docs: name both methods a scraper must define

tests/test_workflow_paths.py

@@ -122,6 +122,17 @@ class DocumentedSteps(unittest.TestCase):
         fields = [*schema["properties"], *item.get("properties", {})]
         self.assertEqual(sorted(f for f in fields if f"`{f}`" not in page), [])
 
+    def test_the_scraper_recipe_names_every_abstract_method(self):
+        """tools.md said implement fetch_requirements(); validate_format() is
+        abstract too, and a scraper written from the page could not be built."""
+        source = (SCRIPTS / "scraper" / "base_scraper.py").read_text(encoding="utf-8")
+        abstract = re.findall(r"@abstractmethod\s+def (\w+)", source)
+        self.assertTrue(abstract)
+        for page in ("tools.md", "adding-a-scraper.md"):
+            text = (REPO_ROOT / "wiki" / page).read_text(encoding="utf-8")
+            with self.subTest(page=page):
+                self.assertEqual([m for m in abstract if f"{m}(" not in text], [])
+
     def test_every_function_the_pages_name_exists(self):
         """verification-modes described _find_best_variant(), deleted on
         2026-10-05, and an algorithm the code no longer follows."""

wiki/tools.md

@@ -717,7 +717,10 @@ using `fetch_large_file()` from `common.py`. The same function is used by
 
 ## Scrapers
 
-Located in `scripts/scraper/`. Each inherits `BaseScraper` and implements `fetch_requirements()`.
+Located in `scripts/scraper/`. Each platform scraper inherits `BaseScraper` and
+implements its two abstract methods, `fetch_requirements()` and
+`validate_format()`; the MAME and FBNeo hash scrapers read a source tree and
+stand alone.
 
 | Scraper | Source | Format |
 |---------|--------|--------|
@@ -743,8 +746,10 @@ and shared CLI), `dat_parser.py` (clrmamepro DAT format parser),
 `fbneo_parser.py` (FBNeo C source BIOS set parser),
 `_hash_merge.py` (text-based YAML patching that preserves formatting).
 
-Adding a scraper: inherit `BaseScraper`, implement `fetch_requirements()`,
-call `scraper_cli(YourScraper)` in `__main__`.
+Adding a scraper: inherit `BaseScraper`, implement `fetch_requirements()` and
+`validate_format()` (a class missing either cannot be instantiated), call
+`scraper_cli(YourScraper)` in `__main__`. The full recipe is in
+[adding-a-scraper.md](adding-a-scraper.md).
 
 ## Dump-catalog provenance