Use different seeds for retries

copienator/gemini_config.py

@@ -1,6 +1,16 @@
+import secrets
+
 from google.genai import types
 
 
+def fresh_seed(previous: int | None = None) -> int:
+    """Choose a random int32 seed, excluding the preceding attempt's seed."""
+    limit = 2**31
+    if previous is None:
+        return secrets.randbelow(limit)
+    return (previous + 1 + secrets.randbelow(limit - 1)) % limit
+
+
 def thinking_config(level: str | None) -> types.ThinkingConfig | None:
     """Use a supported reasoning level, or omit it for the model default."""
     if level is None: