validating-e2e-coverage

A review that checks whether end-to-end acceptance criteria cover the operational parts of a feature. End-to-end testing checks a complete user flow across the systems it touches.

In plain words
What is it for?
Use it after writing a feature specification or when revisiting an existing feature to identify and recommend additional acceptance-test scenarios.
Why use it?
It finds missing scenarios such as timeouts, repeated requests, service failures, and permission limits before they become production problems.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/acendas/shipyard/validating-e2e-coverage
Any agent
npx skills add Acendas/shipyard --skill validating-e2e-coverage
Clone the repo
git clone --depth 1 https://github.com/Acendas/shipyard

Made for: Claude Code, Codex.

Per session 16 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,564 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00016 $0.01564
Opus 5 $0.00008 $0.00782
Sonnet 5 $0.00003 $0.00313
Haiku 4.5 $0.00002 $0.00156

Measured yesterday against content hash 9deb04174841, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

validating-e2e-coverage 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 yesterday.

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.

plugins/shipyard/skills/validating-e2e-coverage/SKILL.md · 120 lines

How it starts

The opening of the file, as written. The whole thing — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Validating E2E Coverage

Render before asking. Before any AskUserQuestion, render the decision context as assistant chat text. Content that exists only in a Read result, a subagent/Agent return, or the question/option strings does not count as rendered (the UI shows a compact card) — restate it in chat first.

Post-hoc validation that reads a written feature spec, detects which operational/architectural surfaces the feature touches, maps them to the E2E taxonomy, gap-analyzes against existing acceptance criteria, and returns recommended additions. The goal is to catch the scenarios that live outside the feature's own logic — timeouts, idempotency, degradation, privilege boundaries — before they become production incidents.

When to Invoke

Caller Trigger
/ship-discuss Phase 3.7 After spec write, before quality gate
/ship-discuss REFINE mode On re-entry to existing feature (backfill)

Inputs

The calling skill provides:

  • Feature file path (the written spec at <SHIPYARD_DATA>/spec/features/FNNN-slug.md)
  • Existing AC list (parsed from the feature file's ## Acceptance Criteria section)
  • Domain hints (e.g., ["payments", "auth"]) from the discussion context

Procedure

Step 1: Detect Touch Surfaces

Read the feature spec: user story, acceptance criteria, interface, data model, technical notes, flows, error handling sections. For each line, match against the touch-surface detection table in ${CLAUDE_PLUGIN_ROOT}/skills/discovering-edge-cases/references/e2e-taxonomy.md.

Collect all activated category slugs. If the feature's domain_tags include domain-specific terms (payments, auth, etc.), also activate categories commonly associated with those domains.

Step 2: Map to Taxonomy Categories

For each activated category, pull the specific types and example GWT scenarios from the taxonomy. This is the "universe" of E2E scenarios that could apply to this feature.

Step 3: Gap Analysis

For each activated type, check whether existing AC already covers it:

  • COVERED — an existing AC's Given/When/Then semantically addresses this type (e.g., existing "timeout returns 504" covers the timeout category)
  • GAP — no existing AC covers this type; recommend addition
  • PARTIAL — an existing AC touches the area but doesn't fully specify the behavior (e.g., "handles errors" without specifying timeout vs. connection refused vs. 5xx)

Read the full file on GitHub · 120 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.

  1. yesterday First seen · 120 lines · 16 tokens per session scan A 9deb04174841

Subscribe to this mod's changes

validating-e2e-coverage is a skill published in the GitHub repository Acendas/shipyard (2 stars, last pushed 20d ago), licensed MIT. It adds 16 tokens to every session and 1,564 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.

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