Add read_file and write_file tools

Also improve `read_dir` description, and make it skip hidden files

pkg/cli/functions.go

@@ -44,6 +44,7 @@ var AvailableTools = map[string]AvailableTool{
 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},
@@ -75,6 +76,83 @@ For directories, size represents the number of entries in that directory.`,
 			return ReadDir(relativeDir), nil
 		},
 	},
+	"read_file": {
+		Tool: openai.Tool{Type: "function", Function: openai.FunctionDefinition{
+			Name: "read_file",
+			Description: `Read the contents of a file relative to the current working directory.
+
+Result is returned as JSON in the following format:
+{
+	"message": "success", // if successful, or a different message indicating failure
+	"result": "the contents\nof the file\n"
+}`,
+			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{"file_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 the provided contents to a file relative to the current working directory.
+
+Result is returned as JSON in the following format:
+{
+	"message": "success", // if successful, or a different message indicating failure
+}`,
+			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{"file_path"},
+			},
+		}},
+		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("Invalido content in function arguments: %v", tmp)
+			}
+			return WriteFile(path, content), nil
+		},
+	},
 }
 
 func resultToJson(result FunctionResult) string {
@@ -143,27 +221,36 @@ func ExecuteToolCalls(toolCalls []openai.ToolCall) ([]Message, error) {
 // VM/container.
 func isPathContained(directory string, path string) (bool, error) {
 	// Clean and resolve symlinks for both paths
-	absPath, err := filepath.Abs(path)
+	path, err := filepath.Abs(path)
-	if err != nil {
-		return false, err
-	}
-	realPath, err := filepath.EvalSymlinks(absPath)
 	if err != nil {
 		return false, err
 	}
 
-	absDirectory, err := filepath.Abs(directory)
+	// 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
 	}
-	realDirectory, err := filepath.EvalSymlinks(absDirectory)
+	directory, err = filepath.EvalSymlinks(directory)
 	if err != nil {
 		return false, err
 	}
 
 	// Case insensitive checks
-	if !strings.EqualFold(realPath, realDirectory) &&
+	if !strings.EqualFold(path, directory) &&
-		!strings.HasPrefix(strings.ToLower(realPath), strings.ToLower(realDirectory)+string(os.PathSeparator)) {
+		!strings.HasPrefix(strings.ToLower(path), strings.ToLower(directory)+string(os.PathSeparator)) {
 		return false, nil
 	}
 
@@ -206,6 +293,11 @@ func ReadDir(path string) string {
 		info, _ := f.Info()
 
 		name := f.Name()
+		if strings.HasPrefix(name, ".") {
+			// skip hidden files
+			continue
+		}
+
 		entryType := "file"
 		size := info.Size()
 
@@ -225,3 +317,29 @@ func ReadDir(path string) string {
 
 	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())})
+	}
+	return resultToJson(FunctionResult{
+		Result: string(data),
+	})
+}
+
+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{})
+}