fix: address code review - nested object hashing and error logging

src/agents/tool-loop-detection.ts

@@ -17,16 +17,25 @@ export const CRITICAL_THRESHOLD = 20;
  */
 export function hashToolCall(toolName: string, params: unknown): string {
   try {
-    const paramsStr =
-      typeof params === "object" && params !== null
-        ? JSON.stringify(params, Object.keys(params).toSorted())
-        : String(params);
+    const paramsStr = stableStringify(params);
     return `${toolName}:${paramsStr}`;
   } catch {
     return `${toolName}:${String(params)}`;
   }
 }
 
+function stableStringify(value: unknown): string {
+  if (value === null || typeof value !== "object") {
+    return JSON.stringify(value);
+  }
+  if (Array.isArray(value)) {
+    return `[${value.map(stableStringify).join(",")}]`;
+  }
+  const obj = value as Record<string, unknown>;
+  const keys = Object.keys(obj).toSorted();
+  return `{${keys.map((k) => `${JSON.stringify(k)}:${stableStringify(obj[k])}`).join(",")}}`;
+}
+
 /**
  * Detect if an agent is stuck in a repetitive tool call loop.
  * Checks if the same tool+params combination has been called excessively.

src/logging/diagnostic.ts

@@ -320,7 +320,9 @@ export function startDiagnosticHeartbeat() {
           pruneStaleCommandPolls(state);
         }
       })
-      .catch(() => {});
+      .catch((err) => {
+        diag.debug(`command-poll-backoff prune failed: ${String(err)}`);
+      });
 
     for (const [, state] of diagnosticSessionStates) {
       const ageMs = now - state.lastActivity;