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.

schema/epd-schema.md

1. Inline data — pasted product names with GWP values
2. File path — a canonical

   epd-library.csv

   or markdown file with EPD data
3. From prior skills — "compare the EPDs I just parsed/found" (uses structured data from the current conversation)
4. Mixed — combine pasted, prior, and canonical local CSV records

epd-library.csv

python3 "<plugin-root>/skills/master-schedule/scripts/csv-library.py" validate epd

init

import

append

update

• Product name and manufacturer
• GWP (A1-A3) value
• Declared unit

• Are all products using the same declared unit (e.g., all per m3, all per kg)?
• If units differ, attempt normalization where possible:
  • kg ↔ ton (multiply/divide by 1000)
  • m2 at different thicknesses (if thickness is known, normalize to same thickness)
• If normalization is impossible, warn: "Product A reports per m2, Product B reports per kg. Direct comparison requires density or thickness data. Provide conversion factors, or I'll compare only within matching units."
• Never silently compare products with different declared units.

• Flag if some are cradle-to-gate (A1-A3) and others cradle-to-grave (A1-A3 + C1-C4 + D).
• Note: "A1-A3 comparison is still valid across both types. Full life cycle comparison is only valid for cradle-to-grave EPDs."

• Flag if products use different PCRs. Products under the same PCR are most directly comparable.
• Note the PCR names if they differ.

• Flag if some use +A1 and others +A2. Impact indicator units may differ (AP in kg SO2e vs. mol H+ eq).
• GWP in kg CO2e is comparable across versions.

• Flag any expired EPDs with their expiration date.

• Flag mix of product-specific and industry-average EPDs. Note that industry-average EPDs are less precise.

undefined

• Default path:

  ./epd-comparison-YYYY-MM-DD.md

• If the user says it's final:

  ./deliverables/epd-comparison-YYYY-MM-DD.md

• If no client context: keep it in the working directory (the default path above)
• Ask the user if they want a different path

Comparison saved to [path].

Next steps:
- /as:epd-to-spec — generate spec language using ECOPact's GWP (242) as the threshold
- /as:epd-research — find more options to compare

• Single product: Can't compare, but can still show the data card with industry average context. Suggest finding more EPDs to compare against.
• Mixed material categories: Warn that cross-material comparison (e.g., concrete vs. steel) is generally not meaningful because declared units and functional roles differ. Offer to group by category.
• Incomplete data: Compare on whatever fields are available. Use

  —

  for missing values. Note which products have more complete data.
• All expired EPDs: Proceed with comparison but add a prominent warning that results are based on expired declarations and should be verified with current EPDs.
• Very large comparisons (10+ products): Show summary table first, then offer to drill into top 3-5 candidates.

• This skill reads, not writes. It does not add records to

  epd-library.csv

  . It produces a comparison report as a markdown file.
• Baselines follow the GWP Baseline Policy above. Cited source + publication year required; uncited from-memory numbers banned. EC3 API integration is in progress and will automate baseline lookups.
• GWP (A1-A3) is the primary metric for most comparisons and LEED. Other indicators (ODP, AP, EP) provide a fuller picture but GWP drives most specification decisions.
• Suggest next skills. After comparison, the natural next steps are

  /as:epd-to-spec

  (to write spec language) or

  /as:epd-research

  (to find alternatives).