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use serde::{Deserialize, Serialize};
use serde_json::Value;
#[derive(Debug, Serialize, Deserialize, PartialEq, Eq, Clone)]
#[serde(rename_all = "snake_case")]
pub enum VerdictStatus {
Allowed,
Blocked,
}
#[derive(Debug, Serialize, Deserialize, PartialEq, Eq, Clone)]
pub struct Verdict {
pub status: VerdictStatus,
pub reason_code: String, // e.g., "OK", "E_ARG_SCHEMA", "E_TOOL_NOT_ALLOWED"
pub details: Value, // JSON details, violations, etc.
}
/// Evaluates tool arguments against a policy (JSON/YAML Value).
/// The policy is expected to be a map of tool_name -> schema.
pub fn evaluate_tool_args(policy: &Value, tool_name: &str, tool_args: &Value) -> Verdict {
// 1. Check if tool exists in policy
let schema_val = match policy.get(tool_name) {
Some(s) => s,
None => {
// Check for potential typos
let mut message = format!("Tool '{}' not defined in policy", tool_name);
if let Some(obj) = policy.as_object() {
// Use our similarity helper
if let Some(match_) =
crate::errors::similarity::closest_prompt(tool_name, obj.keys())
{
message.push_str(&format!(". Did you mean '{}'?", match_.prompt));
}
}
return Verdict {
status: VerdictStatus::Blocked,
reason_code: "E_POLICY_MISSING_TOOL".to_string(),
details: serde_json::json!({
"message": message
}),
};
}
};
// 2. Compile Schema
// In a real high-perf scenario, we'd cache this (Compilation is expensive).
// For this core function, we compile on the fly or need a cached compilation context.
// User Step 1.2: "Compile JSON Schema validators één keer bij policy load".
// Since this function takes `&Value`, it implies per-call.
// To support caching, we'd need a `PolicyState` struct.
// For now, I'll compile on the fly (parity correctness first).
let compiled = match jsonschema::validator_for(schema_val) {
Ok(c) => c,
Err(e) => {
return Verdict {
status: VerdictStatus::Blocked,
reason_code: "E_SCHEMA_COMPILE".to_string(),
details: serde_json::json!({
"message": format!("Invalid schema for tool '{}': {}", tool_name, e)
}),
};
}
};
// 3. Validate
evaluate_schema(&compiled, tool_args)
}
/// Evaluates tool arguments against a compiled schema.
pub fn evaluate_schema(compiled: &jsonschema::Validator, tool_args: &Value) -> Verdict {
if compiled.is_valid(tool_args) {
return Verdict {
status: VerdictStatus::Allowed,
reason_code: "OK".to_string(),
details: serde_json::json!({}),
};
}
let violations: Vec<Value> = compiled
.iter_errors(tool_args)
.map(|e| {
serde_json::json!({
"path": e.instance_path().to_string(),
"constraint": e.to_string(),
"message": e.to_string()
})
})
.collect();
Verdict {
status: VerdictStatus::Blocked,
reason_code: "E_ARG_SCHEMA".to_string(),
details: serde_json::json!({
"violations": violations
}),
}
}
/// Evaluates a sequence of tool calls against a sequence policy (regex-like).
/// For v0.9, simplified: the policy is just a string (regex) of tool names.
/// E.g. "^search (analyze )*report$"
/// The input is a list of tool names invoked in order.
pub fn evaluate_sequence(policy_regex: &str, tool_names: &[String]) -> Verdict {
// 1. Construct the sequence string
// We join tool names with space. Note: tool names should not contain spaces ideally.
// If they do, this simple approach might be ambiguous, but standard tools usually don't.
let trace_str = tool_names.join(" ");
// 2. Compile Regex
// Again, efficiency concern: compile once.
let re = match regex::Regex::new(policy_regex) {
Ok(r) => r,
Err(e) => {
return Verdict {
status: VerdictStatus::Blocked,
reason_code: "E_POLICY_REGEX_INVALID".to_string(),
details: serde_json::json!({
"message": format!("Invalid regex policy '{}': {}", policy_regex, e)
}),
};
}
};
// 3. Match
if re.is_match(&trace_str) {
Verdict {
status: VerdictStatus::Allowed,
reason_code: "OK".to_string(),
details: serde_json::json!({}),
}
} else {
Verdict {
status: VerdictStatus::Blocked,
reason_code: "E_SEQUENCE_VIOLATION".to_string(),
details: serde_json::json!({
"expected": policy_regex,
"found": trace_str
}),
}
}
}