Add Anthropic tool calling support

internal/providers/anthropic/anthropic.go

@@ -2,6 +2,7 @@ package anthropic
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 
 	"github.com/anthropics/anthropic-sdk-go"
@@ -85,6 +86,11 @@ func (p *Provider) Generate(ctx context.Context, messages []api.Message, req *ap
 			anthropicMsgs = append(anthropicMsgs, anthropic.NewUserMessage(anthropic.NewTextBlock(content)))
 		case "assistant":
 			anthropicMsgs = append(anthropicMsgs, anthropic.NewAssistantMessage(anthropic.NewTextBlock(content)))
+		case "tool":
+			// Tool results must be in user message with tool_result blocks
+			anthropicMsgs = append(anthropicMsgs, anthropic.NewUserMessage(
+				anthropic.NewToolResultBlock(msg.CallID, content, false),
+			))
 		case "system", "developer":
 			system = content
 		}
@@ -116,17 +122,47 @@ func (p *Provider) Generate(ctx context.Context, messages []api.Message, req *ap
 		params.TopP = anthropic.Float(*req.TopP)
 	}
 
+	// Add tools if present
+	if req.Tools != nil && len(req.Tools) > 0 {
+		tools, err := parseTools(req)
+		if err != nil {
+			return nil, fmt.Errorf("parse tools: %w", err)
+		}
+		params.Tools = tools
+	}
+
+	// Add tool_choice if present
+	if req.ToolChoice != nil && len(req.ToolChoice) > 0 {
+		toolChoice, err := parseToolChoice(req)
+		if err != nil {
+			return nil, fmt.Errorf("parse tool_choice: %w", err)
+		}
+		params.ToolChoice = toolChoice
+	}
+
 	// Call Anthropic API
 	resp, err := p.client.Messages.New(ctx, params)
 	if err != nil {
 		return nil, fmt.Errorf("anthropic api error: %w", err)
 	}
 
-	// Extract text from response
+	// Extract text and tool calls from response
 	var text string
+	var toolCalls []api.ToolCall
+
 	for _, block := range resp.Content {
-		if block.Type == "text" {
-			text += block.Text
+		switch block.Type {
+		case "text":
+			text += block.AsText().Text
+		case "tool_use":
+			// Extract tool calls
+			toolUse := block.AsToolUse()
+			argsJSON, _ := json.Marshal(toolUse.Input)
+			toolCalls = append(toolCalls, api.ToolCall{
+				ID:        toolUse.ID,
+				Name:      toolUse.Name,
+				Arguments: string(argsJSON),
+			})
 		}
 	}
 
@@ -134,6 +170,7 @@ func (p *Provider) Generate(ctx context.Context, messages []api.Message, req *ap
 		ID:        resp.ID,
 		Model:     string(resp.Model),
 		Text:      text,
+		ToolCalls: toolCalls,
 		Usage: api.Usage{
 			InputTokens:  int(resp.Usage.InputTokens),
 			OutputTokens: int(resp.Usage.OutputTokens),
@@ -177,6 +214,11 @@ func (p *Provider) GenerateStream(ctx context.Context, messages []api.Message, r
 				anthropicMsgs = append(anthropicMsgs, anthropic.NewUserMessage(anthropic.NewTextBlock(content)))
 			case "assistant":
 				anthropicMsgs = append(anthropicMsgs, anthropic.NewAssistantMessage(anthropic.NewTextBlock(content)))
+			case "tool":
+				// Tool results must be in user message with tool_result blocks
+				anthropicMsgs = append(anthropicMsgs, anthropic.NewUserMessage(
+					anthropic.NewToolResultBlock(msg.CallID, content, false),
+				))
 			case "system", "developer":
 				system = content
 			}
@@ -208,20 +250,78 @@ func (p *Provider) GenerateStream(ctx context.Context, messages []api.Message, r
 			params.TopP = anthropic.Float(*req.TopP)
 		}
 
+		// Add tools if present
+		if req.Tools != nil && len(req.Tools) > 0 {
+			tools, err := parseTools(req)
+			if err != nil {
+				errChan <- fmt.Errorf("parse tools: %w", err)
+				return
+			}
+			params.Tools = tools
+		}
+
+		// Add tool_choice if present
+		if req.ToolChoice != nil && len(req.ToolChoice) > 0 {
+			toolChoice, err := parseToolChoice(req)
+			if err != nil {
+				errChan <- fmt.Errorf("parse tool_choice: %w", err)
+				return
+			}
+			params.ToolChoice = toolChoice
+		}
+
 		// Create stream
 		stream := p.client.Messages.NewStreaming(ctx, params)
 
+		// Track content block index and tool call state
+		var contentBlockIndex int
+
 		// Process stream
 		for stream.Next() {
 			event := stream.Current()
 
