Add initial support for tool/function calling

Adds the following tools:
- read_dir - list a directory's contents
- read_file - read the content of a file
- write_file - write contents to a file
- insert_file_lines - insert lines in a file
- replace_file_lines - replace or remove lines in a file

pkg/cli/functions.go

@@ -0,0 +1,582 @@
+package cli
+
+import (
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	openai "github.com/sashabaranov/go-openai"
+)
+
+type FunctionResult struct {
+	Message string `json:"message"`
+	Result  any    `json:"result,omitempty"`
+}
+
+type FunctionParameter struct {
+	Type        string   `json:"type"` // "string", "integer", "boolean"
+	Description string   `json:"description"`
+	Enum        []string `json:"enum,omitempty"`
+}
+
+type FunctionParameters struct {
+	Type       string                       `json:"type"` // "object"
+	Properties map[string]FunctionParameter `json:"properties"`
+	Required   []string                     `json:"required,omitempty"` // required function parameter names
+}
+
+type AvailableTool struct {
+	openai.Tool
+	// The tool's implementation. Returns a string, as tool call results
+	// are treated as normal messages with string contents.
+	Impl func(arguments map[string]interface{}) (string, error)
+}
+
+const (
+	READ_DIR_DESCRIPTION = `Return the contents of the CWD (current working directory).
+
+Results are returned as JSON in the following format:
+{
+	"message": "success", // if successful, or a different message indicating failure
+	// result may be an empty array if there are no files in the directory
+	"result": [
+		{"name": "a_file", "type": "file", "size": 123},
+		{"name": "a_directory/", "type": "dir", "size": 11},
+		... // more files or directories
+	]
+}
+
+For files, size represents the size (in bytes) of the file.
+For directories, size represents the number of entries in that directory.`
+
+	READ_FILE_DESCRIPTION = `Read the contents of a text file relative to the current working directory.
+
+Each line of the file is prefixed with its line number and a tabs (\t) to make
+it make it easier to see which lines to change for other modifications.
+
+Example result:
+{
+	"message": "success", // if successful, or a different message indicating failure
+	"result": "1\tthe contents\n2\tof the file\n"
+}`
+
+	WRITE_FILE_DESCRIPTION = `Write the provided contents to a file relative to the current working directory.
+
+Note: only use this tool when you've been explicitly asked to create or write to a file.
+
+When using this function, you do not need to share the content you intend to write with the user first.
+
+Example result:
+{
+	"message": "success", // if successful, or a different message indicating failure
+}`
+
+	FILE_INSERT_LINES_DESCRIPTION = `Insert lines into a file, must specify path.
+
+Make sure your inserts match the flow and indentation of surrounding content.`
+
+	FILE_REPLACE_LINES_DESCRIPTION = `Replace or remove a range of lines within a file, must specify path.
+
+Useful for re-writing snippets/blocks of code or entire functions.
+
+Be cautious with your edits. When replacing, ensure the replacement content matches the flow and indentation of surrounding content.`
+)
+
+var AvailableTools = map[string]AvailableTool{
+	"read_dir": {
+		Tool: openai.Tool{Type: "function", Function: openai.FunctionDefinition{
+			Name:        "read_dir",
+			Description: READ_DIR_DESCRIPTION,
+			Parameters: FunctionParameters{
+				Type: "object",
+				Properties: map[string]FunctionParameter{
+					"relative_dir": {
+						Type:        "string",
+						Description: "If set, read the contents of a directory relative to the current one.",
+					},
+				},
+			},
+		}},
+		Impl: func(args map[string]interface{}) (string, error) {
+			var relativeDir string
+			tmp, ok := args["relative_dir"]
+			if ok {
+				relativeDir, ok = tmp.(string)
+				if !ok {
+					return "", fmt.Errorf("Invalid relative_dir in function arguments: %v", tmp)
+				}
+			}
+			return ReadDir(relativeDir), nil
+		},
+	},
+	"read_file": {
+		Tool: openai.Tool{Type: "function", Function: openai.FunctionDefinition{
+			Name:        "read_file",
+			Description: READ_FILE_DESCRIPTION,
+			Parameters: FunctionParameters{
+				Type: "object",
+				Properties: map[string]FunctionParameter{
+					"path": {
+						Type:        "string",
+						Description: "Path to a file within the current working directory to read.",
+					},
+				},
