use crate::agent::AgentConfig;
use crate::hitl::TimeoutAction;
use crate::permissions::PermissionDecision;
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum ToolGateApproval {
PermissionAllow,
ConfirmationNotRequired,
}
impl ToolGateApproval {
pub(crate) fn as_str(self) -> &'static str {
match self {
ToolGateApproval::PermissionAllow => "permission_allow",
ToolGateApproval::ConfirmationNotRequired => "confirmation_not_required",
}
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum ToolGateDenial {
SkillRestriction,
HookBlock,
PermissionDeny,
MissingConfirmationManager,
}
impl ToolGateDenial {
pub(crate) fn as_str(self) -> &'static str {
match self {
ToolGateDenial::SkillRestriction => "skill_restriction",
ToolGateDenial::HookBlock => "hook_block",
ToolGateDenial::PermissionDeny => "permission_deny",
ToolGateDenial::MissingConfirmationManager => "missing_confirmation_manager",
}
}
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) enum ToolGateDecision {
Execute {
reason: ToolGateApproval,
},
Confirm {
timeout_ms: u64,
timeout_action: TimeoutAction,
},
Deny {
output: String,
event_reason: String,
reason: ToolGateDenial,
},
}
pub(crate) struct ToolGateInput<'a> {
pub(crate) tool_name: &'a str,
pub(crate) args: &'a serde_json::Value,
pub(crate) pre_tool_block: Option<String>,
}
pub(crate) struct ToolSafetyGate<'a> {
config: &'a AgentConfig,
}
impl<'a> ToolSafetyGate<'a> {
pub(crate) fn new(config: &'a AgentConfig) -> Self {
Self { config }
}
pub(crate) async fn decide(&self, input: ToolGateInput<'_>) -> ToolGateDecision {
if let Some(decision) = self.check_skill_restrictions(input.tool_name) {
return decision;
}
if let Some(reason) = input.pre_tool_block {
return ToolGateDecision::Deny {
output: format!("Tool '{}' blocked by hook: {}", input.tool_name, reason),
event_reason: reason,
reason: ToolGateDenial::HookBlock,
};
}
match self.permission_decision(input.tool_name, input.args) {
PermissionDecision::Deny => ToolGateDecision::Deny {
output: format!(
"Permission denied: Tool '{}' is blocked by permission policy.",
input.tool_name
),
event_reason: "Blocked by deny rule in permission policy".to_string(),
reason: ToolGateDenial::PermissionDeny,
},
PermissionDecision::Allow => ToolGateDecision::Execute {
reason: ToolGateApproval::PermissionAllow,
},
PermissionDecision::Ask => self.confirmation_decision(input.tool_name).await,
}
}
fn check_skill_restrictions(&self, tool_name: &str) -> Option<ToolGateDecision> {
let registry = self.config.skill_registry.as_ref()?;
let instruction_skills = registry.by_kind(crate::skills::SkillKind::Instruction);
let has_restrictions = instruction_skills.iter().any(|s| s.allowed_tools.is_some());
if !has_restrictions {
return None;
}
let allowed = instruction_skills
.iter()
.any(|skill| skill.is_tool_allowed(tool_name));
if allowed {
return None;
}
let msg = format!("Tool '{}' is not allowed by any active skill.", tool_name);
Some(ToolGateDecision::Deny {
output: msg.clone(),
event_reason: msg,
reason: ToolGateDenial::SkillRestriction,
})
}
fn permission_decision(&self, tool_name: &str, args: &serde_json::Value) -> PermissionDecision {
self.config
.permission_checker
.as_ref()
.map(|checker| checker.check(tool_name, args))
.unwrap_or(PermissionDecision::Ask)
}
async fn confirmation_decision(&self, tool_name: &str) -> ToolGateDecision {
let Some(cm) = &self.config.confirmation_manager else {
let msg = format!(
"Tool '{}' requires confirmation but no HITL confirmation manager is configured. \
Configure a confirmation policy to enable tool execution.",
tool_name
);
return ToolGateDecision::Deny {
output: msg.clone(),
event_reason: msg,
reason: ToolGateDenial::MissingConfirmationManager,
};
};
if !cm.requires_confirmation(tool_name).await {
return ToolGateDecision::Execute {
reason: ToolGateApproval::ConfirmationNotRequired,
};
}
let policy = cm.policy().await;
