feat(reporters): add agent reporter to reduce ai agent token usage

docs/config/reporters.md

@@ -42,6 +42,7 @@ Note that the [coverage](/guide/coverage) feature uses a different [`coverage.re
 - [`tap-flat`](/guide/reporters#tap-flat-reporter)
 - [`hanging-process`](/guide/reporters#hanging-process-reporter)
 - [`github-actions`](/guide/reporters#github-actions-reporter)
+- [`agent`](/guide/reporters#agent-reporter)
 - [`blob`](/guide/reporters#blob-reporter)
 
 ## Example

docs/guide/browser/visual-regression-testing.md

@@ -606,7 +606,6 @@ screenshots should use the service.
 
 The cleanest approach is using [Test Projects](/guide/projects):
 
-
 ```ts [vitest.config.ts]
 import { env } from 'node:process'
 import { defineConfig } from 'vitest/config'
@@ -663,7 +662,6 @@ export default defineConfig({
 })
 ```
 
-
 Follow the [official guide to create a Playwright Workspace](https://learn.microsoft.com/en-us/azure/app-testing/playwright-workspaces/quickstart-run-end-to-end-tests?tabs=playwrightcli&pivots=playwright-test-runner#create-a-workspace).
 
 Once your workspace is created, configure Vitest to use it:

docs/guide/cli-generated.md

@@ -102,7 +102,7 @@ Hide logs for skipped tests
 - **CLI:** `--reporter <name>`
 - **Config:** [reporters](/config/reporters)
 
-Specify reporters (default, blob, verbose, dot, json, tap, tap-flat, junit, tree, hanging-process, github-actions)
+Specify reporters (default, agent, blob, verbose, dot, json, tap, tap-flat, junit, tree, hanging-process, github-actions)
 
 ### outputFile
 

docs/guide/cli.md

@@ -237,4 +237,3 @@ Merges every blob report located in the specified folder (`.vitest-reports` by d
 ```sh
 vitest --merge-reports --reporter=junit
 ```
-

docs/guide/reporters.md

@@ -98,6 +98,10 @@ This example will write separate JSON and XML reports as well as printing a verb
 
 By default (i.e. if no reporter is specified), Vitest will display summary of running tests and their status at the bottom. Once a suite passes, its status will be reported on top of the summary.
 
+::: tip
+When Vitest detects it is running inside an AI coding agent, the [`agent`](#agent-reporter) reporter is used instead to reduce output and minimize token usage. You can override this by explicitly configuring the [`reporters`](/config/reporters) option.
+:::
+
 You can disable the summary by configuring the reporter:
 
