add(core): arc_monitor

codex-rs/core/src/guardian.rs

@@ -731,8 +731,8 @@ fn truncate_guardian_action_value(value: Value) -> Value {
     }
 }
 
-fn format_guardian_action_pretty(action: &GuardianApprovalRequest) -> String {
-    let mut value = match action {
+pub(crate) fn guardian_approval_request_to_json(action: &GuardianApprovalRequest) -> Value {
+    match action {
         GuardianApprovalRequest::Shell {
             command,
             cwd,
@@ -871,7 +871,11 @@ fn format_guardian_action_pretty(action: &GuardianApprovalRequest) -> String {
             }
             action
         }
-    };
+    }
+}
+
+fn format_guardian_action_pretty(action: &GuardianApprovalRequest) -> String {
+    let mut value = guardian_approval_request_to_json(action);
     value = truncate_guardian_action_value(value);
     serde_json::to_string_pretty(&value).unwrap_or_else(|_| "null".to_string())
 }

codex-rs/core/src/guardian_tests.rs

@@ -171,6 +171,45 @@ fn format_guardian_action_pretty_truncates_large_string_fields() {
     assert!(rendered.len() < patch.len());
 }
 
+#[test]
+fn guardian_approval_request_to_json_renders_mcp_tool_call_shape() {
+    let action = GuardianApprovalRequest::McpToolCall {
+        server: "mcp_server".to_string(),
+        tool_name: "browser_navigate".to_string(),
+        arguments: Some(serde_json::json!({
+            "url": "https://example.com",
+        })),
+        connector_id: None,
+        connector_name: Some("Playwright".to_string()),
+        connector_description: None,
+        tool_title: Some("Navigate".to_string()),
+        tool_description: None,
+        annotations: Some(GuardianMcpAnnotations {
+            destructive_hint: Some(true),
+            open_world_hint: None,
+            read_only_hint: Some(false),
+        }),
+    };
+
+    assert_eq!(
+        guardian_approval_request_to_json(&action),
+        serde_json::json!({
+            "tool": "mcp_tool_call",
+            "server": "mcp_server",
+            "tool_name": "browser_navigate",
+            "arguments": {
+                "url": "https://example.com",
+            },
+            "connector_name": "Playwright",
+            "tool_title": "Navigate",
+            "annotations": {
+                "destructive_hint": true,
+                "read_only_hint": false,
+            },
+        })
+    );
+}
+
 #[test]
 fn build_guardian_transcript_reserves_separate_budget_for_tool_evidence() {
     let repeated = "signal ".repeat(8_000);

codex-rs/core/src/lib.rs

@@ -9,6 +9,7 @@ mod analytics_client;
 pub mod api_bridge;
 mod apply_patch;
 mod apps;
+mod arc_monitor;
 pub mod auth;
 mod client;
 mod client_common;