diff --git a/.gitignore b/.gitignore
index 013de38f..84df4477 100644
--- a/.gitignore
+++ b/.gitignore
@@ -55,6 +55,8 @@ logs/*
 # analysis directories (generated, not tracked)
 .analysis/
 antigravity-manager-analysis/
+.sisyphus/
+.plans/
 
 # docs (allow specific tracked files)
 docs/*
diff --git a/open-sse/config/providerRegistry.ts b/open-sse/config/providerRegistry.ts
index 7029b972..3519f917 100644
--- a/open-sse/config/providerRegistry.ts
+++ b/open-sse/config/providerRegistry.ts
@@ -537,6 +537,32 @@ export const REGISTRY: Record<string, RegistryEntry> = {
     ],
   },
 
+  "bailian-coding-plan": {
+    id: "bailian-coding-plan",
+    alias: "bcp",
+    format: "claude",
+    executor: "default",
+    baseUrl: "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1/messages",
+    chatPath: "/messages",
+    urlSuffix: "?beta=true",
+    authType: "apikey",
+    authHeader: "x-api-key",
+    headers: {
+      "Anthropic-Version": "2023-06-01",
+      "Anthropic-Beta": "claude-code-20250219,interleaved-thinking-2025-05-14",
+    },
+    models: [
+      { id: "qwen3.5-plus", name: "Qwen3.5 Plus" },
+      { id: "qwen3-max-2026-01-23", name: "Qwen3 Max (2026-01-23)" },
+      { id: "qwen3-coder-next", name: "Qwen3 Coder Next" },
+      { id: "qwen3-coder-plus", name: "Qwen3 Coder Plus" },
+      { id: "MiniMax-M2.5", name: "MiniMax M2.5" },
+      { id: "glm-5", name: "GLM 5" },
+      { id: "glm-4.7", name: "GLM 4.7" },
+      { id: "kimi-k2.5", name: "Kimi K2.5" },
+    ],
+  },
+
   zai: {
     id: "zai",
     alias: "zai",
diff --git a/open-sse/executors/default.ts b/open-sse/executors/default.ts
index fa52037a..cc597bda 100644
--- a/open-sse/executors/default.ts
+++ b/open-sse/executors/default.ts
@@ -54,6 +54,7 @@ export class DefaultExecutor extends BaseExecutor {
         break;
       case "glm":
       case "kimi-coding":
+      case "bailian-coding-plan":
       case "kimi-coding-apikey":
       case "minimax":
       case "minimax-cn":
diff --git a/src/app/(dashboard)/dashboard/providers/[id]/page.tsx b/src/app/(dashboard)/dashboard/providers/[id]/page.tsx
index ff770ed0..56e8217b 100644
--- a/src/app/(dashboard)/dashboard/providers/[id]/page.tsx
+++ b/src/app/(dashboard)/dashboard/providers/[id]/page.tsx
@@ -286,9 +286,13 @@ export default function ProviderDetailPage() {
       if (res.ok) {
         await fetchConnections();
         setShowEditModal(false);
+        return null;
       }
+      const data = await res.json().catch(() => ({}));
+      return data.error?.message || data.error || t("failedSaveConnection");
     } catch (error) {
       console.log("Error updating connection:", error);
+      return t("failedSaveConnectionRetry");
     }
   };
 
@@ -2618,10 +2622,14 @@ function AddApiKeyModal({
   onClose,
 }) {
   const t = useTranslations("providers");
+  const isBailian = provider === "bailian-coding-plan";
+  const defaultBailianUrl = "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1";
+
   const [formData, setFormData] = useState({
     name: "",
     apiKey: "",
     priority: 1,
+    baseUrl: isBailian ? defaultBailianUrl : "",
   });
   const [validating, setValidating] = useState(false);
   const [validationResult, setValidationResult] = useState(null);
@@ -2652,6 +2660,16 @@ function AddApiKeyModal({
     setSaving(true);
     setSaveError(null);
     try {
+      let validatedBailianBaseUrl = null;
+      if (isBailian) {
+        const checked = normalizeAndValidateHttpBaseUrl(formData.baseUrl, defaultBailianUrl);
+        if (checked.error) {
+          setSaveError(checked.error);
+          return;
+        }
+        validatedBailianBaseUrl = checked.value;
+      }
+
       let isValid = false;
       try {
         setValidating(true);
@@ -2675,12 +2693,22 @@ function AddApiKeyModal({
         return;
       }
 
-      const error = await onSave({
+      const payload = {
         name: formData.name,
         apiKey: formData.apiKey,
         priority: formData.priority,
         testStatus: "active",
-      });
+        providerSpecificData: undefined,
+      };
+
+      // Include baseUrl in providerSpecificData for bailian-coding-plan
+      if (isBailian) {
+        payload.providerSpecificData = {
+          baseUrl: validatedBailianBaseUrl,
+        };
+      }
+
+      const error = await onSave(payload);
       if (error) {
         setSaveError(typeof error === "string" ? error : t("failedSaveConnection"));
       }
@@ -2751,6 +2779,15 @@ function AddApiKeyModal({
             setFormData({ ...formData, priority: Number.parseInt(e.target.value) || 1 })
           }
         />
+        {isBailian && (
+          <Input
+            label="Base URL"
+            value={formData.baseUrl}
+            onChange={(e) => setFormData({ ...formData, baseUrl: e.target.value })}
+            placeholder={defaultBailianUrl}
+            hint="Optional: Custom base URL for bailian-coding-plan provider"
+          />
+        )}
         <div className="flex gap-2">
           <Button
             onClick={handleSubmit}
@@ -2778,6 +2815,19 @@ AddApiKeyModal.propTypes = {
   onClose: PropTypes.func.isRequired,
 };
 
