diff --git a/packages/opencode/src/session/prompt/gpt.txt b/packages/opencode/src/session/prompt/gpt.txt
index c10d16497..27f1d2006 100644
--- a/packages/opencode/src/session/prompt/gpt.txt
+++ b/packages/opencode/src/session/prompt/gpt.txt
@@ -223,5 +223,5 @@ These primitives serve different purposes. Use them only when they are present i
 
 ## Reasoning format
 
-Begin every thinking block with the exact string "We need".
-This applies to all turns, including reasoning that follows a tool result.
\ No newline at end of file
+Begin every thinking block with the exact string "We need" or "Need".
+This applies to all turns, including reasoning that before a tool call.
\ No newline at end of file