+				Required: []string{"path"},
+			},
+		}},
+		Impl: func(args map[string]interface{}) (string, error) {
+			tmp, ok := args["path"]
+			if !ok {
+				return "", fmt.Errorf("Path parameter to read_file was not included.")
+			}
+			path, ok := tmp.(string)
+			if !ok {
+				return "", fmt.Errorf("Invalid path in function arguments: %v", tmp)
+			}
+			return ReadFile(path), nil
+		},
+	},
+	"write_file": {
+		Tool: openai.Tool{Type: "function", Function: openai.FunctionDefinition{
+			Name:        "write_file",
+			Description: WRITE_FILE_DESCRIPTION,
+			Parameters: FunctionParameters{
+				Type: "object",
+				Properties: map[string]FunctionParameter{
+					"path": {
+						Type:        "string",
+						Description: "Path to a file within the current working directory to write to.",
+					},
+					"content": {
+						Type:        "string",
+						Description: "The content to write to the file. Overwrites any existing content!",
+					},
+				},
+				Required: []string{"path", "content"},
+			},
+		}},
+		Impl: func(args map[string]interface{}) (string, error) {
+			tmp, ok := args["path"]
+			if !ok {
+				return "", fmt.Errorf("Path parameter to write_file was not included.")
+			}
+			path, ok := tmp.(string)
+			if !ok {
+				return "", fmt.Errorf("Invalid path in function arguments: %v", tmp)
+			}
+			tmp, ok = args["content"]
+			if !ok {
+				return "", fmt.Errorf("Content parameter to write_file was not included.")
+			}
+			content, ok := tmp.(string)
+			if !ok {
+				return "", fmt.Errorf("Invalid content in function arguments: %v", tmp)
+			}
+			return WriteFile(path, content), nil
+		},
+	},
+	"file_insert_lines": {
+		Tool: openai.Tool{Type: "function", Function: openai.FunctionDefinition{
+			Name:        "file_insert_lines",
+			Description: FILE_INSERT_LINES_DESCRIPTION,
+			Parameters: FunctionParameters{
+				Type: "object",
+				Properties: map[string]FunctionParameter{
+					"path": {
+						Type:        "string",
+						Description: "Path of the file to be modified, relative to the current working directory.",
+					},
+					"position": {
+						Type:        "integer",
+						Description: `Which line to insert content *before*.`,
+					},
+					"content": {
+						Type:        "string",
+						Description: `The content to insert.`,
+					},
+				},
+				Required: []string{"path", "position", "content"},
+			},
+		}},
+		Impl: func(args map[string]interface{}) (string, error) {
+			tmp, ok := args["path"]
+			if !ok {
+				return "", fmt.Errorf("path parameter to write_file was not included.")
+			}
+			path, ok := tmp.(string)
+			if !ok {
+				return "", fmt.Errorf("Invalid path in function arguments: %v", tmp)
+			}
+			var position int
+			tmp, ok = args["position"]
+			if ok {
+				tmp, ok := tmp.(float64)
+				if !ok {
+					return "", fmt.Errorf("Invalid position in function arguments: %v", tmp)
+				}
+				position = int(tmp)
+			}
+			var content string
+			tmp, ok = args["content"]
+			if ok {
+				content, ok = tmp.(string)
+				if !ok {
+					return "", fmt.Errorf("Invalid content in function arguments: %v", tmp)
+				}
+			}
+			return FileInsertLines(path, position, content), nil
+		},
+	},
+	"file_replace_lines": {
+		Tool: openai.Tool{Type: "function", Function: openai.FunctionDefinition{
+			Name:        "file_replace_lines",
+			Description: FILE_REPLACE_LINES_DESCRIPTION,
+			Parameters: FunctionParameters{
+				Type: "object",
+				Properties: map[string]FunctionParameter{
+					"path": {
+						Type:        "string",
+						Description: "Path of the file to be modified, relative to the current working directory.",
+					},
+					"start_line": {
+						Type:        "integer",
+						Description: `Line number which specifies the start of the replacement range (inclusive).`,
+					},
+					"end_line": {
+						Type:        "integer",
+						Description: `Line number which specifies the end of the replacement range (inclusive). If unset, range extends to end of file.`,
+					},
+					"content": {
+						Type:        "string",
+						Description: `Content to replace specified range. Omit to remove the specified range.`,
+					},
+				},
+				Required: []string{"path", "start_line"},
+			},
+		}},
+		Impl: func(args map[string]interface{}) (string, error) {
+			tmp, ok := args["path"]
+			if !ok {
+				return "", fmt.Errorf("path parameter to write_file was not included.")
+			}
+			path, ok := tmp.(string)
+			if !ok {