+function normalizeAndValidateHttpBaseUrl(rawValue, fallbackUrl) {
+  const value = (typeof rawValue === "string" ? rawValue.trim() : "") || fallbackUrl;
+  try {
+    const parsed = new URL(value);
+    if (parsed.protocol !== "http:" && parsed.protocol !== "https:") {
+      return { value: null, error: "Base URL must use http or https" };
+    }
+    return { value, error: null };
+  } catch {
+    return { value: null, error: "Base URL must be a valid URL" };
+  }
+}
+
 function EditConnectionModal({ isOpen, connection, onSave, onClose }) {
   const t = useTranslations("providers");
   const [formData, setFormData] = useState({
@@ -2785,22 +2835,29 @@ function EditConnectionModal({ isOpen, connection, onSave, onClose }) {
     priority: 1,
     apiKey: "",
     healthCheckInterval: 60,
+    baseUrl: "",
   });
   const [testing, setTesting] = useState(false);
   const [testResult, setTestResult] = useState(null);
   const [validating, setValidating] = useState(false);
   const [validationResult, setValidationResult] = useState(null);
   const [saving, setSaving] = useState(false);
+  const [saveError, setSaveError] = useState<string | null>(null);
   const [extraApiKeys, setExtraApiKeys] = useState<string[]>([]);
   const [newExtraKey, setNewExtraKey] = useState("");
 
+  const isBailian = connection?.provider === "bailian-coding-plan";
+  const defaultBailianUrl = "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1";
+
   useEffect(() => {
     if (connection) {
+      const existingBaseUrl = connection.providerSpecificData?.baseUrl;
       setFormData({
         name: connection.name || "",
         priority: connection.priority || 1,
         apiKey: "",
         healthCheckInterval: connection.healthCheckInterval ?? 60,
+        baseUrl: existingBaseUrl || (isBailian ? defaultBailianUrl : ""),
       });
       // Load existing extra keys from providerSpecificData
       const existing = connection.providerSpecificData?.extraApiKeys;
@@ -2808,8 +2865,9 @@ function EditConnectionModal({ isOpen, connection, onSave, onClose }) {
       setNewExtraKey("");
       setTestResult(null);
       setValidationResult(null);
+      setSaveError(null);
     }
-  }, [connection]);
+  }, [connection, isBailian]);
 
   const handleTest = async () => {
     if (!connection?.provider) return;
@@ -2855,12 +2913,24 @@ function EditConnectionModal({ isOpen, connection, onSave, onClose }) {
 
   const handleSubmit = async () => {
     setSaving(true);
+    setSaveError(null);
     try {
       const updates: any = {
         name: formData.name,
         priority: formData.priority,
         healthCheckInterval: formData.healthCheckInterval,
       };
+
+      let validatedBailianBaseUrl = null;
+      if (isBailian) {
+        const checked = normalizeAndValidateHttpBaseUrl(formData.baseUrl, defaultBailianUrl);
+        if (checked.error) {
+          setSaveError(checked.error);
+          return;
+        }
+        validatedBailianBaseUrl = checked.value;
+      }
+
       if (!isOAuth && formData.apiKey) {
         updates.apiKey = formData.apiKey;
         let isValid = validationResult === "success";
@@ -2892,14 +2962,21 @@ function EditConnectionModal({ isOpen, connection, onSave, onClose }) {
           updates.rateLimitedUntil = null;
         }
       }
-      // Persist extra API keys in providerSpecificData
+      // Persist extra API keys and baseUrl in providerSpecificData
       if (!isOAuth) {
         updates.providerSpecificData = {
           ...(connection.providerSpecificData || {}),
           extraApiKeys: extraApiKeys.filter((k) => k.trim().length > 0),
         };
+        // Update baseUrl for bailian-coding-plan
+        if (isBailian) {
+          updates.providerSpecificData.baseUrl = validatedBailianBaseUrl;
+        }
+      }
+      const error = await onSave(updates);
+      if (error) {
+        setSaveError(typeof error === "string" ? error : t("failedSaveConnection"));
       }
-      await onSave(updates);
     } finally {
       setSaving(false);
     }
@@ -2980,9 +3057,24 @@ function EditConnectionModal({ isOpen, connection, onSave, onClose }) {
                 {validationResult === "success" ? t("valid") : t("invalid")}
               </Badge>
             )}
+            {saveError && (
+              <div className="text-sm text-red-500 bg-red-500/10 border border-red-500/20 rounded-lg px-3 py-2">
+                {saveError}
+              </div>
+            )}
           </>
         )}
 
+        {isBailian && (
+          <Input
+            label="Base URL"
+            value={formData.baseUrl}
+            onChange={(e) => setFormData({ ...formData, baseUrl: e.target.value })}
+            placeholder={defaultBailianUrl}
+            hint="Custom base URL for bailian-coding-plan provider"
+          />
+        )}
+
         {/* T07: Extra API Keys for round-robin rotation */}
         {!isOAuth && (
           <div className="flex flex-col gap-2">
diff --git a/src/app/api/providers/[id]/models/route.ts b/src/app/api/providers/[id]/models/route.ts
index e204b0f3..0a73753d 100644
--- a/src/app/api/providers/[id]/models/route.ts
+++ b/src/app/api/providers/[id]/models/route.ts
@@ -37,7 +37,7 @@ const KIMI_CODING_MODELS_CONFIG: ProviderModelsConfigEntry = {
 };
 
