| 1 | package hook |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/json" |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "maps" |
| 9 | "strings" |
| 10 | "sync" |
| 11 | ) |
| 12 | |
| 13 | // Runner binds a set of resolved hooks to a session: a working directory, the |
| 14 | // spawner, and a notify callback that surfaces non-blocking hook messages to the |
| 15 | // user. It is the single object the agent (tool events) and the controller |
| 16 | // (prompt/stop events) fire hooks through, so neither has to know how hooks load |
| 17 | // or run. A nil *Runner is a valid no-op (no hooks configured). |
| 18 | type Runner struct { |
| 19 | hooks []ResolvedHook |
| 20 | cwd string |
| 21 | spawner Spawner |
| 22 | notify func(string) // surface a non-blocking (warn/error) hook message; may be nil |
| 23 | mu sync.RWMutex |
| 24 | sessionID string |
| 25 | parent *Runner // set by ForRole; the session ID is then derived from it |
| 26 | role string |
| 27 | } |
| 28 | |
| 29 | // SetSessionID updates the Claude-compatible session identifier used in hook |
| 30 | // payloads. It is safe to call when a controller rotates sessions. |
| 31 | func (r *Runner) SetSessionID(id string) { |
| 32 | if r == nil { |
| 33 | return |
| 34 | } |
| 35 | r.mu.Lock() |
| 36 | r.sessionID = id |
| 37 | r.mu.Unlock() |
| 38 | } |
| 39 | |
| 40 | func (r *Runner) payload(event Event) Payload { |
| 41 | return Payload{Event: event, Cwd: r.cwd, SessionID: r.currentSessionID()} |
| 42 | } |
| 43 | |
| 44 | func (r *Runner) currentSessionID() string { |
| 45 | if r.parent != nil { |
| 46 | if id := r.parent.currentSessionID(); id != "" { |
| 47 | return id + ":" + r.role |
| 48 | } |
| 49 | return r.role |
| 50 | } |
| 51 | r.mu.RLock() |
| 52 | defer r.mu.RUnlock() |
| 53 | return r.sessionID |
| 54 | } |
| 55 | |
| 56 | // NewRunner builds a Runner. spawner nil uses DefaultSpawner; notify nil drops |
| 57 | // non-blocking messages. |
| 58 | func NewRunner(hooks []ResolvedHook, cwd string, spawner Spawner, notify func(string)) *Runner { |
| 59 | return &Runner{hooks: hooks, cwd: cwd, spawner: spawner, notify: notify} |
| 60 | } |
| 61 | |
| 62 | // ForSession gives a child session the same resolved rules and execution |
| 63 | // environment without sharing mutable session identity with its parent. |
| 64 | func (r *Runner) ForSession(id string) *Runner { |
| 65 | if r == nil { |
| 66 | return nil |
| 67 | } |
| 68 | child := NewRunner(r.hooks, r.cwd, r.spawner, r.notify) |
| 69 | child.SetSessionID(id) |
| 70 | return child |
| 71 | } |
| 72 | |
| 73 | // ForRole gives an agent that works for this runner's session, such as the |
| 74 | // planner, the same rules under session "<parent session>:<role>". The parent's |
| 75 | // ID is read each time a hook fires, so a later SetSessionID on it reaches the role. |
| 76 | func (r *Runner) ForRole(role string) *Runner { |
| 77 | if r == nil { |
| 78 | return nil |
| 79 | } |
| 80 | child := NewRunner(r.hooks, r.cwd, r.spawner, r.notify) |
| 81 | child.parent, child.role = r, role |
| 82 | return child |
| 83 | } |
| 84 | |
| 85 | // NoCwdCommandSearchEnv is honoured by cmd.exe and CreateProcess: when set, |
| 86 | // a bare command name is not resolved against the current directory. |
| 87 | const NoCwdCommandSearchEnv = "NoDefaultCurrentDirectoryInExePath" |
| 88 | |
| 89 | // WithoutCwdCommandSearch gives hooks the same cwd but sets |
