Introduce "agents"

An agent is currently a name given to a system prompt and a set of
tools which the agent has access to.

This resolves the previous issue of the set of configured tools being
available in *all* contexts, which wasn't always desired. Tools are now
only available when an agent is explicitly requested using the
`-a/--agent` flag.

Agents are expected to be expanded on: the concept of task-specilized
agents (e.g. coding), the ability to define a set of files an agent
should always have access to for RAG purposes, etc.

Other changes:

- Removes the "tools" top-level config structure (though this is expected
to come back along with the abillity to define custom tools).

- Renamed `pkg/agent` to `pkg/agents`

pkg/agents/toolbox/file_insert_lines.go

@@ -0,0 +1,114 @@
+package toolbox
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	toolutil "git.mlow.ca/mlow/lmcli/pkg/agents/toolbox/util"
+	"git.mlow.ca/mlow/lmcli/pkg/api"
+)
+
+const FILE_INSERT_LINES_DESCRIPTION = `Insert lines into a file, must specify path.
+
+Make sure your inserts match the flow and indentation of surrounding content.`
+
+var FileInsertLinesTool = api.ToolSpec{
+	Name:        "file_insert_lines",
+	Description: FILE_INSERT_LINES_DESCRIPTION,
+	Parameters: []api.ToolParameter{
+		{
+			Name:        "path",
+			Type:        "string",
+			Description: "Path of the file to be modified, relative to the current working directory.",
+			Required:    true,
+		},
+		{
+			Name:        "position",
+			Type:        "integer",
+			Description: `Which line to insert content *before*.`,
+			Required:    true,
+		},
+		{
+			Name:        "content",
+			Type:        "string",
+			Description: `The content to insert.`,
+			Required:    true,
+		},
+	},
+	Impl: func(tool *api.ToolSpec, 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)
+			}
+		}
+
+		result := fileInsertLines(path, position, content)
+		ret, err := result.ToJson()
+		if err != nil {
+			return "", fmt.Errorf("Could not serialize result: %v", err)
+		}
+		return ret, nil
+	},
+}
+
+func fileInsertLines(path string, position int, content string) api.CallResult {
+	ok, reason := toolutil.IsPathWithinCWD(path)
+	if !ok {
+		return api.CallResult{Message: reason}
+	}
+
+	// Read the existing file's content
+	data, err := os.ReadFile(path)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return api.CallResult{Message: fmt.Sprintf("Could not read path: %s", err.Error())}
+		}
+		_, err = os.Create(path)
+		if err != nil {
+			return api.CallResult{Message: fmt.Sprintf("Could not create new file: %s", err.Error())}
+		}
+		data = []byte{}
+	}
+
+	if position < 1 {
+		return api.CallResult{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 api.CallResult{Message: fmt.Sprintf("Could not write to path: %s", err.Error())}
+	}
+
+	return api.CallResult{Result: newContent}
+}