 // Providers that return hardcoded models (no remote /models API)
-const STATIC_MODEL_PROVIDERS = {
+const STATIC_MODEL_PROVIDERS: Record<string, () => Array<{ id: string; name: string }>> = {
   deepgram: () => [
     { id: "nova-3", name: "Nova 3 (Transcription)" },
     { id: "nova-2", name: "Nova 2 (Transcription)" },
@@ -61,8 +61,31 @@ const STATIC_MODEL_PROVIDERS = {
     { id: "sonar-reasoning-pro", name: "Sonar Reasoning Pro (Advanced CoT + Search)" },
     { id: "sonar-deep-research", name: "Sonar Deep Research (Expert Analysis)" },
   ],
+  "bailian-coding-plan": () => [
+    { id: "qwen3.5-plus", name: "Qwen3.5 Plus" },
+    { id: "qwen3-max-2026-01-23", name: "Qwen3 Max (2026-01-23)" },
+    { id: "qwen3-coder-next", name: "Qwen3 Coder Next" },
+    { id: "qwen3-coder-plus", name: "Qwen3 Coder Plus" },
+    { id: "MiniMax-M2.5", name: "MiniMax M2.5" },
+    { id: "glm-5", name: "GLM 5" },
+    { id: "glm-4.7", name: "GLM 4.7" },
+    { id: "kimi-k2.5", name: "Kimi K2.5" },
+  ],
 };
 
+/**
+ * Get static models for a provider (if available).
+ * Exported for testing purposes.
+ * @param provider - Provider ID
+ * @returns Array of models or undefined if provider doesn't use static models
+ */
+export function getStaticModelsForProvider(
+  provider: string
+): Array<{ id: string; name: string }> | undefined {
+  const staticModelsFn = STATIC_MODEL_PROVIDERS[provider];
+  return staticModelsFn ? staticModelsFn() : undefined;
+}
+
 // Provider models endpoints configuration
 const PROVIDER_MODELS_CONFIG: Record<string, ProviderModelsConfigEntry> = {
   claude: {
diff --git a/src/app/api/providers/route.ts b/src/app/api/providers/route.ts
index 46783053..9db48295 100644
--- a/src/app/api/providers/route.ts
+++ b/src/app/api/providers/route.ts
@@ -46,8 +46,16 @@ export async function POST(request: Request) {
     if (isValidationFailure(validation)) {
       return NextResponse.json({ error: validation.error }, { status: 400 });
     }
-    const { provider, apiKey, name, priority, globalPriority, defaultModel, testStatus } =
-      validation.data;
+    const {
+      provider,
+      apiKey,
+      name,
+      priority,
+      globalPriority,
+      defaultModel,
+      testStatus,
+      providerSpecificData: incomingPsd,
+    } = validation.data;
 
     // Business validation
     const isValidProvider =
@@ -59,7 +67,7 @@ export async function POST(request: Request) {
       return NextResponse.json({ error: "Invalid provider" }, { status: 400 });
     }
 
-    let providerSpecificData: Record<string, any> | null = null;
+    let providerSpecificData = incomingPsd || null;
     const allowMultipleCompatibleConnections =
       process.env.ALLOW_MULTI_CONNECTIONS_PER_COMPAT_NODE === "true";
 
@@ -78,6 +86,7 @@ export async function POST(request: Request) {
       }
 
       providerSpecificData = {
+        ...(providerSpecificData || {}),
         prefix: node.prefix,
         apiType: node.apiType,
         baseUrl: node.baseUrl,
@@ -100,6 +109,7 @@ export async function POST(request: Request) {
       }
 
       providerSpecificData = {
+        ...(providerSpecificData || {}),
         prefix: node.prefix,
         baseUrl: node.baseUrl,
         nodeName: node.name,
diff --git a/src/lib/providers/validation.ts b/src/lib/providers/validation.ts
index 5825d713..dd71ef91 100644
--- a/src/lib/providers/validation.ts
+++ b/src/lib/providers/validation.ts
@@ -300,6 +300,52 @@ async function validateInworldProvider({ apiKey }: any) {
   }
 }
 