| 90 | // NoCwdCommandSearchEnv, so on Windows a bare `python` in a hook command can |
| 91 | // never resolve to a python.exe that the cwd ships. It is inherited by |
| 92 | // ForSession and ForRole, and is harmless on other platforms. |
| 93 | func (r *Runner) WithoutCwdCommandSearch() *Runner { |
| 94 | if r == nil { |
| 95 | return nil |
| 96 | } |
| 97 | base := r.spawner |
| 98 | if base == nil { |
| 99 | base = DefaultSpawner |
| 100 | } |
| 101 | child := r.ForSession(r.currentSessionID()) |
| 102 | child.spawner = func(ctx context.Context, in SpawnInput) SpawnResult { |
| 103 | env := make(map[string]string, len(in.Env)+1) |
| 104 | maps.Copy(env, in.Env) |
| 105 | env[NoCwdCommandSearchEnv] = "1" |
| 106 | in.Env = env |
| 107 | return base(ctx, in) |
| 108 | } |
| 109 | return child |
| 110 | } |
| 111 | |
| 112 | // Hooks returns the resolved hooks (for `/hooks` listing). |
| 113 | func (r *Runner) Hooks() []ResolvedHook { |
| 114 | if r == nil { |
| 115 | return nil |
| 116 | } |
| 117 | return r.hooks |
| 118 | } |
| 119 | |
| 120 | // Enabled reports whether any hooks are configured. |
| 121 | func (r *Runner) Enabled() bool { return r != nil && len(r.hooks) > 0 } |
| 122 | |
| 123 | // Has reports whether any configured hook listens for the given event. Callers |
| 124 | // use it to skip work that only matters when a specific hook exists (e.g. the |
| 125 | // agent buffers reasoning for transform only when a PostLLMCall hook is set). |
| 126 | func (r *Runner) Has(event Event) bool { |
| 127 | if r == nil { |
| 128 | return false |
| 129 | } |
| 130 | for _, h := range r.hooks { |
| 131 | if h.Event == event { |
| 132 | return true |
| 133 | } |
| 134 | } |
| 135 | return false |
| 136 | } |
| 137 | |
| 138 | // HasPostLLMCall reports whether a PostLLMCall hook is configured, so the agent |
| 139 | // keeps streaming reasoning live unless a transform is actually wired up. |
| 140 | func (r *Runner) HasPostLLMCall() bool { return r.Has(PostLLMCall) } |
| 141 | |
| 142 | // ToolMutationHooksEnabled reports whether any hook runs around a tool call. |
| 143 | // These hooks execute user shell code and may mutate paths that the tool itself |
| 144 | // does not declare, so checkpoint coverage must account for them. |
| 145 | func (r *Runner) ToolMutationHooksEnabled() bool { |
| 146 | return r.Has(PreToolUse) || r.Has(PostToolUse) || r.Has(PostToolUseFailure) |
| 147 | } |
| 148 | |
| 149 | // PreToolUse fires before a tool call. block=true means the call must be |
| 150 | // refused; message is the reason (fed back to the model and shown to the user). |
| 151 | func (r *Runner) PreToolUse(ctx context.Context, name string, args json.RawMessage) (block bool, message string) { |
| 152 | if !r.Enabled() { |
| 153 | return false, "" |
| 154 | } |
| 155 | p := r.payload(PreToolUse) |
| 156 | p.ToolName, p.ToolArgs = name, args |
| 157 | rep := Run(ctx, p, r.hooks, r.spawner) |
| 158 | return r.handle(rep) |
| 159 | } |
| 160 | |
| 161 | // PostToolUse fires after a tool call. It can't block; non-pass outcomes are |
| 162 | // surfaced to the user via notify. |
| 163 | func (r *Runner) PostToolUse(ctx context.Context, name string, args json.RawMessage, result string) { |
| 164 | if !r.Enabled() { |
| 165 | return |
| 166 | } |
| 167 | p := r.payload(PostToolUse) |
| 168 | p.ToolName, p.ToolArgs, p.ToolResult = name, args, result |
| 169 | rep := Run(ctx, p, r.hooks, r.spawner) |
| 170 | r.handle(rep) |
| 171 | } |
| 172 | |
