diff --git a/tests/boundary/mcp/bundleComparisonMcp.test.ts b/tests/boundary/mcp/bundleComparisonMcp.test.ts
index b80c9ccd9c..9020ff9320 100644
--- a/tests/boundary/mcp/bundleComparisonMcp.test.ts
+++ b/tests/boundary/mcp/bundleComparisonMcp.test.ts
@@ -155,22 +155,22 @@ it("requires absolute bundle paths without changing server-cwd semantics", async
         },
       });
     const relativeCases = [
-      ["left.json", "right.json", "left_bundle_path"],
-      ["left.json", join(root, "right.json"), "left_bundle_path"],
-      [join(root, "left.json"), "right.json", "right_bundle_path"],
+      ["left.json", "right.json", ["left_bundle_path", "right_bundle_path"]],
+      ["left.json", join(root, "right.json"), ["left_bundle_path"]],
+      [join(root, "left.json"), "right.json", ["right_bundle_path"]],
     ] as const;
-    for (const [leftPath, rightPath, rejectedField] of relativeCases) {
+    for (const [leftPath, rightPath, rejectedFields] of relativeCases) {
       const result = await compare(leftPath, rightPath);
-      expect(parseMcpToolError(result).error).toMatchObject({
+      const { error } = parseMcpToolError(result);
+      expect(error).toMatchObject({
         code: "invalid_request",
         category: "invalid_input",
+        details: { operation: "compare_bundles" },
       });
-      expect(result.content[0]).toMatchObject({
-        text: expect.stringContaining(
-          `${rejectedField}: must be an absolute local filesystem path`,
-        ),
-      });
+      const details = JSON.stringify(error.details);
+      for (const field of rejectedFields) expect(details).toContain(field);
     }
+    expect(connected.session.exportEvidenceBundle().records).toEqual([]);
     expect(
       bundleComparisonInputSchema.parse({
         left_bundle_path: "left.json",