diff --git a/src/base.ts b/src/base.ts
index f5d40d0..f9d32a2 100644
--- a/src/base.ts
+++ b/src/base.ts
@@ -26,9 +26,17 @@ const context: Context = {
   chain: [],
 }
 
-export interface Plugins {[k: string]: [object, any, any, any, any]}
+export interface PluginDef {
+  output: object
+  a1: any
+  a2: any
+  a3: any
+  a4: any
+}
+
+export interface Plugins {[k: string]: PluginDef}
 
-export type Fancy<I extends Context, T extends Plugins> = {
+export type Base<I extends Context, T extends Plugins> = {
   it: {
     (expectation: string, cb?: (context: I) => any): void
     (cb?: (context: I) => any): void
@@ -37,12 +45,12 @@ export type Fancy<I extends Context, T extends Plugins> = {
     (expectation: string, cb?: (context: I) => any): void
     (cb?: (context: I) => any): void
   }
-  add<K extends string, O>(key: K, cb: (context: I) => Promise<O> | O): Fancy<I & {[P in K]: O}, T>
-  do(cb: (context: I) => any): Fancy<I, T>
-  register<K extends string, O, A1, A2, A3, A4>(key: K, plugin: (arg1?: A1, arg2?: A2, arg3?: A3, arg4?: A4) => Plugin<O & I>): Fancy<I, T & {[P in K]: [O, A1, A2, A3, A4]}>
-} & {[P in keyof T]: (arg1?: T[P][1], arg2?: T[P][2], arg3?: T[P][3], arg4?: T[P][4]) => Fancy<T[P][0] & I, T>}
+  add<K extends string, O>(key: K, cb: (context: I) => Promise<O> | O): Base<I & {[P in K]: O}, T>
+  do(cb: (context: I) => any): Base<I, T>
+  register<K extends string, O, A1, A2, A3, A4>(key: K, plugin: (arg1?: A1, arg2?: A2, arg3?: A3, arg4?: A4) => Plugin<O & I>): Base<I, T & {[P in K]: {output: O, a1: A1, a2: A2, a3: A3, a4: A4}}>
+} & {[P in keyof T]: (arg1?: T[P]['a1'], arg2?: T[P]['a2'], arg3?: T[P]['a3'], arg4?: T[P]['a4']) => Base<T[P]['output'] & I, T>}
 
-const base = <I extends Context>(context: I): Fancy<I, {}> => {
+const base = <I extends Context>(context: I): Base<I, {}> => {
   const end = (arg1: any, cb: any) => {
     context = assignWithProps({}, context)
     if (_.isFunction(arg1)) {
diff --git a/src/env.ts b/src/env.ts
index e5a3600..7025aeb 100644
--- a/src/env.ts
+++ b/src/env.ts
@@ -1,16 +1,20 @@
+import {Plugin} from './base'
+
 export interface EnvOptions {
   clear?: boolean
 }
 
+export interface Env extends Plugin<{envs: (typeof process.env)[]}> {}
+
 export default (env: {[k: string]: string | undefined}, opts: EnvOptions = {}) => ({
-  run(ctx: {envs: (typeof process.env)[]}) {
+  run(ctx) {
     ctx.envs = ctx.envs || []
     ctx.envs.push(process.env)
     if (opts.clear) process.env = {...env}
     else process.env = {...process.env, ...env}
   },
-  finally(ctx: {envs: (typeof process.env)[]}) {
+  finally(ctx) {
     const env = ctx.envs.pop()
     if (env) process.env = env
   },
-})
+}) as Env
diff --git a/src/index.ts b/src/index.ts
index e5ce13e..d3c5aed 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,4 +1,4 @@
-import base, {Context, Fancy, Plugin} from './base'
+import base, {Base, Context, Plugin} from './base'
 import _catch from './catch'
 import env, {EnvOptions} from './env'
 import nock, {NockScope} from './nock'
@@ -13,9 +13,11 @@ export const fancy = base
 .register('stderr', stderr)
 .register('stdout', stdout)
 
+export type Fancy = typeof fancy
+
 export {
   Context,
-  Fancy,
+  Base,
   Plugin,
   EnvOptions,
   NockScope,