b/packages/hydrooj/src/service/storage.ts
@@ -423,7 +423,7 @@ export async function apply(ctx: Context, config: ReturnType<typeof FileSetting>
     ctx.provide('storage', service);
 }
 
-declare module '../context' {
+declare module 'cordis' {
     interface Context {
         storage: RemoteStorageService | LocalStorageService;
     }
diff --git a/packages/hydrooj/src/service/worker.ts b/packages/hydrooj/src/service/worker.ts
index 202d1d4e8..0718b07c0 100644
--- a/packages/hydrooj/src/service/worker.ts
+++ b/packages/hydrooj/src/service/worker.ts
@@ -4,7 +4,7 @@ import { sleep } from '@hydrooj/utils';
 import { Context, Service } from '../context';
 import db from './db';
 
-declare module '../context' {
+declare module 'cordis' {
     interface Context {
         worker: WorkerService;
     }
diff --git a/packages/prom-client/metrics.ts b/packages/prom-client/metrics.ts
index ef16552be..0542e1964 100644
--- a/packages/prom-client/metrics.ts
+++ b/packages/prom-client/metrics.ts
@@ -3,7 +3,7 @@ import {
 } from 'prom-client';
 import { Context, db } from 'hydrooj';
 
-declare module 'hydrooj' {
+declare module 'cordis' {
     interface Context {
         metrics: Registry;
     }
diff --git a/packages/sonic/index.ts b/packages/sonic/index.ts
index bc7d88a5c..dc18a4a09 100644
--- a/packages/sonic/index.ts
+++ b/packages/sonic/index.ts
@@ -7,7 +7,7 @@ import {
     Logger, ProblemModel, Schema, Service, SystemModel,
 } from 'hydrooj';
 
-declare module 'hydrooj' {
+declare module 'cordis' {
     interface Context {
         sonic?: SonicService;
     }
diff --git a/packages/ui-default/components/scratchpad/index.tsx b/packages/ui-default/components/scratchpad/index.tsx
index d7020315a..dbd8ae696 100644
--- a/packages/ui-default/components/scratchpad/index.tsx
+++ b/packages/ui-default/components/scratchpad/index.tsx
@@ -54,7 +54,7 @@ class ScratchpadService extends Service {
     rerenderCallback?.();
   }
 }
-declare module '../../context' {
+declare module 'cordis' {
   interface Context {
     scratchpad: ScratchpadService;
   }
diff --git a/packages/ui-default/context.ts b/packages/ui-default/context.ts
index 022dce826..d9c4be5ef 100644
--- a/packages/ui-default/context.ts
+++ b/packages/ui-default/context.ts
@@ -1,20 +1,11 @@
-/* eslint-disable ts/no-unsafe-declaration-merging */
-
-import * as cordis from 'cordis';
+import { Context } from 'cordis';
 import type { EventMap } from './api';
 
-export interface Events<C extends Context = Context> extends cordis.Events<C>, EventMap { }
-
-export type { Disposable, FiberState, Plugin } from 'cordis';
-
-export interface Context {
-  [Context.events]: Events<this>;
-  broadcast: Context['emit'];
+declare module 'cordis' {
+  export interface Events extends EventMap { }
 }
 
-export class Context extends cordis.Context { }
-export type Fiber = cordis.Fiber<Context>;
+export type { Disposable, Plugin } from 'cordis';
+export { Context, Fiber, FiberState, Service } from 'cordis';
 
-export class Service<C extends Context = Context> extends cordis.Service<C> {
-}
 export const ctx = new Context();
diff --git a/packages/ui-default/pages/home_messages.page.tsx b/packages/ui-default/pages/home_messages.page.tsx
index 7e2876d8c..78045c86c 100644
--- a/packages/ui-default/pages/home_messages.page.tsx
+++ b/packages/ui-default/pages/home_messages.page.tsx
@@ -18,7 +18,7 @@ class MessagePadService extends Service {
   }
 }
 
-declare module '../context' {
+declare module 'cordis' {
   interface Context {
     messagepad: MessagePadService;
   }
diff --git a/packages/vjudge/src/index.ts b/packages/vjudge/src/index.ts
index 893b613ab..4e18cb520 100644
--- a/packages/vjudge/src/index.ts
+++ b/packages/vjudge/src/index.ts
@@ -177,7 +177,7 @@ class AccountService {
     }
 }
 
-declare module 'hydrooj' {
+declare module 'cordis' {
     interface Context {
         vjudge: VJudgeService;
     }