Merge pull request #1245 from simstudioai/fix/copilot-billing

improvement(copilot): billing multiplier adjustments

Author: Sg312

apps/docs/content/docs/copilot/index.mdx

@@ -91,4 +91,31 @@ Copilot is your in-editor assistant that helps you build, understand, and improv
   >
     <div className="m-0 text-sm">Maximum reasoning for deep planning, debugging, and complex architectural changes.</div>
   </Card>
-</Cards> 
+</Cards>
+
+## Billing and Cost Calculation
+
+### How Costs Are Calculated
+
+Copilot usage is billed per token from the underlying LLM:
+
+- **Input tokens**: billed at the provider's base rate (**at-cost**)
+- **Output tokens**: billed at **1.5×** the provider's base output rate
+
+```javascript
+copilotCost = (inputTokens × inputPrice + outputTokens × (outputPrice × 1.5)) / 1,000,000
+```
+
+| Component | Rate Applied         |
+|----------|----------------------|
+| Input    | inputPrice           |
+| Output   | outputPrice × 1.5    |
+
+<Callout type="warning">
+  Pricing shown reflects rates as of September 4, 2025. Check provider documentation for current pricing.
+</Callout>
+
+<Callout type="info">
+  Model prices are per million tokens. The calculation divides by 1,000,000 to get the actual cost. See <a href="/execution/advanced#cost-calculation">Logging and Cost Calculation</a> for background and examples.
+</Callout>
+

apps/sim/app/api/billing/update-cost/route.ts

@@ -16,7 +16,8 @@ const UpdateCostSchema = z.object({
   input: z.number().min(0, 'Input tokens must be a non-negative number'),
   output: z.number().min(0, 'Output tokens must be a non-negative number'),
   model: z.string().min(1, 'Model is required'),
-  multiplier: z.number().min(0),
+  inputMultiplier: z.number().min(0),
+  outputMultiplier: z.number().min(0),
 })
 
 /**
@@ -75,14 +76,15 @@ export async function POST(req: NextRequest) {
       )
     }
 
-    const { userId, input, output, model, multiplier } = validation.data
+    const { userId, input, output, model, inputMultiplier, outputMultiplier } = validation.data
 
     logger.info(`[${requestId}] Processing cost update`, {
       userId,
       input,
       output,
       model,
-      multiplier,
+      inputMultiplier,
+      outputMultiplier,
     })
 
     const finalPromptTokens = input
@@ -95,7 +97,8 @@ export async function POST(req: NextRequest) {
       finalPromptTokens,
       finalCompletionTokens,
       false,
-      multiplier
+      inputMultiplier,
+      outputMultiplier
     )
 
     logger.info(`[${requestId}] Cost calculation result`, {
@@ -104,7 +107,8 @@ export async function POST(req: NextRequest) {
       promptTokens: finalPromptTokens,
       completionTokens: finalCompletionTokens,
       totalTokens: totalTokens,
-      multiplier,
+      inputMultiplier,
+      outputMultiplier,
       costResult,
     })
 

apps/sim/app/api/copilot/chat/route.test.ts

@@ -226,6 +226,7 @@ describe('Copilot Chat API Route', () => {
             mode: 'agent',
             messageId: 'mock-uuid-1234-5678',
             depth: 0,
+            chatId: 'chat-123',
           }),
         })
       )
@@ -289,6 +290,7 @@ describe('Copilot Chat API Route', () => {
             mode: 'agent',
             messageId: 'mock-uuid-1234-5678',
             depth: 0,
+            chatId: 'chat-123',
           }),
         })
       )
@@ -341,6 +343,7 @@ describe('Copilot Chat API Route', () => {
             mode: 'agent',
             messageId: 'mock-uuid-1234-5678',
             depth: 0,
+            chatId: 'chat-123',
           }),
         })
       )
@@ -430,6 +433,7 @@ describe('Copilot Chat API Route', () => {
             mode: 'ask',
             messageId: 'mock-uuid-1234-5678',
             depth: 0,
+            chatId: 'chat-123',
           }),
         })
       )

apps/sim/app/api/copilot/chat/route.ts

@@ -378,6 +378,7 @@ export async function POST(req: NextRequest) {
       ...(typeof effectivePrefetch === 'boolean' ? { prefetch: effectivePrefetch } : {}),
       ...(session?.user?.name && { userName: session.user.name }),
       ...(agentContexts.length > 0 && { context: agentContexts }),
+      ...(actualChatId ? { chatId: actualChatId } : {}),
     }
 
     try {

apps/sim/providers/utils.ts

@@ -1,4 +1,4 @@
-import { getCostMultiplier, isHosted } from '@/lib/environment'
+import { isHosted } from '@/lib/environment'
 import { createLogger } from '@/lib/logs/console/logger'
 import { anthropicProvider } from '@/providers/anthropic'
 import { azureOpenAIProvider } from '@/providers/azure-openai'
@@ -444,7 +444,8 @@ export function calculateCost(
   promptTokens = 0,
   completionTokens = 0,
   useCachedInput = false,
-  customMultiplier?: number
+  inputMultiplier?: number,
+  outputMultiplier?: number
 ) {
   // First check if it's an embedding model
   let pricing = getEmbeddingModelPricing(model)
@@ -479,13 +480,9 @@ export function calculateCost(
       : pricing.input / 1_000_000)
 
   const outputCost = completionTokens * (pricing.output / 1_000_000)
-  const totalCost = inputCost + outputCost
-
-  const costMultiplier = customMultiplier ?? getCostMultiplier()
-
-  const finalInputCost = inputCost * costMultiplier
-  const finalOutputCost = outputCost * costMultiplier
-  const finalTotalCost = totalCost * costMultiplier
+  const finalInputCost = inputCost * (inputMultiplier ?? 1)
+  const finalOutputCost = outputCost * (outputMultiplier ?? 1)
+  const finalTotalCost = finalInputCost + finalOutputCost
 
   return {
     input: Number.parseFloat(finalInputCost.toFixed(8)), // Use 8 decimal places for small costs