Security audit

Piano

Security checks for vulnerabilities and agentic risk

Overview

This piano coaching skill is coherent and purpose-aligned, with disclosed local progress tracking but no evidence of hidden, destructive, or network behavior.

Before installing, be aware that this skill may create a ~/piano/ folder and keep local records of pieces, goals, technique issues, and practice sessions. Use it on a shared or managed device only if you are comfortable with those local notes being stored there.

A.I.G

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

SkillSpector

Vulnerability Patterns

Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code

Findings (3)

Missing User Warnings

Medium

Confidence: 95% confidence
Finding: The skill instructs the agent to create a local workspace and log practice progress in the user's home directory without clearly disclosing this behavior in the skill description or requiring explicit user consent. Silent file creation and persistence can surprise users, expose personal practice/history data on shared systems, and normalize unauthorized filesystem side effects from a seemingly low-risk advisory skill.

Missing User Warnings

Medium

Confidence: 96% confidence
Finding: The progress-tracking section states that pieces, completed repertoire, and recurring issues should be logged to ~/piano/, but it does not present a clear user-facing warning that personal data will be stored locally. Even though the data is not highly sensitive by default, retaining behavioral history without transparent notice can violate user expectations and create privacy issues, especially on shared or managed devices.

Vague Triggers

Medium

Confidence: 96% confidence
Finding: The logging triggers are broad enough to activate during normal conversation, such as casual mentions of practice, struggles, or finishing a piece. This can lead to unintended persistence of user activity details and create privacy or consent issues, especially if the agent logs information without an explicit request from the user.

Static analysis

No suspicious patterns detected.