use std::collections::BTreeMap;
use std::sync::Arc;
use serde_json::json;
use crate::tools::{
ApprovalPolicy, ApprovalRequirement, CanUseToolPredicate, ToolContext, ToolExecutor,
ToolPolicy, ToolRunContext,
};
use crate::types::{Metadata, ToolCall, ToolDirective, ToolExecutionResult, ToolResultStatus};
pub type BeforeToolDispatch = Arc<
dyn Fn(&ToolCall, &mut ToolContext) -> Result<(), crate::tools::ToolError>
+ Send
+ Sync
+ 'static,
>;
#[derive(Clone, Default)]
pub struct ToolRunOptions {
planned_tools: Option<Vec<String>>,
allowed_tools: Option<Vec<String>>,
disallowed_tools: Vec<String>,
can_use_tool: Option<CanUseToolPredicate>,
approval: ApprovalPolicy,
idempotency_key: Option<String>,
before_dispatch: Option<BeforeToolDispatch>,
}
impl ToolRunOptions {
pub fn from_policy(policy: &ToolPolicy) -> Self {
Self {
planned_tools: None,
allowed_tools: policy.allowed_tools.clone(),
disallowed_tools: policy.disallowed_tools.clone(),
can_use_tool: policy.can_use_tool.clone(),
approval: policy.approval,
idempotency_key: None,
before_dispatch: None,
}
}
pub fn planned_names(mut self, tools: impl IntoIterator<Item = impl Into<String>>) -> Self {
self.planned_tools = Some(tools.into_iter().map(Into::into).collect());
self
}
pub fn allow_only(mut self, tools: impl IntoIterator<Item = impl Into<String>>) -> Self {
self.allowed_tools = Some(tools.into_iter().map(Into::into).collect());
self
}
pub fn disallow(mut self, tool: impl Into<String>) -> Self {
self.disallowed_tools.push(tool.into());
self
}
pub fn can_use_tool<F>(mut self, predicate: F) -> Self
where
F: Fn(&str, &crate::types::ToolArguments) -> bool + Send + Sync + 'static,
{
self.can_use_tool = Some(Arc::new(predicate));
self
}
pub fn idempotency_key(mut self, idempotency_key: Option<String>) -> Self {
self.idempotency_key = idempotency_key;
self
}
pub fn before_dispatch(mut self, callback: BeforeToolDispatch) -> Self {
self.before_dispatch = Some(callback);
self
}
}
#[derive(Clone, Default)]
pub struct ToolOrchestrator {
tools: BTreeMap<String, Arc<dyn ToolExecutor>>,
}
impl ToolOrchestrator {
pub fn from_tools(tools: Vec<Arc<dyn ToolExecutor>>) -> Self {
let tools = tools
.into_iter()
.map(|tool| (tool.name().to_string(), tool))
.collect();
Self { tools }
}
pub async fn run_one(
&self,
call: ToolCall,
context: &mut ToolContext,
options: ToolRunOptions,
) -> Result<ToolExecutionResult, crate::tools::ToolError> {
self.run_one_with_approval(call, context, options, |_call, _requirement, _context| None)
.await
}
pub(crate) async fn run_one_with_approval<F>(
&self,
call: ToolCall,
context: &mut ToolContext,
options: ToolRunOptions,
approval: F,
) -> Result<ToolExecutionResult, crate::tools::ToolError>
where
F: FnOnce(&ToolCall, ApprovalRequirement, &ToolContext) -> Option<ToolExecutionResult>,
{
self.run_one_with_approval_and_metadata(
call,
context,
options,
|call, requirement, context, _metadata| approval(call, requirement, context),
)
.await
}
pub(crate) async fn run_one_with_approval_and_metadata<F>(
&self,
call: ToolCall,
context: &mut ToolContext,
options: ToolRunOptions,
approval: F,
) -> Result<ToolExecutionResult, crate::tools::ToolError>
where
F: FnOnce(
&ToolCall,
ApprovalRequirement,
&ToolContext,
&Metadata,
) -> Option<ToolExecutionResult>,
{
if let Some(allowed) = options.allowed_tools.as_ref() {
if !allowed.iter().any(|tool| tool == &call.name) {
return Ok(policy_denial(&call, "allowed_tools"));
}
}
if options
.disallowed_tools
.iter()
.any(|tool| tool == &call.name)
{
return Ok(policy_denial(&call, "disallowed_tools"));
}
if options
.can_use_tool
.as_ref()
.is_some_and(|predicate| !predicate(&call.name, &call.arguments))
{
return Ok(policy_denial(&call, "can_use_tool"));
}
if options
