/as:epd-compare — EPD Comparator

Harness note: use /as:<skill> on Claude Code and $<skill> on Codex. Resolve <skill-root> as the directory containing this loaded SKILL.md and <plugin-root> as the plugin root that contains skills/, and use equivalent native tools when host tool names differ.

Compare 2 or more products side-by-side on environmental impact metrics. Validates comparability (declared units, system boundaries, PCR alignment), generates comparison tables with percentage deltas, and checks LEED v4.1 MRc2 eligibility.

This skill reads EPD records but does not persist or modify them. Fields follow schema/epd-schema.md, which is distinct from the FF&E product schema. Output is a markdown comparison report.

Input

The user provides EPD data in one of these ways:

Inline data — pasted product names with GWP values
File path — a canonical epd-library.csv or markdown file with EPD data
From prior skills — "compare the EPDs I just parsed/found" (uses structured data from the current conversation)
Mixed — combine pasted, prior, and canonical local CSV records

If the user doesn't specify a source, first use structured EPD data from the current conversation. Otherwise ask for pasted values or an EPD CSV path. When reading epd-library.csv, validate it with python3 "<plugin-root>/skills/master-schedule/scripts/csv-library.py" validate epd; reject FF&E-shaped or malformed files. Validation is read-only; never invoke init, import, append, or update.