fix(oauth): align codebuddy-cn OAuth User-Agent with chat/usage (#12702)

OAuth device-code auth/poll and token-refresh for codebuddy-cn presented
CLI/2.63.2 CodeBuddy/2.63.2 while chat-completion and usage/quota requests
presented CLI/2.108.1 CodeBuddy/2.108.1 for the same account. A 45-minor-
version-apart client fingerprint across auth vs. chat calls is exactly the
kind of internally-inconsistent signal an anti-abuse WAF flags as anomalous
(Tencent gateway code 11128 'request illegal').

Centralize the version string into CODEBUDDY_CN_USER_AGENT (exported from
src/lib/oauth/constants/oauth.ts) and reference it from the chat registry
entry and the usage handler so all three surfaces can never drift apart
again. Adds a permanent regression test asserting the OAuth, chat and
usage User-Agent headers all match.

changelog.d/fixes/12702-codebuddy-cn-useragent-consistency.md

@@ -0,0 +1 @@
+- fix(oauth): align codebuddy-cn OAuth User-Agent with the chat/usage CLI version to avoid WAF false positives (#12702)

open-sse/config/providers/registry/codebuddy-cn/index.ts

@@ -1,3 +1,4 @@
+import { CODEBUDDY_CN_USER_AGENT } from "@/lib/oauth/constants/oauth";
 import type { RegistryEntry } from "../../shared.ts";
 
 /**
@@ -20,7 +21,7 @@ export const codebuddy_cnProvider: RegistryEntry = {
   authType: "oauth",
   authHeader: "bearer",
   headers: {
-    "User-Agent": "CLI/2.108.1 CodeBuddy/2.108.1",
+    "User-Agent": CODEBUDDY_CN_USER_AGENT,
     "X-Product": "SaaS",
     "X-IDE-Type": "CLI",
     "X-IDE-Name": "CLI",

open-sse/services/usage/codebuddy-cn.ts

@@ -14,6 +14,8 @@
  * packs, "Bonus Pack N" for bonus packs (soonest-expiring first).
  */
 
+import { CODEBUDDY_CN_USER_AGENT } from "@/lib/oauth/constants/oauth";
+
 const USAGE_URL = "https://copilot.tencent.com/v2/billing/meter/get-user-resource";
 
 interface TencentAccount {
@@ -130,7 +132,7 @@ export async function getCodeBuddyCnUsage(
         Authorization: `Bearer ${token}`,
         "Content-Type": "application/json",
         Accept: "application/json",
-        "User-Agent": "CLI/2.108.1 CodeBuddy/2.108.1",
+        "User-Agent": CODEBUDDY_CN_USER_AGENT,
         "X-Product": "SaaS",
         "X-IDE-Type": "CLI",
         "X-IDE-Name": "CLI",

src/lib/oauth/constants/oauth.ts

@@ -106,12 +106,21 @@ export const QODER_CONFIG = {
 // CodeBuddy CN (Tencent — copilot.tencent.com) OAuth Configuration
 // (Custom Device-Auth Flow: POST stateUrl → open authUrl → GET pollUrl?state=).
 // No client_id/secret — the upstream CLI ships none.
+//
+// CODEBUDDY_CN_USER_AGENT is the single source of truth for the CLI/CodeBuddy version
+// string. It MUST stay identical across OAuth (this file), chat completions
+// (open-sse/config/providers/registry/codebuddy-cn/index.ts) and usage/quota
+// (open-sse/services/usage/codebuddy-cn.ts) — a mismatched version string across a
+// single account's auth vs. chat calls is exactly the kind of internally-inconsistent
+// client fingerprint Tencent's WAF flags as anomalous (#12702).
+export const CODEBUDDY_CN_USER_AGENT = "CLI/2.108.1 CodeBuddy/2.108.1";
+
 export const CODEBUDDY_CN_CONFIG = {
   baseUrl: "https://copilot.tencent.com",
   stateUrl: "https://copilot.tencent.com/v2/plugin/auth/state",
   tokenUrl: "https://copilot.tencent.com/v2/plugin/auth/token",
   refreshUrl: "https://copilot.tencent.com/v2/plugin/auth/token/refresh",
-  userAgent: "CLI/2.63.2 CodeBuddy/2.63.2",
+  userAgent: CODEBUDDY_CN_USER_AGENT,
   platform: "CLI",
   pollInterval: 5000,
 };

tests/unit/codebuddy-cn-provider.test.ts

@@ -585,3 +585,38 @@ test("codebuddy-cn is treated as a managed dual-auth provider (oauth + apikey ac
     "codebuddy-cn must be admitted by the dual-auth gate"
   );
 });
+
+test("#12702: codebuddy-cn presents the same CLI/CodeBuddy version across OAuth, chat and usage calls", async () => {
+  // A mismatched version string across a single account's auth vs. chat calls is exactly the
+  // kind of internally-inconsistent client fingerprint Tencent's WAF flags as anomalous
+  // (code 11128 "request illegal" / "blocked by security policy"). All three surfaces must
+  // read from the same CODEBUDDY_CN_USER_AGENT constant so they can never drift apart again.
+  const oauthUserAgent = CODEBUDDY_CN_CONFIG.userAgent;
+  const chatUserAgent = REGISTRY["codebuddy-cn"].headers?.["User-Agent"];
+  assert.equal(
+    oauthUserAgent,
+    chatUserAgent,
+    `codebuddy-cn OAuth User-Agent (${oauthUserAgent}) must match the chat User-Agent (${chatUserAgent})`
+  );
+
+  const { CODEBUDDY_CN_USER_AGENT } = await import("../../src/lib/oauth/constants/oauth.ts");
+  assert.equal(oauthUserAgent, CODEBUDDY_CN_USER_AGENT);
+
+  const origFetch = globalThis.fetch;
+  let capturedUserAgent: string | undefined;
+  globalThis.fetch = (async (_url: unknown, init?: RequestInit) => {
+    capturedUserAgent = (init?.headers as Record<string, string> | undefined)?.["User-Agent"];
+    return new Response(JSON.stringify({}), { status: 200 });
+  }) as typeof fetch;
+  try {
+    const { getCodeBuddyCnUsage } = await import("../../open-sse/services/usage/codebuddy-cn.ts");
+    await getCodeBuddyCnUsage("ACCESS_TOKEN", undefined, undefined);
+    assert.equal(
+      capturedUserAgent,
+      CODEBUDDY_CN_USER_AGENT,
+      "codebuddy-cn usage/quota User-Agent must match the shared constant"
+    );
+  } finally {
+    globalThis.fetch = origFetch;
+  }
+});