.planned_tools
.as_ref()
.is_some_and(|planned| !planned.iter().any(|tool| tool == &call.name))
{
return Ok(policy_denial(&call, "planned_name"));
}
let Some(tool) = self.tools.get(&call.name) else {
return Ok(tool_error(
&call,
"tool_not_found",
format!("Unknown tool: {}", call.name),
None,
));
};
context.begin_tool_call(&call);
context.idempotency_key = options.idempotency_key.clone();
let approval_requirement = match options.approval {
ApprovalPolicy::Never => ApprovalRequirement::NotRequired,
ApprovalPolicy::Always => ApprovalRequirement::Required,
ApprovalPolicy::Default | ApprovalPolicy::OnRequest => {
tool.approval_requirement(&call, &ToolRunContext::new(context))
}
};
let approval_result = approval(&call, approval_requirement, context, tool.metadata());
if let Some(mut result) = approval_result {
if result.tool_call_id.trim().is_empty() || result.tool_call_id == "pending" {
result.tool_call_id = call.id;
}
return Ok(result);
}
if let Some(callback) = options.before_dispatch.as_ref() {
callback(&call, context)?;
}
let future = tool.run(call.clone(), ToolRunContext::new(context));
let mut result = if let Some(timeout) = tool.timeout() {
match tokio::time::timeout(timeout, future).await {
Ok(result) => result?,
Err(_) => {
return Ok(crate::tools::ToolOutput::error(format!(
"Tool {} timed out after {} seconds.",
call.name,
timeout.as_secs_f64()
))
.with_code("tool_timeout")
.retryable(true)
.to_result(&call.id));
}
}
} else {
future.await?
};
if result.tool_call_id.trim().is_empty() || result.tool_call_id == "pending" {
result.tool_call_id = call.id;
}
Ok(result)
}
}
fn policy_denial(call: &ToolCall, policy_source: &str) -> ToolExecutionResult {
tool_error(
call,
"tool_not_allowed",
format!("Tool {} is not allowed for these arguments.", call.name),
Some(policy_source),
)
}
fn tool_error(
call: &ToolCall,
error_code: &str,
message: impl Into<String>,
policy_source: Option<&str>,
) -> ToolExecutionResult {
let error_code = error_code.to_string();
let message = message.into();
let mut metadata = BTreeMap::new();
if let Some(policy_source) = policy_source {
metadata.insert("mode".to_string(), json!("permission_denied"));
metadata.insert("policy_source".to_string(), json!(policy_source));
metadata.insert("tool_name".to_string(), json!(call.name));
metadata.insert("arguments".to_string(), json!(call.arguments));
metadata.insert("message".to_string(), json!(message));
}
ToolExecutionResult {
tool_call_id: call.id.clone(),
content: json!({
"ok": false,
"error": message,
"error_code": error_code,
"tool_name": call.name,
})
.to_string(),
status: ToolResultStatus::Error,
directive: ToolDirective::Continue,
error_code: Some(error_code),
metadata,
image_url: None,
image_path: None,
}
}
#[cfg(test)]
mod tests {
use serde_json::{json, Value};
use super::*;
use crate::tools::{FunctionTool, ToolOutput};
#[tokio::test]
async fn metadata_aware_approval_callback_receives_effective_requirement() {
let tool = FunctionTool::builder("guarded")
.metadata("risk_level", json!("high"))
.needs_approval_if(|_context, _arguments| true)
.handler(|_context, _arguments: Value| async { Ok(ToolOutput::text("ran")) })
.build()
.expect("guarded tool");
let orchestrator = ToolOrchestrator::from_tools(vec![tool.to_executor()]);
let mut context = ToolContext::new("./workspace");
let result = orchestrator
.run_one_with_approval_and_metadata(
ToolCall::from_raw_arguments("guarded_call", "guarded", json!({})),
&mut context,
ToolRunOptions::default(),
|_call, requirement, _context, metadata| {
assert_eq!(requirement, ApprovalRequirement::Required);
assert_eq!(metadata["risk_level"], json!("high"));
None
},
)
.await
.expect("tool result");
assert_eq!(result.status, ToolResultStatus::Success);
}
}