Options

Every option below is a key on pluginMsw({ ... }).

Option	Type	Default	Description
output	Output	{ path: 'handlers' }	Where the generated files are written and exported
group	Group	—	Split output into per-tag or per-path folders
baseURL	string	—	Base URL prepended to every handler's request
handlers	boolean	false	Emit a handlers.ts that re-exports every handler
parser	'data' | 'faker'	'data'	Source of the response body each handler returns
include	Array<Include>	—	Keep only operations that match
exclude	Array<Exclude>	—	Skip operations that match
override	Array<Override>	—	Apply different options per pattern
resolver	ResolverPatch<ResolverMsw>	—	Customize generated names and file paths
macros	Array<Macro>	—	Rewrite AST nodes before printing

output

Where the generated handler files are written and how they are exported.

output.path

Folder where the plugin writes its files, resolved against the global output.path on defineConfig and defaulting to 'handlers'. To write everything to one file instead, set output.mode: 'file' and give path a file name with its extension, such as 'handlers.ts'.

output.mode

How the plugin consolidates its generated code into files. 'file' (the default) writes everything into a single file, so output.path must include the extension. 'directory' writes one file per operation under output.path. Pair 'directory' with group to organize output into subdirectories.

IMPORTANT

group requires mode: 'directory'. Pairing group with mode: 'file' (or leaving mode unset) stops the build with a KUBB_INVALID_PLUGIN_OPTIONS error.

output.barrel

Toggle the export style and depth to see the generated barrels.

• src/gen/
• models/
• Pet.ts
• User.ts
• clients/
• pet/
• getPetById.ts
• store/
• getInventory.ts

src/gen/index.ts

Controls how the generated index.ts (barrel) re-exports the output. Accepts { type: 'named' } or { type: 'all' }, optionally with nested: true (for example { type: 'named', nested: true }) to write an index.ts in every subdirectory, or false to skip the barrel entirely. Each generator plugin defaults output.barrel to { type: 'named' }; the root output.barrel on defineConfig defaults to false.

output.banner

Text added to the top of every generated file, such as a license header or @ts-nocheck directive. Pass a string, or a function (meta: BannerMeta) => string that receives the document info (title, description, version, baseURL) and per-file context (filePath, baseName, isBarrel, isAggregation), so a directive can skip barrel files.

output.footer

Text added to the bottom of every generated file (string or (meta: BannerMeta) => string), like banner but for closing comments. Pair banner: '/* eslint-disable */' with footer: '/* eslint-enable */' to scope a lint disable to the generated file.

group

Switch the mode to see where these operations land on disk.

clients/pet/

• getPetById
• addPet

clients/store/

• getInventory

clients/order/

• placeOrder
• getOrderById

clients/user/

• loginUser

group: { type: "tag" } splits the output by the operation tag, so placeOrder follows its order tag.

Splits generated files into subfolders by the operation's tag or URL path, each under {output.path}/{groupName}/. Without group, every file lands directly in output.path. It applies only to output.mode: 'directory'.

IMPORTANT

Combining group with output.mode: 'file' stops the build with a KUBB_INVALID_PLUGIN_OPTIONS error.

group.type

Property used to assign each operation to a group ('tag' | 'path'), required whenever group is set. An operation with no tag goes in the default group.

• 'tag' uses the operation's first tag.
• 'path' uses the first URL segment, such as pet for /pet/{petId}.

group.name

Function that turns a group key into the subdirectory name. It defaults to ({ group }) => camelCase(group) for tag groups, while type: 'path' groups default to the raw first URL segment, uncased.

baseURL

Base URL prepended to every handler's request. When omitted, no host is prepended and each handler matches the operation's relative path from the spec. Set it to point at a different environment than the spec.

handlers

Emits a handlers.ts file that re-exports every generated handler in operation order. Spread it into your MSW setupServer(...handlers) or setupWorker(...handlers) call.

gen/handlers.ts

import { getPetHandler } from './getPetHandler'
import { addPetHandler } from './addPetHandler'

export const handlers = [getPetHandler(), addPetHandler()] as const

parser

Source of the response body each handler returns. 'data' (the default) returns a typed payload from @kubb/plugin-ts that you fill in from tests, so the handler body is new Response(JSON.stringify(data), ...). 'faker' falls back to a value built by @kubb/plugin-faker when you pass no data. Register pluginFaker() in the plugins array, since the plugin depends on Faker only for this value.

'faker'

export function getPetHandler(data?: GetPetQueryResponse | ((info: Parameters<Parameters<typeof http.get>[1]>[0]) => Response | Promise<Response>)) {
  return http.get('/pet/:petId', function handler(info) {
    if (typeof data === 'function') return data(info)

    return new Response(JSON.stringify(data || createGetPetQueryResponse(data)), {
      status: 200,
      headers: { 'Content-Type': 'application/json' },
    })
  })
}

include

Generates only the operations and schemas that match at least one entry, and skips the rest. Each entry filters by tag, operationId, path, method, contentType, or schemaName, with a pattern that can be a string or a RegExp, both matched as a regular expression against the value. A string pattern is compiled with new RegExp(pattern), so it is not an exact match: pattern: 'pet' also matches 'petType' or 'superpet'.

Type definition

export type Include = {
  type: 'tag' | 'operationId' | 'path' | 'method' | 'contentType' | 'schemaName'
  pattern: string | RegExp
}

exclude

Skips any operation or schema that matches at least one entry, the opposite of include. Entries use the same type and pattern fields as include, and when both options match an item, exclude wins.

override

Applies different plugin options to operations that match a pattern. Each entry takes the same type and pattern as include, plus an options object that accepts any plugin option except override, so rules cannot nest. The first matching entry merges onto the plugin defaults, and later entries do not stack.

Type definition

export type Override = {
  type: 'tag' | 'operationId' | 'path' | 'method' | 'contentType' | 'schemaName'
  pattern: string | RegExp
  options: Omit<Partial<Options>, 'override'>
}

resolver

Changes how the plugin names generated files and symbols. Pass a partial patch. Override only the members you want, and anything you omit keeps resolverMsw. See Override a resolver for the this context and how a patch layers over the default.

TIP

Inside a method this is the full resolver, so this.default.name(name) reuses the built-in casing.

Partial override

type ResolverMswPatch = {
  name?(name: string): string
  file?: {
    baseName?(params: { name: string; extname: string }): string
    path?(params: { baseName: string; output: Output }): string
  }
  handler?: {
    name?(node: OperationNode): string
    listName?(): string
  }
}

macros

Rewrites AST nodes before they are printed, without forking the generator. Each macro callback (such as schema or operation) receives the node and a context object, and returns a replacement or undefined to leave it as is. Omitted callbacks keep their defaults, and macros run in order, so a later one sees the output of an earlier one.