wigolo-diff

# wigolo diff Structural comparison of two page versions. Point it at a live URL and its cached copy, two URLs, or two raw markdown blobs, and it returns a git-style patch, structured per-section hunks, or a counts-only summary. ## Quick Reference ```json // Live page vs its cached version (re-fetches `new` side) { "old": { "url": "https://docs.example.com/api" }, "new": { "url": "https://docs.example.com/api" } } // Two different URLs { "old": { "url": "https://v1.example.com/spec" }, "new": { "url": "https://v2.example.com/spec" } } // Two markdown blobs directly { "old": { "markdown": "# Title\nold body" }, "new": { "markdown": "# Title\nnew body" } } // Structured per-section hunks at word granularity { "old": { "url": "https://example.com" }, "new": { "url": "https://example.com" }, "output": "hunks", "granularity": "word" } // Counts only { "old": { "url": "https://example.com" }, "new": { "url": "https://example.com" }, "output": "summary" } ``` ## Parameters | Parameter | Type | Default | When to use | |-----------|------|---------|-------------| | `old` | object | required | Left-hand side. One of `{ url, markdown, content_hash }` | | `new` | object | required | Right-hand side. One of `{ url, markdown }` | | `output` | string | "unified" | "unified" (git-style patch), "hunks" (per-section), "summary" (counts only) | | `granularity` | string | "line" | "line", "word" (changed tokens only — tighter), "section" (walks H1/H2/H3) | ## Output Shapes - **`unified`** — a git-style unified patch, ready to read or store. - **`hunks`** — structured per-section change blocks. Combine with `granularity: "section"` to align hunks to headings, or `granularity: "word"` for tight intra-line edits. - **`summary`** — counts only: `added_lines`, `removed_lines`, `modified_lines`, and `total_changed_chars` (sum of added + removed line chars across the edit script). Cheapest way to answer "did anything change, and how much". ## Comparing Against the Cache The most common use is drift detection: fetch a page now and diff it against the copy wigolo cached earlier. Pass the same URL for both sides — wigolo reads the cached body for `old` and re-fetches for `new`. For a scoped, multi-URL sweep, prefer `cache` with `check_changes: true`. ## Anti-Patterns - DON'T pass an `old`/`new` object without one of the accepted side keys — the handler rejects it. - DON'T use `output: "unified"` when you only need counts — `summary` is cheaper. - DON'T diff two unrelated pages expecting a meaningful changelog — diff versions of the same content. ## When NOT to use wigolo-diff - **Bulk change detection across many cached URLs** — use `cache` with `check_changes: true`. - **Ongoing scheduled monitoring** — use `watch`, which diffs on each check. ## See Also - [wigolo-cache](../wigolo-cache/SKILL.md) — `check_changes` for bulk drift detection - [wigolo-watch](../wigolo-watch/SKILL.md) — scheduled change monitoring - [wigolo-fetch](../wigolo-fetch/SKILL.md) — pull a fresh version to compare