1use std::collections::BTreeMap;
2use std::panic::{catch_unwind, AssertUnwindSafe};
3use std::sync::Arc;
4use std::time::Instant;
5
6use serde_json::json;
7
8use crate::tools::{
9 ApprovalPolicy, ApprovalRequirement, CanUseToolPredicate, ToolContext, ToolExecutor,
10 ToolMetadata, ToolPolicy, ToolRunContext,
11};
12use crate::types::{Metadata, ToolCall, ToolDirective, ToolExecutionResult, ToolResultStatus};
13
14pub type BeforeToolDispatch = Arc<
15 dyn Fn(&ToolCall, &mut ToolContext) -> Result<(), crate::tools::ToolError>
16 + Send
17 + Sync
18 + 'static,
19>;
20
21pub type ToolLifecycleCallback = Arc<dyn Fn(ToolLifecycleEvent) + Send + Sync + 'static>;
22
23#[derive(Debug, Clone)]
24pub enum ToolLifecycleEvent {
25 Planned {
26 call: ToolCall,
27 tool_metadata: Option<ToolMetadata>,
28 },
29 Started {
30 call: ToolCall,
31 tool_metadata: Option<ToolMetadata>,
32 },
33 Completed {
34 call: ToolCall,
35 result: Box<ToolExecutionResult>,
36 execution_started: bool,
37 duration_ms: Option<u64>,
38 tool_metadata: Option<ToolMetadata>,
39 },
40}
41
42pub(crate) struct DeferredToolExecution {
43 result: ToolExecutionResult,
44 lifecycle: Option<DeferredToolLifecycle>,
45}
46
47struct DeferredToolLifecycle {
48 call: ToolCall,
49 execution_started: bool,
50 duration_ms: Option<u64>,
51 tool_metadata: Option<ToolMetadata>,
52 callback: Option<ToolLifecycleCallback>,
53}
54
55impl DeferredToolExecution {
56 pub(crate) fn without_lifecycle(result: ToolExecutionResult) -> Self {
57 Self {
58 result,
59 lifecycle: None,
60 }
61 }
62
63 fn with_lifecycle(
64 call: ToolCall,
65 result: ToolExecutionResult,
66 execution_started: bool,
67 duration_ms: Option<u64>,
68 tool_metadata: Option<ToolMetadata>,
69 callback: Option<ToolLifecycleCallback>,
70 ) -> Self {
71 Self {
72 result,
73 lifecycle: Some(DeferredToolLifecycle {
74 call,
75 execution_started,
76 duration_ms,
77 tool_metadata,
78 callback,
79 }),
80 }
81 }
82
83 pub(crate) fn result(&self) -> &ToolExecutionResult {
84 &self.result
85 }
86
87 pub(crate) fn replace_result(&mut self, result: ToolExecutionResult) {
88 self.result = result;
89 }
90
91 pub(crate) fn execution_started(&self) -> bool {
92 self.lifecycle
93 .as_ref()
94 .is_some_and(|lifecycle| lifecycle.execution_started)
95 }
96
97 pub(crate) fn complete(self) -> ToolExecutionResult {
98 if let Some(lifecycle) = self.lifecycle {
99 emit_completed(
100 &lifecycle.call,
101 &self.result,
102 lifecycle.execution_started,
103 lifecycle.duration_ms,
104 lifecycle.tool_metadata,
105 lifecycle.callback.as_ref(),
106 );
107 }
108 self.result
109 }
110}
111
112#[derive(Clone, Default)]
113pub struct ToolRunOptions {
114 planned_tools: Option<Vec<String>>,
115 allowed_tools: Option<Vec<String>>,
116 disallowed_tools: Vec<String>,
117 can_use_tool: Option<CanUseToolPredicate>,
118 approval: ApprovalPolicy,
119 denied_side_effects: Vec<crate::tools::ToolSideEffect>,
120 denied_capability_tags: Vec<String>,
121 deny_terminal_tools: bool,
122 denied_cost_dimensions: Vec<String>,
123 idempotency_key: Option<String>,
124 before_dispatch: Option<BeforeToolDispatch>,
125 lifecycle_callback: Option<ToolLifecycleCallback>,
126}
127
128impl ToolRunOptions {
129 pub fn from_policy(policy: &ToolPolicy) -> Self {
130 Self {
131 planned_tools: None,
132 allowed_tools: policy.allowed_tools.clone(),
133 disallowed_tools: policy.disallowed_tools.clone(),
134 can_use_tool: policy.can_use_tool.clone(),
135 approval: policy.approval,
136 denied_side_effects: policy.denied_side_effects.clone(),
137 denied_capability_tags: policy.denied_capability_tags.clone(),
138 deny_terminal_tools: policy.deny_terminal_tools,
139 denied_cost_dimensions: policy.denied_cost_dimensions.clone(),
140 idempotency_key: None,
141 before_dispatch: None,
142 lifecycle_callback: None,
143 }
144 }
145
