diff --git a/adk/human-in-the-loop/6_plan-execute-replan/agent.go b/adk/human-in-the-loop/6_plan-execute-replan/agent.go
index 5e6de56..39cb546 100644
--- a/adk/human-in-the-loop/6_plan-execute-replan/agent.go
+++ b/adk/human-in-the-loop/6_plan-execute-replan/agent.go
@@ -110,7 +110,7 @@ func formatInput(in []adk.Message) string {
 func formatExecutedSteps(in []planexecute.ExecutedStep) string {
 	var sb strings.Builder
 	for idx, m := range in {
-		sb.WriteString(fmt.Sprintf("## %d. Step: %v\n  Result: %v\n\n", idx+1, m.Step, m.Result))
+		_, _ = fmt.Fprintf(&sb, "## %d. Step: %v\n  Result: %v\n\n", idx+1, m.Step, m.Result)
 	}
 	return sb.String()
 }
diff --git a/adk/human-in-the-loop/8_supervisor-plan-execute/agent.go b/adk/human-in-the-loop/8_supervisor-plan-execute/agent.go
index fae8422..56eace1 100644
--- a/adk/human-in-the-loop/8_supervisor-plan-execute/agent.go
+++ b/adk/human-in-the-loop/8_supervisor-plan-execute/agent.go
@@ -147,7 +147,7 @@ func formatInput(in []adk.Message) string {
 func formatExecutedSteps(in []planexecute.ExecutedStep) string {
 	var sb strings.Builder
 	for idx, m := range in {
-		sb.WriteString(fmt.Sprintf("## %d. Step: %v\n  Result: %v\n\n", idx+1, m.Step, m.Result))
+		_, _ = fmt.Fprintf(&sb, "## %d. Step: %v\n  Result: %v\n\n", idx+1, m.Step, m.Result)
 	}
 	return sb.String()
 }
diff --git a/adk/intro/agent_with_summarization/tools.go b/adk/intro/agent_with_summarization/tools.go
index 3f252b5..b7d0ad8 100644
--- a/adk/intro/agent_with_summarization/tools.go
+++ b/adk/intro/agent_with_summarization/tools.go
@@ -65,7 +65,7 @@ func NewRepeatSectionsTool() tool.InvokableTool {
 			callCount++
 			adk.AddSessionValue(ctx, "_tool_call_count", callCount)
 
-			b.WriteString(fmt.Sprintf("Tool calls so far: %d", callCount))
+			_, _ = fmt.Fprintf(&b, "Tool calls so far: %d", callCount)
 			return b.String(), nil
 		},
 	)