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firebase-security-rules-auditor

Audits Firebase (Firestore, Cloud Storage) security rules for vulnerabilities, privilege escalation, role bypasses, create vs update inconsistencies, resource exhaustion, type safety, size limits, and hasOnly ownership checks. Use when auditing/reviewing rules, running red-team rule assessments, or scoring against auditor checklists. Don't use for Firebase CLI (login, deploy), Auth, Crashlytics, Remote Config, or database queries.

Quality

86%

Does it follow best practices?

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SecuritybySnyk

Passed

No findings from the security scan

SKILL.md
Quality
Evals
Security

Quality

Content

75%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 audit protocol: a concrete six-item checklist with real rule syntax, a sensible admin-bootstrapping exception, an explicit 1-5 severity scale, and a JSON output contract. It would benefit from an explicit severity-to-score mapping and one worked example.

Suggestions

Add a worked example: a short vulnerable rule snippet (e.g., a create/update pair allowing role escalation) with the filled-in JSON assessment showing score and findings, to calibrate how checklist items translate into output.

State explicitly how finding severities (critical|major|moderate|minor) map to the 1-5 score (e.g., any critical finding caps the score at 1) so the output format and scoring scale are directly linked.

Tighten the persona section to one or two sentences and fix the duplicated 'Scoring Criteria' heading levels to reduce token overhead and improve navigation.

DimensionReasoningScore

Conciseness

The body is mostly lean and domain-specific (hasOnly vs. ownership-check semantics, email_verified requirements), but has minor trimmable padding: the persona framing ('You are a Senior Security Auditor... find the hole in the wall') and a duplicated 'Scoring Criteria' heading at two levels.

4 / 5

Actionability

Concrete, executable guidance: each checklist item names exact fields and expressions ('request.resource.data', 'resource.data.uid == request.auth.uid', 'request.auth.token.email_verified'), and the JSON output template is copy-paste ready. Minor gap: no worked example of a vulnerable rule pair or a filled-in scored output to calibrate findings.

4 / 5

Workflow Clarity

The audit flow (apply checklist -> apply admin-bootstrapping exception -> score 1-5 -> emit JSON) is coherent and this read-only skill needs no destructive-operation validation loop, but the mapping between finding severities (critical|major|moderate|minor) and the 1-5 score bands is left implicit.

4 / 5

Progressive Disclosure

A single self-contained file with well-labeled sections (Overview, checklist, bootstrapping exception, scoring scale, output format); no bundle files exist and none are needed at this size. Slightly below the top anchor due to the redundant heading hierarchy ('# Scoring Criteria' wrapping '### Scoring Criteria (1-5)').

4 / 5

Total

16

/

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 strong description: concrete capability list, explicit use-when triggers, third-person voice, and a sharp don't-use boundary. Only minor gap is missing file-extension mentions and a few natural synonyms in the trigger terms.

DimensionReasoningScore

Specificity

The description enumerates concrete audit targets — 'privilege escalation, role bypasses, create vs update inconsistencies, resource exhaustion, type safety, size limits, and hasOnly ownership checks' — a comprehensive, non-generic list of specific actions. It is written in third person ('Audits') with no padding.

5 / 5

Completeness

Explicitly answers both what ('Audits Firebase (Firestore, Cloud Storage) security rules for...') and when ('Use when auditing/reviewing rules, running red-team rule assessments, or scoring against auditor checklists'), with concrete trigger phrases and an explicit don't-use boundary.

5 / 5

Trigger Term Quality

Good natural-term coverage: 'auditing/reviewing rules', 'red-team rule assessments', 'scoring against auditor checklists', plus product names (Firestore, Cloud Storage). Falls short of the top anchor because file extensions (e.g., 'firestore.rules', 'storage.rules') and common synonyms like 'rule bypass testing' or 'hardening' are absent.

4 / 5

Distinctiveness Conflict Risk

Clear niche (Firebase security rules auditing) with an explicit exclusion list ('Don't use for Firebase CLI (login, deploy), Auth, Crashlytics, Remote Config, or database queries') that sharply separates it from adjacent Firebase 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

metadata_version

'metadata.version' is missing

Warning

Total

15

/

16

Passed

Repository

firebase/agent-skills

Path

skills/firebase-security-rules-auditor/SKILL.md

Reviewed

Table of Contents

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