ToolGateDecision::Confirm {
timeout_ms: policy.default_timeout_ms,
timeout_action: policy.timeout_action,
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::hitl::{ConfirmationManager, ConfirmationPolicy};
use crate::permissions::{PermissionChecker, PermissionDecision};
use crate::queue::SessionLane;
use crate::skills::{Skill, SkillKind, SkillRegistry};
use serde_json::json;
use std::sync::Arc;
use tokio::sync::broadcast;
struct StaticPermission(PermissionDecision);
impl PermissionChecker for StaticPermission {
fn check(&self, _tool_name: &str, _args: &serde_json::Value) -> PermissionDecision {
self.0
}
}
fn restricted_registry() -> Arc<SkillRegistry> {
let registry = SkillRegistry::new();
registry.register_unchecked(Arc::new(Skill {
name: "read-only".to_string(),
description: String::new(),
allowed_tools: Some("read(*), grep(*)".to_string()),
disable_model_invocation: false,
kind: SkillKind::Instruction,
content: String::new(),
tags: Vec::new(),
version: None,
}));
Arc::new(registry)
}
#[tokio::test]
async fn skill_restriction_denies_before_permission_allow() {
let config = AgentConfig {
skill_registry: Some(restricted_registry()),
permission_checker: Some(Arc::new(StaticPermission(PermissionDecision::Allow))),
..Default::default()
};
let gate = ToolSafetyGate::new(&config);
let decision = gate
.decide(ToolGateInput {
tool_name: "write",
args: &json!({"file_path": "x"}),
pre_tool_block: None,
})
.await;
assert!(matches!(
decision,
ToolGateDecision::Deny {
reason: ToolGateDenial::SkillRestriction,
..
}
));
}
#[tokio::test]
async fn hook_block_denies_before_permission_allow() {
let config = AgentConfig {
skill_registry: None,
permission_checker: Some(Arc::new(StaticPermission(PermissionDecision::Allow))),
..Default::default()
};
let gate = ToolSafetyGate::new(&config);
let decision = gate
.decide(ToolGateInput {
tool_name: "bash",
args: &json!({"command": "echo ok"}),
pre_tool_block: Some("blocked by policy".to_string()),
})
.await;
assert!(matches!(
decision,
ToolGateDecision::Deny {
reason: ToolGateDenial::HookBlock,
..
}
));
}
#[tokio::test]
async fn ask_without_confirmation_manager_is_safe_deny() {
let config = AgentConfig {
skill_registry: None,
permission_checker: None,
confirmation_manager: None,
..Default::default()
};
let gate = ToolSafetyGate::new(&config);
let decision = gate
.decide(ToolGateInput {
tool_name: "bash",
args: &json!({"command": "echo ok"}),
pre_tool_block: None,
})
.await;
assert!(matches!(
decision,
ToolGateDecision::Deny {
reason: ToolGateDenial::MissingConfirmationManager,
..
}
));
}
#[tokio::test]
async fn ask_with_confirmation_manager_requests_confirmation() {
let (event_tx, _) = broadcast::channel(8);
let manager = Arc::new(ConfirmationManager::new(
ConfirmationPolicy::enabled().with_timeout(1234, crate::hitl::TimeoutAction::Reject),
event_tx,
));
let config = AgentConfig {
skill_registry: None,
confirmation_manager: Some(manager),
..Default::default()
};
let gate = ToolSafetyGate::new(&config);
let decision = gate
.decide(ToolGateInput {
tool_name: "bash",
args: &json!({"command": "echo ok"}),
pre_tool_block: None,
})
.await;
assert_eq!(
decision,
ToolGateDecision::Confirm {
timeout_ms: 1234,
timeout_action: crate::hitl::TimeoutAction::Reject,
}
);
}
#[tokio::test]
async fn yolo_lane_executes_without_confirmation() {
let (event_tx, _) = broadcast::channel(8);
let manager = Arc::new(ConfirmationManager::new(
ConfirmationPolicy::enabled().with_yolo_lanes([SessionLane::Query]),
event_tx,
));
let config = AgentConfig {
skill_registry: None,
confirmation_manager: Some(manager),
..Default::default()
};
let gate = ToolSafetyGate::new(&config);
let decision = gate
.decide(ToolGateInput {
tool_name: "read",
args: &json!({"file_path": "README.md"}),
pre_tool_block: None,
})
.await;
assert_eq!(
decision,
ToolGateDecision::Execute {
reason: ToolGateApproval::ConfirmationNotRequired,
}
);
}
}