| 173 | // PostToolUseFailure fires when a tool invocation returns an error. |
| 174 | func (r *Runner) PostToolUseFailure(ctx context.Context, name string, args json.RawMessage, result string, err error) { |
| 175 | if !r.Enabled() { |
| 176 | return |
| 177 | } |
| 178 | p := r.payload(PostToolUseFailure) |
| 179 | p.ToolName, p.ToolArgs, p.ToolResult = name, args, result |
| 180 | if err != nil { |
| 181 | p.Error = err.Error() |
| 182 | p.IsInterrupt = errors.Is(err, context.Canceled) |
| 183 | } |
| 184 | r.handle(Run(ctx, p, r.hooks, r.spawner)) |
| 185 | // Native Reasonix PostToolUse historically observed both success and |
| 186 | // failure. Preserve that contract while Claude hooks use the distinct event. |
| 187 | legacy := r.nativeHooks(PostToolUse) |
| 188 | if len(legacy) > 0 { |
| 189 | p.Event = PostToolUse |
| 190 | r.handle(Run(ctx, p, legacy, r.spawner)) |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | // PermissionRequest fires before a tool approval prompt is shown. A native |
| 195 | // Reasonix hook here can't answer the dialog (non-pass outcomes are surfaced |
| 196 | // via notify only); a Claude-imported hook (PayloadFormat "claude") can |
| 197 | // answer it on the user's behalf via exit 2 or a JSON decision, matching |
| 198 | // Claude's own contract. decision == nil means "no opinion, show the prompt |
| 199 | // normally"; a non-nil decision means the caller should skip the prompt and |
| 200 | // treat it as denied (false) or auto-approved (true). |
| 201 | func (r *Runner) PermissionRequest(ctx context.Context, name, subject string, args json.RawMessage) (decision *bool, message string) { |
| 202 | if !r.Enabled() { |
| 203 | return nil, "" |
| 204 | } |
| 205 | p := r.payload(PermissionRequest) |
| 206 | p.ToolName, p.ToolArgs, p.Subject = name, args, subject |
| 207 | rep := Run(ctx, p, r.hooks, r.spawner) |
| 208 | block, msg := r.handle(rep) |
| 209 | switch { |
| 210 | case block: |
| 211 | deny := false |
| 212 | return &deny, msg |
| 213 | case rep.Allowed: |
| 214 | allow := true |
| 215 | return &allow, msg |
| 216 | default: |
| 217 | return nil, msg |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | // PromptSubmit fires before a turn starts. block=true aborts the turn; message |
| 222 | // is the reason. |
| 223 | func (r *Runner) PromptSubmit(ctx context.Context, prompt string, turn int) (block bool, message string) { |
| 224 | if !r.Enabled() { |
| 225 | return false, "" |
| 226 | } |
| 227 | p := r.payload(UserPromptSubmit) |
| 228 | p.Prompt, p.Turn = prompt, turn |
| 229 | rep := Run(ctx, p, r.hooks, r.spawner) |
| 230 | return r.handle(rep) |
| 231 | } |
| 232 | |
| 233 | // Stop fires after a turn finishes. It can't block. |
| 234 | func (r *Runner) Stop(ctx context.Context, lastAssistant string, turn int) { |
| 235 | if !r.Enabled() { |
| 236 | return |
| 237 | } |
| 238 | p := r.payload(Stop) |
| 239 | p.LastAssistant, p.Turn = lastAssistant, turn |
| 240 | rep := Run(ctx, p, r.hooks, r.spawner) |
| 241 | r.handle(rep) |
| 242 | } |
| 243 | |
| 244 | // StopResult emits Stop on success and StopFailure when the turn failed. |
| 245 | func (r *Runner) StopResult(ctx context.Context, lastAssistant string, turn int, err error) { |
| 246 | if err == nil { |
| 247 | r.Stop(ctx, lastAssistant, turn) |
| 248 | return |
| 249 | } |
| 250 | if !r.Enabled() { |
| 251 | return |
| 252 | } |
| 253 | p := r.payload(StopFailure) |
| 254 | p.LastAssistant, p.Turn, p.Error = lastAssistant, turn, err.Error() |
