From 98916a31e3908c61f7f3422fe89c725c75b3b7d5 Mon Sep 17 00:00:00 2001
From: Xubin Ren <52506698+Re-bin@users.noreply.github.com>
Date: Sat, 20 Jun 2026 22:44:45 +0800
Subject: [PATCH] perf(tokens): document tool schema cache assumption

---
 nanobot/utils/helpers.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/nanobot/utils/helpers.py b/nanobot/utils/helpers.py
index 7a5d808c..4243671b 100644
--- a/nanobot/utils/helpers.py
+++ b/nanobot/utils/helpers.py
@@ -44,6 +44,7 @@ def _estimate_tools_tokens(
     leading_separator: bool,
 ) -> int:
     """Estimate stable tool definition tokens without re-encoding every loop."""
+    # ToolRegistry keeps the returned definitions list alive until the registry changes.
     tools_id = id(tools)
     fingerprint = tuple(id(tool) for tool in tools)
     cached = _TOOLS_TOKEN_CACHE.get(tools_id)