Fireshield Tools — Architecture & MCP Guide

Overview

Fireshield Tools is a Cloudflare Pages platform hosting two structural steel fire protection utilities. Both tools share a common section database and calculation engine — built once, used everywhere.

Architecture

Key Design Decisions

• esbuild bundles everything at build time. Section JSONs (278 sections, 7 types) and product DFT tables are embedded into each worker. No runtime database calls for lookups — fast and offline-capable for the MCP server.
• Shared library, multiple consumers. lib/section-lookup.js and lib/calculator.js are imported by the Cloudflare Pages Function, the SteelVision client app, and the MCP server — all via esbuild bundling.
• D1 for mutable state only. The Cloudflare D1 SQLite database stores fuzzy match approvals (section_aliases) and completed project schedules (projects, members). Static data never touches D1.
• Section database on R2. The canonical section JSONs in data/sections/ are synced to a Cloudflare R2 bucket (steel-sections) so external projects can pull the same data without depending on this repo.

Section Matching Pipeline

1. Exact match — normalise input, check 278 sections + stored aliases (100% confidence)
2. Custom alias — check D1 section_aliases for user-approved mappings
3. Fuzzy match — parse components, score candidates by dimensional proximity; auto-accept ≥ 80%
4. Unmatched — surface candidate suggestions in the UI for manual selection and approval

Shared Section Database

Excel Parser — Input Formats

The FireCalc parser (public/firecalc/app.js → findHeaders()) auto-detects the header row within the first 10 rows and maps columns by pattern matching. Two formats are tested and supported:

Parser Guard Rules

These prevent summary/metadata rows from being parsed as section data:

• Numeric profile cells skipped — Summary by Zone tables have total lengths (e.g. 319.2) in the profile column as numeric Excel cells. A typeof === 'number' check catches these before string conversion.
• Header-like text skipped — Cells starting with Total, Summary, Notes, Steel, Section, Profile, Designation, or Size are rejected as section designations.
• Area removed from zone patterns — "Area (m²)" is surface area, not a zone/location column. Only Zone, Location, and Level match the zone column.

Test Files

MCP Server

The MCP (Model Context Protocol) server exposes the FireCalc calculation engine as tools that an AI assistant can call directly — no browser, no Excel. It runs as a local stdio process and is pre-configured for Claude Code via .mcp.json.

Available Tools

{ "profile": "310UB40.4" }
→ { "designation": "310UB40.4", "type": "UB", "hp_3sided_mm": 189, "hp_4sided_mm": 243, "area_mm2": 5170, ... }

{ "profile": "310UB40.4", "product": "SQ476", "sides": 3, "fire_rating": 60, "length": 6 }
→ { "dft_mm": 1.245, "wft_mm": 1.245, "surface_area_m2": 7.21, "weight_kg": 10.75, ... }

{ "profile": "310UB40.4", "sides": 3, "fire_rating": 60, "length": 6 }
→ { "SQ476": { "dft_mm": 1.245, ... }, "920KS": { "dft_mm": 0.89, ... }, "delta": { "lower_dft": "920KS", ... } }

{ "type": "UB" }
→ [ { "designation": "150UB14.0", "hp_3sided_mm": 328, ... }, ... ]  // 50 sections

What the MCP Server Can Answer Today

• "What's the DFT for a 500UB92 at 90 minutes with SQ476, 3-sided?"
• "Which of 920KS or SQ476 gives a thinner coating on a 250UC89.5 column at 60 min?"
• "List all SHS sections available in the database."
• "Can you find the section closest to 'SHS100x5'?" (fuzzy match)
• "For a 6m 310UB32 beam at 30 min, how much paint weight does 920KS add vs SQ476?"

HTTP API (ChatGPT / Other LLMs)

The same four operations are available over HTTP at https://fireshield.pages.dev/api/calc — no authentication required. This is the endpoint used for ChatGPT GPT Actions.

# GET
curl 'https://fireshield.pages.dev/api/calc?action=lookup_section&profile=310UB40.4'

# POST
curl -X POST https://fireshield.pages.dev/api/calc \
  -H 'Content-Type: application/json' \
  -d '{"action":"compare_products","profile":"310UB40.4","sides":3,"fire_rating":60}'

OpenAPI spec (for ChatGPT Action import): https://fireshield.pages.dev/firecalc/openapi.json

Future MCP Ideas

The MCP server currently covers single-member lookups and calculations. Here's what could be added as the platform grows: