diff --git a/docs/user/providers-opencode.md b/docs/user/providers-opencode.md
index 9ecee2a0439c2..9166469791d9f 100644
--- a/docs/user/providers-opencode.md
+++ b/docs/user/providers-opencode.md
@@ -22,6 +22,15 @@ started on 1.x continue on 2.x.
 
 Plan mode uses OpenCode's `plan` agent.
 
+## Compaction
+
+OpenCode compacts long conversations itself, and T3 Code has no setting for it. On
+OpenCode 2, change it under `compaction` in an OpenCode configuration file, such as
+`opencode.json`: `auto` turns
+automatic compaction on or off, `buffer` sets the token headroom, and `keep.tokens`
+sets how much recent context stays. OpenCode 1.x configures compaction differently.
+Send `/compact` to compact a thread yourself.
+
 ## Local or external server
 
 Leave **Server URL** empty to let T3 Code start OpenCode locally. A password in