Tighten forced tool no-call guard

ober

831eee7400c27d49b4f4d8ba99dbf68cf34981fb

diff --git a/src/jcode/provider/provider.ss b/src/jcode/provider/provider.ss
index 8b1444d..5defea7 100644
--- a/src/jcode/provider/provider.ss
+++ b/src/jcode/provider/provider.ss
@@ -1023,7 +1023,7 @@
 (def forced-tool-choice-retry-marker
   "JCODE_INTERNAL_FORCE_FIRST_EDIT_RETRY")
 
-(def *forced-tool-no-call-default-char-limit* 4096)
+(def *forced-tool-no-call-default-char-limit* 512)
 
 (def (forced-tool-no-call-char-limit)
   (or (positive-int-value (getenv "JCODE_FORCED_TOOL_NO_CALL_CHAR_LIMIT"))