git.giacomolli.uk - onechat/blob - agent.go

   1 package main
   2
   3 import (
   4         "bytes"
   5         "crypto/rand"
   6         "encoding/hex"
   7         "encoding/json"
   8         "errors"
   9         "fmt"
  10         "io"
  11         "os"
  12         "path/filepath"
  13         "slices"
  14         "strings"
  15
  16         "golang.org/x/sys/unix"
  17 )
  18
  19 const (
  20         // agentInstructionsFileName is the file of the user's instructions in
  21         // the directory of an agent.
  22         agentInstructionsFileName = "instructions.md"
  23
  24         // agentIDBytes is the number of random bytes of an agent ID.
  25         agentIDBytes = 16
  26 )
  27
  28 // Agent is one agent and its directory. The directory holds config.json, the
  29 // user's instructions in instructions.md, the chat, and the usage file.
  30 type Agent struct {
  31         dir    string
  32         config AgentConfig
  33 }
  34
  35 // AgentConfig holds the settings of the config.json of an agent. ID is random,
  36 // made once when the file is made, and never changes. The cache key comes from
  37 // the ID, so a rename keeps the prompt cache and two agents with one name do
  38 // not share a key. Workdir is the directory where the commands of the agent
  39 // run. Responsibility and Parent are set together for a child agent.
  40 type AgentConfig struct {
  41         Name           string `json:"name"`
  42         ID             string `json:"id"`
  43         Model          string `json:"model"`
  44         Effort         string `json:"effort"`
  45         Workdir        string `json:"workdir"`
  46         Responsibility string `json:"responsibility,omitempty"`
  47         Parent         string `json:"parent,omitempty"`
  48 }
  49
  50 // openAgent reads the config.json of the agent in dir. When the file does not
  51 // exist, it makes the directory and writes the file with the defaults and a new
  52 // ID. A missing field of an existing file takes the default, but the ID must be
  53 // there. An unknown field is an error, so a typo does not become a silent
  54 // default.
  55 func openAgent(dir string) (*Agent, error) {
  56         err := os.MkdirAll(dir, 0o700)
  57         if err != nil {
  58                 return nil, fmt.Errorf("create agent directory: %w", err)
  59         }
  60
  61         path := filepath.Join(dir, "config.json")
  62         data, err := os.ReadFile(path)
  63         if errors.Is(err, os.ErrNotExist) {
  64                 return createAgent(dir)
  65         }
  66
  67         if err != nil {
  68                 return nil, fmt.Errorf("read agent config: %w", err)
  69         }
  70
  71         config, err := defaultAgentConfig()
  72         if err != nil {
  73                 return nil, fmt.Errorf("prepare agent defaults: %w", err)
  74         }
  75
  76         decoder := json.NewDecoder(bytes.NewReader(data))
  77         decoder.DisallowUnknownFields()
  78
  79         err = decoder.Decode(&config)
  80         if err == nil && !errors.Is(decoder.Decode(&struct{}{}), io.EOF) {
  81                 err = errors.New("data after the JSON object")
  82         }
  83
  84         if err == nil {
  85                 err = config.validate()
  86         }
  87
  88         if err != nil {
  89                 return nil, fmt.Errorf("%s: %w", path, err)
  90         }
  91
  92         return &Agent{
  93                 dir:    dir,
  94                 config: config,
  95         }, nil
  96 }
  97
  98 // Images returns the shared data-directory image store, also for a child.
  99 func (a *Agent) Images() *ImageStore {
 100         root := a.dir
 101         if a.config.Parent != "" {
 102                 root = filepath.Dir(filepath.Dir(root))
 103         }
 104
 105         return &ImageStore{dir: filepath.Join(filepath.Dir(root), imageDirName)}
 106 }
 107
 108 // Voices returns the shared data-directory audio store, also for a child.
 109 func (a *Agent) Voices() *VoiceStore {
 110         root := a.dir
 111         if a.config.Parent != "" {
 112                 root = filepath.Dir(filepath.Dir(root))
 113         }
 114
 115         return &VoiceStore{dir: filepath.Join(filepath.Dir(root), voiceDirName)}
 116 }
 117
 118 // Prompt returns the system prompt of the agent with the user's instructions
 119 // from instructions.md. It reads the file on each call, so a change applies at
 120 // the next call. A missing file means no instructions.
 121 func (a *Agent) Prompt() (string, error) {
 122         instructions, err := a.instructions()
 123         if err != nil {
 124                 return "", fmt.Errorf("read prompt instructions: %w", err)
 125         }
 126
 127         path, err := filepath.Abs(filepath.Join(a.dir, agentInstructionsFileName))
 128         if err != nil {
 129                 return "", fmt.Errorf("find instructions path: %w", err)
 130         }
 131
 132         if a.config.Parent != "" {
 133                 return promptChild(a.config.Name, a.config.Parent, a.config.Responsibility, path, instructions), nil
 134         }
 135
 136         return prompt(a.config.Name, path, instructions), nil
 137 }
 138
 139 // instructions reads the user's instructions from instructions.md. A missing
 140 // file means no instructions.
