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.
npx agentmods add skills/fastslack/mtw-e2e-runner/e2e-testingnpx skills add fastslack/mtw-e2e-runner --skill e2e-testinggit clone --depth 1 https://github.com/fastslack/mtw-e2e-runnerWhat 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 | $0.00022 | $0.02022 |
| Opus 5 | $0.00011 | $0.01011 |
| Sonnet 5 | $0.00004 | $0.00404 |
| Haiku 4.5 | $0.00002 | $0.00202 |
Grade A, and why
e2e-testing 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 2d 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.
How it starts
The opening of the file, as written. The whole thing — 182 lines — stays where its author put it; the contents beside it link to each section on GitHub.
E2E Testing with @matware/e2e-runner
Overview
@matware/e2e-runner is a JSON-driven E2E test runner. Tests are defined as JSON files with sequential browser actions — no JavaScript test code. Tests run in parallel against a Chrome pool (browserless/chrome via Docker) using Puppeteer.
Key capabilities: 13 MCP tools for running tests, creating test files, capturing screenshots, analyzing network traffic, verifying GitHub/GitLab issues, and querying a learning system for stability insights.
Prerequisites
Before running any tests, verify the Chrome pool is available:
e2e_pool_status → check "Available: yes" and session capacity
If the pool is not running, the user must start it via CLI (not available via MCP):
npx e2e-runner pool start
Core Workflow
The standard test execution flow:
- Check pool →
e2e_pool_status— confirm Chrome pool is ready - List suites →
e2e_list— discover available test files and modules - Run tests →
e2e_run— execute withall,suite, orfileparameter - Interpret results — check
summary,failures,narratives,networkSummary - View screenshots →
e2e_screenshot— retrieve error/verification screenshots byss:HASH - Drill into network →
e2e_network_logs— userunDbIdto inspect requests/responses - Check learnings →
e2e_learnings— query stability trends, flaky tests, error patterns
Interpreting Run Results
The e2e_run response includes:
- summary: pass/fail counts, duration,
runDbIdfor drill-down - failures: failed test names with error messages and error screenshot hashes
- narratives: step-by-step human-readable story of each test execution
- networkSummary: per-test request stats (status distribution, slow/failed requests)
- verifications: tests with
expectfield — calle2e_screenshotto visually verify - learnings: stability insights from the learning system (new failures, flaky patterns)
Creating Tests
What ships with it
10 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- references/action-types.md 8.7 KB
- references/auth-strategies.md 3.4 KB
- references/graphql.md 2.8 KB
- references/issue-verification.md 2.4 KB
- references/multi-pool.md 2.5 KB
- references/network-debugging.md 2.7 KB
- references/test-json-format.md 4.6 KB
- references/troubleshooting.md 7.4 KB
- references/variables.md 1.5 KB
- references/visual-verification.md 2.8 KB
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.
- 2d ago First seen · 182 lines · 22 tokens per session scan A 31b668474e9a
e2e-testing is a skill published in the GitHub repository fastslack/mtw-e2e-runner (3 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 22 tokens to every session and 2,022 once invoked, about $0.0001 per session on Opus 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 2026-08-31.
Other skills, from other repositories
project-release
Prepare, publish, verify, or recover a cloakbrowser-mcp release only when the user explicitly requests release work. Require a Prompt MCP-confirmed target version and stability, follow the repository's version, changelog, PR, GitHub Release, npm, Docker, MCP Registry, and docs process, and never tag, publish…
project-pull-request
Create, update, prepare, or review a cloakbrowser-mcp GitHub Pull Request only when the user explicitly requests PR work. Follow the repository's branch, base/head, assignee, title, template, check, security, and reporting rules; review remains read-only, and commit, push, PR creation/update, readiness changes, merge…
spec-driven-development
Author the authoritative /spec workflow for a substantial cloakbrowser-mcp change when the user invokes /spec, explicitly requests a specification, or authorizes specification work that lacks a durable contract. Establish repository facts, use the globally installed Prompt MCP for every material decision, persist…
planning-and-task-breakdown
Author the authoritative /plan workflow for substantial cloakbrowser-mcp work when the user invokes /plan or explicitly requests implementation planning, decomposition, milestones, or review-gated task packets. Require an approved specification, use Prompt MCP for unresolved material planning and authorization…
code-review-and-quality
Review a proposed or completed cloakbrowser-mcp change only when the user explicitly requests code review, quality review, or a pre-merge assessment. Evaluate strict TypeScript, CLI and transport contracts, upstream-tool parity, child-process and session boundaries, tests, docs, packaging, workflows, security, and…
documentation-and-adrs
Write or revise cloakbrowser-mcp technical documentation or record a settled architecture decision only when the user explicitly requests documentation, an ADR, or documentation required by an authorized public-contract change. Use for bridge architecture, CLI and environment configuration, stdio or Streamable HTTP…