diff --git a/cmd/launch/claude.go b/cmd/launch/claude.go
index 6fd116def..ca96991b8 100644
--- a/cmd/launch/claude.go
+++ b/cmd/launch/claude.go
@@ -179,10 +179,10 @@ func (c *Claude) modelEnvVars(model string) []string {
 	if isCloudModelName(model) {
 		if l, ok := lookupCloudModelLimit(model); ok {
 			window := strconv.Itoa(l.Context)
-			env = append(env,
-				"CLAUDE_CODE_MAX_CONTEXT_TOKENS="+window,
-				"CLAUDE_CODE_AUTO_COMPACT_WINDOW="+window,
-			)
+			env = append(env, "CLAUDE_CODE_MAX_CONTEXT_TOKENS="+window)
+			if os.Getenv("CLAUDE_CODE_AUTO_COMPACT_WINDOW") == "" {
+				env = append(env, "CLAUDE_CODE_AUTO_COMPACT_WINDOW="+window)
+			}
 		}
 	}
 
diff --git a/cmd/launch/claude_test.go b/cmd/launch/claude_test.go
index 4bfeeba93..e89bc08ab 100644
--- a/cmd/launch/claude_test.go
+++ b/cmd/launch/claude_test.go
@@ -431,6 +431,7 @@ func TestClaudeModelEnvVars(t *testing.T) {
 	c := &Claude{}
 
 	windowKeys := []string{"CLAUDE_CODE_MAX_CONTEXT_TOKENS", "CLAUDE_CODE_AUTO_COMPACT_WINDOW"}
+	t.Setenv("CLAUDE_CODE_AUTO_COMPACT_WINDOW", "")
 
 	envMap := func(envs []string) map[string]string {
 		m := make(map[string]string)
@@ -497,6 +498,18 @@ func TestClaudeModelEnvVars(t *testing.T) {
 		}
 	})
 
+	t.Run("keeps the user's auto compact window but not their context window", func(t *testing.T) {
+		t.Setenv("CLAUDE_CODE_AUTO_COMPACT_WINDOW", "150000")
+		t.Setenv("CLAUDE_CODE_MAX_CONTEXT_TOKENS", "150000")
+		got := envMap(c.modelEnvVars("kimi-k2.6:cloud"))
+		if v, ok := got["CLAUDE_CODE_AUTO_COMPACT_WINDOW"]; ok {
+			t.Errorf("AUTO_COMPACT_WINDOW = %q, want left to the user's setting", v)
+		}
+		if got["CLAUDE_CODE_MAX_CONTEXT_TOKENS"] != "262144" {
+			t.Errorf("MAX_CONTEXT_TOKENS = %q, want 262144", got["CLAUDE_CODE_MAX_CONTEXT_TOKENS"])
+		}
+	})
+
 	t.Run("does not set windows for unknown cloud models", func(t *testing.T) {
 		got := envMap(c.modelEnvVars("unknown-model:cloud"))
 		for _, key := range windowKeys {