| 255 | p.IsInterrupt = errors.Is(err, context.Canceled) |
| 256 | r.handle(Run(ctx, p, r.hooks, r.spawner)) |
| 257 | legacy := r.nativeHooks(Stop) |
| 258 | if len(legacy) > 0 { |
| 259 | p.Event = Stop |
| 260 | r.handle(Run(ctx, p, legacy, r.spawner)) |
| 261 | } |
| 262 | } |
| 263 | |
| 264 | func (r *Runner) nativeHooks(event Event) []ResolvedHook { |
| 265 | var out []ResolvedHook |
| 266 | for _, h := range r.hooks { |
| 267 | if h.Event == event && h.PayloadFormat != "claude" { |
| 268 | out = append(out, h) |
| 269 | } |
| 270 | } |
| 271 | return out |
| 272 | } |
| 273 | |
| 274 | // SessionStart fires when a session becomes active. It can't block; successful |
| 275 | // stdout may contribute one-shot context for the next model request. |
| 276 | func (r *Runner) SessionStart(ctx context.Context, source ...string) []string { |
| 277 | if !r.Enabled() { |
| 278 | return nil |
| 279 | } |
| 280 | p := r.payload(SessionStart) |
| 281 | p.Source = "startup" |
| 282 | if len(source) > 0 && strings.TrimSpace(source[0]) != "" { |
| 283 | p.Source = strings.TrimSpace(source[0]) |
| 284 | } |
| 285 | rep := Run(ctx, p, r.hooks, r.spawner) |
| 286 | r.handle(rep) |
| 287 | return r.additionalContexts(rep) |
| 288 | } |
| 289 | |
| 290 | // SessionEnd fires when a session is closed or rotated (/new). It can't block. |
| 291 | func (r *Runner) SessionEnd(ctx context.Context, reason ...string) { |
| 292 | if !r.Enabled() { |
| 293 | return |
| 294 | } |
| 295 | p := r.payload(SessionEnd) |
| 296 | p.Reason = "other" |
| 297 | if len(reason) > 0 && strings.TrimSpace(reason[0]) != "" { |
| 298 | p.Reason = strings.TrimSpace(reason[0]) |
| 299 | } |
| 300 | r.handle(Run(ctx, p, r.hooks, r.spawner)) |
| 301 | } |
| 302 | |
| 303 | // SubagentStop fires when a `task` sub-agent finishes. It can't block; last is |
| 304 | // the sub-agent's final answer. |
| 305 | func (r *Runner) SubagentStop(ctx context.Context, last string) { |
| 306 | if !r.Enabled() { |
| 307 | return |
| 308 | } |
| 309 | p := r.payload(SubagentStop) |
| 310 | p.LastAssistant = last |
| 311 | r.handle(Run(ctx, p, r.hooks, r.spawner)) |
| 312 | } |
| 313 | |
| 314 | // Notification fires when the agent needs the user's attention (e.g. a pending |
| 315 | // approval). It can't block; message describes what's waiting. |
| 316 | func (r *Runner) Notification(ctx context.Context, message string, notificationType ...string) { |
| 317 | if !r.Enabled() { |
| 318 | return |
| 319 | } |
| 320 | p := r.payload(Notification) |
| 321 | p.Message = message |
| 322 | if len(notificationType) > 0 { |
| 323 | p.NotificationType = strings.TrimSpace(notificationType[0]) |
| 324 | } |
| 325 | r.handle(Run(ctx, p, r.hooks, r.spawner)) |
| 326 | } |
| 327 | |
| 328 | // PostLLMCall fires after every model turn completes but before the |
| 329 | // reasoning_content is stored in the session. It returns the hook's stdout as |
| 330 | // the new reasoning text, or the original reasoning if the hook passes with |
| 331 | // empty stdout / doesn't exist / fails. A non-pass outcome is surfaced via |
| 332 | // notify but doesn't block. |
| 333 | func (r *Runner) PostLLMCall(ctx context.Context, reasoning string, turn int) string { |
| 334 | if !r.Has(PostLLMCall) { |
| 335 | return reasoning |
| 336 | } |
| 337 | p := r.payload(PostLLMCall) |
| 338 | p.Reasoning, p.Turn = reasoning, turn |
| 339 | rep := Run(ctx, p, r.hooks, r.spawner) |