 141 func (a *Agent) instructions() (string, error) {
 142         data, err := os.ReadFile(filepath.Join(a.dir, agentInstructionsFileName))
 143         if err != nil && !errors.Is(err, os.ErrNotExist) {
 144                 return "", fmt.Errorf("read instructions: %w", err)
 145         }
 146
 147         return string(data), nil
 148 }
 149
 150 // Tools returns the tools shared by the turns and compactions of this agent. A
 151 // child has no image output, WhatsApp, child creation, or route tools.
 152 func (a *Agent) Tools() []ModelTool {
 153         tools := promptTools()
 154         if a.config.Parent != "" {
 155                 tools = slices.DeleteFunc(tools, func(tool ModelTool) bool {
 156                         return strings.HasPrefix(tool.Name, "whatsapp_") || tool.Name == "image_show" || tool.Name == "agent_create" || tool.Name == "route" || tool.Name == "unroute" || tool.Name == "routes"
 157                 })
 158         }
 159
 160         return tools
 161 }
 162
 163 // Children reads the direct children in directory order. Each child needs an
 164 // existing config with its directory name and this agent as parent. Children
 165 // cannot have children. A missing children directory means no children.
 166 func (a *Agent) Children() ([]*Agent, error) {
 167         dir := filepath.Join(a.dir, "children")
 168         entries, err := os.ReadDir(dir)
 169         if errors.Is(err, os.ErrNotExist) {
 170                 return nil, nil
 171         }
 172
 173         if err != nil {
 174                 return nil, fmt.Errorf("read children: %w", err)
 175         }
 176
 177         if a.config.Parent != "" && len(entries) != 0 {
 178                 return nil, errors.New("children cannot have children")
 179         }
 180
 181         var children []*Agent
 182
 183         keys := map[string]bool{a.CacheKey(): true}
 184
 185         for _, entry := range entries {
 186                 name := entry.Name()
 187                 if !entry.IsDir() {
 188                         return nil, fmt.Errorf("child %q must be a directory", name)
 189                 }
 190
 191                 path := filepath.Join(dir, name)
 192                 _, err = os.Stat(filepath.Join(path, "config.json"))
 193                 if err != nil {
 194                         return nil, fmt.Errorf("child %q config: %w", name, err)
 195                 }
 196
 197                 child, err := openAgent(path)
 198                 if err != nil {
 199                         return nil, fmt.Errorf("open child %q: %w", name, err)
 200                 }
 201
 202                 if child.config.Name != name || child.config.Parent != a.config.Name {
 203                         return nil, fmt.Errorf("child %q needs name %q and parent %q", name, name, a.config.Name)
 204                 }
 205
 206                 if child.config.Name == a.config.Name || keys[child.CacheKey()] {
 207                         return nil, fmt.Errorf("child %q must have its own name and ID", name)
 208                 }
 209
 210                 keys[child.CacheKey()] = true
 211                 _, err = child.Children()
 212                 if err != nil {
 213                         return nil, fmt.Errorf("read child %q: %w", name, err)
 214                 }
 215
 216                 children = append(children, child)
 217         }
 218
 219         return children, nil
 220 }
 221
 222 // CacheKey returns the prompt cache key of every model call of the agent.
 223 func (a *Agent) CacheKey() string {
 224         return "onechat-" + a.config.ID
 225 }
 226
 227 // CreateChild writes a new direct child with its own ID and the model, effort,
 228 // and working directory of the root. Child and subagent names share a
 229 // namespace. The config is complete before an atomic rename publishes the
 230 // child. Preparation stays outside children, so an interrupted write cannot
 231 // stop startup.
 232 func (a *Agent) CreateChild(name, responsibility string, subagents *Subagents) (_ *Agent, err error) {
 233         if a.config.Parent != "" {
 234                 return nil, errors.New("only the root can create children")
 235         }
 236
 237         if !agentChildNameValid(name) {
 238                 return nil, errors.New("name must have 2 to 32 ASCII letters and start with a capital letter")
 239         }
 240
 241         if name == a.config.Name {
 242                 return nil, errors.New("the name is already used by the root")
 243         }
 244
 245         responsibility = strings.TrimSpace(responsibility)
 246         if responsibility == "" {
 247                 return nil, errors.New("responsibility must not be empty")
 248         }
 249
 250         err = subagents.Reserve(name)
 251         if err != nil {
 252                 return nil, fmt.Errorf("reserve child name: %w", err)
 253         }
 254
 255         published := false
 256         defer func() {
 257                 if !published {
 258                         subagents.Release(name)
 259                 }
 260         }()
 261
 262         staged, err := os.MkdirTemp(a.dir, ".child-*")
 263         if err != nil {
 264                 return nil, fmt.Errorf("prepare child directory: %w", err)
 265         }
 266
 267         defer func() {
 268                 cleanupErr := os.RemoveAll(staged)
 269                 if cleanupErr != nil {
 270                         err = errors.Join(err, fmt.Errorf("remove prepared child: %w", cleanupErr))
 271                 }
 272         }()
 273
 274         config := a.config
 275         config.Name = name
 276         config.ID = ""
 277         config.Parent = a.config.Name
 278         config.Responsibility = responsibility
 279         child, err := writeAgent(staged, config)
 280         if err != nil {
 281                 return nil, fmt.Errorf("write child: %w", err)
 282         }
 283
 284         dir := filepath.Join(a.dir, "children")
 285         err = os.MkdirAll(dir, 0o700)
 286         if err != nil {
 287                 return nil, fmt.Errorf("create children directory: %w", err)
 288         }
 289
 290         dir = filepath.Join(dir, name)
 291         err = unix.Renameat2(unix.AT_FDCWD, staged, unix.AT_FDCWD, dir, unix.RENAME_NOREPLACE)
 292         if err != nil {
 293                 return nil, fmt.Errorf("publish child directory: %w", err)
 294         }
 295
 296         published = true
 297         child.dir = dir
 298
 299         return child, nil
 300 }
 301
 302 // SubagentPrompt returns the system prompt of a subagent of the agent, with the
 303 // user's instructions as Prompt reads them.
