v3.9.6: add Gemini state-continuity docs to README

README.md

@@ -535,6 +535,20 @@ The launcher generates model catalog JSON with dual field naming to satisfy both
 
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+## Gemini Antigravity State Continuity
+
+Codex Launcher includes special handling for Gemini 3 / Antigravity OAuth:
+
+- **Thought signature preservation**: Captures `thoughtSignature` from Gemini responses
+  and reattaches them on follow-up requests to maintain tool-call continuity.
+- **Edit-intent detection**: When follow-up requests contain edit keywords, a tool-use
+  nudge is injected to prevent text-only responses.
+- **User instruction enforcement**: The latest user message is guaranteed to be the
+  final content turn sent to Gemini, even after compaction.
+- **Smart compaction**: Old tool outputs capped at 3000 chars, recent 6 at 20000 chars.
+
+---
+
 ## Multi-Account Rotation
 
 Codex Launcher supports **multiple accounts per provider** with automatic rotation