+				return "", fmt.Errorf("Invalid path in function arguments: %v", tmp)
+			}
+			var start_line int
+			tmp, ok = args["start_line"]
+			if ok {
+				tmp, ok := tmp.(float64)
+				if !ok {
+					return "", fmt.Errorf("Invalid start_line in function arguments: %v", tmp)
+				}
+				start_line = int(tmp)
+			}
+			var end_line int
+			tmp, ok = args["end_line"]
+			if ok {
+				tmp, ok := tmp.(float64)
+				if !ok {
+					return "", fmt.Errorf("Invalid end_line in function arguments: %v", tmp)
+				}
+				end_line = int(tmp)
+			}
+			var content string
+			tmp, ok = args["content"]
+			if ok {
+				content, ok = tmp.(string)
+				if !ok {
+					return "", fmt.Errorf("Invalid content in function arguments: %v", tmp)
+				}
+			}
+
+			return FileReplaceLines(path, start_line, end_line, content), nil
+		},
+	},
+}
+
+func resultToJson(result FunctionResult) string {
+	if result.Message == "" {
+		// When message not supplied, assume success
+		result.Message = "success"
+	}
+
+	jsonBytes, err := json.Marshal(result)
+	if err != nil {
+		fmt.Printf("Could not marshal FunctionResult to JSON: %v\n", err)
+	}
+	return string(jsonBytes)
+}
+
+// ExecuteToolCalls handles the execution of all tool_calls provided, and
+// returns their results formatted as []Message(s) with role: 'tool' and.
+func ExecuteToolCalls(toolCalls []openai.ToolCall) ([]Message, error) {
+	var toolResults []Message
+	for _, toolCall := range toolCalls {
+		if toolCall.Type != "function" {
+			// unsupported tool type
+			continue
+		}
+
+		tool, ok := AvailableTools[toolCall.Function.Name]
+		if !ok {
+			return nil, fmt.Errorf("Requested tool '%s' does not exist. Hallucination?", toolCall.Function.Name)
+		}
+
+		var functionArgs map[string]interface{}
+		err := json.Unmarshal([]byte(toolCall.Function.Arguments), &functionArgs)
+		if err != nil {
+			return nil, fmt.Errorf("Could not unmarshal tool arguments. Malformed JSON? Error: %v", err)
+		}
+
+		// TODO: ability to silence this
+		fmt.Fprintf(os.Stderr, "INFO: Executing tool '%s' with args %s\n", toolCall.Function.Name, toolCall.Function.Arguments)
+
+		// Execute the tool
+		toolResult, err := tool.Impl(functionArgs)
+		if err != nil {
+			// This can happen if the model missed or supplied invalid tool args
+			return nil, fmt.Errorf("Tool '%s' error: %v\n", toolCall.Function.Name, err)
+		}
+
+		toolResults = append(toolResults, Message{
+			Role:            "tool",
+			OriginalContent: toolResult,
+			ToolCallID:      sql.NullString{String: toolCall.ID, Valid: true},
+			// name is not required since the introduction of ToolCallID
+			// hypothesis: by setting it, we inform the model of what a
+			// function's purpose was if future requests omit the function
+			// definition
+		})
+	}
+	return toolResults, nil
+}
+
+// isPathContained attempts to verify whether `path` is the same as or
+// contained within `directory`. It is overly cautious, returning false even if
+// `path` IS contained within `directory`, but the two paths use different
+// casing, and we happen to be on a case-insensitive filesystem.
+// This is ultimately to attempt to stop an LLM from going outside of where I
+// tell it to. Additional layers of security should be considered.. run in a
+// VM/container.
+func isPathContained(directory string, path string) (bool, error) {
+	// Clean and resolve symlinks for both paths
+	path, err := filepath.Abs(path)
+	if err != nil {
+		return false, err
+	}
+
+	// check if path exists
+	_, err = os.Stat(path)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return false, fmt.Errorf("Could not stat path: %v", err)
+		}
+	} else {
+		path, err = filepath.EvalSymlinks(path)
+		if err != nil {
+			return false, err
+		}
+	}
+
+	directory, err = filepath.Abs(directory)
+	if err != nil {
+		return false, err
+	}
+	directory, err = filepath.EvalSymlinks(directory)
+	if err != nil {
+		return false, err
+	}
+
+	// Case insensitive checks
+	if !strings.EqualFold(path, directory) &&
+		!strings.HasPrefix(strings.ToLower(path), strings.ToLower(directory)+string(os.PathSeparator)) {
+		return false, nil
+	}
+
+	return true, nil
+}
+
+func isPathWithinCWD(path string) (bool, *FunctionResult) {
+	cwd, err := os.Getwd()
+	if err != nil {
+		return false, &FunctionResult{Message: "Failed to determine current working directory"}
+	}
+	if ok, err := isPathContained(cwd, path); !ok {
+		if err != nil {
+			return false, &FunctionResult{Message: fmt.Sprintf("Could not determine whether path '%s' is within the current working directory: %s", path, err.Error())}
