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/read_dir.go

@@ -0,0 +1,100 @@
+package toolbox
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	toolutil "git.mlow.ca/mlow/lmcli/pkg/agents/toolbox/util"
+	"git.mlow.ca/mlow/lmcli/pkg/api"
+)
+
+const READ_DIR_DESCRIPTION = `Return the contents of the CWD (current working directory).
+
+Example result:
+{
+	"message": "success",
+	"result": [
+		{"name": "a_file.txt", "type": "file", "size": 123},
+		{"name": "a_directory/", "type": "dir", "size": 11},
+		...
+	]
+}
+
+For files, size represents the size of the file, in bytes.
+For directories, size represents the number of entries in that directory.`
+
+var ReadDirTool = api.ToolSpec{
+	Name:        "read_dir",
+	Description: READ_DIR_DESCRIPTION,
+	Parameters: []api.ToolParameter{
+		{
+			Name:        "relative_dir",
+			Type:        "string",
+			Description: "If set, read the contents of a directory relative to the current one.",
+		},
+	},
+	Impl: func(tool *api.ToolSpec, 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)
+			}
+		}
+		result := readDir(relativeDir)
+		ret, err := result.ToJson()
+		if err != nil {
+			return "", fmt.Errorf("Could not serialize result: %v", err)
+		}
+		return ret, nil
+	},
+}
+
+func readDir(path string) api.CallResult {
+	if path == "" {
+		path = "."
+	}
+	ok, reason := toolutil.IsPathWithinCWD(path)
+	if !ok {
+		return api.CallResult{Message: reason}
+	}
+
+	files, err := os.ReadDir(path)
+	if err != nil {
+		return api.CallResult{
+			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 api.CallResult{Result: dirContents}
+}