The Agent Skills Directory

Prompt Injection (HIGH): The skill is highly vulnerable to Indirect Prompt Injection because it is designed to ingest, analyze, and 'exactly match' the formatting of external Excel and CSV files.
Ingestion points: SKILL.md and references/openpyxl-patterns.md demonstrate loading untrusted data using pd.read_excel() and load_workbook().
Boundary markers: Absent. There are no instructions to treat cell content as untrusted or to ignore embedded instructions. The instruction to 'study and EXACTLY match' existing patterns increases the risk of the agent obeying hidden instructions in cell metadata or text.
Capability inventory: The agent has full access to the Python environment (pandas, openpyxl), file system (reading/writing spreadsheets), and the ability to execute the recalc.py wrapper script.
Sanitization: Absent. Data is processed directly by the libraries and used to influence the agent's next steps, such as fixing errors identified by recalc.py.
Command Execution (MEDIUM): The recalc.py script uses subprocess.run() to execute system-level commands (soffice, timeout, gtimeout). While it avoids direct shell interpolation by using a list of arguments, it relies on the presence and specific configuration of external system binaries which could be exploited in shared environments.
Persistence Mechanisms (MEDIUM): recalc.py contains logic in setup_libreoffice_macro() to write a StarBasic macro to the user's local LibreOffice configuration directory (~/.config/libreoffice/ or ~/Library/Application Support/LibreOffice/). Modifying application configuration files to enable execution of custom macros is a security risk and functions as a form of persistence.

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