+		}
+		return false, &FunctionResult{Message: fmt.Sprintf("Path '%s' is not within the current working directory", path)}
+	}
+	return true, nil
+}
+
+func ReadDir(path string) string {
+	// TODO(?): implement whitelist - list of directories which model is allowed to work in
+	if path == "" {
+		path = "."
+	}
+	ok, res := isPathWithinCWD(path)
+	if !ok {
+		return resultToJson(*res)
+	}
+
+	files, err := os.ReadDir(path)
+	if err != nil {
+		return resultToJson(FunctionResult{
+			Message: err.Error(),
+		})
+	}
+
+	var dirContents []map[string]interface{}
+	for _, f := range files {
+		info, _ := f.Info()
+
+		name := f.Name()
+		if strings.HasPrefix(name, ".") {
+			// skip hidden files
+			continue
+		}
+
+		entryType := "file"
+		size := info.Size()
+
+		if info.IsDir() {
+			name += "/"
+			entryType = "dir"
+			subdirfiles, _ := os.ReadDir(filepath.Join(".", path, info.Name()))
+			size = int64(len(subdirfiles))
+		}
+
+		dirContents = append(dirContents, map[string]interface{}{
+			"name": name,
+			"type": entryType,
+			"size": size,
+		})
+	}
+
+	return resultToJson(FunctionResult{Result: dirContents})
+}
+
+func ReadFile(path string) string {
+	ok, res := isPathWithinCWD(path)
+	if !ok {
+		return resultToJson(*res)
+	}
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not read path: %s", err.Error())})
+	}
+
+	lines := strings.Split(string(data), "\n")
+	content := strings.Builder{}
+	for i, line := range lines {
+		content.WriteString(fmt.Sprintf("%d\t%s\n", i+1, line))
+	}
+
+	return resultToJson(FunctionResult{
+		Result: content.String(),
+	})
+}
+
+func WriteFile(path string, content string) string {
+	ok, res := isPathWithinCWD(path)
+	if !ok {
+		return resultToJson(*res)
+	}
+	err := os.WriteFile(path, []byte(content), 0644)
+	if err != nil {
+		return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not write to path: %s", err.Error())})
+	}
+	return resultToJson(FunctionResult{})
+}
+
+func FileInsertLines(path string, position int, content string) string {
+	ok, res := isPathWithinCWD(path)
+	if !ok {
+		return resultToJson(*res)
+	}
+
+	// Read the existing file's content
+	data, err := os.ReadFile(path)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not read path: %s", err.Error())})
+		}
+		_, err = os.Create(path)
+		if err != nil {
+			return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not create new file: %s", err.Error())})
+		}
+		data = []byte{}
+	}
+
+	if position < 1 {
+		return resultToJson(FunctionResult{Message: "start_line cannot be less than 1"})
+	}
+
+	lines := strings.Split(string(data), "\n")
+	contentLines := strings.Split(strings.Trim(content, "\n"), "\n")
+
+	before := lines[:position-1]
+	after := lines[position-1:]
+	lines = append(before, append(contentLines, after...)...)
+
+	newContent := strings.Join(lines, "\n")
+
+	// Join the lines and write back to the file
+	err = os.WriteFile(path, []byte(newContent), 0644)
+	if err != nil {
+		return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not write to path: %s", err.Error())})
+	}
+
+	return resultToJson(FunctionResult{Result: newContent})
+}
+
+func FileReplaceLines(path string, startLine int, endLine int, content string) string {
+	ok, res := isPathWithinCWD(path)
+	if !ok {
+		return resultToJson(*res)
+	}
+
+	// Read the existing file's content
+	data, err := os.ReadFile(path)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not read path: %s", err.Error())})
+		}
+		_, err = os.Create(path)
+		if err != nil {
+			return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not create new file: %s", err.Error())})
+		}
+		data = []byte{}
+	}
+
+	if startLine < 1 {
+		return resultToJson(FunctionResult{Message: "start_line cannot be less than 1"})
+	}
+
+	lines := strings.Split(string(data), "\n")
+	contentLines := strings.Split(strings.Trim(content, "\n"), "\n")
+
+	if endLine == 0 || endLine > len(lines) {
+		endLine = len(lines)
+	}
+
+	before := lines[:startLine-1]
+	after := lines[endLine:]
+
+	lines = append(before, append(contentLines, after...)...)
+	newContent := strings.Join(lines, "\n")
+
+	// Join the lines and write back to the file
+	err = os.WriteFile(path, []byte(newContent), 0644)
+	if err != nil {
+		return resultToJson(FunctionResult{Message: fmt.Sprintf("Could not write to path: %s", err.Error())})
+	}
+
+	return resultToJson(FunctionResult{Result: newContent})
+
+}