+async function validateBailianCodingPlanProvider({ apiKey, providerSpecificData = {} }: any) {
+  try {
+    const rawBaseUrl =
+      normalizeBaseUrl(providerSpecificData.baseUrl) ||
+      "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1";
+    const baseUrl = rawBaseUrl.endsWith("/messages")
+      ? rawBaseUrl.slice(0, -"/messages".length)
+      : rawBaseUrl;
+    // bailian-coding-plan uses DashScope Anthropic-compatible messages endpoint
+    // It does NOT expose /v1/models — use messages probe directly
+    const messagesUrl = `${baseUrl}/messages`;
+
+    const response = await fetch(messagesUrl, {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+        "x-api-key": apiKey,
+        "anthropic-version": "2023-06-01",
+      },
+      body: JSON.stringify({
+        model: "qwen3-coder-plus",
+        max_tokens: 1,
+        messages: [{ role: "user", content: "test" }],
+      }),
+    });
+
+    // 401/403 => invalid key
+    if (response.status === 401 || response.status === 403) {
+      return { valid: false, error: "Invalid API key" };
+    }
+
+    // Non-auth 4xx (e.g., 400 bad request) means auth passed but request was malformed
+    if (response.status >= 400 && response.status < 500) {
+      return { valid: true, error: null };
+    }
+
+    if (response.ok) {
+      return { valid: true, error: null };
+    }
+
+    return { valid: false, error: `Validation failed: ${response.status}` };
+  } catch (error: any) {
+    return { valid: false, error: error.message || "Validation failed" };
+  }
+}
+
 async function validateOpenAICompatibleProvider({ apiKey, providerSpecificData = {} }: any) {
   const baseUrl = normalizeBaseUrl(providerSpecificData.baseUrl);
   if (!baseUrl) {
@@ -537,6 +583,7 @@ export async function validateProviderApiKey({ provider, apiKey, providerSpecifi
     nanobanana: validateNanoBananaProvider,
     elevenlabs: validateElevenLabsProvider,
     inworld: validateInworldProvider,
+    "bailian-coding-plan": validateBailianCodingPlanProvider,
     // Search providers — use factored validator
     ...Object.fromEntries(
       Object.entries(SEARCH_VALIDATOR_CONFIGS).map(([id, configFn]) => [
diff --git a/src/shared/constants/config.ts b/src/shared/constants/config.ts
index 1eca6161..f04a80ca 100644
--- a/src/shared/constants/config.ts
+++ b/src/shared/constants/config.ts
@@ -33,6 +33,7 @@ export const API_ENDPOINTS = {
 export const PROVIDER_ENDPOINTS = {
   openrouter: "https://openrouter.ai/api/v1/chat/completions",
   glm: "https://api.z.ai/api/anthropic/v1/messages",
+  "bailian-coding-plan": "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1/messages",
   kimi: "https://api.moonshot.ai/v1/chat/completions",
   "kimi-coding": "https://api.kimi.com/coding/v1/messages",
   "kimi-coding-apikey": "https://api.kimi.com/coding/v1/messages",
diff --git a/src/shared/constants/providers.ts b/src/shared/constants/providers.ts
index b8dee930..ee0a8d96 100644
--- a/src/shared/constants/providers.ts
+++ b/src/shared/constants/providers.ts
@@ -74,6 +74,15 @@ export const APIKEY_PROVIDERS = {
     textIcon: "GL",
     website: "https://open.bigmodel.cn",
   },
+  "bailian-coding-plan": {
+    id: "bailian-coding-plan",
+    alias: "bcp",
+    name: "Alibaba Coding Plan",
+    icon: "code",
+    color: "#FF6A00",
+    textIcon: "BCP",
+    website: "https://www.alibabacloud.com/help/en/model-studio/coding-plan",
+  },
   kimi: {
     id: "kimi",
     alias: "kimi",
diff --git a/src/shared/validation/schemas.ts b/src/shared/validation/schemas.ts
index bc63a9ac..1e99caa1 100644
--- a/src/shared/validation/schemas.ts
+++ b/src/shared/validation/schemas.ts
@@ -1,5 +1,14 @@
 import { z } from "zod";
 
+function isHttpUrl(value: string): boolean {
+  try {
+    const parsed = new URL(value);
+    return parsed.protocol === "http:" || parsed.protocol === "https:";
+  } catch {
+    return false;
+  }
+}
+
 // Re-export validation helpers from dedicated module to avoid webpack barrel-file
 // optimization bug that truncates exports from large files.
 export { validateBody, isValidationFailure } from "./helpers";
@@ -15,6 +24,21 @@ export const createProviderSchema = z.object({
   globalPriority: z.number().int().min(1).max(100).nullable().optional(),
   defaultModel: z.string().max(200).nullable().optional(),
   testStatus: z.string().max(50).optional(),
+  providerSpecificData: z
+    .record(z.string(), z.unknown())
+    .optional()
+    .superRefine((data, ctx) => {
+      if (!data) return;
+      const baseUrl = data.baseUrl;
+      if (baseUrl === undefined) return;
+      if (typeof baseUrl !== "string" || !isHttpUrl(baseUrl)) {
+        ctx.addIssue({
+          code: z.ZodIssueCode.custom,
+          message: "providerSpecificData.baseUrl must be a valid http(s) URL",
+          path: ["baseUrl"],
+        });
+      }
+    }),
 });
 
