fix: gemini function declaration conversion

core/changelog.md

@@ -1 +1,2 @@
-- fix: empty string handling in Anthropic provider to prevent sending empty content blocks in chat requests
+- fix: empty string handling in Anthropic provider to prevent sending empty content blocks in chat requests
+- fix: Gemini/Vertex tool conversion to append all function declarations to a single Tool object

core/providers/gemini/responses.go

@@ -2076,12 +2076,10 @@ func (r *GeminiGenerationRequest) convertParamsToGenerationConfigResponses(param
 
 // convertResponsesToolsToGemini converts Responses tools to Gemini tools
 func convertResponsesToolsToGemini(tools []schemas.ResponsesTool) []Tool {
-	var geminiTools []Tool
+	geminiTool := Tool{}
 
 	for _, tool := range tools {
 		if tool.Type == "function" {
-			geminiTool := Tool{}
-
 			// Extract function information from ResponsesExtendedTool
 			if tool.ResponsesToolFunction != nil {
 				if tool.Name != nil && tool.ResponsesToolFunction != nil {
@@ -2100,17 +2098,16 @@ func convertResponsesToolsToGemini(tools []schemas.ResponsesTool) []Tool {
 							return nil
 						}(),
 					}
-					geminiTool.FunctionDeclarations = []*FunctionDeclaration{funcDecl}
+					geminiTool.FunctionDeclarations = append(geminiTool.FunctionDeclarations, funcDecl)
 				}
 			}
-
-			if len(geminiTool.FunctionDeclarations) > 0 {
-				geminiTools = append(geminiTools, geminiTool)
-			}
 		}
 	}
 
-	return geminiTools
+	if len(geminiTool.FunctionDeclarations) > 0 {
+		return []Tool{geminiTool}
+	}
+	return []Tool{}
 }
 
 // convertResponsesToolChoiceToGemini converts Responses tool choice to Gemini tool config

core/providers/gemini/utils.go

@@ -457,7 +457,7 @@ func convertParamsToGenerationConfig(params *schemas.ChatParameters, responseMod
 
 // convertBifrostToolsToGemini converts Bifrost tools to Gemini format
 func convertBifrostToolsToGemini(bifrostTools []schemas.ChatTool) []Tool {
-	var geminiTools []Tool
+	geminiTool := Tool{}
 
 	for _, tool := range bifrostTools {
 		if tool.Type == "" {
@@ -473,14 +473,14 @@ func convertBifrostToolsToGemini(bifrostTools []schemas.ChatTool) []Tool {
 			if tool.Function.Description != nil {
 				fd.Description = *tool.Function.Description
 			}
-			geminiTool := Tool{
-				FunctionDeclarations: []*FunctionDeclaration{fd},
-			}
-			geminiTools = append(geminiTools, geminiTool)
+			geminiTool.FunctionDeclarations = append(geminiTool.FunctionDeclarations, fd)
 		}
 	}
 
-	return geminiTools
+	if len(geminiTool.FunctionDeclarations) > 0 {
+		return []Tool{geminiTool}
+	}
+	return []Tool{}
 }
 
 // convertFunctionParametersToSchema converts Bifrost function parameters to Gemini Schema

core/providers/vertex/vertex_test.go

@@ -36,7 +36,7 @@ func TestVertex(t *testing.T) {
 			MultiTurnConversation: true,
 			ToolCalls:             true,
 			ToolCallsStreaming:    true,
-			MultipleToolCalls:     false, // multiple tool calls supported on gemini endpoint only if all tools are search tools
+			MultipleToolCalls:     true,
 			End2EndToolCalling:    true,
 			AutomaticFunctionCall: true,
 			ImageURL:              true,

transports/changelog.md

@@ -1,2 +1,3 @@
 - chore: added max_tokens -> max_completion_tokens mapping for chat completions
-- fix: empty string handling in Anthropic provider to prevent sending empty content blocks in chat requests
+- fix: empty string handling in Anthropic provider to prevent sending empty content blocks in chat requests
+- fix: Gemini/Vertex tool conversion to append all function declarations to a single Tool object