{
  "id": "web-change-brief",
  "title": "Web Change Brief",
  "level": 3,
  "levelName": "Engineer",
  "tagline": "Turn noisy HTML snapshots into a small report of exact readable text changes.",
  "summary": "Turn noisy HTML snapshots into a small report of exact readable text changes.",
  "youWillBuild": "A standalone change report, changes.json and a reusable baseline.json snapshot.",
  "usefulFor": [
    "Two saved HTML snapshots of the same URL, or a saved JSON baseline and one explicit live HTTP(S) URL."
  ],
  "hours": 8,
  "languages": [
    "Go"
  ],
  "languageWhy": {
    "Go": "Go's standard library exposes HTTP limits, context cancellation, atomic file replacement and safe HTML templates with no framework."
  },
  "status": "ready",
  "source": "core",
  "author": {
    "name": "AI Engineering from Scratch",
    "github": "rohitg00"
  },
  "skills": [
    "Extract text before comparing pages",
    "Compare exact text and preserve duplicates",
    "Fetch one page without losing the baseline",
    "Export a brief a person can inspect"
  ],
  "prerequisites": [
    "Write Go functions, slices, maps and error returns.",
    "Understand an HTTP response status, Content-Type and body.",
    "Understand that a text snapshot and a rendered web page expose different information."
  ],
  "figures": true,
  "overviewFigure": "pj-web-change-brief-1",
  "demo": {
    "command": [
      "python3",
      "demo.py"
    ],
    "cwd": "solution"
  },
  "stages": [
    {
      "id": "01-extract-readable-blocks",
      "title": "Extract text before comparing pages",
      "summary": "Scan HTML into normalized readable blocks and exclude known noise regions.",
      "hours": 2,
      "difficulty": "starter",
      "language": "go",
      "languageWhy": "Go's standard library exposes HTTP limits, context cancellation, atomic file replacement and safe HTML templates with no framework.",
      "concepts": [
        "scanning",
        "normalization",
        "noise filtering"
      ],
      "figure": "pj-web-change-brief-1"
    },
    {
      "id": "02-compare-snapshots",
      "title": "Compare exact text and preserve duplicates",
      "summary": "Build stable snapshots and count added and removed text occurrences.",
      "hours": 2,
      "difficulty": "core",
      "language": "go",
      "languageWhy": "Go's standard library exposes HTTP limits, context cancellation, atomic file replacement and safe HTML templates with no framework.",
      "concepts": [
        "canonical URLs",
        "content hashes",
        "multiset diffs"
      ],
      "figure": "pj-web-change-brief-2"
    },
    {
      "id": "03-fetch-and-save",
      "title": "Fetch one page without losing the baseline",
      "summary": "Bound live HTTP work and verify saved snapshot integrity.",
      "hours": 2,
      "difficulty": "core",
      "language": "go",
      "languageWhy": "Go's standard library exposes HTTP limits, context cancellation, atomic file replacement and safe HTML templates with no framework.",
      "concepts": [
        "HTTP bounds",
        "context cancellation",
        "atomic writes"
      ],
      "figure": "pj-web-change-brief-3"
    },
    {
      "id": "04-export-change-evidence",
      "title": "Export a brief a person can inspect",
      "summary": "Show exact added and removed statements beside the source and hashes.",
      "hours": 2,
      "difficulty": "stretch",
      "language": "go",
      "languageWhy": "Go's standard library exposes HTTP limits, context cancellation, atomic file replacement and safe HTML templates with no framework.",
      "concepts": [
        "safe templates",
        "portable reports",
        "explicit acceptance"
      ],
      "figure": "pj-web-change-brief-4"
    }
  ],
  "demos": [
    {
      "gif": "media/run.gif",
      "poster": "media/run.png",
      "title": "Build and grade",
      "caption": "A fresh starter fails; the complete original solution passes all four stages."
    },
    {
      "gif": "media/output.gif",
      "poster": "media/output.png",
      "title": "Inspect the application output",
      "caption": "Actual output from authored offline fixtures. See the README for provider and evidence boundaries."
    }
  ]
}