 // ──── API Key Schemas ────
@@ -945,7 +969,21 @@ export const updateProviderConnectionSchema = z
     healthCheckInterval: z.coerce.number().int().min(0).optional(),
     group: z.union([z.string().max(100), z.null()]).optional(),
     // Partial patch of per-connection provider-specific settings (e.g. quota toggles)
-    providerSpecificData: z.record(z.string(), z.unknown()).optional(),
+    providerSpecificData: z
+      .record(z.string(), z.unknown())
+      .optional()
+      .superRefine((data, ctx) => {
+        if (!data) return;
+        const baseUrl = data.baseUrl;
+        if (baseUrl === undefined) return;
+        if (typeof baseUrl !== "string" || !isHttpUrl(baseUrl)) {
+          ctx.addIssue({
+            code: z.ZodIssueCode.custom,
+            message: "providerSpecificData.baseUrl must be a valid http(s) URL",
+            path: ["baseUrl"],
+          });
+        }
+      }),
   })
   .superRefine((value, ctx) => {
     if (Object.keys(value).length === 0) {
diff --git a/tests/e2e/providers-bailian-coding-plan.spec.ts b/tests/e2e/providers-bailian-coding-plan.spec.ts
new file mode 100644
index 00000000..ab26ae35
--- /dev/null
+++ b/tests/e2e/providers-bailian-coding-plan.spec.ts
@@ -0,0 +1,239 @@
+import { expect, test } from "@playwright/test";
+
+const DEFAULT_BAILIAN_URL = "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1";
+
+test.describe("Bailian Coding Plan Provider", () => {
+  test.describe.configure({ mode: "serial" });
+
+  test("default URL visible and editable in Add API Key modal", async ({ page }) => {
+    const capturedPayloads: { createProvider?: Record<string, unknown> } = {};
+
+    await page.route("**/api/providers", async (route) => {
+      const method = route.request().method();
+      if (method === "GET") {
+        await route.fulfill({
+          status: 200,
+          contentType: "application/json",
+          body: JSON.stringify({ connections: [] }),
+        });
+        return;
+      }
+
+      if (method === "POST") {
+        const payload = route.request().postDataJSON();
+        capturedPayloads.createProvider = payload;
+        await route.fulfill({
+          status: 200,
+          contentType: "application/json",
+          body: JSON.stringify({
+            connection: {
+              id: "conn-bailian-test",
+              provider: "bailian-coding-plan",
+              name: payload.name || "Test Connection",
+              testStatus: "active",
+              providerSpecificData: payload.providerSpecificData,
+            },
+          }),
+        });
+        return;
+      }
+
+      await route.fulfill({ status: 405 });
+    });
+
+    await page.route("**/api/providers/validate", async (route) => {
+      await route.fulfill({
+        status: 200,
+        contentType: "application/json",
+        body: JSON.stringify({ valid: true }),
+      });
+    });
+
+    await page.route("**/api/provider-nodes", async (route) => {
+      await route.fulfill({
+        status: 200,
+        contentType: "application/json",
+        body: JSON.stringify({ nodes: [] }),
+      });
+    });
+
+    await page.goto("/dashboard/providers/bailian-coding-plan");
+    await page.waitForLoadState("networkidle");
+
+    const redirectedToLogin = page.url().includes("/login");
+    test.skip(redirectedToLogin, "Authentication enabled without a login fixture.");
+
+    const addKeyButton = page.getByRole("button", {
+      name: /add.*api.*key|add.*key|add.*connection|connect/i,
+    });
+
+    if (
+      await addKeyButton
+        .first()
+        .isVisible({ timeout: 5000 })
+        .catch(() => false)
+    ) {
+      await addKeyButton.first().click();
+    }
+
+    const dialog = page.getByRole("dialog").first();
+    await expect(dialog).toBeVisible({ timeout: 10000 });
+
+    const baseUrlInput = dialog
+      .getByLabel(/base.*url/i)
+      .or(dialog.locator("input").filter({ has: page.locator("..").getByText(/base.*url/i) }));
+
+    await expect(baseUrlInput).toBeVisible({ timeout: 5000 });
+
+    const inputValue = await baseUrlInput.inputValue();
+    expect(inputValue).toBe(DEFAULT_BAILIAN_URL);
+
+    const nameInput = dialog.getByLabel(/name/i).or(dialog.locator("input").first());
+    await nameInput.fill("Test Bailian Connection");
+
+    const apiKeyInput = dialog
+      .getByLabel(/api.*key/i)
+      .or(dialog.locator('input[type="password"]').first());
+    await apiKeyInput.fill("test-api-key-12345");
+
+    const customUrl = "https://custom.example.com/anthropic/v1";
+    await baseUrlInput.fill(customUrl);
+
+    const saveButton = dialog
+      .getByRole("button", {
+        name: /save|add|create|connect/i,
+      })
+      .last();
+    await expect(saveButton).toBeEnabled({ timeout: 5000 });
+    await saveButton.click();
+
+    await expect(dialog)
+      .toBeHidden({ timeout: 10000 })
+      .catch(() => undefined);
+
+    expect(capturedPayloads.createProvider).toBeDefined();
+    const payload = capturedPayloads.createProvider;
+    expect(payload?.providerSpecificData).toBeDefined();
+    expect((payload?.providerSpecificData as Record<string, unknown>)?.baseUrl).toBe(customUrl);
+  });
+
+  test("invalid URL blocks save with validation error", async ({ page }) => {
+    let validationErrorCaptured = false;
+    let createAttempted = false;
+
+    await page.route("**/api/providers", async (route) => {
+      const method = route.request().method();
+      if (method === "GET") {
+        await route.fulfill({
+          status: 200,
+          contentType: "application/json",
+          body: JSON.stringify({ connections: [] }),
+        });
+        return;
+      }
+
+      if (method === "POST") {
+        createAttempted = true;
+        await route.fulfill({
+          status: 400,
+          contentType: "application/json",
+          body: JSON.stringify({
+            message: "Invalid request",
+            details: [
+              {
+                field: "providerSpecificData.baseUrl",
