support for gemini thinking model

src/providers/google-vertex-ai/api.ts

@@ -2,6 +2,15 @@ import { Options } from '../../types/requestBody';
 import { endpointStrings, ProviderAPIConfig } from '../types';
 import { getModelAndProvider, getAccessToken } from './utils';
 
+const shouldUseBeta1Version = (provider: string, inputModel: string) => {
+  if (
+    provider === 'meta' ||
+    inputModel.includes('gemini-2.0-flash-thinking-exp')
+  )
+    return true;
+  return false;
+};
+
 const getProjectRoute = (
   providerOptions: Options,
   inputModel: string
@@ -17,7 +26,10 @@ const getProjectRoute = (
   }
 
   const { provider } = getModelAndProvider(inputModel as string);
-  const routeVersion = provider === 'meta' ? 'v1beta1' : 'v1';
+  let routeVersion = provider === 'meta' ? 'v1beta1' : 'v1';
+  if (shouldUseBeta1Version(provider, inputModel)) {
+    routeVersion = 'v1beta1';
+  }
   return `/${routeVersion}/projects/${projectId}/locations/${vertexRegion}`;
 };
 

src/providers/google-vertex-ai/chatComplete.ts

@@ -644,11 +644,26 @@ export const GoogleChatCompleteResponseTransform: (
       provider: GOOGLE_VERTEX_AI,
       choices:
         response.candidates?.map((generation, index) => {
+          const containsChainOfThoughtMessage =
+            generation.content?.parts.length > 1;
           let message: Message = { role: 'assistant', content: '' };
           if (generation.content?.parts[0]?.text) {
+            let content: string = generation.content.parts[0]?.text;
+            if (
+              containsChainOfThoughtMessage &&
+              generation.content.parts[1]?.text
+            ) {
+              if (strictOpenAiCompliance)
+                content = generation.content.parts[1]?.text;
+              else
+                content =
+                  generation.content.parts[0]?.text +
+                  '\r\n\r\n' +
+                  generation.content.parts[1]?.text;
+            }
             message = {
               role: 'assistant',
-              content: generation.content.parts[0]?.text,
+              content,
             };
           } else if (generation.content?.parts[0]?.functionCall) {
             message = {
@@ -751,9 +766,11 @@ export const GoogleChatCompleteStreamChunkTransform: (
 ) => string = (
   responseChunk,
   fallbackId,
-  _streamState,
+  streamState,
   strictOpenAiCompliance
 ) => {
+  streamState.containsChainOfThoughtMessage =
+    streamState?.containsChainOfThoughtMessage ?? false;
   const chunk = responseChunk
     .trim()
     .replace(/^data: /, '')
@@ -784,9 +801,30 @@ export const GoogleChatCompleteStreamChunkTransform: (
       parsedChunk.candidates?.map((generation, index) => {
         let message: Message = { role: 'assistant', content: '' };
         if (generation.content?.parts[0]?.text) {
+          if (generation.content.parts[0].thought)
+            streamState.containsChainOfThoughtMessage = true;
+
+          let content: string =
+            strictOpenAiCompliance && streamState.containsChainOfThoughtMessage
+              ? ''
+              : generation.content.parts[0]?.text;
+          if (generation.content.parts[1]?.text) {
+            if (strictOpenAiCompliance)
+              content = generation.content.parts[1].text;
+            else content += '\r\n\r\n' + generation.content.parts[1]?.text;
+            streamState.containsChainOfThoughtMessage = false;
+          } else if (
+            streamState.containsChainOfThoughtMessage &&
+            !generation.content.parts[0]?.thought
+          ) {
+            if (strictOpenAiCompliance)
+              content = generation.content.parts[0].text;
+            else content = '\r\n\r\n' + content;
+            streamState.containsChainOfThoughtMessage = false;
+          }
           message = {
             role: 'assistant',
-            content: generation.content.parts[0]?.text,
+            content,
           };
         } else if (generation.content?.parts[0]?.functionCall) {
           message = {

src/providers/google-vertex-ai/types.ts

@@ -19,6 +19,7 @@ export interface GoogleGenerateContentResponse {
     content: {
       parts: {
         text?: string;
+        thought?: string; // for models like gemini-2.0-flash-thinking-exp refer: https://ai.google.dev/gemini-api/docs/thinking-mode#streaming_model_thinking
         functionCall?: GoogleGenerateFunctionCall;
       }[];
     };

src/providers/google/api.ts

@@ -1,23 +1,27 @@
 import { ProviderAPIConfig } from '../types';
 
