diff --git a/apps/sim/app/workspace/[workspaceId]/logs/components/log-details/log-details.tsx b/apps/sim/app/workspace/[workspaceId]/logs/components/log-details/log-details.tsx
index 4307d40b5c5..963aba17143 100644
--- a/apps/sim/app/workspace/[workspaceId]/logs/components/log-details/log-details.tsx
+++ b/apps/sim/app/workspace/[workspaceId]/logs/components/log-details/log-details.tsx
@@ -598,6 +598,24 @@ export const LogDetails = memo(function LogDetails({
                             {formatCost(log.cost?.output || 0)}
                           </span>
                         </div>
+                        {(() => {
+                          const models = (log.cost as Record<string, unknown>)?.models as
+                            | Record<string, { toolCost?: number }>
+                            | undefined
+                          const totalToolCost = models
+                            ? Object.values(models).reduce((sum, m) => sum + (m?.toolCost || 0), 0)
+                            : 0
+                          return totalToolCost > 0 ? (
+                            <div className='flex items-center justify-between'>
+                              <span className='font-medium text-[var(--text-tertiary)] text-caption'>
+                                Tool Usage:
+                              </span>
+                              <span className='font-medium text-[var(--text-secondary)] text-caption'>
+                                {formatCost(totalToolCost)}
+                              </span>
+                            </div>
+                          ) : null
+                        })()}
                       </div>
 
                       <div className='border-[var(--border)] border-t' />
@@ -626,7 +644,7 @@ export const LogDetails = memo(function LogDetails({
                     <div className='flex items-center justify-center rounded-md bg-[var(--surface-2)] p-2 text-center'>
                       <p className='font-medium text-[var(--text-subtle)] text-xs'>
                         Total cost includes a base execution charge of{' '}
-                        {formatCost(BASE_EXECUTION_CHARGE)} plus any model usage costs.
+                        {formatCost(BASE_EXECUTION_CHARGE)} plus any model and tool usage costs.
                       </p>
                     </div>
                   </div>
diff --git a/apps/sim/lib/tokenization/streaming.ts b/apps/sim/lib/tokenization/streaming.ts
index ad684b38fa0..b7304b18fd0 100644
--- a/apps/sim/lib/tokenization/streaming.ts
+++ b/apps/sim/lib/tokenization/streaming.ts
@@ -30,6 +30,11 @@ export function processStreamingBlockLog(log: BlockLog, streamedContent: string)
     return false
   }
 
+  // Skip recalculation if cost was explicitly set by the billing layer (e.g. BYOK zero cost)
+  if (log.output?.cost?.pricing) {
+    return false
+  }
+
   // Check if we have content to tokenize
   if (!streamedContent?.trim()) {
     return false
diff --git a/apps/sim/providers/index.ts b/apps/sim/providers/index.ts
index a6f03e721f6..ea617e33789 100644
--- a/apps/sim/providers/index.ts
+++ b/apps/sim/providers/index.ts
@@ -54,6 +54,38 @@ function isReadableStream(response: any): response is ReadableStream {
   return response instanceof ReadableStream
 }
 
+const ZERO_COST = Object.freeze({
+  input: 0,
+  output: 0,
+  total: 0,
+  pricing: Object.freeze({ input: 0, output: 0, updatedAt: new Date(0).toISOString() }),
+})
+
+/**
+ * Prevents streaming callbacks from writing non-zero model cost for BYOK users
+ * while preserving tool costs. The property is frozen via defineProperty because
+ * providers set cost inside streaming callbacks that fire after this function returns.
+ */
+function zeroCostForBYOK(response: StreamingExecution): void {
+  const output = response.execution?.output
+  if (!output || typeof output !== 'object') {
+    logger.warn('zeroCostForBYOK: output not available at intercept time; cost may not be zeroed')
+    return
+  }
+
+  let toolCost = 0
+  Object.defineProperty(output, 'cost', {
+    get: () => (toolCost > 0 ? { ...ZERO_COST, toolCost, total: toolCost } : ZERO_COST),
+    set: (value: Record<string, unknown>) => {
+      if (value?.toolCost && typeof value.toolCost === 'number') {
+        toolCost = value.toolCost
+      }
+    },
+    configurable: true,
+    enumerable: true,
+  })
+}
+
 export async function executeProviderRequest(
   providerId: string,
   request: ProviderRequest
@@ -80,6 +112,12 @@ export async function executeProviderRequest(
       )
       resolvedRequest = { ...resolvedRequest, apiKey: result.apiKey }
       isBYOK = result.isBYOK
+      logger.info('API key resolved', {
+        provider: providerId,
+        model: request.model,
+        workspaceId: request.workspaceId,
+        isBYOK,
+      })
     } catch (error) {
       logger.error('Failed to resolve API key:', {
         provider: providerId,
@@ -118,7 +156,10 @@ export async function executeProviderRequest(
   const response = await provider.executeRequest(sanitizedRequest)
 
   if (isStreamingExecution(response)) {
-    logger.info('Provider returned StreamingExecution')
+    logger.info('Provider returned StreamingExecution', { isBYOK })
+    if (isBYOK) {
+      zeroCostForBYOK(response)
+    }
     return response
   }
 
@@ -154,9 +195,9 @@ export async function executeProviderRequest(
         },
       }
       if (isBYOK) {
-        logger.debug(`Not billing model usage for ${response.model} - workspace BYOK key used`)
+        logger.info(`Not billing model usage for ${response.model} - workspace BYOK key used`)
       } else {
-        logger.debug(
+        logger.info(
           `Not billing model usage for ${response.model} - user provided API key or not hosted model`
         )
       }