diff --git a/src/agents/live-auth-keys.test.ts b/src/agents/live-auth-keys.test.ts
new file mode 100644
index 00000000000..4c889598276
--- /dev/null
+++ b/src/agents/live-auth-keys.test.ts
@@ -0,0 +1,35 @@
+import { describe, expect, it } from "vitest";
+import { isAnthropicBillingError } from "./live-auth-keys.js";
+
+describe("isAnthropicBillingError", () => {
+  it("does not false-positive on plain 'a 402' prose", () => {
+    const samples = [
+      "Use a 402 stainless bolt",
+      "Book a 402 room",
+      "There is a 402 near me",
+      "The building at 402 Main Street",
+    ];
+
+    for (const sample of samples) {
+      expect(isAnthropicBillingError(sample)).toBe(false);
+    }
+  });
+
+  it("matches real 402 billing payload contexts including JSON keys", () => {
+    const samples = [
+      "HTTP 402 Payment Required",
+      "status: 402",
+      "error code 402",
+      '{"status":402,"type":"error"}',
+      '{"code":402,"message":"payment required"}',
+      '{"error":{"code":402,"message":"billing hard limit reached"}}',
+      "got a 402 from the API",
+      "returned 402",
+      "received a 402 response",
+    ];
+
+    for (const sample of samples) {
+      expect(isAnthropicBillingError(sample)).toBe(true);
+    }
+  });
+});
diff --git a/src/agents/live-auth-keys.ts b/src/agents/live-auth-keys.ts
index 8266d4a1b52..e272d4cf9f5 100644
--- a/src/agents/live-auth-keys.ts
+++ b/src/agents/live-auth-keys.ts
@@ -90,7 +90,11 @@ export function isAnthropicBillingError(message: string): boolean {
   if (lower.includes("billing") && lower.includes("disabled")) {
     return true;
   }
-  if (lower.includes("402")) {
+  if (
+    /["']?(?:status|code)["']?\s*[:=]\s*402\b|\bhttp\s*402\b|\berror(?:\s+code)?\s*[:=]?\s*402\b|\b(?:got|returned|received)\s+(?:a\s+)?402\b|^\s*402\s+payment/i.test(
+      lower,
+    )
+  ) {
     return true;
   }
   return false;
diff --git a/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts b/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts
index ed23f93d772..69b04e8bb37 100644
--- a/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts
+++ b/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts
@@ -27,4 +27,41 @@ describe("isBillingErrorMessage", () => {
     expect(isBillingErrorMessage("invalid api key")).toBe(false);
     expect(isBillingErrorMessage("context length exceeded")).toBe(false);
   });
+  it("does not false-positive on issue IDs or text containing 402", () => {
+    const falsePositives = [
+      "Fixed issue CHE-402 in the latest release",
+      "See ticket #402 for details",
+      "ISSUE-402 has been resolved",
+      "Room 402 is available",
+      "Error code 403 was returned, not 402-related",
+      "The building at 402 Main Street",
+      "processed 402 records",
+      "402 items found in the database",
+      "port 402 is open",
+      "Use a 402 stainless bolt",
+      "Book a 402 room",
+      "There is a 402 near me",
+    ];
+    for (const sample of falsePositives) {
+      expect(isBillingErrorMessage(sample)).toBe(false);
+    }
+  });
+  it("still matches real HTTP 402 billing errors", () => {
+    const realErrors = [
+      "HTTP 402 Payment Required",
+      "status: 402",
+      "error code 402",
+      "http 402",
+      "status=402 payment required",
+      "got a 402 from the API",
+      "returned 402",
+      "received a 402 response",
+      '{"status":402,"type":"error"}',
+      '{"code":402,"message":"payment required"}',
+      '{"error":{"code":402,"message":"billing hard limit reached"}}',
+    ];
+    for (const sample of realErrors) {
+      expect(isBillingErrorMessage(sample)).toBe(true);
+    }
+  });
 });
diff --git a/src/agents/pi-embedded-helpers/errors.ts b/src/agents/pi-embedded-helpers/errors.ts
index 12461074fa6..2a346293ac2 100644
--- a/src/agents/pi-embedded-helpers/errors.ts
+++ b/src/agents/pi-embedded-helpers/errors.ts
@@ -535,7 +535,7 @@ const ERROR_PATTERNS = {
   overloaded: [/overloaded_error|"type"\s*:\s*"overloaded_error"/i, "overloaded"],
   timeout: ["timeout", "timed out", "deadline exceeded", "context deadline exceeded"],
   billing: [
-    /\b402\b/,
+    /["']?(?:status|code)["']?\s*[:=]\s*402\b|\bhttp\s*402\b|\berror(?:\s+code)?\s*[:=]?\s*402\b|\b(?:got|returned|received)\s+(?:a\s+)?402\b|^\s*402\s+payment/i,
     "payment required",
     "insufficient credits",
     "credit balance",