diff --git a/src/agents/pi-embedded-runner/tool-result-char-estimator.ts b/src/agents/pi-embedded-runner/tool-result-char-estimator.ts
index 16bdc5e43eb..6d022d62289 100644
--- a/src/agents/pi-embedded-runner/tool-result-char-estimator.ts
+++ b/src/agents/pi-embedded-runner/tool-result-char-estimator.ts
@@ -46,6 +46,20 @@ function getToolResultContent(msg: AgentMessage): unknown[] {
   return Array.isArray(content) ? content : [];
 }
 
+function estimateContentBlockChars(content: unknown[]): number {
+  let chars = 0;
+  for (const block of content) {
+    if (isTextBlock(block)) {
+      chars += block.text.length;
+    } else if (isImageBlock(block)) {
+      chars += IMAGE_CHAR_ESTIMATE;
+    } else {
+      chars += estimateUnknownChars(block);
+    }
+  }
+  return chars;
+}
+
 export function getToolResultText(msg: AgentMessage): string {
   const content = getToolResultContent(msg);
   const chunks: string[] = [];
@@ -67,19 +81,10 @@ function estimateMessageChars(msg: AgentMessage): number {
     if (typeof content === "string") {
       return content.length;
     }
-    let chars = 0;
     if (Array.isArray(content)) {
-      for (const block of content) {
-        if (isTextBlock(block)) {
-          chars += block.text.length;
-        } else if (isImageBlock(block)) {
-          chars += IMAGE_CHAR_ESTIMATE;
-        } else {
-          chars += estimateUnknownChars(block);
-        }
-      }
+      return estimateContentBlockChars(content);
     }
-    return chars;
+    return 0;
   }
 
   if (msg.role === "assistant") {
@@ -115,17 +120,8 @@ function estimateMessageChars(msg: AgentMessage): number {
   }
 
   if (isToolResultMessage(msg)) {
-    let chars = 0;
     const content = getToolResultContent(msg);
-    for (const block of content) {
-      if (isTextBlock(block)) {
-        chars += block.text.length;
-      } else if (isImageBlock(block)) {
-        chars += IMAGE_CHAR_ESTIMATE;
-      } else {
-        chars += estimateUnknownChars(block);
-      }
-    }
+    let chars = estimateContentBlockChars(content);
     const details = (msg as { details?: unknown }).details;
     chars += estimateUnknownChars(details);
     const weightedChars = Math.ceil(