pkg/cli/openai.go

@@ -2,7 +2,10 @@ package cli
 
 import (
 	"context"
+	"database/sql"
+	"encoding/json"
 	"errors"
+	"fmt"
 	"io"
 	"strings"
 
@@ -12,10 +15,29 @@ import (
 func CreateChatCompletionRequest(model string, messages []Message, maxTokens int) openai.ChatCompletionRequest {
 	chatCompletionMessages := []openai.ChatCompletionMessage{}
 	for _, m := range messages {
-		chatCompletionMessages = append(chatCompletionMessages, openai.ChatCompletionMessage{
+		message := openai.ChatCompletionMessage{
 			Role:    m.Role,
 			Content: m.OriginalContent,
-		})
+		}
+		if m.ToolCallID.Valid {
+			message.ToolCallID = m.ToolCallID.String
+		}
+		if m.ToolCalls.Valid {
+			// unmarshal directly into chatMessage.ToolCalls
+			err := json.Unmarshal([]byte(m.ToolCalls.String), &message.ToolCalls)
+			if err != nil {
+				// TODO: handle, this shouldn't really happen since
+				// we only save the successfully marshal'd data to database
+				fmt.Printf("Error unmarshalling the tool_calls JSON: %v\n", err)
+			}
+		}
+		chatCompletionMessages = append(chatCompletionMessages, message)
+	}
+
+	var tools []openai.Tool
+	for _, t := range AvailableTools {
+		// TODO: support some way to limit which tools are available per-request
+		tools = append(tools, t.Tool)
 	}
 
 	return openai.ChatCompletionRequest{
@@ -23,11 +45,14 @@ func CreateChatCompletionRequest(model string, messages []Message, maxTokens int
 		Messages:   chatCompletionMessages,
 		MaxTokens:  maxTokens,
 		N:          1, // limit responses to 1 "choice". we use choices[0] to reference it
+		Tools:      tools,
+		ToolChoice: "auto", // TODO: allow limiting/forcing which function is called?
 	}
 }
 