 export const GoogleApiConfig: ProviderAPIConfig = {
-  getBaseURL: () => 'https://generativelanguage.googleapis.com/v1beta',
+  getBaseURL: () => 'https://generativelanguage.googleapis.com',
   headers: () => {
     return { 'Content-Type': 'application/json' };
   },
   getEndpoint: ({ fn, providerOptions, gatewayRequestBodyJSON }) => {
+    let routeVersion = 'v1beta';
     let mappedFn = fn;
     const { model, stream } = gatewayRequestBodyJSON;
+    if (model?.includes('gemini-2.0-flash-thinking-exp')) {
+      routeVersion = 'v1alpha';
+    }
     const { apiKey } = providerOptions;
     if (stream && fn === 'chatComplete') {
-      return `/models/${model}:streamGenerateContent?key=${apiKey}`;
+      return `/${routeVersion}/models/${model}:streamGenerateContent?key=${apiKey}`;
     }
     switch (mappedFn) {
       case 'chatComplete': {
-        return `/models/${model}:generateContent?key=${apiKey}`;
+        return `/${routeVersion}/models/${model}:generateContent?key=${apiKey}`;
       }
       case 'embed': {
-        return `/models/${model}:embedContent?key=${apiKey}`;
+        return `/${routeVersion}/models/${model}:embedContent?key=${apiKey}`;
       }
       default:
         return '';

src/providers/google/chatComplete.ts

@@ -402,6 +402,7 @@ interface GoogleGenerateContentResponse {
     content: {
       parts: {
         text?: string;
+        thought?: string; // for models like gemini-2.0-flash-thinking-exp refer: https://ai.google.dev/gemini-api/docs/thinking-mode#streaming_model_thinking
         functionCall?: GoogleGenerateFunctionCall;
       }[];
     };
@@ -489,11 +490,26 @@ export const GoogleChatCompleteResponseTransform: (
       provider: 'google',
       choices:
         response.candidates?.map((generation, idx) => {
+          const containsChainOfThoughtMessage =
+            generation.content?.parts.length > 1;
           let message: Message = { role: 'assistant', content: '' };
           if (generation.content?.parts[0]?.text) {
+            let content: string = generation.content.parts[0]?.text;
+            if (
+              containsChainOfThoughtMessage &&
+              generation.content.parts[1]?.text
+            ) {
+              if (strictOpenAiCompliance)
+                content = generation.content.parts[1]?.text;
+              else
+                content =
+                  generation.content.parts[0]?.text +
+                  '\r\n\r\n' +
+                  generation.content.parts[1]?.text;
+            }
             message = {
               role: 'assistant',
-              content: generation.content.parts[0]?.text,
+              content,
             };
           } else if (generation.content?.parts[0]?.functionCall) {
             message = {
@@ -540,9 +556,11 @@ export const GoogleChatCompleteStreamChunkTransform: (
 ) => string = (
   responseChunk,
   fallbackId,
-  _streamState,
+  streamState,
   strictOpenAiCompliance
 ) => {
+  streamState.containsChainOfThoughtMessage =
+    streamState?.containsChainOfThoughtMessage ?? false;
   let chunk = responseChunk.trim();
   if (chunk.startsWith('[')) {
     chunk = chunk.slice(1);
@@ -572,10 +590,32 @@ export const GoogleChatCompleteStreamChunkTransform: (
       choices:
         parsedChunk.candidates?.map((generation, index) => {
           let message: Message = { role: 'assistant', content: '' };
-          if (generation.content.parts[0]?.text) {
+          if (generation.content?.parts[0]?.text) {
+            if (generation.content.parts[0].thought)
+              streamState.containsChainOfThoughtMessage = true;
+
+            let content: string =
+              strictOpenAiCompliance &&
+              streamState.containsChainOfThoughtMessage
+                ? ''
+                : generation.content.parts[0]?.text;
+            if (generation.content.parts[1]?.text) {
+              if (strictOpenAiCompliance)
+                content = generation.content.parts[1].text;
+              else content += '\r\n\r\n' + generation.content.parts[1]?.text;
+              streamState.containsChainOfThoughtMessage = false;
+            } else if (
+              streamState.containsChainOfThoughtMessage &&
+              !generation.content.parts[0]?.thought
+            ) {
+              if (strictOpenAiCompliance)
+                content = generation.content.parts[0].text;
+              else content = '\r\n\r\n' + content;
+              streamState.containsChainOfThoughtMessage = false;
+            }
             message = {
               role: 'assistant',
-              content: generation.content.parts[0]?.text,
+              content,
             };
           } else if (generation.content.parts[0]?.functionCall) {
             message = {