146 pub fn planned_names(mut self, tools: impl IntoIterator<Item = impl Into<String>>) -> Self {
147 self.planned_tools = Some(tools.into_iter().map(Into::into).collect());
148 self
149 }
150
151 pub fn allow_only(mut self, tools: impl IntoIterator<Item = impl Into<String>>) -> Self {
152 self.allowed_tools = Some(tools.into_iter().map(Into::into).collect());
153 self
154 }
155
156 pub fn disallow(mut self, tool: impl Into<String>) -> Self {
157 self.disallowed_tools.push(tool.into());
158 self
159 }
160
161 pub fn can_use_tool<F>(mut self, predicate: F) -> Self
162 where
163 F: Fn(&str, &crate::types::ToolArguments) -> bool + Send + Sync + 'static,
164 {
165 self.can_use_tool = Some(Arc::new(predicate));
166 self
167 }
168
169 pub fn idempotency_key(mut self, idempotency_key: Option<String>) -> Self {
170 self.idempotency_key = idempotency_key;
171 self
172 }
173
174 pub fn before_dispatch(mut self, callback: BeforeToolDispatch) -> Self {
175 self.before_dispatch = Some(callback);
176 self
177 }
178
179 pub fn lifecycle_callback(mut self, callback: ToolLifecycleCallback) -> Self {
180 self.lifecycle_callback = Some(callback);
181 self
182 }
183}
184
185#[derive(Clone, Default)]
186pub struct ToolOrchestrator {
187 tools: BTreeMap<String, Arc<dyn ToolExecutor>>,
188}
189
190impl ToolOrchestrator {
191 pub fn from_tools(tools: Vec<Arc<dyn ToolExecutor>>) -> Self {
192 let tools = tools
193 .into_iter()
194 .map(|tool| (tool.name().to_string(), tool))
195 .collect();
196 Self { tools }
197 }
198
199 pub async fn run_one(
200 &self,
201 call: ToolCall,
202 context: &mut ToolContext,
203 options: ToolRunOptions,
204 ) -> Result<ToolExecutionResult, crate::tools::ToolError> {
205 self.run_one_with_approval(call, context, options, |_call, _requirement, _context| None)
206 .await
207 }
208
209 pub(crate) async fn run_one_with_approval<F>(
210 &self,
211 call: ToolCall,
212 context: &mut ToolContext,
213 options: ToolRunOptions,
214 approval: F,
215 ) -> Result<ToolExecutionResult, crate::tools::ToolError>
216 where
217 F: FnOnce(&ToolCall, ApprovalRequirement, &ToolContext) -> Option<ToolExecutionResult>,
218 {
219 self.run_one_with_approval_and_metadata(
220 call,
221 context,
222 options,
223 |call, requirement, context, _metadata| approval(call, requirement, context),
224 )
225 .await
226 }
227
228 pub(crate) async fn run_one_with_approval_and_metadata<F>(
229 &self,
230 call: ToolCall,
231 context: &mut ToolContext,
232 options: ToolRunOptions,
233 approval: F,
234 ) -> Result<ToolExecutionResult, crate::tools::ToolError>
235 where
236 F: FnOnce(
237 &ToolCall,
238 ApprovalRequirement,
239 &ToolContext,
240 &Metadata,
241 ) -> Option<ToolExecutionResult>,
242 {
243 self.run_one_with_approval_and_metadata_deferred(call, context, options, approval)
244 .await
245 .map(DeferredToolExecution::complete)
246 }
247
248 pub(crate) async fn run_one_with_approval_and_metadata_deferred<F>(
249 &self,
250 call: ToolCall,
251 context: &mut ToolContext,
252 options: ToolRunOptions,
253 approval: F,
254 ) -> Result<DeferredToolExecution, crate::tools::ToolError>
255 where
256 F: FnOnce(
257 &ToolCall,
258 ApprovalRequirement,
259 &ToolContext,
260 &Metadata,
261 ) -> Option<ToolExecutionResult>,
262 {
263 if let Some(result) = crate::tools::dispatcher::argument_error_result(&call) {
264 return Ok(DeferredToolExecution::without_lifecycle(result));
265 }
266
267 let tool = self.tools.get(&call.name);
268 let tool_metadata = tool.and_then(|tool| tool.tool_metadata()).cloned();
269 emit_lifecycle(
270 options.lifecycle_callback.as_ref(),
271 ToolLifecycleEvent::Planned {
272 call: call.clone(),
273 tool_metadata: tool_metadata.clone(),
274 },
275 );
276
277 if let Some(tool) = tool {
278 if let Some(result) = tool.validate_arguments(&call)? {
279 return Ok(deferred_without_execution(
280 &call,
281 result,
282 tool_metadata,
283 options.lifecycle_callback.as_ref(),
