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testland/manifest-v3-test-surface-reference

Pure-reference catalog of the Manifest V3 test surface for Firefox + Chromium browser extensions. Maps each manifest field that changed from MV2 (manifest_version, background.service_worker vs background.scripts, action vs browser_action / page_action, host_permissions split, web_accessible_resources object-form, content_security_policy object-form), the runtime restrictions service workers impose (no DOM, no XMLHttpRequest, no localStorage, ephemeral lifecycle, synchronous listener registration, alarms instead of setTimeout), and the Firefox-vs-Chrome key matrix (browser_specific_settings.gecko, externally_connectable / offline_enabled gaps, MV2-only user_scripts manifest key); references/ carry Mozilla's web-ext CLI (lint via addons-linter, run on firefox-desktop / firefox-android / chromium targets, deterministic build, AMO sign). Use as the manifest-surface reference when authoring extension tests across both browsers, or when driving Firefox runs / AMO signing with web-ext.

72

Quality

90%

Does it follow best practices?

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SecuritybySnyk

Passed

No findings from the security scan

Overview
Quality
Evals
Security
Files

Quality

Content

85%Weight 40%Scale 1-5

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

A well-structured reference body: lean summary tables, actionable anti-patterns with fixes, and clean one-level-deep disclosure into two verified reference files. The only imperfections are repeated reference pointers and the absence of any inline runnable commands.

DimensionReasoningScore

Conciseness

Dense, information-bearing tables with no tutorial padding and no explanation of concepts Claude already knows beyond one framing paragraph. Minor trimmable redundancy: the pointer to references/manifest-matrix.md is repeated in four sections, and the Overview restates known MV3 background.

4 / 5

Actionability

Concrete guidance throughout — exact field shapes ("service_worker": "sw.js"), named APIs (chrome.offscreen.createDocument, chrome.alarms.create, chrome.storage.local), and an anti-patterns table with exact fixes. Per the rubric's code_vs_instruction note, missing code is not penalized, but nothing in the body is copy-paste runnable since commands live in the references, so it sits just below anchor 5.

4 / 5

Workflow Clarity

A single-purpose lookup reference with no multi-step process; the simple-skill exception applies: the action (field -> test implication -> reference for detail) is unambiguous, the When-to-use section maps each scenario to a section, and no destructive/batch operations require validation checkpoints.

5 / 5

Progressive Disclosure

SKILL.md is a genuine overview (summary tables), deep detail is split into two real, one-level-deep reference files clearly signaled with markdown links at point of need, and external sources are consolidated in a References section with stable URLs.

5 / 5

Total

18

/

20

Passed

Description

92%Weight 40%Scale 1-5

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 specific, comprehensive description with an explicit use-when clause and a well-defined niche. Its only weakness is keyword coverage that misses a few natural synonyms users would say.

DimensionReasoningScore

Specificity

The description enumerates multiple concrete mappings — changed manifest fields (background.service_worker vs background.scripts, host_permissions split, web_accessible_resources object-form), service-worker restrictions (no DOM, no XMLHttpRequest, no localStorage, alarms instead of setTimeout), and web-ext CLI capabilities (lint via addons-linter, run on firefox-desktop / firefox-android / chromium targets, AMO sign) — giving comprehensive coverage of its domain.

5 / 5

Completeness

The "what" is explicit ("Pure-reference catalog of the Manifest V3 test surface...") and the "when" is an explicit trigger clause: "Use as the manifest-surface reference when authoring extension tests across both browsers, or when driving Firefox runs / AMO signing with web-ext."

5 / 5

Trigger Term Quality

Good natural-term coverage: "Manifest V3", "MV3", "Firefox", "Chromium", "browser extensions", "extension tests", "web-ext", "AMO signing". A few common variants are missing — users more often say "Chrome" than "Chromium", and "WebExtensions" / "cross-browser" never appear.

4 / 5

Distinctiveness Conflict Risk

Clear niche (MV3 manifest field test surface + Firefox web-ext tooling) with distinct, specific triggers; unlikely to fire for unrelated skills.

5 / 5

Total

19

/

20

Passed

Validation

93%

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

Validation — 15 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

referenced_paths_exist

Referenced path issues: 3 missing

Warning

Total

15

/

16

Passed

Reviewed

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