 304 func (a *Agent) SubagentPrompt() (string, error) {
 305         instructions, err := a.instructions()
 306         if err != nil {
 307                 return "", err
 308         }
 309
 310         return promptSubagent(a.config.Name, instructions), nil
 311 }
 312
 313 // validate makes sure that each setting has a valid value.
 314 func (c AgentConfig) validate() error {
 315         if c.Name == "" || strings.ContainsAny(c.Name, "\r\n") {
 316                 return errors.New("name must be one line of text")
 317         }
 318
 319         id, err := hex.DecodeString(c.ID)
 320         if err != nil || len(id) != agentIDBytes {
 321                 return fmt.Errorf("id must be %d hexadecimal digits", 2*agentIDBytes)
 322         }
 323
 324         if c.Model == "" || c.Effort == "" {
 325                 return errors.New("agent needs a model and an effort")
 326         }
 327
 328         if (strings.TrimSpace(c.Responsibility) == "") != (c.Parent == "") {
 329                 return errors.New("a child needs both responsibility and parent")
 330         }
 331
 332         if strings.ContainsAny(c.Parent, "\r\n") {
 333                 return errors.New("parent must be one line of text")
 334         }
 335
 336         if !filepath.IsAbs(c.Workdir) {
 337                 return fmt.Errorf("workdir %q is not an absolute path", c.Workdir)
 338         }
 339
 340         return nil
 341 }
 342
 343 // createAgent writes the config.json of a new agent in dir with the defaults
 344 // and a new ID.
 345 func createAgent(dir string) (*Agent, error) {
 346         config, err := defaultAgentConfig()
 347         if err != nil {
 348                 return nil, fmt.Errorf("prepare agent defaults: %w", err)
 349         }
 350
 351         return writeAgent(dir, config)
 352 }
 353
 354 // defaultAgentConfig returns the settings of a new agent, without an ID. The
 355 // commands run in the home directory of the user.
 356 func defaultAgentConfig() (AgentConfig, error) {
 357         home, err := os.UserHomeDir()
 358         if err != nil {
 359                 return AgentConfig{}, fmt.Errorf("find working directory: %w", err)
 360         }
 361
 362         return AgentConfig{
 363                 Name:    "OneChat",
 364                 Model:   "gpt-6.1-sol",
 365                 Effort:  "medium",
 366                 Workdir: home,
 367         }, nil
 368 }
 369
 370 // agentChildNameValid accepts one word of 2 to 32 ASCII letters with an initial
 371 // capital letter. Child names describe their area.
 372 func agentChildNameValid(name string) bool {
 373         if len(name) < 2 || len(name) > 32 || name[0] < 'A' || name[0] > 'Z' {
 374                 return false
 375         }
 376
 377         for i := 1; i < len(name); i++ {
 378                 letter := name[i]
 379                 if (letter < 'A' || letter > 'Z') && (letter < 'a' || letter > 'z') {
 380                         return false
 381                 }
 382         }
 383
 384         return true
 385 }
 386
 387 // writeAgent gives config a new ID and writes it in dir.
 388 func writeAgent(dir string, config AgentConfig) (*Agent, error) {
 389         id := make([]byte, agentIDBytes)
 390         _, err := rand.Read(id)
 391         if err != nil {
 392                 return nil, fmt.Errorf("make agent ID: %w", err)
 393         }
 394
 395         config.ID = hex.EncodeToString(id)
 396         data, err := json.MarshalIndent(config, "", "  ")
 397         if err != nil {
 398                 return nil, fmt.Errorf("encode agent config: %w", err)
 399         }
 400
 401         err = writeFileAtomic(filepath.Join(dir, "config.json"), append(data, '\n'))
 402         if err != nil {
 403                 return nil, fmt.Errorf("write agent config: %w", err)
 404         }
 405
 406         return &Agent{
 407                 dir:    dir,
 408                 config: config,
 409         }, nil
 410 }