+                message: "providerSpecificData.baseUrl must be a valid URL",
+              },
+            ],
+          }),
+        });
+        return;
+      }
+
+      await route.fulfill({ status: 405 });
+    });
+
+    await page.route("**/api/providers/validate", async (route) => {
+      await route.fulfill({
+        status: 200,
+        contentType: "application/json",
+        body: JSON.stringify({ valid: true }),
+      });
+    });
+
+    await page.route("**/api/provider-nodes", async (route) => {
+      await route.fulfill({
+        status: 200,
+        contentType: "application/json",
+        body: JSON.stringify({ nodes: [] }),
+      });
+    });
+
+    await page.goto("/dashboard/providers/bailian-coding-plan");
+    await page.waitForLoadState("networkidle");
+
+    const redirectedToLogin = page.url().includes("/login");
+    test.skip(redirectedToLogin, "Authentication enabled without a login fixture.");
+
+    const addKeyButton = page.getByRole("button", {
+      name: /add.*api.*key|add.*key|add.*connection|connect/i,
+    });
+
+    if (
+      await addKeyButton
+        .first()
+        .isVisible({ timeout: 5000 })
+        .catch(() => false)
+    ) {
+      await addKeyButton.first().click();
+    }
+
+    const dialog = page.getByRole("dialog").first();
+    await expect(dialog).toBeVisible({ timeout: 10000 });
+
+    const baseUrlInput = dialog
+      .getByLabel(/base.*url/i)
+      .or(dialog.locator("input").filter({ has: page.locator("..").getByText(/base.*url/i) }));
+    await expect(baseUrlInput).toBeVisible({ timeout: 5000 });
+
+    const nameInput = dialog.getByLabel(/name/i).or(dialog.locator("input").first());
+    await nameInput.fill("Test Invalid URL Connection");
+
+    const apiKeyInput = dialog
+      .getByLabel(/api.*key/i)
+      .or(dialog.locator('input[type="password"]').first());
+    await apiKeyInput.fill("test-api-key-12345");
+
+    await baseUrlInput.fill("not-a-url");
+
+    const saveButton = dialog
+      .getByRole("button", {
+        name: /save|add|create|connect/i,
+      })
+      .last();
+    await saveButton.click();
+
+    const errorLocator = page
+      .locator("text=/invalid.*url|url.*invalid|must be a valid url/i")
+      .or(
+        page
+          .locator(".text-red-500")
+          .or(page.locator('[class*="error"]').or(page.locator('[class*="text-destructive"]')))
+      );
+
+    await page.waitForTimeout(1000);
+
+    const errorVisible = await errorLocator.isVisible({ timeout: 5000 }).catch(() => false);
+
+    if (!errorVisible) {
+      await page.waitForTimeout(2000);
+      const modalStillOpen = await dialog.isVisible();
+      if (modalStillOpen) {
+        validationErrorCaptured = true;
+      }
+    }
+
+    expect(errorVisible).toBe(true);
+    expect(createAttempted).toBe(false);
+  });
+});
diff --git a/tests/unit/bailian-coding-plan-provider.test.mjs b/tests/unit/bailian-coding-plan-provider.test.mjs
new file mode 100644
index 00000000..6229cf5c
--- /dev/null
+++ b/tests/unit/bailian-coding-plan-provider.test.mjs
@@ -0,0 +1,631 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+// Import the constants directly
+const { APIKEY_PROVIDERS, OAUTH_PROVIDERS } =
+  await import("../../src/shared/constants/providers.ts");
+
+// Import validateProviderApiKey for Scenario C tests
+const { validateProviderApiKey } = await import("../../src/lib/providers/validation.ts");
+
+test("APIKEY_PROVIDERS includes bailian-coding-plan", () => {
+  assert.ok(
+    APIKEY_PROVIDERS["bailian-coding-plan"],
+    "bailian-coding-plan should be present in APIKEY_PROVIDERS"
+  );
+
+  const provider = APIKEY_PROVIDERS["bailian-coding-plan"];
+  assert.equal(provider.id, "bailian-coding-plan", "Provider id should be 'bailian-coding-plan'");
+  assert.equal(provider.alias, "bcp", "Provider alias should be 'bcp'");
+  assert.ok(provider.name, "Provider should have a name");
+});
+
+test("bailian-coding-plan not in OAUTH_PROVIDERS", () => {
+  assert.equal(
+    OAUTH_PROVIDERS["bailian-coding-plan"],
+    undefined,
+    "bailian-coding-plan should NOT be present in OAUTH_PROVIDERS"
+  );
+});
+
+// Schema validation tests for providerSpecificData.baseUrl
+const { validateBody, createProviderSchema, updateProviderConnectionSchema } =
+  await import("../../src/shared/validation/schemas.ts");
+
+const VALID_BAILIAN_URL = "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1";
+
+test("createProviderSchema accepts valid baseUrl in providerSpecificData", () => {
+  const validation = validateBody(createProviderSchema, {
+    provider: "bailian-coding-plan",
+    apiKey: "sk-test-key",
+    name: "Test Bailian",
+    providerSpecificData: {
+      baseUrl: VALID_BAILIAN_URL,
+    },
+  });
+
+  assert.equal(validation.success, true, "Should accept valid URL");
+  if (validation.success) {
+    assert.equal(
+      validation.data.providerSpecificData?.baseUrl,
+      VALID_BAILIAN_URL,
+      "Should preserve valid baseUrl"
+    );
+  }
+});
+
+test("createProviderSchema accepts missing providerSpecificData", () => {
+  const validation = validateBody(createProviderSchema, {
+    provider: "bailian-coding-plan",
+    apiKey: "sk-test-key",
+    name: "Test Bailian",
+  });
+
+  assert.equal(validation.success, true, "Should accept without providerSpecificData");
+});
+
+test("createProviderSchema accepts empty providerSpecificData", () => {
+  const validation = validateBody(createProviderSchema, {
+    provider: "bailian-coding-plan",
+    apiKey: "sk-test-key",
+    name: "Test Bailian",
+    providerSpecificData: {},
+  });
+
+  assert.equal(validation.success, true, "Should accept empty providerSpecificData");
+});
+
+test("createProviderSchema rejects invalid baseUrl in providerSpecificData", () => {
+  const validation = validateBody(createProviderSchema, {
+    provider: "bailian-coding-plan",
+    apiKey: "sk-test-key",
+    name: "Test Bailian",
+    providerSpecificData: {
+      baseUrl: "not-a-valid-url",
+    },
+  });
+
+  assert.equal(validation.success, false, "Should reject invalid URL");