 :::code-group
@@ -637,6 +641,26 @@ export default defineConfig({
 })
 ```
 
+### Agent Reporter
+
+Outputs a minimal report optimized for AI coding assistants and LLM-based workflows. Only failed tests and their error messages are displayed. Console logs from passing tests and the summary section are suppressed to reduce token usage.
+
+This reporter is automatically enabled when no `reporters` option is configured and Vitest detects it is running inside an AI coding agent. If you configure custom reporters, you can explicitly add `agent`:
+
+:::code-group
+```bash [CLI]
+npx vitest --reporter=agent
+```
+
+```ts [vitest.config.ts]
+export default defineConfig({
+  test: {
+    reporters: ['agent']
+  },
+})
+```
+:::
+
 ### Blob Reporter
 
 Stores test results on the machine so they can be later merged using [`--merge-reports`](/guide/cli#merge-reports) command.

packages/vitest/src/node/config/resolveConfig.ts

@@ -23,7 +23,7 @@ import {
   defaultPort,
 } from '../../constants'
 import { benchmarkConfigDefaults, configDefaults } from '../../defaults'
-import { isCI, stdProvider } from '../../utils/env'
+import { isAgent, isCI, stdProvider } from '../../utils/env'
 import { getWorkersCountByPercentage } from '../../utils/workers'
 import { BaseSequencer } from '../sequencers/BaseSequencer'
 import { RandomSequencer } from '../sequencers/RandomSequencer'
@@ -729,7 +729,7 @@ export function resolveConfig(
   }
 
   if (!resolved.reporters.length) {
-    resolved.reporters.push(['default', {}])
+    resolved.reporters.push([isAgent ? 'agent' : 'default', {}])
 
     // also enable github-actions reporter as a default
     if (process.env.GITHUB_ACTIONS === 'true') {

packages/vitest/src/node/reporters/agent.ts

@@ -0,0 +1,31 @@
+import type { TestSpecification } from '../test-specification'
+import type { DefaultReporterOptions } from './default'
+import type { TestCase, TestModule, TestModuleState } from './reported-tasks'
+import { DefaultReporter } from './default'
+
+export class AgentReporter extends DefaultReporter {
+  renderSucceed = false
+
+  constructor(options: DefaultReporterOptions = {}) {
+    super({ silent: 'passed-only', ...options, summary: false })
+  }
+
+  onTestRunStart(specifications: ReadonlyArray<TestSpecification>): void {
+    super.onTestRunStart(specifications)
+    this.renderSucceed = false
+  }
+
+  protected printTestModule(testModule: TestModule): void {
+    if (testModule.state() !== 'failed') {
+      return
+    }
+    super.printTestModule(testModule)
+  }
+
+  protected printTestCase(moduleState: TestModuleState, test: TestCase): void {
+    const testResult = test.result()
+    if (testResult.state === 'failed') {
+      super.printTestCase(moduleState, test)
+    }
+  }
+}

packages/vitest/src/node/reporters/base.ts

@@ -37,6 +37,7 @@ const BADGE_PADDING = '       '
 
 export interface BaseOptions {
   isTTY?: boolean
+  silent?: boolean | 'passed-only'
 }
 
 export abstract class BaseReporter implements Reporter {
@@ -49,16 +50,19 @@ export abstract class BaseReporter implements Reporter {
   renderSucceed = false
 
   protected verbose = false
+  protected silent?: boolean | 'passed-only'
 
   private _filesInWatchMode = new Map<string, number>()
   private _timeStart = formatTimeString(new Date())
 
   constructor(options: BaseOptions = {}) {
     this.isTTY = options.isTTY ?? isTTY
+    this.silent = options.silent
   }
 
   onInit(ctx: Vitest): void {
     this.ctx = ctx
+    this.silent ??= this.ctx.config.silent
 
     this.ctx.logger.printBanner()
   }
@@ -117,8 +121,8 @@ export abstract class BaseReporter implements Reporter {
     this.printTestModule(testModule)
   }
 
-  private logFailedTask(task: Task) {
-    if (this.ctx.config.silent === 'passed-only') {
+  protected logFailedTask(task: Task): void {
+    if (this.silent === 'passed-only') {
       for (const log of task.logs || []) {
         this.onUserConsoleLog(log, 'failed')
       }
@@ -504,11 +508,11 @@ export abstract class BaseReporter implements Reporter {
   }
 
   shouldLog(log: UserConsoleLog, taskState?: TestResult['state']): boolean {
-    if (this.ctx.config.silent === true) {
+    if (this.silent === true) {
       return false
     }
 
-    if (this.ctx.config.silent === 'passed-only' && taskState !== 'failed') {
+    if (this.silent === 'passed-only' && taskState !== 'failed') {
       return false
     }
 

packages/vitest/src/node/reporters/index.ts

@@ -6,6 +6,7 @@ import type { GithubActionsReporterOptions } from './github-actions'
 import type { HTMLOptions } from './html'
 import type { JsonOptions } from './json'
 import type { JUnitOptions } from './junit'
+import { AgentReporter } from './agent'
 import { BlobReporter } from './blob'
 import { DefaultReporter } from './default'
 import { DotReporter } from './dot'
@@ -19,6 +20,7 @@ import { TreeReporter } from './tree'
 import { VerboseReporter } from './verbose'
 
 export {
+  AgentReporter,
   DefaultReporter,
   DotReporter,
   GithubActionsReporter,
@@ -46,6 +48,7 @@ export type {
 
 export const ReportersMap = {