 // CreateChatCompletion submits a Chat Completion API request and returns the
-// response.
+// response. CreateChatCompletion will recursively call itself in the case of
+// tool calls, until a response is received with the final user-facing output.
 func CreateChatCompletion(model string, messages []Message, maxTokens int) (string, error) {
 	client := openai.NewClient(*config.OpenAI.APIKey)
 	req := CreateChatCompletionRequest(model, messages, maxTokens)
@@ -36,7 +61,32 @@ func CreateChatCompletion(model string, messages []Message, maxTokens int) (stri
 		return "", err
 	}
 
-	return resp.Choices[0].Message.Content, nil
+	choice := resp.Choices[0]
+
+	if len(choice.Message.ToolCalls) > 0 {
+		if choice.Message.Content != "" {
+			return "", fmt.Errorf("Model replied with user-facing content in addition to tool calls. Unsupported.")
+		}
+
+		// Append the assistant's reply with its request for tool calls
+		toolCallJson, _ := json.Marshal(choice.Message.ToolCalls)
+		messages = append(messages, Message{
+			Role:      "assistant",
+			ToolCalls: sql.NullString{String: string(toolCallJson), Valid: true},
+		})
+
+		toolReplies, err := ExecuteToolCalls(choice.Message.ToolCalls)
+		if err != nil {
+			return "", err
+		}
+
+		// Recurse into CreateChatCompletion with the tool call replies added
+		// to the original messages
+		return CreateChatCompletion(model, append(messages, toolReplies...), maxTokens)
+	}
+
+	// Return the user-facing message.
+	return choice.Message.Content, nil
 }
 
 // CreateChatCompletionStream submits a streaming Chat Completion API request
@@ -52,7 +102,10 @@ func CreateChatCompletionStream(model string, messages []Message, maxTokens int,
 	}
 	defer stream.Close()
 
-	sb := strings.Builder{}
+	content := strings.Builder{}
+	toolCalls := []openai.ToolCall{}
+
+	// Iterate stream segments
 	for {
 		response, e := stream.Recv()
 		if errors.Is(e, io.EOF) {
@@ -63,9 +116,47 @@ func CreateChatCompletionStream(model string, messages []Message, maxTokens int,
 			err = e
 			break
 		}
-		chunk := response.Choices[0].Delta.Content
-		output <- chunk
-		sb.WriteString(chunk)
+
+		delta := response.Choices[0].Delta
+		if len(delta.ToolCalls) > 0 {
+			// Construct streamed tool_call arguments
+			for _, tc := range delta.ToolCalls {
+				if tc.Index == nil {
+					return "", fmt.Errorf("Unexpected nil index for streamed tool call.")
 				}
-	return sb.String(), err
+				if len(toolCalls) <= *tc.Index {
+					toolCalls = append(toolCalls, tc)
+				} else {
+					toolCalls[*tc.Index].Function.Arguments += tc.Function.Arguments
+				}
+			}
+		} else {
+			output <- delta.Content
+			content.WriteString(delta.Content)
+		}
+	}
+
+	if len(toolCalls) > 0 {
+		if content.String() != "" {
+			return "", fmt.Errorf("Model replied with user-facing content in addition to tool calls. Unsupported.")
+		}
+
+		// Append the assistant's reply with its request for tool calls
+		toolCallJson, _ := json.Marshal(toolCalls)
+		messages = append(messages, Message{
+			Role:      "assistant",
+			ToolCalls: sql.NullString{String: string(toolCallJson), Valid: true},
+		})
+
+		toolReplies, err := ExecuteToolCalls(toolCalls)
+		if err != nil {
+			return "", err
+		}
+
+		// Recurse into CreateChatCompletionStream with the tool call replies
+		// added to the original messages
+		return CreateChatCompletionStream(model, append(messages, toolReplies...), maxTokens, output)
+	}
+
+	return content.String(), err
 }

pkg/cli/store.go

@@ -23,8 +23,10 @@ type Message struct {
 	ConversationID  uint `gorm:"foreignKey:ConversationID"`
 	Conversation    Conversation
 	OriginalContent string
-	Role            string // 'user' or 'assistant'
+	Role            string // one of: 'user', 'assistant', 'tool'
 	CreatedAt       time.Time
+	ToolCallID		sql.NullString
+	ToolCalls		sql.NullString // a json-encoded array of tool calls from the model
 }
 
 type Conversation struct {