+  if (!validation.success && typeof validation.error === "object" && validation.error !== null) {
+    const errorObj = validation.error;
+    const details = Array.isArray(errorObj.details) ? errorObj.details : [];
+    const errorStr = details.map((d) => d.message || "").join(", ");
+    assert.ok(
+      errorStr.includes("baseUrl") && errorStr.includes("URL"),
+      `Error should mention baseUrl and URL. Got: ${errorStr}`
+    );
+  }
+});
+
+test("createProviderSchema rejects malformed baseUrl (no protocol)", () => {
+  const validation = validateBody(createProviderSchema, {
+    provider: "bailian-coding-plan",
+    apiKey: "sk-test-key",
+    name: "Test Bailian",
+    providerSpecificData: {
+      baseUrl: "example.com/path",
+    },
+  });
+
+  assert.equal(validation.success, false, "Should reject URL without protocol");
+});
+
+test("createProviderSchema rejects baseUrl with non-string value", () => {
+  const validation = validateBody(createProviderSchema, {
+    provider: "bailian-coding-plan",
+    apiKey: "sk-test-key",
+    name: "Test Bailian",
+    providerSpecificData: {
+      baseUrl: 12345,
+    },
+  });
+
+  assert.equal(validation.success, false, "Should reject non-string baseUrl");
+});
+
+test("updateProviderConnectionSchema accepts valid baseUrl in providerSpecificData", () => {
+  const validation = validateBody(updateProviderConnectionSchema, {
+    providerSpecificData: {
+      baseUrl: VALID_BAILIAN_URL,
+    },
+  });
+
+  assert.equal(validation.success, true, "Should accept valid URL");
+  if (validation.success) {
+    assert.equal(
+      validation.data.providerSpecificData?.baseUrl,
+      VALID_BAILIAN_URL,
+      "Should preserve valid baseUrl"
+    );
+  }
+});
+
+test("updateProviderConnectionSchema rejects invalid baseUrl in providerSpecificData", () => {
+  const validation = validateBody(updateProviderConnectionSchema, {
+    providerSpecificData: {
+      baseUrl: "invalid-url-abc",
+    },
+  });
+
+  assert.equal(validation.success, false, "Should reject invalid URL");
+  if (!validation.success && typeof validation.error === "object" && validation.error !== null) {
+    const errorObj = validation.error;
+    const details = Array.isArray(errorObj.details) ? errorObj.details : [];
+    const errorStr = details.map((d) => d.message || "").join(", ");
+    assert.ok(
+      errorStr.includes("baseUrl") && errorStr.includes("URL"),
+      `Error should mention baseUrl and URL. Got: ${errorStr}`
+    );
+  }
+});
+
+test("updateProviderConnectionSchema accepts partial update without baseUrl", () => {
+  const validation = validateBody(updateProviderConnectionSchema, {
+    name: "Updated Name",
+    priority: 5,
+  });
+
+  assert.equal(validation.success, true, "Should accept update without baseUrl");
+});
+
+test("updateProviderConnectionSchema rejects baseUrl with trailing garbage", () => {
+  const validation = validateBody(updateProviderConnectionSchema, {
+    providerSpecificData: {
+      baseUrl: "https://example.com not-a-url",
+    },
+  });
+
+  assert.equal(validation.success, false, "Should reject URL with trailing garbage");
+});
+
+test("updateProviderConnectionSchema accepts https protocol", () => {
+  const validation = validateBody(updateProviderConnectionSchema, {
+    providerSpecificData: {
+      baseUrl: "https://secure.example.com/v1",
+    },
+  });
+
+  assert.equal(validation.success, true, "Should accept https URL");
+});
+
+test("updateProviderConnectionSchema accepts http protocol", () => {
+  const validation = validateBody(updateProviderConnectionSchema, {
+    providerSpecificData: {
+      baseUrl: "http://localhost:3000/v1",
+    },
+  });
+
+  assert.equal(validation.success, true, "Should accept http URL");
+});
+
+// ============================================================================
+// ROUTE-LEVEL TESTS: Static model listing behavior for bailian-coding-plan
+// ============================================================================
+
+// Import the exported helper function from the route
+const { getStaticModelsForProvider } =
+  await import("../../src/app/api/providers/[id]/models/route.ts");
+
+test("getStaticModelsForProvider returns 8 models for bailian-coding-plan", () => {
+  const models = getStaticModelsForProvider("bailian-coding-plan");
+
+  assert.ok(models, "Should return models for bailian-coding-plan");
+  assert.ok(Array.isArray(models), "Should return an array");
+  assert.equal(models.length, 8, "Should return exactly 8 models");
+});
+
+test("getStaticModelsForProvider returns correct model IDs for bailian-coding-plan", () => {
+  const models = getStaticModelsForProvider("bailian-coding-plan");
+
+  if (!models) {
+    assert.fail("Models should not be undefined");
+    return;
+  }
+
+  const expectedIds = [
+    "qwen3.5-plus",
+    "qwen3-max-2026-01-23",
+    "qwen3-coder-next",
+    "qwen3-coder-plus",
+    "MiniMax-M2.5",
+    "glm-5",
+    "glm-4.7",
+    "kimi-k2.5",
+  ];
+
+  const actualIds = models.map((m) => m.id);
+
+  for (const expectedId of expectedIds) {
+    assert.ok(actualIds.includes(expectedId), `Should include model: ${expectedId}`);
+  }
+
+  // Verify no extra models
+  assert.equal(actualIds.length, expectedIds.length, "Should have exactly the expected models");
+});
+
+test("getStaticModelsForProvider returns models with correct structure", () => {
+  const models = getStaticModelsForProvider("bailian-coding-plan");
+
+  if (!models) {
+    assert.fail("Models should not be undefined");
+    return;
+  }
+
+  for (const model of models) {
+    assert.ok(model.id, `Model should have id: ${JSON.stringify(model)}`);
+    assert.ok(model.name, `Model should have name: ${JSON.stringify(model)}`);
+    assert.equal(typeof model.id, "string", "Model id should be string");
+    assert.equal(typeof model.name, "string", "Model name should be string");
+  }
+});
+
+test("getStaticModelsForProvider returns undefined for non-static providers", () => {
