diff --git a/packages/opencode/src/session/compaction.ts b/packages/opencode/src/session/compaction.ts
index fb3825302918..88ff201b55a2 100644
--- a/packages/opencode/src/session/compaction.ts
+++ b/packages/opencode/src/session/compaction.ts
@@ -32,7 +32,7 @@ export namespace SessionCompaction {
     if (config.compaction?.auto === false) return false
     const context = input.model.limit.context
     if (context === 0) return false
-    const count = input.tokens.input + input.tokens.cache.read + input.tokens.output
+    const count = input.tokens.input + input.tokens.cache.read + input.tokens.cache.write + input.tokens.output
     const output = Math.min(input.model.limit.output, SessionPrompt.OUTPUT_TOKEN_MAX) || SessionPrompt.OUTPUT_TOKEN_MAX
     const usable = input.model.limit.input || context - output
     return count > usable