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Security audit

Tcg Strategy Advisor

Security checks for vulnerabilities and agentic risk

Overview

The skill appears non-malicious, but its documentation mixes a general deck-structure helper with unsupported current-meta and card-purchase advice.

Install only if you want a general TCG structure helper. Treat any current metagame, matchup-ranking, card-price, or value-retention advice as needing fresh external verification; the artifact itself does not provide live data or market sources.

Vulnerability Patterns
  • Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
  • Agent Memory PoisoningWrites attacker-controlled rules into memory that affect later sessions
  • Remote Payload Retrieval and ExecutionFetches external code whose behavior can change after review
  • Embedded Malicious CodeShips malicious scripts inside the skill and executes them locally
  • Unauthorized Access and Privilege EscalationObtains permissions beyond the task's legitimate needs
Vulnerability Patterns
  • Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep
  • System Prompt LeakageDirect Leakage, Indirect Extraction, Tool-Based Exfiltration
  • Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
  • MCP Least PrivilegeUnderdeclared Capability, Wildcard Permission, Missing Permission Declaration
  • MCP Tool PoisoningHidden Instructions, Unicode Deception, Parameter Description Injection
Findings (12)

Description-Behavior Mismatch

High
Category
Not specified by scanner
Confidence
96% confidence
Finding

The manifest frames the skill as a deck-structure advisor, but the body expands into competitive deckbuilding, matchup tuning, and financial-style purchase advice. Scope drift increases the chance that an agent will apply the skill in contexts where it lacks authority, data, or safeguards, producing misleading or overconfident outputs.

Content

No source excerpt is available for this finding.

Intent-Code Divergence

High
Category
Not specified by scanner
Confidence
97% confidence
Finding

The skill claims it is descriptive-only and does not use live metagame data, but later examples instruct current-meta recommendations and market-style guidance. This mismatch can mislead users and downstream agents into over-trusting unsupported advice, causing unsafe hallucinated recommendations presented as current fact.

Content

No source excerpt is available for this finding.

Intent-Code Divergence

High
Category
Not specified by scanner
Confidence
98% confidence
Finding

The quality bar says outputs must stay honest about not using live metagame data, yet the examples directly depend on live tiering, matchup resources, and current-environment analysis. This internal contradiction is dangerous because it encourages deceptive presentation of stale or fabricated information as timely guidance.

Content

No source excerpt is available for this finding.

Direct Prompt Extraction

High
Category
System Prompt Leakage
Confidence
85% confidence
Finding

Skill contains instructions that could directly expose system prompts, internal rules, or hidden instructions to users or external parties.

Content

Scanner excerpt · handler.py (reported line 122)May include surrounding context.

python
def _load_prompt_template(skill_name: str) -> str:
    del skill_name
    return PROMPT_TEMPLATE


def _normalize_key(key: Any) -> str:

Description-Behavior Mismatch

Medium
Category
Not specified by scanner
Confidence
92% confidence
Finding

The skill description is expanded from structural deck-planning into live metagame coaching and collection-investment guidance, which introduces unsupported domains requiring current external data and financial-style recommendations. When an agent is induced to operate outside its stated competence, it is more likely to hallucinate market conditions, give outdated competitive advice, or mislead users about investment value.

Content

No source excerpt is available for this finding.

Intent-Code Divergence

Medium
Category
Not specified by scanner
Confidence
96% confidence
Finding

The README creates conflicting instructions: the metadata says the skill should not pretend to know the live metagame, but the example asks for current-meta competitive decklists and matchup advice. This can cause the agent to overclaim current knowledge, fabricate up-to-date recommendations, or present stale advice as authoritative, which is a scope-drift and reliability vulnerability.

Content

No source excerpt is available for this finding.

Undeclared Tool Scope

Medium
Category
MCP Least Privilege
Confidence
70% confidence
Finding

Without declared permissions the skill's intent is opaque and cannot be validated.

Content

No source excerpt is available for this finding.

Context-Inappropriate Capability

Medium
Category
Not specified by scanner
Confidence
90% confidence
Finding

Advising users on card purchases, value retention, and investment priority goes beyond deck-structure coaching into financial recommendation territory. Even in a hobby setting, this can cause monetary harm by encouraging unsupported speculation or implied investment advice without appropriate scope, data, or disclaimers.

Content

No source excerpt is available for this finding.

Autonomous Decision Making

Medium
Category
Excessive Agency
Confidence
75% confidence
Finding

Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.

Content

Scanner excerpt · handler.py (reported line 45)May include surrounding context.

python
'mistakes': [
            'Loading up on finishers while cutting early interaction.',
            'Using premium answers on low-value threats because of panic.',
            'Drawing cards without checking whether the deck still has time to cash them in.',
        ],
    },
    'combo': {

Vague Triggers

Low
Category
Not specified by scanner
Confidence
83% confidence
Finding

The description says to use the skill when a user wants a cleaner deck plan and also frames it as applicable to 'real-life resource planning,' which broadens the trigger beyond a specific card-game context. Because the file does not provide exclusion conditions or clear boundaries for when non-TCG planning requests should not invoke the skill, activation scope is somewhat ambiguous.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
77% confidence
Finding

The markdown includes a Chinese name and later provides a full Chinese usage scenario and expected output, but it does not state that language should follow the user's preference. This can be read as implicitly steering output toward a specific language/locale without an explicit opt-in or choice.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
78% confidence
Finding

The normalization regex explicitly preserves CJK characters, and later parsing/scoring logic includes Chinese field names and keywords. Because the code embeds support for a specific language/locale without any visible user choice or opt-in in this file, it may conflict with a policy requiring neutral language handling or explicit language selection.

Content

No source excerpt is available for this finding.

Static analysis

No suspicious patterns detected.