Lookup CSI

Retrieve a CSI MasterFormat 2020 section number — XX YY ZZ — Title — for a product, scope, or work category, from a source the user authorizes. No internal MasterFormat values; every output row cites a verbatim quote with a SourceURL.

For plain-English interpretation of an actual spec section, use /explain-spec. For a full spec audit, use the spec-review skill.

Inputs the command needs

1. Product or scope keyword — name what is being specified. Examples:
   • air barrier — fluid-applied membrane
   • aluminum-framed entrance and storefront
   • metal panel rainscreen
   • EPDM single-ply roofing
   • gypsum board assemblies
   • acoustic ceiling panels
   • carpet tile
   • chilled-water piping
   • LED interior lighting
   • low-voltage structured cabling
2. Division hint (optional) — if the user already knows the division: Div 03 — Concrete, Div 07 — Thermal & Moisture, Div 08 — Openings, Div 09 — Finishes, Div 23 — HVAC, Div 26 — Electrical, Div 27 — Communications, Div 28 — Electronic Safety & Security. Narrows the search.
3. Spec format — MasterSpec (AIA), ARCAT, SpecLink+, 4specs, project custom. Different libraries may sub-divide differently below the XX YY ZZ level.

Step 1 — Source preference (always ask first)

Tell the user, all at once:

"Where should I retrieve the CSI section number from? (a) Standard — CSI public preview (limited free pages at https://www.csiresources.org/) and the CSI Numbers and Titles reference list. Note: the full MasterFormat 2020 publication is paywalled, so paste preferred for precise sub-section numbers. (b) Your own source — paste from a project spec book, your company's spec library (MasterSpec, ARCAT, SpecLink+), an arch-rag-indexed MasterFormat PDF, or a manufacturer's spec listing. (c) Both — fetch standard preview AND check your source; report any divergence (sub-section numbering can differ by spec library).

Pick (a), (b), or (c)."

The command does not proceed without an explicit pick. Because MasterFormat 2020 is paywalled, (b) Your own source is typically the higher-confidence path for sub-section precision.

Step 2 — Acquire source

• (a) Standard fetch — WebFetch https://www.csiresources.org/ with the keyword. Where the public preview is sufficient (division + level-2 group), quote the verbatim listing. For sub-section precision, ask the user to paste from their licensed MasterFormat access.
• (b) Own source — accept paste from the user's spec library, run arch-rag query against an indexed MasterFormat PDF, or accept a user-provided URL on confirmation. Quote verbatim.
• (c) Both — execute (a) and (b); present both quotes; flag any divergence (especially below level 3 — XX YY ZZ).

If a fetch returns a paywall (most MasterFormat content is licensed), fall back to: WebSearch <keyword> CSI MasterFormat 2020 section site:csiresources.org OR site:arcat.com OR site:masterspec.com → ask user to confirm match → ask user to paste from their access.

Step 3 — Output

# Lookup CSI — [Product or scope, plain title]

**Keyword:** [air barrier — fluid-applied membrane]
**Division hint:** [Div 07 — Thermal & Moisture / unspecified]
**Spec format:** [MasterSpec / ARCAT / SpecLink+ / custom / unspecified]
**Source preference:** [(a) CSI preview / (b) own source — name / (c) both]

## Reference area
CSI MasterFormat 2020 — `Numbers and Titles`. CSI public preview at `https://www.csiresources.org/`. Manufacturer-specific section assignments may vary slightly across `MasterSpec`, `ARCAT`, and `SpecLink+`.

## Source quote
> [Verbatim section number + title — e.g., `07 27 26 — Fluid-Applied Membrane Air Barriers`. Quote the listing block as printed in the source.]

(Source: WebFetched from `<URL>` on <YYYY-MM-DD> / pasted by user from <doc> / arch-rag query against `<indexed PDF>`)

## Section table
| Field | Value (per quoted source) |
|---|---|
| Section number | `XX YY ZZ` |
| Section title | "<verbatim>" |
| Division | "<verbatim, e.g., 07 — Thermal and Moisture Protection>" |
| Level-2 group | "<verbatim, e.g., 07 20 — Thermal Protection>" |
| Level-3 (if shown) | "<verbatim, e.g., 07 27 — Air Barriers>" |
| Scope notes | "<verbatim, if printed>" |
| Source year / edition | "<verbatim, e.g., MasterFormat 2020>" |

## Divergence (if (c))
- [Bullet — any section# / title difference between CSI preview and own source. Spec libraries (`MasterSpec`, `ARCAT`, `SpecLink+`) can sub-divide below level 3 differently.]

## Caveats
- This is a section-number retrieval, not a spec edit. The Architect of Record assigns section numbers and stamps the project spec; this command does not modify or generate spec content.
- `MasterFormat 2020` is the current edition. Older projects may reference `MasterFormat 2018`, `MasterFormat 2016`, or `MasterFormat 2010` — verify the project's spec base year before using a 2020 number on a legacy project.
- Sub-section precision (below `XX YY ZZ`) often varies by spec library. Use the user's project / company library for sub-section, not a generic `MasterFormat` lookup.
- For an actual spec section's content, use `/explain-spec`.
- Binding interpretation is the AOR's stamped spec book.

NA AEC conventions (enforce)

• English only.
• CSI section format XX YY ZZ — six digits, single spaces, no periods, no dashes between digit groups. Examples: 07 27 26, 08 11 13, 09 30 13, 23 21 13, 26 51 13. Never 07.27.26 or 7-27-26.
• Imperial-first throughout (although CSI numbers are dimensionless).
• Codes / standards: CSI MasterFormat 2020, CSI SectionFormat / PageFormat 2020. Reject KBC, KS, EN, BS, JIS, DIN.
• Spec libraries / publishers: MasterSpec (AIA), ARCAT, SpecLink+, 4specs. Manufacturer-spec sources cited per library.
• AHJs named when the spec section interacts with a code-driven product (e.g., NYC FDNY-listed materials, CA HCAI seismic anchorage): NYC DOB, LADBS, DSA, CA HCAI, Toronto Building, NYC SCA. Never the AHJ or the city.
• Floors: Level 3 / L3 / 3rd floor. Never 3F.
• Roles: Architect of Record (AOR), Spec Writer, Engineer of Record (EOR), MEP Engineer. Never Director as a project role.

Constraints

• Never invent CSI section numbers from recall.
• Never paraphrase the section title — verbatim only.
• Always ask the source-preference question at Step 1; do not skip.
• Never claim sub-section precision (below XX YY ZZ) from recall — sub-section numbering varies by spec library.
• Always include the SourceURL + timestamp.
• Always state the MasterFormat edition (2020 vs older) when known.
• Caveat block always present.
• Markdown only. No Word / PDF.

Anti-patterns (never do)

• Stating "air barriers are 07 27 26" from recall — never. The section # comes from a fetch or paste.
• Asserting sub-section numbers (07 27 26.13) from recall — sub-sections vary by spec library and edition.
• Treating MasterFormat 1995 legacy 5-digit numbers as equivalent to MasterFormat 2020 6-digit (07 27 26 ≠ 07270).
• Auto-fetching from manufacturer marketing pages as the source — MasterFormat is the publisher of record.
• Auto-fetching without explicit user authorization.
• Skipping Step 1 (source preference question) — never.
• Running /explain-spec from inside this command — pointer-only.