From a5a72efb8a4ffc1212f3259e4fdefd825c9c9fb8 Mon Sep 17 00:00:00 2001
From: Vikhyath Mondreti <vikhyath@simstudio.ai>
Date: Wed, 7 Jan 2026 14:43:00 -0800
Subject: [PATCH 1/2] fix(preproc-errors): should not charge base execution
 cost in this case

---
 apps/sim/lib/execution/preprocessing.ts       |  1 +
 .../sim/lib/logs/execution/logging-session.ts | 28 +++++++++++++++----
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/apps/sim/lib/execution/preprocessing.ts b/apps/sim/lib/execution/preprocessing.ts
index b0fcc6c1b9..cab28145e0 100644
--- a/apps/sim/lib/execution/preprocessing.ts
+++ b/apps/sim/lib/execution/preprocessing.ts
@@ -541,6 +541,7 @@ async function logPreprocessingError(params: {
         stackTrace: undefined,
       },
       traceSpans: [],
+      skipCost: true, // Preprocessing errors should not charge - no execution occurred
     })
 
     logger.debug(`[${requestId}] Logged preprocessing error to database`, {
diff --git a/apps/sim/lib/logs/execution/logging-session.ts b/apps/sim/lib/logs/execution/logging-session.ts
index 37004d688d..cc689f49a9 100644
--- a/apps/sim/lib/logs/execution/logging-session.ts
+++ b/apps/sim/lib/logs/execution/logging-session.ts
@@ -45,6 +45,7 @@ export interface SessionErrorCompleteParams {
     stackTrace?: string
   }
   traceSpans?: TraceSpan[]
+  skipCost?: boolean
 }
 
 export interface SessionCancelledParams {
@@ -342,7 +343,7 @@ export class LoggingSession {
     }
 
     try {
-      const { endedAt, totalDurationMs, error, traceSpans } = params
+      const { endedAt, totalDurationMs, error, traceSpans, skipCost } = params
 
       const endTime = endedAt ? new Date(endedAt) : new Date()
       const durationMs = typeof totalDurationMs === 'number' ? totalDurationMs : 0
@@ -350,19 +351,34 @@ export class LoggingSession {
 
       const hasProvidedSpans = Array.isArray(traceSpans) && traceSpans.length > 0
 
-      const costSummary = hasProvidedSpans
-        ? calculateCostSummary(traceSpans)
-        : {
-            totalCost: BASE_EXECUTION_CHARGE,
+      // When skipCost is true (preprocessing errors), don't charge anything
+      // When we have trace spans, calculate actual cost from them
+      // Otherwise, charge the base execution fee for errors that occurred during execution
+      const costSummary = skipCost
+        ? {
+            totalCost: 0,
             totalInputCost: 0,
             totalOutputCost: 0,
             totalTokens: 0,
             totalPromptTokens: 0,
             totalCompletionTokens: 0,
-            baseExecutionCharge: BASE_EXECUTION_CHARGE,
+            baseExecutionCharge: 0,
             modelCost: 0,
             models: {},
           }
+        : hasProvidedSpans
+          ? calculateCostSummary(traceSpans)
+          : {
+              totalCost: BASE_EXECUTION_CHARGE,
+              totalInputCost: 0,
+              totalOutputCost: 0,
+              totalTokens: 0,
+              totalPromptTokens: 0,
+              totalCompletionTokens: 0,
+              baseExecutionCharge: BASE_EXECUTION_CHARGE,
+              modelCost: 0,
+              models: {},
+            }
 
       const message = error?.message || 'Execution failed before starting blocks'
 

From 7fd63a4f7b41e5754035317386892066f2df557e Mon Sep 17 00:00:00 2001
From: Vikhyath Mondreti <vikhyath@simstudio.ai>
Date: Wed, 7 Jan 2026 14:44:49 -0800
Subject: [PATCH 2/2] remove comment

---
 apps/sim/lib/logs/execution/logging-session.ts | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/apps/sim/lib/logs/execution/logging-session.ts b/apps/sim/lib/logs/execution/logging-session.ts
index cc689f49a9..d618be12bc 100644
--- a/apps/sim/lib/logs/execution/logging-session.ts
+++ b/apps/sim/lib/logs/execution/logging-session.ts
@@ -351,9 +351,6 @@ export class LoggingSession {
 
       const hasProvidedSpans = Array.isArray(traceSpans) && traceSpans.length > 0
 
-      // When skipCost is true (preprocessing errors), don't charge anything
-      // When we have trace spans, calculate actual cost from them
-      // Otherwise, charge the base execution fee for errors that occurred during execution
       const costSummary = skipCost
         ? {
             totalCost: 0,