284 ));
285 }
286 }
287
288 if let Some(allowed) = options.allowed_tools.as_ref() {
289 if !allowed.iter().any(|tool| tool == &call.name) {
290 return Ok(deferred_without_execution(
291 &call,
292 policy_denial(&call, "allowed_tools"),
293 tool_metadata,
294 options.lifecycle_callback.as_ref(),
295 ));
296 }
297 }
298 if options
299 .disallowed_tools
300 .iter()
301 .any(|tool| tool == &call.name)
302 {
303 return Ok(deferred_without_execution(
304 &call,
305 policy_denial(&call, "disallowed_tools"),
306 tool_metadata,
307 options.lifecycle_callback.as_ref(),
308 ));
309 }
310 if options
311 .can_use_tool
312 .as_ref()
313 .is_some_and(|predicate| !predicate(&call.name, &call.arguments))
314 {
315 return Ok(deferred_without_execution(
316 &call,
317 policy_denial(&call, "can_use_tool"),
318 tool_metadata,
319 options.lifecycle_callback.as_ref(),
320 ));
321 }
322 if options
323 .planned_tools
324 .as_ref()
325 .is_some_and(|planned| !planned.iter().any(|tool| tool == &call.name))
326 {
327 return Ok(deferred_without_execution(
328 &call,
329 policy_denial(&call, "planned_name"),
330 tool_metadata,
331 options.lifecycle_callback.as_ref(),
332 ));
333 }
334
335 let Some(tool) = tool else {
336 let result = tool_error(
337 &call,
338 "tool_not_found",
339 format!("Unknown tool: {}", call.name),
340 None,
341 );
342 return Ok(deferred_without_execution(
343 &call,
344 result,
345 None,
346 options.lifecycle_callback.as_ref(),
347 ));
348 };
349
350 if let Some(policy_source) = (ToolPolicy {
351 denied_side_effects: options.denied_side_effects.clone(),
352 denied_capability_tags: options.denied_capability_tags.clone(),
353 deny_terminal_tools: options.deny_terminal_tools,
354 denied_cost_dimensions: options.denied_cost_dimensions.clone(),
355 ..ToolPolicy::default()
356 })
357 .metadata_denial_source(tool_metadata.as_ref())
358 {
359 return Ok(deferred_without_execution(
360 &call,
361 policy_denial(&call, policy_source),
362 tool_metadata,
363 options.lifecycle_callback.as_ref(),
364 ));
365 }
366
367 context.begin_tool_call(&call);
368 context.idempotency_key = options.idempotency_key.clone();
369 let approval_requirement = match options.approval {
370 ApprovalPolicy::Never => ApprovalRequirement::NotRequired,
371 ApprovalPolicy::Always => ApprovalRequirement::Required,
372 ApprovalPolicy::Default | ApprovalPolicy::OnRequest => {
373 tool.approval_requirement(&call, &ToolRunContext::new(context))
374 }
375 };
376 let approval_result = approval(&call, approval_requirement, context, tool.metadata());
377 if let Some(mut result) = approval_result {
378 if result.tool_call_id.trim().is_empty() || result.tool_call_id == "pending" {
379 result.tool_call_id = call.id.clone();
380 }
381 return Ok(deferred_without_execution(
382 &call,
383 result,
384 tool_metadata,
385 options.lifecycle_callback.as_ref(),
386 ));
387 }
388
389 if let Some(callback) = options.before_dispatch.as_ref() {
390 callback(&call, context)?;
391 }
392
393 let started_at = Instant::now();
394 emit_lifecycle(
395 options.lifecycle_callback.as_ref(),
396 ToolLifecycleEvent::Started {
397 call: call.clone(),
398 tool_metadata: tool_metadata.clone(),
399 },
400 );
401 let future = tool.run(call.clone(), ToolRunContext::new(context));
402 let mut result = if let Some(timeout) = tool.timeout() {
403 match tokio::time::timeout(timeout, future).await {
404 Ok(result) => result?,
405 Err(_) => {
406 let result = crate::tools::ToolOutput::error(format!(
407 "Tool {} timed out after {} seconds.",
408 call.name,
409 timeout.as_secs_f64()
410 ))
411 .with_code("tool_timeout")
412 .retryable(true)
413 .to_result(&call.id);
414 return Ok(DeferredToolExecution::with_lifecycle(
415 call,
416 result,
417 true,
418 Some(elapsed_millis(started_at)),
419 tool_metadata,
420 options.lifecycle_callback,
421 ));
422 }
423 }
424 } else {
425 future.await?
