Fingerprint repeated eval tool calls as a JSON name-args tuple

A NUL delimiter made git treat the metrics module as binary.
A JSON array owns the name/args boundary without a magic separator.

Author: TheGreatAxios

evals/capability/behaviors.ts

@@ -225,7 +225,10 @@ export function deriveBehaviorMetrics(summary: CapturedRunSummary): BehaviorMetr
     }
     for (const call of turn.toolCalls) {
       toolCallsByName[call.name] = (toolCallsByName[call.name] ?? 0) + 1;
-      const signature = `${call.name}\0${normalizeToolArguments(call.arguments)}`;
+      const signature = JSON.stringify([
+        call.name,
+        normalizeToolArguments(call.arguments),
+      ]);
       if (seenCalls.has(signature)) repeatedSearchCount++;
       else seenCalls.add(signature);
 

src/tui/geometry.test.ts

@@ -560,4 +560,3 @@ describe("resolveGeometry — stack-only layout", () => {
     expect(layout.regions.agents).toBeUndefined();
   });
 });
-