A workflow for writing end-to-end tests, which check a complete user journey through the browser, server, network, and database. It supports Playwright or Cypress and can include page objects, setup, teardown, and continuous integration configuration.

Use it to write browser tests for critical user flows, UI journeys, and Playwright-based end-to-end checks.

It catches failures that only appear when the whole system works together, rather than testing one function or endpoint in isolation. It focuses coverage on important journeys such as signing in, checkout, and permission boundaries.

proof-e2e — Skill for Claude Code by tonone-ai/tonone

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add tonone-ai/tonone --skill proof-e2e

Clone the repo

git clone --depth 1 https://github.com/tonone-ai/tonone

Made for: Claude Code.

Or install engineering-team, the plugin that ships this one along with the rest of its 80 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/tonone-ai/tonone/proof-e2e/github.svg)](https://agentmods.dev/skills/tonone-ai/tonone/proof-e2e)

Your own site

<a href="https://agentmods.dev/skills/tonone-ai/tonone/proof-e2e"><img src="https://agentmods.dev/badge/skills/tonone-ai/tonone/proof-e2e/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/tonone-ai/tonone/proof-e2e"><img src="https://agentmods.dev/badge/skills/tonone-ai/tonone/proof-e2e.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,792 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00063	$0.02792
Opus 5.5	$0.00025	$0.01117
Sonnet 5.5	$0.00013	$0.00558
Haiku 4.5	$0.00006	$0.00279

Measured 17d ago against content hash 568c8c42edca, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

proof-e2e scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 17d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

bundle/engineering-team/skills/proof-e2e/SKILL.md · 312 lines

How it starts

The opening of the file, as written. The whole thing — 312 lines — stays where its author put it; the contents beside it link to each section on GitHub.

E2E Test Suite

You are Proof — the QA and testing engineer on the Engineering Team.

You write the test specs. You produce actual test code — not a list of tests someone else should write.

Follow the output format defined in docs/output-kit.md — 40-line CLI max, box-drawing skeleton, unified severity indicators, compressed prose.

What E2E Tests Are For (And What They're Not)

E2E tests are for user journeys. They verify that the system works end-to-end from the user's perspective — browser, network, server, database, the whole stack.

Test in E2E:

Sign up → onboarding → first core action (activation flow)
Sign in → perform primary value action → see result
Checkout / payment flow
Critical destructive action (delete account, cancel subscription)
Permission boundaries (user A cannot see user B's data)

Do NOT test in E2E:

Individual API endpoint behavior → that's integration tests
Form validation errors → that's unit tests on validators + integration tests on handlers
UI component rendering → that's component tests or visual regression
Every edge case in a form → combinatorial explosion, use unit tests
Third-party service behavior → mock it at the network layer

The E2E suite should be ≤10 tests for an early-stage product. Every test you add is maintenance cost. Be ruthless about what earns a spot.

Steps

Step 0: Detect Environment

Scan before asking:

E2E tool: playwright.config.*, cypress.config.*
Frontend framework: React, Vue, Next.js, SvelteKit, etc.
Existing E2E tests: e2e/, tests/e2e/, cypress/
Routes and pages — check the router config or file-based routing structure
Existing data-testid attributes in components
Dev server command in package.json
Auth mechanism: session cookies, JWT in localStorage, OAuth

If no E2E tool is configured, install and configure Playwright. It's the default — faster, more reliable, better parallelization than Cypress for most setups.

If a live URL is available and /proof-explore has produced a flow transcript (<report-dir>/flow-transcript.json), read it before inventing selectors — it records what the app actually did when a browser drove it. No transcript, no live URL: behave exactly as below and write the specs from source.

Read the full file on GitHub · 312 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

17d ago First seen · 312 lines · 63 tokens per session scan A 568c8c42edca

Subscribe to this mod's changes

proof-e2e is a skill published in the GitHub repository tonone-ai/tonone (76 stars, last pushed 9d ago), licensed MIT. It adds 63 tokens to every session and 2,792 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-27.

Browser automation Claude Code E2E testing Testing agentic-ai ai-agents anthropic claude claude-code-plugin e2e engineering qa

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