-			if event.Type == "content_block_delta" && event.Delta.Type == "text_delta" {
+			switch event.Type {
+			case "content_block_start":
+				// New content block (text or tool_use)
+				contentBlockIndex = int(event.Index)
+				if event.ContentBlock.Type == "tool_use" {
+					// Send tool call delta with ID and name
+					toolUse := event.ContentBlock.AsToolUse()
+					delta := &api.ToolCallDelta{
+						Index: contentBlockIndex,
+						ID:    toolUse.ID,
+						Name:  toolUse.Name,
+					}
+					select {
+					case deltaChan <- &api.ProviderStreamDelta{ToolCallDelta: delta}:
+					case <-ctx.Done():
+						errChan <- ctx.Err()
+						return
+					}
+				}
+
+			case "content_block_delta":
+				if event.Delta.Type == "text_delta" {
+					// Text streaming
 					select {
 					case deltaChan <- &api.ProviderStreamDelta{Text: event.Delta.Text}:
 					case <-ctx.Done():
 						errChan <- ctx.Err()
 						return
 					}
+				} else if event.Delta.Type == "input_json_delta" {
+					// Tool arguments streaming
+					delta := &api.ToolCallDelta{
+						Index:     int(event.Index),
+						Arguments: event.Delta.PartialJSON,
+					}
+					select {
+					case deltaChan <- &api.ProviderStreamDelta{ToolCallDelta: delta}:
+					case <-ctx.Done():
+						errChan <- ctx.Err()
+						return
+					}
+				}
 			}
 		}
 

internal/providers/anthropic/convert.go

@@ -0,0 +1,154 @@
+package anthropic
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/ajac-zero/latticelm/internal/api"
+	"github.com/anthropics/anthropic-sdk-go"
+)
+
+// parseTools converts Open Responses tools to Anthropic format
+func parseTools(req *api.ResponseRequest) ([]anthropic.ToolUnionParam, error) {
+	if req.Tools == nil || len(req.Tools) == 0 {
+		return nil, nil
+	}
+
+	var toolDefs []map[string]interface{}
+	if err := json.Unmarshal(req.Tools, &toolDefs); err != nil {
+		return nil, fmt.Errorf("unmarshal tools: %w", err)
+	}
+
+	var tools []anthropic.ToolUnionParam
+	for _, td := range toolDefs {
+		// Extract: name, description, parameters
+		// Note: Anthropic uses "input_schema" instead of "parameters"
+		name, _ := td["name"].(string)
+		desc, _ := td["description"].(string)
+		params, _ := td["parameters"].(map[string]interface{})
+
+		inputSchema := anthropic.ToolInputSchemaParam{
+			Type:       "object",
+			Properties: params["properties"],
+		}
+
+		// Add required fields if present
+		if required, ok := params["required"].([]interface{}); ok {
+			requiredStrs := make([]string, 0, len(required))
+			for _, r := range required {
+				if str, ok := r.(string); ok {
+					requiredStrs = append(requiredStrs, str)
+				}
+			}
+			inputSchema.Required = requiredStrs
+		}
+
+		// Create the tool using ToolUnionParamOfTool
+		tool := anthropic.ToolUnionParamOfTool(inputSchema, name)
+
+		if desc != "" {
+			tool.OfTool.Description = anthropic.String(desc)
+		}
+
+		tools = append(tools, tool)
+	}
+
+	return tools, nil
+}
+
+// parseToolChoice converts Open Responses tool_choice to Anthropic format
+func parseToolChoice(req *api.ResponseRequest) (anthropic.ToolChoiceUnionParam, error) {
+	var result anthropic.ToolChoiceUnionParam
+
+	if req.ToolChoice == nil || len(req.ToolChoice) == 0 {
+		return result, nil
+	}
+
+	var choice interface{}
+	if err := json.Unmarshal(req.ToolChoice, &choice); err != nil {
+		return result, fmt.Errorf("unmarshal tool_choice: %w", err)
+	}
+
+	// Handle string values: "auto", "any", "required"
+	if str, ok := choice.(string); ok {
+		switch str {
+		case "auto":
+			result.OfAuto = &anthropic.ToolChoiceAutoParam{
+				Type: "auto",
+			}
+		case "any", "required":
+			result.OfAny = &anthropic.ToolChoiceAnyParam{
+				Type: "any",
+			}
+		case "none":
+			result.OfNone = &anthropic.ToolChoiceNoneParam{
+				Type: "none",
+			}
+		default:
+			return result, fmt.Errorf("unknown tool_choice string: %s", str)
+		}
+		return result, nil
+	}
+
+	// Handle specific tool selection: {"type": "tool", "function": {"name": "..."}}
+	if obj, ok := choice.(map[string]interface{}); ok {
+		// Check for OpenAI format: {"type": "function", "function": {"name": "..."}}
+		if funcObj, ok := obj["function"].(map[string]interface{}); ok {
+			if name, ok := funcObj["name"].(string); ok {
+				result.OfTool = &anthropic.ToolChoiceToolParam{
+					Type: "tool",
+					Name: name,
+				}
+				return result, nil
+			}
+		}
+
+		// Check for direct name field
+		if name, ok := obj["name"].(string); ok {
+			result.OfTool = &anthropic.ToolChoiceToolParam{
+				Type: "tool",
+				Name: name,
+			}
+			return result, nil
+		}
+	}
+
+	return result, fmt.Errorf("invalid tool_choice format")
+}
+
+// extractToolCalls converts Anthropic content blocks to api.ToolCall
+func extractToolCalls(content []anthropic.ContentBlockUnion) []api.ToolCall {
+	var toolCalls []api.ToolCall
+
+	for _, block := range content {
+		// Check if this is a tool_use block
+		if block.Type == "tool_use" {
+			// Cast to ToolUseBlock to access the fields
+			toolUse := block.AsToolUse()
+
+			// Marshal the input to JSON string for Arguments
+			argsJSON, _ := json.Marshal(toolUse.Input)
+
+			toolCalls = append(toolCalls, api.ToolCall{
+				ID:        toolUse.ID,
+				Name:      toolUse.Name,
+				Arguments: string(argsJSON),
+			})
+		}
+	}
+
+	return toolCalls
+}
+
+// extractToolCallDelta extracts tool call delta from streaming content block delta
+func extractToolCallDelta(delta anthropic.RawContentBlockDeltaUnion, index int) *api.ToolCallDelta {
+	// Check if this is an input_json_delta (streaming tool arguments)
+	if delta.Type == "input_json_delta" {
+		return &api.ToolCallDelta{
+			Index:     index,
+			Arguments: delta.PartialJSON,
+		}
+	}
+
+	return nil
+}

