diff --git a/src/auto_reverse/doc/schema.py b/src/auto_reverse/doc/schema.py
index 4fb1fa9..a397326 100644
--- a/src/auto_reverse/doc/schema.py
+++ b/src/auto_reverse/doc/schema.py
@@ -2,14 +2,15 @@ from __future__ import annotations
 
 from typing import Any
 
-from genson import SchemaBuilder
+from genson import SchemaBuilder  # pyright: ignore[reportMissingTypeStubs]
 
 
 class SchemaAccumulator:
     """Accumulate JSON samples into a widening JSON Schema (genson-backed)."""
 
     def __init__(self) -> None:
-        self._builder = SchemaBuilder()
+        # genson is untyped; pin builder to Any so member/return types stay clean.
+        self._builder: Any = SchemaBuilder()
         self._count = 0
 
     def add(self, value: Any) -> None: