e2e: agentic end-to-end tests

e2e runs UI tests that mix agent goals with exact steps. agent.act drives one goal; agent.assert, agent.waitFor, and agent.extract judge the screen; screen, app, browser, and expect act and check exactly. UI targets use @e2e-dev/web for browsers or @e2e-dev/mobile for iOS simulators, Android emulators, and connected phones.

Start here: pick the reference for the job

Read the one reference that matches the request before doing anything else. Each stands on its own; a reference names another topic only for a side trip. npx e2e guide <topic> prints the installed package's version of a reference; prefer it when it differs from this copy. The Rules and Feedback sections below still apply.

For anything the references do not cover, the full documentation ships in the docs/ directory of the installed e2e package (node_modules/e2e/docs in a single-package project); a link such as /reference/cli is docs/reference/cli.mdx. Complete projects for Vite, Next.js, Astro, Expo, SwiftUI, Jetpack Compose, Kotlin Multiplatform, Flutter, and .NET MAUI are in https://github.com/tester-army/e2e/tree/main/examples.

Quick start

A config with one web target and a model, and a test that drives one goal and pins the outcome:

// e2e.config.ts
import type { E2EConfig } from 'e2e';
import { web } from '@e2e-dev/web';
import { gateway } from 'ai';

export default {
  targets: [
    {
      engine: web(),
      app: {
        url: 'http://127.0.0.1:3000',
        command: { executable: 'pnpm', args: ['dev'], log: '.e2e/logs/app.log' },
      },
    },
  ],
  // The model behind every agent.* step: an AI SDK instance; gateway() from 'ai' reads AI_GATEWAY_API_KEY or a Vercel OIDC token.
  agents: {
    default: {
      model: gateway('openai/gpt-6-luna-fast'),
      system: 'You are a thorough QA agent. Verify every outcome on screen.',
    },
  },
} satisfies E2EConfig;

// tests/billing.e2e.ts
import { test } from '@e2e-dev/web';
import { expect } from 'e2e';

test('a member upgrades to Pro', async ({ app, agent, screen, browser }) => {
  await app.open('/settings/billing');
  await agent.act('upgrade the workspace to the Pro plan');
  await expect(screen.getByRole('status')).toContainText('Pro');
  await expect(browser).toHaveURL('/settings/billing');
});

Workflow: writing a test

1. Look at what exists: e2e.config.ts or e2e.config.mts, the tests glob (default tests/**/*.e2e.ts), e2e in package.json. Nothing there: follow setup when the user has requested e2e (see Rules).
2. Learn the screens before writing a test: routes, labels, roles, button text. Semantic locators need the accessible names the app renders, so read the components, open the page with --headed, or drive the live app over a connected e2e mcp server (topic mcp): open_session, observe, and locate show exact names and check a locator before you write it.
3. Write tests/<feature>.e2e.ts. Drive the flow with agent.act, one atomic goal per call, and pin each outcome right after with expect or agent.assert. A test with three goals makes three calls. Exact values go through screen: a sign-in form in a setup test, a field that must receive one specific string, a count that must be one number.
4. Run one file: npx e2e run tests/<feature>.e2e.ts. Agent steps need a model in the config and that provider's authentication (a saved subscription login, an API key); a local endpoint may need none. Tests without agent steps need no model.
5. Read the trace page the terminal names under each failed test (.e2e/results/<test>/trace.md): every step with what it did, the cache's decision, what the app logged, the agent's turns, and the screen at failure. Fix the locator, the expectation, or the app. Never add a sleep.

Rules

• In a project without e2e, set it up when the user requests it. Otherwise ask before adding a test framework, and name any existing framework.
• Live MCP tools need the project's own e2e mcp server registered in the client (topic mcp); writing and running tests use the CLI directly.
• Run the CLI as npx e2e ... (or pnpm exec e2e ...).
• The config is export default { ... } satisfies E2EConfig with import type { E2EConfig } from 'e2e'. targets is required; a UI target names an engine and declares the app beside it: { engine: web(), app: { url, command } }. A tools-only target can omit the engine and set platform.
• Import test, describe, the hooks, expect, credentials, and secrets from e2e. A test that uses the browser fixture imports test, describe, and the hooks from @e2e-dev/web: the same runtime functions, typed with browser.
• Config and tests are ES modules whatever package.json sets as type.
• Locators resolve when used. Actions wait for readiness and expect retries assertions. Reads such as textContent() wait for one match until the action timeout, then answer the current value; count() and isVisible() answer from the current screen. Nothing waits for a value to change, so use a matcher when a value has to settle.
• A locator that matches two nodes fails with LOCATOR_AMBIGUOUS; narrow it (topic writing-tests).
• Secrets never appear in test code. Declare accounts under credentials and every other sensitive value under secrets in the config; resolve with credentials.user(name).password or secrets.get(name) (separate namespaces: secrets.get never returns a password), and hand the opaque Secret only to fill() or agent.act params.
• Agent instructions: one goal per act, the wording on screen, real values in params. A goal is atomic: one outcome that one check confirms. Two outcomes worth checking are two goals, so split them into two act calls (topic agent). Bad: 'add a todo and mark it done'. Good: 'add a todo', check, then 'mark the todo as done', check. Judge meaning, not phrasing: toContain('Pro'), not an exact sentence a model produced.
• Check each agent goal's outcome. A passing act with a recorded check can be cached and replayed without model calls (topic agent).
• Shape the agent for this app: context for vocabulary the screens use, system for how it works, tools for a test API, named personas under agents. When a step fails, tighten the goal first, then the context, then the agent.
• .e2e/ is output (report.json, results/, cache/, logs/; the config's output moves the report and artifacts, never cache/ or the app's log). Read it, never edit it.

Feedback

When e2e itself gets in your way, offer to tell the e2e team: a command or API that broke (bug), docs or this skill that misled you (docs), or a capability you needed and did not find (feature). Once per problem, after you worked around it or gave up. Never report:

• failures of the app under test, or its own behavior;
• a problem you saw once and could not see again;
• anything on an outdated e2e: the command refuses it, so upgrade and check the problem still happens first.

Search existing issues first (gh issue list -R tester-army/e2e --search "<words>"); comment on a match instead of sending a new report.

A bug needs --repro, steps that reproduce it every time without app content. Without such steps, or when the bug needs your app to show, omit --repro: the command then prints a prefilled GitHub issue and sends nothing; show the user the link and tell them to add a minimal reproduction and submit it. Never file the issue yourself.

Run it with --dry-run first, show the user what would be sent, and send it only when they agree.

npx e2e feedback --type bug -m "<one or two sentences>" \
  --repro "<steps that reproduce it every time>" --error-code LOCATOR_AMBIGUOUS \
  --task "<what you were doing>" --expected "<...>" --actual "<error message>" \
  --approach "<what you tried>" --command "<e2e command>" --agent "<agent / model>"

Describe e2e's behavior only, briefly: never paste app content, page text, test files, URLs of private apps, or credentials. Secret-named environment variables and common token shapes are redacted, but do not rely on it. After sending, give the user the reference id it prints.