internal/providers/anthropic/convert_test.go

@@ -0,0 +1,119 @@
+package anthropic
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/ajac-zero/latticelm/internal/api"
+)
+
+func TestParseTools(t *testing.T) {
+	// Create a sample tool definition
+	toolsJSON := `[{
+		"type": "function",
+		"name": "get_weather",
+		"description": "Get the weather for a location",
+		"parameters": {
+			"type": "object",
+			"properties": {
+				"location": {
+					"type": "string",
+					"description": "The city and state"
+				}
+			},
+			"required": ["location"]
+		}
+	}]`
+
+	req := &api.ResponseRequest{
+		Tools: json.RawMessage(toolsJSON),
+	}
+
+	tools, err := parseTools(req)
+	if err != nil {
+		t.Fatalf("parseTools failed: %v", err)
+	}
+
+	if len(tools) != 1 {
+		t.Fatalf("expected 1 tool, got %d", len(tools))
+	}
+
+	tool := tools[0]
+	if tool.OfTool == nil {
+		t.Fatal("expected OfTool to be set")
+	}
+
+	if tool.OfTool.Name != "get_weather" {
+		t.Errorf("expected name 'get_weather', got '%s'", tool.OfTool.Name)
+	}
+
+	desc := tool.GetDescription()
+	if desc == nil || *desc != "Get the weather for a location" {
+		t.Errorf("expected description 'Get the weather for a location', got '%v'", desc)
+	}
+
+	if len(tool.OfTool.InputSchema.Required) != 1 || tool.OfTool.InputSchema.Required[0] != "location" {
+		t.Errorf("expected required=['location'], got %v", tool.OfTool.InputSchema.Required)
+	}
+}
+
+func TestParseToolChoice(t *testing.T) {
+	tests := []struct {
+		name        string
+		choiceJSON  string
+		expectAuto  bool
+		expectAny   bool
+		expectTool  bool
+		expectedName string
+	}{
+		{
+			name:       "auto",
+			choiceJSON: `"auto"`,
+			expectAuto: true,
+		},
+		{
+			name:       "any",
+			choiceJSON: `"any"`,
+			expectAny:  true,
+		},
+		{
+			name:       "required",
+			choiceJSON: `"required"`,
+			expectAny:  true,
+		},
+		{
+			name:         "specific tool",
+			choiceJSON:   `{"type": "function", "function": {"name": "get_weather"}}`,
+			expectTool:   true,
+			expectedName: "get_weather",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req := &api.ResponseRequest{
+				ToolChoice: json.RawMessage(tt.choiceJSON),
+			}
+
+			choice, err := parseToolChoice(req)
+			if err != nil {
+				t.Fatalf("parseToolChoice failed: %v", err)
+			}
+
+			if tt.expectAuto && choice.OfAuto == nil {
+				t.Error("expected OfAuto to be set")
+			}
+			if tt.expectAny && choice.OfAny == nil {
+				t.Error("expected OfAny to be set")
+			}
+			if tt.expectTool {
+				if choice.OfTool == nil {
+					t.Fatal("expected OfTool to be set")
+				}
+				if choice.OfTool.Name != tt.expectedName {
+					t.Errorf("expected name '%s', got '%s'", tt.expectedName, choice.OfTool.Name)
+				}
+			}
+		})
+	}
+}

internal/providers/openai/convert.go

@@ -22,7 +22,7 @@ func parseTools(req *api.ResponseRequest) ([]openai.ChatCompletionToolUnionParam
 
 	var tools []openai.ChatCompletionToolUnionParam
 	for _, td := range toolDefs {
-		// Convert Open Responses tool to OpenAI function tool
+		// Convert Open Responses tool to OpenAI ChatCompletionFunctionToolParam
 		// Extract: name, description, parameters
 		name, _ := td["name"].(string)
 		desc, _ := td["description"].(string)