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testland/stale-while-revalidate-reference

Pure-reference catalog of RFC 5861's stale-while-revalidate + stale-if-error Cache-Control extensions. Defines stale-while-revalidate=N (caches MAY serve a stale response while asynchronously revalidating, up to N seconds after expiry) and stale-if-error=N (caches MAY serve stale on 5xx upstream errors). Distinguishes from RFC 9111's must-revalidate (forbids serving stale) and from manual cache-aside refresh (synchronous). Covers the interaction with the freshness lifetime (max-age) and the cache-stampede-mitigation properties. Use when designing the cache-refresh boundary or auditing existing Cache-Control headers.

73

Quality

92%

Does it follow best practices?

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SecuritybySnyk

Passed

No findings from the security scan

Overview
Quality
Evals
Security
Files

Quality

Content

80%

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

A dense, well-structured reference catalog with concrete syntax and executable test recipes that scores well on conciseness and actionability. It is held back only by its monolithic single-file layout and the absence of explicit validation checkpoints in an operational-workflow sense.

Suggestions

Split the per-vendor support and testable-behaviours tables into a separate reference file (e.g. references/vendor-support.md) referenced one level deep from SKILL.md to improve progressive disclosure.

Add an explicit audit/checklist workflow section (e.g. '1. Inspect headers → 2. Verify against the Testable behaviours table → 3. Flag anti-patterns') with a validate-and-retry loop to raise workflow clarity.

Tighten the Overview paragraph, which partially restates the frontmatter description, to reclaim tokens.

DimensionReasoningScore

Conciseness

Lean, table-driven reference content that assumes competence — vendor differences, lifecycle steps, test recipes, and limitations are all non-obvious facts delivered with little padding. It does not explain concepts Claude already knows; the RFC quotes are appropriate reference material.

3 / 3

Actionability

Provides concrete, copy-paste-ready header syntax ('Cache-Control: max-age=60, stale-while-revalidate=300') and executable test procedures ('Set max-age=1, SWR=300; wait 5s; request → stale served + async revalidate'), plus a concrete anti-patterns-to-fix table.

3 / 3

Workflow Clarity

The Lifecycle (steps 1-4) and Composition timeline give a clear sequence, and the Testable behaviours table acts as a verification checklist, but as descriptive reference material it lacks explicit validate-then-proceed checkpoints and error-recovery feedback loops the top anchor requires.

2 / 3

Progressive Disclosure

The single file is well-organized into clear sections with a clearly signaled References block, but at ~175 lines with no bundle files, detailed sections (per-vendor support, testable behaviours) are kept inline rather than split into one-level-deep reference files.

2 / 3

Total

10

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12

Passed

Description

100%

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A strong, specific description that names concrete capabilities, uses natural domain trigger terms, and gives an explicit 'Use when' clause. Third-person voice is maintained throughout with no over-claims.

DimensionReasoningScore

Specificity

Lists multiple concrete capabilities: 'Defines stale-while-revalidate=N ...', 'Defines stale-if-error=N ...', 'Distinguishes from RFC 9111's must-revalidate', and 'Covers the interaction with the freshness lifetime (max-age)'. Each is a specific, verifiable action rather than vague language.

3 / 3

Completeness

Clearly answers 'what' ('Pure-reference catalog of RFC 5861's stale-while-revalidate + stale-if-error Cache-Control extensions') and 'when' with an explicit 'Use when designing the cache-refresh boundary or auditing existing Cache-Control headers' clause.

3 / 3

Trigger Term Quality

Uses the exact natural terms a caching-focused user would say — 'stale-while-revalidate', 'stale-if-error', 'Cache-Control', 'max-age', 'cache-refresh boundary', 'auditing existing Cache-Control headers' — with good coverage of the domain vocabulary.

3 / 3

Distinctiveness Conflict Risk

Occupies a clear, narrow niche (RFC 5861's two specific Cache-Control extensions) with distinct triggers that are unlikely to collide with other skills.

3 / 3

Total

12

/

12

Passed

Validation

100%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation16 / 16 Passed

Validation for skill structure

No warnings or errors.

Reviewed

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