fix: strip models/ prefix from Google Gemini model names for correct cost calculation

Author: ink-the-squid

valhalla/jawn/src/lib/handlers/ResponseBodyHandler.ts

@@ -201,10 +201,11 @@ export class ResponseBodyHandler extends AbstractLogHandler {
           } else if (parsedUsage.data) {
             context.usage = parsedUsage.data ?? null;
 
-            const providerModelId =
+            const providerModelId = (
               context.message.heliconeMeta.providerModelId ??
               (!isAIGateway ? context.processedLog.model : "") ??
-              "";
+              ""
+            ).replace(/^models\//, "");
 
             const breakdown = modelCostBreakdownFromRegistry({
               modelUsage: parsedUsage.data,

valhalla/jawn/src/utils/modelMapper.ts

@@ -6,7 +6,9 @@ export function getModelFromRequest(
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   if (requestBody && (requestBody as any).model) {
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    return (requestBody as any).model;
+    const model = (requestBody as any).model;
+    // Strip Google's "models/" prefix for consistent cost registry lookups
+    return typeof model === "string" ? model.replace(/^models\//, "") : model;
   }
 
   if (targetUrl && targetUrl.toLowerCase().includes("firecrawl")) {
@@ -53,13 +55,14 @@ function getModelFromPath(path: string) {
 }
 
 export function getModelFromResponse(responseBody: any) {
-  return (
+  const model =
     responseBody?.model ??
     responseBody?.body?.model ??
     responseBody?.body?.modelVersion ??
     responseBody?.providerMetadata?.gateway?.routing?.originalModelId ??
-    null
-  );
+    null;
+  // Strip Google's "models/" prefix for consistent cost registry lookups
+  return typeof model === "string" ? model.replace(/^models\//, "") : model;
 }
 
 export function calculateModel(