diff --git a/src/main/apiServer/routes/messages.ts b/src/main/apiServer/routes/messages.ts
index f0eaac8e4e..907b498273 100644
--- a/src/main/apiServer/routes/messages.ts
+++ b/src/main/apiServer/routes/messages.ts
@@ -41,6 +41,51 @@ const logger = loggerService.withContext('ApiServerMessagesRoutes')
 const router = express.Router()
 const providerRouter = express.Router({ mergeParams: true })
 
+/**
+ * Estimate token count from messages
+ * Simple approximation: ~4 characters per token for English text
+ */
+interface CountTokensInput {
+  messages: Array<{ role: string; content: string | Array<{ type: string; text?: string }> }>
+  system?: string | Array<{ type: string; text?: string }>
+}
+
+function estimateTokenCount(input: CountTokensInput): number {
+  const { messages, system } = input
+  let totalChars = 0
+
+  // Count system message tokens
+  if (system) {
+    if (typeof system === 'string') {
+      totalChars += system.length
+    } else if (Array.isArray(system)) {
+      for (const block of system) {
+        if (block.type === 'text' && block.text) {
+          totalChars += block.text.length
+        }
+      }
+    }
+  }
+
+  // Count message tokens
+  for (const msg of messages) {
+    if (typeof msg.content === 'string') {
+      totalChars += msg.content.length
+    } else if (Array.isArray(msg.content)) {
+      for (const block of msg.content) {
+        if (block.type === 'text' && block.text) {
+          totalChars += block.text.length
+        }
+      }
+    }
+    // Add overhead for role
+    totalChars += 10
+  }
+
+  // Estimate tokens (~4 chars per token, with some overhead)
+  return Math.ceil(totalChars / 4) + messages.length * 3
+}
+
 // Helper function for basic request validation
 async function validateRequestBody(req: Request): Promise<{ valid: boolean; error?: any }> {
   const request: MessageCreateParams = req.body
@@ -589,45 +634,11 @@ router.post('/count_tokens', async (req: Request, res: Response) => {
       })
     }
 
-    // Simple token estimation based on character count
-    // This is a rough approximation: ~4 characters per token for English text
-    let totalChars = 0
-
-    // Count system message tokens
-    if (system) {
-      if (typeof system === 'string') {
-        totalChars += system.length
-      } else if (Array.isArray(system)) {
-        for (const block of system) {
-          if (block.type === 'text' && block.text) {
-            totalChars += block.text.length
-          }
-        }
-      }
-    }
-
-    // Count message tokens
-    for (const msg of messages) {
-      if (typeof msg.content === 'string') {
-        totalChars += msg.content.length
-      } else if (Array.isArray(msg.content)) {
-        for (const block of msg.content) {
-          if (block.type === 'text' && block.text) {
-            totalChars += block.text.length
-          }
-        }
-      }
-      // Add overhead for role
-      totalChars += 10
-    }
-
-    // Estimate tokens (~4 chars per token, with some overhead)
-    const estimatedTokens = Math.ceil(totalChars / 4) + messages.length * 3
+    const estimatedTokens = estimateTokenCount({ messages, system })
 
     logger.debug('Token count estimated', {
       model,
       messageCount: messages.length,
-      totalChars,
       estimatedTokens
     })
 
@@ -663,35 +674,7 @@ providerRouter.post('/count_tokens', async (req: Request, res: Response) => {
       })
     }
 
-    // Simple token estimation
-    let totalChars = 0
-
-    if (system) {
-      if (typeof system === 'string') {
-        totalChars += system.length
-      } else if (Array.isArray(system)) {
-        for (const block of system) {
-          if (block.type === 'text' && block.text) {
-            totalChars += block.text.length
-          }
-        }
-      }
-    }
-
-    for (const msg of messages) {
-      if (typeof msg.content === 'string') {
-        totalChars += msg.content.length
-      } else if (Array.isArray(msg.content)) {
-        for (const block of msg.content) {
-          if (block.type === 'text' && block.text) {
-            totalChars += block.text.length
-          }
-        }
-      }
-      totalChars += 10
-    }
-
-    const estimatedTokens = Math.ceil(totalChars / 4) + messages.length * 3
+    const estimatedTokens = estimateTokenCount({ messages, system })
 
     logger.debug('Token count estimated (provider route)', {
       providerId: req.params.provider,