fix(gemini): resolve the lowest thinking level for Vertex resource-name model IDs

Author: waleedlatif1

apps/sim/providers/gemini/core.test.ts

@@ -143,6 +143,7 @@ describe('Vertex Gemini request compatibility', () => {
   it.each([
     ['vertex/gemini-3.6-flash', 'MINIMAL'],
     ['vertex/gemini-3.8-flash', 'LOW'],
+    ['vertex/projects/p/locations/global/publishers/google/models/gemini-3.8-flash', 'LOW'],
   ])("sends the lowest thinking level for 'none' on %s", async (model, thinkingLevel) => {
     const generateContent = vi.fn().mockResolvedValue(textTurn())
     await run(model, generateContent, { thinkingLevel: 'none' })

apps/sim/providers/gemini/core.ts

@@ -57,6 +57,7 @@ import {
   prepareToolExecution,
   prepareToolsWithUsageControl,
   sumToolCosts,
+  toBareGeminiModelId,
 } from '@/providers/utils'
 import type { ExecutionState, GeminiProviderType, GeminiUsage } from './types'
 
@@ -1013,9 +1014,11 @@ export async function executeGeminiRequest(
     const isGemini3 = isGemini3OrLaterModel(model)
     // Gemini 3 has no off switch and omitting thinkingConfig means the model's default level, so
     // 'none' sends the lowest declared level (levels are listed lowest-first; MINIMAL is closest to off).
+    // The catalog keys Vertex entries as vertex/<bare id>, so resource-name IDs are reduced first.
+    const catalogModelId = `${providerType === 'vertex' ? 'vertex/' : ''}${toBareGeminiModelId(model)}`
     const thinkingLevel =
       isGemini3 && request.thinkingLevel === 'none'
-        ? getThinkingLevelsForModel(request.model)?.[0]
+        ? getThinkingLevelsForModel(catalogModelId)?.[0]
         : request.thinkingLevel
     if (thinkingLevel && thinkingLevel !== 'none') {
       const thinkingConfig: ThinkingConfig = { includeThoughts: request.agentEvents === true }

apps/sim/providers/utils.ts

@@ -1491,16 +1491,23 @@ export function isDeepResearchModel(model: string): boolean {
   return MODELS_WITH_DEEP_RESEARCH.includes(model.toLowerCase())
 }
 
-/** Accepts bare Gemini IDs, google/ or vertex/ prefixes, and Google publisher resource names. */
-export function isGemini3OrLaterModel(model: string): boolean {
-  const normalized = model
+/**
+ * Reduces a Gemini model reference to its bare lowercase ID (`gemini-3.8-flash`). Accepts bare
+ * Gemini IDs, google/ or vertex/ prefixes, and Google publisher resource names.
+ */
+export function toBareGeminiModelId(model: string): string {
+  return model
     .toLowerCase()
     .replace(/^vertex\//, '')
     .replace(
       /^(?:google\/|(?:projects\/[^/]+\/locations\/[^/]+\/)?publishers\/google\/models\/)/,
       ''
     )
-  return Number(normalized.match(/^gemini-(\d+)(?:[.-]|$)/)?.[1]) >= 3
+}
+
+/** Accepts bare Gemini IDs, google/ or vertex/ prefixes, and Google publisher resource names. */
+export function isGemini3OrLaterModel(model: string): boolean {
+  return Number(toBareGeminiModelId(model).match(/^gemini-(\d+)(?:[.-]|$)/)?.[1]) >= 3
 }
 
 /**