426 };
427 if result.tool_call_id.trim().is_empty() || result.tool_call_id == "pending" {
428 result.tool_call_id = call.id.clone();
429 }
430 Ok(DeferredToolExecution::with_lifecycle(
431 call,
432 result,
433 true,
434 Some(elapsed_millis(started_at)),
435 tool_metadata,
436 options.lifecycle_callback,
437 ))
438 }
439
440 pub(crate) fn observe_result_without_execution(
441 &self,
442 call: ToolCall,
443 result: ToolExecutionResult,
444 options: &ToolRunOptions,
445 ) -> DeferredToolExecution {
446 if crate::tools::dispatcher::argument_error_result(&call).is_some() {
447 return DeferredToolExecution::without_lifecycle(result);
448 }
449 let tool_metadata = self
450 .tools
451 .get(&call.name)
452 .and_then(|tool| tool.tool_metadata())
453 .cloned();
454 emit_lifecycle(
455 options.lifecycle_callback.as_ref(),
456 ToolLifecycleEvent::Planned {
457 call: call.clone(),
458 tool_metadata: tool_metadata.clone(),
459 },
460 );
461 deferred_without_execution(
462 &call,
463 result,
464 tool_metadata,
465 options.lifecycle_callback.as_ref(),
466 )
467 }
468}
469
470fn deferred_without_execution(
471 call: &ToolCall,
472 result: ToolExecutionResult,
473 tool_metadata: Option<ToolMetadata>,
474 callback: Option<&ToolLifecycleCallback>,
475) -> DeferredToolExecution {
476 DeferredToolExecution::with_lifecycle(
477 call.clone(),
478 result,
479 false,
480 None,
481 tool_metadata,
482 callback.cloned(),
483 )
484}
485
486fn emit_completed(
487 call: &ToolCall,
488 result: &ToolExecutionResult,
489 execution_started: bool,
490 duration_ms: Option<u64>,
491 tool_metadata: Option<ToolMetadata>,
492 callback: Option<&ToolLifecycleCallback>,
493) {
494 emit_lifecycle(
495 callback,
496 ToolLifecycleEvent::Completed {
497 call: call.clone(),
498 result: Box::new(result.clone()),
499 execution_started,
500 duration_ms,
501 tool_metadata,
502 },
503 );
504}
505
506fn emit_lifecycle(callback: Option<&ToolLifecycleCallback>, event: ToolLifecycleEvent) {
507 let Some(callback) = callback else {
508 return;
509 };
510 let _ = catch_unwind(AssertUnwindSafe(|| callback(event)));
511}
512
513fn elapsed_millis(started_at: Instant) -> u64 {
514 const JSON_SAFE_INTEGER_MAX: u128 = (1_u128 << 53) - 1;
515 started_at.elapsed().as_millis().min(JSON_SAFE_INTEGER_MAX) as u64
516}
517
518fn policy_denial(call: &ToolCall, policy_source: &str) -> ToolExecutionResult {
519 tool_error(
520 call,
521 "tool_not_allowed",
522 format!("Tool {} is not allowed for these arguments.", call.name),
523 Some(policy_source),
524 )
525}
526
527fn tool_error(
528 call: &ToolCall,
529 error_code: &str,
530 message: impl Into<String>,
531 policy_source: Option<&str>,
532) -> ToolExecutionResult {
533 let error_code = error_code.to_string();
534 let message = message.into();
535 let mut metadata = BTreeMap::new();
536 if let Some(policy_source) = policy_source {
537 metadata.insert("mode".to_string(), json!("permission_denied"));
538 metadata.insert("policy_source".to_string(), json!(policy_source));
539 metadata.insert("tool_name".to_string(), json!(call.name));
540 metadata.insert("arguments".to_string(), json!(call.arguments));
541 metadata.insert("message".to_string(), json!(message));
542 }
543 ToolExecutionResult {
544 tool_call_id: call.id.clone(),
545 content: json!({
546 "ok": false,
547 "error": message,
548 "error_code": error_code,
549 "tool_name": call.name,
550 })
551 .to_string(),
552 status: ToolResultStatus::Error,
553 directive: ToolDirective::Continue,
554 error_code: Some(error_code),
