diff --git a/internal/app/godoc.go b/internal/app/godoc.go
index 2a289c1..c53b4bd 100644
--- a/internal/app/godoc.go
+++ b/internal/app/godoc.go
@@ -103,7 +103,13 @@ func ReadGoDocPaged(
 
 		// If no documentation found, try to parse the README section
 		if !matched {
-			_, parsedDoc = parseReadme(doc)
+			matched, parsedDoc = parseReadme(doc)
+		}
+
+		// Nothing parsed: treat as not found instead of caching and returning
+		// an empty document, which would mask pkg.go.dev markup drift.
+		if !matched || strings.TrimSpace(parsedDoc) == "" {
+			return "", 0, false, ErrNotFound
 		}
 
 		document = parsedDoc
@@ -178,7 +184,13 @@ func SearchWithinGoDoc(
 
 		// If no documentation found, try to parse the README section
 		if !matched {
-			_, parsedDoc = parseReadme(doc)
+			matched, parsedDoc = parseReadme(doc)
+		}
+
+		// Nothing parsed: treat as not found instead of caching and returning
+		// an empty document, which would mask pkg.go.dev markup drift.
+		if !matched || strings.TrimSpace(parsedDoc) == "" {
+			return nil, ErrNotFound
 		}
 
 		document = parsedDoc
diff --git a/internal/app/pydoc.go b/internal/app/pydoc.go
index 7655ace..b0d32c5 100644
--- a/internal/app/pydoc.go
+++ b/internal/app/pydoc.go
@@ -103,7 +103,13 @@ func ReadPyDocPaged(
 			return "", 0, false, errors.Wrap(err, "failed to parse HTML")
 		}
 
-		_, document = parsePyDocPage(doc)
+		matched, parsed := parsePyDocPage(doc)
+		// Nothing parsed: treat as not found instead of caching and returning
+		// an empty document, which would mask docs.python.org markup drift.
+		if !matched || strings.TrimSpace(parsed) == "" {
+			return "", 0, false, ErrNotFound
+		}
+		document = parsed
 
 		docCache.Set(cacheKey, document, cache.DefaultExpiration)
 	}
@@ -161,7 +167,13 @@ func SearchWithinPyDoc(
 			return nil, errors.Wrap(err, "failed to parse HTML")
 		}
 
-		_, document = parsePyDocPage(doc)
+		matched, parsed := parsePyDocPage(doc)
+		// Nothing parsed: treat as not found instead of caching and returning
+		// an empty document, which would mask docs.python.org markup drift.
+		if !matched || strings.TrimSpace(parsed) == "" {
+			return nil, ErrNotFound
+		}
+		document = parsed
 
 		docCache.Set(cacheKey, document, cache.DefaultExpiration)
 	}
diff --git a/internal/app/rustdoc.go b/internal/app/rustdoc.go
index 61ae3da..4d66ecf 100644
--- a/internal/app/rustdoc.go
+++ b/internal/app/rustdoc.go
@@ -71,7 +71,13 @@ func ReadRustDocPaged(
 			return "", 0, false, errors.Wrap(err, "failed to parse HTML")
 		}
 
-		_, document = parseDocsRsDocument(doc)
+		matched, parsed := parseDocsRsDocument(doc)
+		// Nothing parsed: treat as not found instead of caching and returning
+		// an empty document, which would mask docs.rs markup drift.
+		if !matched || strings.TrimSpace(parsed) == "" {
+			return "", 0, false, ErrNotFound
+		}
+		document = parsed
 
 		docCache.Set(cacheKey, document, cache.DefaultExpiration)
 	}
@@ -129,7 +135,13 @@ func SearchWithinRustDoc(
 			return nil, errors.Wrap(err, "failed to parse HTML")
 		}
 
-		_, document = parseDocsRsDocument(doc)
+		matched, parsed := parseDocsRsDocument(doc)
+		// Nothing parsed: treat as not found instead of caching and returning
+		// an empty document, which would mask docs.rs markup drift.
+		if !matched || strings.TrimSpace(parsed) == "" {
+			return nil, ErrNotFound
+		}
+		document = parsed
 
 		docCache.Set(cacheKey, document, cache.DefaultExpiration)
 	}