diff --git a/lib/utils/pii.test.ts b/lib/utils/pii.test.ts
index 872214a..644b806 100644
--- a/lib/utils/pii.test.ts
+++ b/lib/utils/pii.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { redactPii } from "./pii";
+import { redactEmails, redactPhones, redactPii } from "./pii";
 
 describe("redactPii", () => {
   it("redacts email addresses and phone numbers", () => {
@@ -10,4 +10,40 @@ describe("redactPii", () => {
       "Reach me at [EMAIL REDACTED] or [PHONE REDACTED] before launch.",
     );
   });
+
+  it("redacts every email in one string", () => {
+    expect(
+      redactEmails("Contact alice@example.com and bob@domain.org today"),
+    ).toBe("Contact [EMAIL REDACTED] and [EMAIL REDACTED] today");
+  });
+
+  it("redacts international phone numbers", () => {
+    expect(redactPhones("Call me at +44 7700 900123")).toBe(
+      "Call me at [PHONE REDACTED]",
+    );
+  });
+
+  it("leaves a short extension-only digit run alone", () => {
+    expect(redactPhones("ext 12")).toBe("ext 12");
+  });
+
+  it("documents that an extension attached to a phone is redacted together", () => {
+    // Known over-match: PHONE_PATTERN includes the `ext 12` suffix, so the
+    // whole match is redacted rather than only the main number.
+    expect(redactPhones("call 555-1212 ext 12")).toBe("call [PHONE REDACTED]");
+  });
+
+  it("documents that a long non-phone digit run is over-redacted", () => {
+    // Known over-match: an order ID with enough digits is treated as a phone
+    // number. Conservative redaction is intentional in the utility.
+    expect(redactPhones("Order 12345678901234567890")).toBe(
+      "Order [PHONE REDACTED]",
+    );
+  });
+
+  it("passes text without PII through unchanged", () => {
+    expect(redactPii("This sentence has no PII.")).toBe(
+      "This sentence has no PII.",
+    );
+  });
 });