diff --git a/packages/core/src/services/chatCompressionService.test.ts b/packages/core/src/services/chatCompressionService.test.ts
index 4ddd38e25c..855da90068 100644
--- a/packages/core/src/services/chatCompressionService.test.ts
+++ b/packages/core/src/services/chatCompressionService.test.ts
@@ -718,8 +718,9 @@ describe('ChatCompressionService', () => {
 
     it('should use high-fidelity original history for summarization when under the limit, but truncated version for active window', async () => {
       // Large response in the "to compress" section (first message)
-      // 300,000 chars is ~75k tokens, well under the 1,000,000 summarizer limit.
-      const massiveText = 'a'.repeat(300000);
+      // 500,000 chars is ~125k tokens, well under the 1,000,000 summarizer limit
+      // but exceeds COMPRESSION_FUNCTION_RESPONSE_TOKEN_BUDGET (75k).
+      const massiveText = 'a'.repeat(500000);
       const history: Content[] = [
         {
           role: 'user',
diff --git a/packages/core/src/services/chatCompressionService.ts b/packages/core/src/services/chatCompressionService.ts
index 5303a1a82a..272d4c0939 100644
--- a/packages/core/src/services/chatCompressionService.ts
+++ b/packages/core/src/services/chatCompressionService.ts
@@ -43,12 +43,12 @@ const DEFAULT_COMPRESSION_TOKEN_THRESHOLD = 0.5;
  * The fraction of the latest chat history to keep. A value of 0.3
  * means that only the last 30% of the chat history will be kept after compression.
  */
-const COMPRESSION_PRESERVE_THRESHOLD = 0.3;
+const COMPRESSION_PRESERVE_THRESHOLD = 0.4;
 
 /**
  * The budget for function response tokens in the preserved history.
  */
-const COMPRESSION_FUNCTION_RESPONSE_TOKEN_BUDGET = 50_000;
+const COMPRESSION_FUNCTION_RESPONSE_TOKEN_BUDGET = 75_000;
 
 /**
  * Returns the index of the oldest item to keep when compressing. May return