# Compare EPDs

> Compare environmental declarations on a supported common basis.

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## Start here

- [Install](https://architecturestudio.ai/capabilities/skill-epd-compare#capability-setup)
- [New to skills?](https://architecturestudio.ai/docs/agents)
- [All skills](https://architecturestudio.ai/capabilities?kind=skills)

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## What it does

Give Norma the declarations and the comparison question. Norma checks whether units, product scope and life-cycle boundaries align before comparing impacts. Incompatible evidence stays visibly unresolved.

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## Install

Connect Arch Studio in Claude or ChatGPT, then return to your conversation and ask Norma for the task. Your assistant uses its available file access and tools to carry out the skill.

- [Add to Claude](https://architecturestudio.ai/docs/install?host=claude&surface=app&method=mcp)
- [Add to ChatGPT](https://architecturestudio.ai/docs/install?host=chatgpt&surface=app&method=mcp)
- [Setup guide](https://architecturestudio.ai/docs/install)

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## Versions and source

Arch Studio 1.5.1.2 · MCP — Available as MCP workflow instructions in compatible Claude and ChatGPT connections. The assistant performs the work with its own tools and permissions and verifies the actual result before reporting completion.

Arch Studio 1.5.1.2 · Open source — Included in the public plugin for Claude Code and Codex. In this version: Compare EPDs — Compare product impacts, declared units and system boundaries, with LEED eligibility checks.

- [Hosted release details](https://architecturestudio.ai/releases/hosted-1-5-1-2-0692a162)
- [Read public source](https://github.com/AlpacaLabsLLC/skills-for-architects/blob/b85cba155ddbabe8e721fc79044e5a9ef4aa7540/skills/epd-compare/SKILL.md)
- [Public release details](https://architecturestudio.ai/releases/public-1-5-1-2)

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## Usage

Ask Norma in plain language. With Arch Studio connected through MCP, no $ or / command is required. Norma is your assistant working with Arch Studio.

```text
Use Arch Studio to compare these two flooring EPDs. First check declared units, product variants, impact indicators and life-cycle stages. If the inputs are incompatible, explain the gap instead of ranking the products.
```

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## What it checks

### Product and unit

Norma verifies the product variant and declared or functional unit for each declaration.

### Stages and indicators

Norma checks that the reported life-cycle stages and impact indicators support the intended comparison.

### Conversions and ranking

Norma converts only from supported inputs and explains any excluded data. Norma does not rank products on incompatible evidence.

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## Workflow

1. **Identify** — Norma reads the declarations and comparison criteria.
2. **Align** — Norma checks units, scope and boundaries and identifies missing conversion evidence.
3. **Compare** — Norma presents the supported comparisons and unresolved differences.

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## Pairs with

Norma can use reviewed comparison evidence when drafting environmental specification requirements.

- [EPD specification clauses](https://architecturestudio.ai/capabilities/skill-epd-to-spec)

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## Related skills

Read EPDs — Read an EPD into structured, source-linked environmental data.

EPD specification clauses — Turn reviewed environmental evidence into draft specification requirements.

- [Read EPDs](https://architecturestudio.ai/capabilities/skill-epd-parser)
- [EPD specification clauses](https://architecturestudio.ai/capabilities/skill-epd-to-spec)