555 metadata,
556 image_url: None,
557 image_path: None,
558 truncated: false,
559 truncation_reason: None,
560 original_bytes: None,
561 visible_bytes: None,
562 artifact: None,
563 cursor: None,
564 }
565}
566
567#[cfg(test)]
568mod tests {
569 use std::sync::atomic::{AtomicUsize, Ordering};
570 use std::sync::Mutex;
571
572 use serde_json::{json, Value};
573
574 use super::*;
575 use crate::tools::{FunctionTool, ToolOutput};
576
577 #[tokio::test]
578 async fn metadata_aware_approval_callback_receives_effective_requirement() {
579 let tool = FunctionTool::builder("guarded")
580 .metadata("risk_level", json!("high"))
581 .needs_approval_if(|_context, _arguments| true)
582 .handler(|_context, _arguments: Value| async { Ok(ToolOutput::text("ran")) })
583 .build()
584 .expect("guarded tool");
585 let orchestrator = ToolOrchestrator::from_tools(vec![tool.to_executor()]);
586 let mut context = ToolContext::new("./workspace");
587
588 let result = orchestrator
589 .run_one_with_approval_and_metadata(
590 ToolCall::from_raw_arguments("guarded_call", "guarded", json!({})),
591 &mut context,
592 ToolRunOptions::default(),
593 |_call, requirement, _context, metadata| {
594 assert_eq!(requirement, ApprovalRequirement::Required);
595 assert_eq!(metadata["risk_level"], json!("high"));
596 None
597 },
598 )
599 .await
600 .expect("tool result");
601
602 assert_eq!(result.status, ToolResultStatus::Success);
603 }
604
605 #[tokio::test]
606 async fn schema_invalid_arguments_fail_before_approval_or_execution() {
607 let approval_calls = Arc::new(AtomicUsize::new(0));
608 let handler_calls = Arc::new(AtomicUsize::new(0));
609 let observed_approval = approval_calls.clone();
610 let observed_handler = handler_calls.clone();
611 let tool = FunctionTool::builder("guarded")
612 .json_schema(json!({
613 "type": "object",
614 "properties": {"value": {"type": "integer"}},
615 "required": ["value"],
616 "additionalProperties": false,
617 }))
618 .needs_approval_if(move |_context, _arguments| {
619 observed_approval.fetch_add(1, Ordering::SeqCst);
620 true
621 })
622 .handler(move |_context, _arguments: Value| {
623 let observed_handler = observed_handler.clone();
624 async move {
625 observed_handler.fetch_add(1, Ordering::SeqCst);
626 Ok(ToolOutput::text("ran"))
627 }
628 })
629 .build()
630 .expect("guarded tool");
631 let events = Arc::new(Mutex::new(Vec::new()));
632 let observed_events = events.clone();
633 let options = ToolRunOptions::default().lifecycle_callback(Arc::new(move |event| {
634 let name = match event {
635 ToolLifecycleEvent::Planned { .. } => "planned",
636 ToolLifecycleEvent::Started { .. } => "started",
637 ToolLifecycleEvent::Completed { .. } => "completed",
638 };
639 observed_events.lock().expect("events").push(name);
640 }));
641 let orchestrator = ToolOrchestrator::from_tools(vec![tool.to_executor()]);
642 let mut context = ToolContext::new("./workspace");
643
644 let result = orchestrator
645 .run_one(
646 ToolCall::from_raw_arguments(
647 "guarded_call",
648 "guarded",
649 json!({"value": "wrong", "extra": true}),
650 ),
651 &mut context,
652 options,
653 )
654 .await
655 .expect("tool result");
656
657 assert_eq!(
658 result.error_code.as_deref(),
659 Some(crate::tools::argument_validation::INVALID_TOOL_ARGUMENTS_ERROR_CODE)
660 );
661 assert_eq!(approval_calls.load(Ordering::SeqCst), 0);
662 assert_eq!(handler_calls.load(Ordering::SeqCst), 0);
663 assert_eq!(
664 events.lock().expect("events").as_slice(),
665 ["planned", "completed"]
666 );
667 }
668}