| 340 | r.handle(rep) |
| 341 | for _, o := range rep.Outcomes { |
| 342 | if o.Decision == DecisionPass { |
| 343 | if s := strings.TrimSpace(o.Stdout); s != "" { |
| 344 | return s |
| 345 | } |
| 346 | } |
| 347 | } |
| 348 | return reasoning |
| 349 | } |
| 350 | |
| 351 | // PreCompact fires just before a compaction pass and returns the concatenated |
| 352 | // stdout of its hooks as extra summary guidance, so a hook can steer what the |
| 353 | // summary keeps. Non-pass outcomes are surfaced via notify. |
| 354 | func (r *Runner) PreCompact(ctx context.Context, trigger string) string { |
| 355 | if !r.Enabled() { |
| 356 | return "" |
| 357 | } |
| 358 | p := r.payload(PreCompact) |
| 359 | p.Trigger = trigger |
| 360 | rep := Run(ctx, p, r.hooks, r.spawner) |
| 361 | r.handle(rep) |
| 362 | var b strings.Builder |
| 363 | for _, o := range rep.Outcomes { |
| 364 | if s := strings.TrimSpace(o.Stdout); s != "" { |
| 365 | if b.Len() > 0 { |
| 366 | b.WriteString("\n") |
| 367 | } |
| 368 | b.WriteString(s) |
| 369 | } |
| 370 | } |
| 371 | return b.String() |
| 372 | } |
| 373 | |
| 374 | func (r *Runner) additionalContexts(rep Report) []string { |
| 375 | var contexts []string |
| 376 | for _, o := range rep.Outcomes { |
| 377 | if o.Decision != DecisionPass { |
| 378 | continue |
| 379 | } |
| 380 | out, warnings := ParseOutput(rep.Event, o.Stdout) |
| 381 | for _, warning := range warnings { |
| 382 | if r.notify != nil { |
| 383 | r.notify(FormatOutcome(Outcome{ |
| 384 | Hook: o.Hook, |
| 385 | Decision: DecisionWarn, |
| 386 | Stdout: warning, |
| 387 | })) |
| 388 | } |
| 389 | } |
| 390 | if out.AdditionalContext != "" { |
| 391 | contexts = append(contexts, out.AdditionalContext) |
| 392 | } |
| 393 | } |
| 394 | return contexts |
| 395 | } |
| 396 | |
| 397 | // handle surfaces every non-pass outcome to the user (notify) and returns the |
| 398 | // block decision plus the blocking hook's message. |
| 399 | func (r *Runner) handle(rep Report) (bool, string) { |
| 400 | var blockMsg string |
| 401 | for _, o := range rep.Outcomes { |
| 402 | if o.Decision == DecisionPass { |
| 403 | continue |
| 404 | } |
| 405 | msg := FormatOutcome(o) |
| 406 | if r.notify != nil { |
| 407 | r.notify(msg) |
| 408 | } |
| 409 | if o.Decision == DecisionBlock { |
| 410 | blockMsg = msg |
| 411 | } |
| 412 | } |
| 413 | return rep.Blocked, blockMsg |
| 414 | } |
| 415 | |
| 416 | // FormatOutcome renders a non-pass outcome as a one-line human message. |
| 417 | func FormatOutcome(o Outcome) string { |
| 418 | detail := strings.TrimSpace(o.Stderr) |
| 419 | if detail == "" { |
| 420 | detail = strings.TrimSpace(o.Stdout) |
| 421 | } |
| 422 | tag := string(o.Hook.Scope) + "/" + string(o.Hook.Event) |
| 423 | cmd := o.Hook.Command |
| 424 | if cmd == "" && o.Hook.ContextFile != "" { |
| 425 | cmd = "context:" + o.Hook.ContextFile |
| 426 | } |
| 427 | cmd = clipRunes(cmd, 60) |
| 428 | trunc := "" |
| 429 | if o.Truncated { |
| 430 | trunc = " (output truncated)" |
| 431 | } |
| 432 | head := fmt.Sprintf("hook [%s] %s — %s%s", tag, cmd, o.Decision, trunc) |
| 433 | if detail != "" { |
| 434 | return head + ": " + detail |
| 435 | } |
| 436 | return head |
| 437 | } |
| 438 | |
| 439 | func clipRunes(s string, max int) string { |
| 440 | r := []rune(s) |
| 441 | if len(r) <= max { |
| 442 | return s |
| 443 | } |
| 444 | if max < 1 { |
| 445 | return "" |
| 446 | } |
| 447 | return string(r[:max]) + "…" |
| 448 | } |
| 449 |