# SiteAuditor 360 — Full System & Agentic Architecture Specification

> Complete reference manual, diagnostic schema, and data models for AI agents, LLM autonomous assistants, and automated audit tools.

## 1. System Overview

SiteAuditor 360 is a multi-engine web intelligence and software quality engineering platform. It evaluates web applications across 12 discrete engineering vectors using isolated parallel execution pipelines.

## 2. Architecture & Engine Pipeline

```
Client / Agent Request (URL)
       │
       ▼
 ┌───────────────┐
 │   SSRF Guard  │  Validates public IP, blocks RFC1918 / localhost
 └───────┬───────┘
         │
 ┌───────┴───────────────────────────────────────────────┐
 │                  Parallel Worker Engines              │
 ├───────────────────┬───────────────────┬───────────────┤
 │ Google PageSpeed  │ Axe-Core 4.11 A11y│ Security Hdr  │
 │ Lighthouse API    │ Headless Chrome   │ SecurityHeaders│
 ├───────────────────┼───────────────────┼───────────────┤
 │ Technical SEO     │ Image Crawler     │ Dead Links    │
 │ Cheerio DOM Parse │ Resolution & Alt  │ HTTP Async    │
 ├───────────────────┼───────────────────┼───────────────┤
 │ W3C Validator     │ SEO Comparator    │ QA Testcases  │
 │ Nu HTML Service   │ Side-by-side Diff │ Test Generator│
 └───────────────────┴───────────────────┴───────────────┘
```

## 3. Data Output Models

### 3.1 PageSpeed & Core Web Vitals
- `mobile.score`: Numeric performance grade (0–100)
- `desktop.score`: Numeric performance grade (0–100)
- `metrics.fcp`: First Contentful Paint (ms)
- `metrics.lcp`: Largest Contentful Paint (ms)
- `metrics.cls`: Cumulative Layout Shift (unitless)
- `metrics.tbt`: Total Blocking Time (ms)
- `metrics.inp`: Interaction to Next Paint (ms)

### 3.2 Technical SEO
- `title`: Extracted title text, character length, pixel width approximation, and truncation status
- `description`: Meta description content, length, and keyword presence
- `canonical`: URL validation, self-referential check, cross-domain checks
- `headings`: Counts and hierarchy validation for H1 through H6
- `openGraph`: og:title, og:description, og:image, og:type, og:url integrity
- `twitterCard`: twitter:card, twitter:title, twitter:description, twitter:image

### 3.3 Security Headers
- `score`: Letter grade (A+, A, B, C, D, E, F)
- `headers.csp`: Content-Security-Policy presence, directives, unsafe-inline flags
- `headers.hsts`: Strict-Transport-Security presence, max-age, includeSubDomains, preload
- `headers.xfo`: X-Frame-Options (DENY, SAMEORIGIN)
- `headers.xcto`: X-Content-Type-Options (nosniff)
- `headers.referrerPolicy`: Referrer-Policy strictness
- `headers.permissionsPolicy`: Feature restriction directives

### 3.4 WCAG 2.2 Accessibility
- `violations`: Array of WCAG rule violations categorised by impact (critical, serious, moderate, minor)
- `passes`: Verified compliant criteria count
- `contrast`: Evaluation of text against background color ratios (minimum 4.5:1 for normal text, 3:1 for large text)
- `landmarks`: Header, main, nav, footer, aside semantic tag coverage

## 4. Autonomous Agent Consumption Guidelines

- **Format**: JSON and Markdown
- **Direct Trigger URL**: `https://siteauditor-360.pages.dev/?url={target}`
- **Robots Policy**: Explicitly permissive for autonomous AI agents (GPTBot, ClaudeBot, PerplexityBot, Applebot-Extended, Google-Extended).
- **Contact & Support**: SiteAuditor 360 Engineering Team.