fix: resolve google provider default API to google-generative-ai (#88480)

xin · xin · commit b14ff960d60c · 2026-05-31T11:42:12.000+08:00
When a configured Google provider/model row had no explicit
but had a baseUrl set, the fallback defaulted to openai-completions,
causing Gemini requests to route through the OpenAI Responses
transport instead of the native @google/genai transport.

Made resolveConfiguredProviderDefaultApi provider-aware: for the
google provider, the default API is now google-generative-ai.

Root cause: the generic fallback assumed any provider with a baseUrl
should use openai-completions, which is incorrect for Google's native
Gemini API.
diff --git a/src/agents/embedded-agent-runner/model.ts b/src/agents/embedded-agent-runner/model.ts
@@ -339,12 +339,19 @@ function resolveProviderTransport(params: {
 
 function resolveConfiguredProviderDefaultApi(
   providerConfig: InlineProviderConfig | undefined,
+  provider?: string,
 ): Api | undefined {
   const explicit = normalizeResolvedTransportApi(providerConfig?.api);
   if (explicit) {
     return explicit;
   }
-  return providerConfig?.baseUrl ? "openai-completions" : undefined;
+  if (!providerConfig?.baseUrl) {
+    return undefined;
+  }
+  if (provider === "google") {
+    return "google-generative-ai";
+  }
+  return "openai-completions";
 }
 
 function resolveProviderRequestTimeoutMs(timeoutSeconds: unknown): number | undefined {
@@ -665,7 +672,7 @@ function applyConfiguredProviderOverrides(params: {
       metadataOverrideModel?.api ??
       providerConfig.api ??
       discoveredModel.api ??
-      resolveConfiguredProviderDefaultApi(providerConfig),
+      resolveConfiguredProviderDefaultApi(providerConfig, params.provider),
     baseUrl: metadataOverrideModel?.baseUrl ?? providerConfig.baseUrl ?? discoveredModel.baseUrl,
     cfg: params.cfg,
     workspaceDir: params.workspaceDir,
@@ -688,7 +695,7 @@ function applyConfiguredProviderOverrides(params: {
     api:
       resolvedTransport.api ??
       normalizeResolvedTransportApi(discoveredModel.api) ??
-      resolveConfiguredProviderDefaultApi(providerConfig) ??
+      resolveConfiguredProviderDefaultApi(providerConfig, params.provider) ??
       "openai-responses",
     baseUrl: resolvedTransport.baseUrl ?? discoveredModel.baseUrl,
     discoveredHeaders,
@@ -1031,7 +1038,7 @@ function resolveConfiguredFallbackModel(params: {
     provider,
     api:
       normalizeResolvedTransportApi(configuredModel?.api) ??
-      resolveConfiguredProviderDefaultApi(providerConfig) ??
+      resolveConfiguredProviderDefaultApi(providerConfig, provider) ??
       normalizeResolvedTransportApi(staticCatalogModel?.api) ??
       "openai-responses",
     baseUrl: configuredModel?.baseUrl ?? providerConfig?.baseUrl ?? staticCatalogModel?.baseUrl,