   'default': DefaultReporter as typeof DefaultReporter,
+  'agent': AgentReporter as typeof AgentReporter,
   'blob': BlobReporter as typeof BlobReporter,
   'verbose': VerboseReporter as typeof VerboseReporter,
   'dot': DotReporter as typeof DotReporter,
@@ -62,6 +65,7 @@ export type BuiltinReporters = keyof typeof ReportersMap
 
 export interface BuiltinReporterOptions {
   'default': DefaultReporterOptions
+  'agent': DefaultReporterOptions
   'verbose': DefaultReporterOptions
   'dot': BaseOptions
   'tree': BaseOptions

packages/vitest/src/public/node.ts

@@ -43,6 +43,7 @@ export { VmThreadsPoolWorker } from '../node/pools/workers/vmThreadsWorker'
 export type { SerializedTestProject, TestProject } from '../node/project'
 
 export {
+  AgentReporter,
   BenchmarkReporter,
   BenchmarkReportsMap,
   DefaultReporter,

packages/vitest/src/public/reporters.ts

@@ -1,4 +1,5 @@
 export {
+  AgentReporter,
   BenchmarkReporter,
   BenchmarkReportsMap,
   DefaultReporter,

packages/vitest/src/utils/env.ts

@@ -12,4 +12,4 @@ export const isDeno: boolean
 export const isWindows: boolean = (isNode || isDeno) && process.platform === 'win32'
 export const isBrowser: boolean = typeof window !== 'undefined'
 export const isTTY: boolean = ((isNode || isDeno) && process.stdout?.isTTY && !isCI)
-export { isCI, provider as stdProvider } from 'std-env'
+export { isAgent, isCI, provider as stdProvider } from 'std-env'

pnpm-workspace.yaml

@@ -78,7 +78,7 @@ catalog:
   pathe: ^2.0.3
   playwright: ^1.58.2
   sirv: ^3.0.2
-  std-env: ^3.10.0
+  std-env: ^4.0.0-rc.1
   strip-literal: ^3.1.0
   tinyexec: ^1.0.2
   tinyglobby: ^0.2.15

test/cli/test/config/browser-configs.test.ts

@@ -649,7 +649,7 @@ function getCliConfig(options: TestUserConfig, cli: string[], fs: TestFsStructur
     {
       nodeOptions: {
         env: {
-          CI: 'false',
+          CI: '',
           GITHUB_ACTIONS: undefined,
         },
       },

test/cli/test/reporters/agent.test.ts

@@ -0,0 +1,92 @@
+import { runVitest, StableTestFileOrderSorter } from '#test-utils'
+import { describe, expect, test } from 'vitest'
+import { DefaultReporter } from 'vitest/node'
+import { trimReporterOutput } from './utils'
+
+describe('agent reporter', async () => {
+  test('hides passed module headers, shows only failed tests, and prints end summary', async () => {
+    const { stdout } = await runVitest({
+      include: ['b1.test.ts', 'b2.test.ts'],
+      root: 'fixtures/reporters/default',
+      reporters: [['agent', {}]],
+      fileParallelism: false,
+      sequence: {
+        sequencer: StableTestFileOrderSorter,
+      },
+    })
+
+    const output = trimReporterOutput(stdout)
+    expect(output).toMatchInlineSnapshot(`
+      "❯ b1.test.ts (13 tests | 1 failed) [...]ms
+           × b failed test [...]ms
+       ❯ b2.test.ts (13 tests | 1 failed) [...]ms
+           × b failed test [...]ms"
+    `)
+
+    const summary = stdout.replace(/\d+ms/g, '[...]ms').split('\n').filter(line => /Test Files|^\s*Tests\b/.test(line)).map(line => line.trim()).join('\n')
+    expect(summary).toMatchInlineSnapshot(`
+      "Test Files  2 failed (2)
+      Tests  2 failed | 24 passed (26)"
+    `)
+  })
+
+  test('hides all output for passed-only modules', async () => {
+    const { stdout } = await runVitest({
+      include: ['b1.test.ts', 'b2.test.ts'],
+      root: 'fixtures/reporters/default',
+      reporters: [['agent', {}]],
+      fileParallelism: false,
+      testNamePattern: 'passed',
+      sequence: {
+        sequencer: StableTestFileOrderSorter,
+      },
+    })
+
+    const output = trimReporterOutput(stdout)
+    expect(output).toMatchInlineSnapshot(`""`)
+  })
+
+  test('shows console logs only from failed file, suite, and tests', async () => {
+    const { stdout } = await runVitest({
+      config: false,
+      include: ['./fixtures/reporters/console-some-failing.test.ts'],
+      reporters: [['agent', { isTTY: true }]],
+    })
+
+    const logs = stdout.split('\n').filter(line => line.includes('Log from')).join('\n')
+    expect(logs).toMatchInlineSnapshot(`
+      "Log from failed test
+      Log from failed test
+      Log from failed suite
+      Log from failed file"
+    `)
+  })
+
+  test('does not change silent behavior for other reporters', async () => {
+    const { stdout } = await runVitest({
+      config: false,
+      include: ['./fixtures/reporters/console-some-failing.test.ts'],
+      reporters: [new LogReporter(), ['agent', { isTTY: true }]],
+    })
+
+    const logs = stdout.split('\n').filter(line => line.includes('Log from')).join('\n')
+    expect(logs).toMatchInlineSnapshot(`
+      "Log from failed file
+      Log from passed test
+      Log from failed test
+      Log from failed suite
+      Log from passed test
+      Log from failed test
+      Log from passed suite
+      Log from passed test
+      Log from failed test
+      Log from failed test
+      Log from failed suite
+      Log from failed file"
+    `)
+  })
+}, 120000)
+
+class LogReporter extends DefaultReporter {
+  isTTY = true
+}