+  // Test with providers that are NOT in STATIC_MODEL_PROVIDERS
+  const nonStaticProviders = ["openai", "anthropic", "deepseek", "groq", "unknown-provider"];
+
+  for (const provider of nonStaticProviders) {
+    const models = getStaticModelsForProvider(provider);
+    assert.equal(models, undefined, `Should return undefined for non-static provider: ${provider}`);
+  }
+});
+
+test("getStaticModelsForProvider returns models for other static providers", () => {
+  // Verify other static providers still work
+  const staticProviders = ["deepgram", "assemblyai", "nanobanana", "perplexity"];
+
+  for (const provider of staticProviders) {
+    const models = getStaticModelsForProvider(provider);
+    assert.ok(models, `Should return models for static provider: ${provider}`);
+    assert.ok(models.length > 0, `Should return non-empty models for: ${provider}`);
+  }
+});
+
+test("getStaticModelsForProvider returns models matching registry for bailian-coding-plan", async () => {
+  const { REGISTRY } = await import("../../open-sse/config/providerRegistry.ts");
+
+  const models = getStaticModelsForProvider("bailian-coding-plan");
+  const registryEntry = REGISTRY["bailian-coding-plan"];
+
+  assert.ok(models, "Static models should be defined");
+  assert.ok(registryEntry, "Registry entry should exist");
+
+  const registryModels = registryEntry.models;
+
+  // Verify counts match
+  assert.equal(
+    models.length,
+    registryModels.length,
+    `Static model count (${models.length}) should match registry (${registryModels.length})`
+  );
+
+  // Verify all model IDs match
+  const staticIds = new Set(models.map((m) => m.id));
+  const registryIds = new Set(registryModels.map((m) => m.id));
+
+  assert.equal(staticIds.size, registryIds.size, "Should have same number of unique model IDs");
+
+  // Verify each model ID exists in both
+  for (const model of models) {
+    assert.ok(registryIds.has(model.id), `Registry should have model: ${model.id}`);
+  }
+});
+
+test("bailian-coding-plan static models have no duplicates", () => {
+  const models = getStaticModelsForProvider("bailian-coding-plan");
+
+  if (!models) {
+    assert.fail("Models should not be undefined");
+    return;
+  }
+
+  const ids = models.map((m) => m.id);
+  const uniqueIds = new Set(ids);
+
+  assert.equal(ids.length, uniqueIds.size, "All model IDs should be unique (no duplicates)");
+});
+
+test("bailian-coding-plan static models are complete and valid", () => {
+  const models = getStaticModelsForProvider("bailian-coding-plan");
+
+  if (!models) {
+    assert.fail("Models should not be undefined");
+    return;
+  }
+
+  // Verify array is not empty
+  assert.ok(models.length > 0, "Models array should not be empty");
+
+  // Verify no null/undefined entries
+  for (let i = 0; i < models.length; i++) {
+    assert.ok(models[i], `Model at index ${i} should not be null/undefined`);
+  }
+
+  // Verify no empty model IDs or names
+  for (const model of models) {
+    assert.ok(
+      model.id && model.id.trim().length > 0,
+      `Model ID should be non-empty: ${JSON.stringify(model)}`
+    );
+    assert.ok(
+      model.name && model.name.trim().length > 0,
+      `Model name should be non-empty: ${JSON.stringify(model)}`
+    );
+  }
+});
+
+// ============================================================================
+// SCENARIO C TESTS: validateProviderApiKey for bailian-coding-plan
+// These test the key validation outcomes with mocked fetch
+// ============================================================================
+
+test("validateProviderApiKey returns invalid for 401 response (bailian-coding-plan)", async () => {
+  const originalFetch = globalThis.fetch;
+
+  globalThis.fetch = async () =>
+    new Response(JSON.stringify({ error: "Unauthorized" }), {
+      status: 401,
+      headers: { "content-type": "application/json" },
+    });
+
+  try {
+    const result = await validateProviderApiKey({
+      provider: "bailian-coding-plan",
+      apiKey: "invalid-key",
+      providerSpecificData: {
+        baseUrl: "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1",
+      },
+    });
+
+    assert.equal(result.valid, false, "Should return invalid for 401");
+    assert.equal(result.error, "Invalid API key", "Error should be 'Invalid API key'");
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("validateProviderApiKey returns invalid for 403 response (bailian-coding-plan)", async () => {
+  const originalFetch = globalThis.fetch;
+
+  globalThis.fetch = async () =>
+    new Response(JSON.stringify({ error: "Forbidden" }), {
+      status: 403,
+      headers: { "content-type": "application/json" },
+    });
+
+  try {
+    const result = await validateProviderApiKey({
+      provider: "bailian-coding-plan",
+      apiKey: "forbidden-key",
+      providerSpecificData: {
+        baseUrl: "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1",
+      },
+    });
+
+    assert.equal(result.valid, false, "Should return invalid for 403");
+    assert.equal(result.error, "Invalid API key", "Error should be 'Invalid API key'");
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("validateProviderApiKey returns valid for 400 response (bailian-coding-plan)", async () => {
+  const originalFetch = globalThis.fetch;
+
+  // 400 means auth passed but request was malformed
+  // This is a valid auth path for bailian-coding-plan
+  globalThis.fetch = async () =>
+    new Response(JSON.stringify({ error: "invalid request" }), {
+      status: 400,
+      headers: { "content-type": "application/json" },
+    });
+
+  try {
+    const result = await validateProviderApiKey({
+      provider: "bailian-coding-plan",
+      apiKey: "valid-key",
+      providerSpecificData: {
+        baseUrl: "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1",
+      },
+    });
+
+    assert.equal(
+      result.valid,
+      true,
+      "Should return valid for 400 (auth passed, request malformed)"
+    );
+    assert.equal(result.error, null, "Error should be null for valid auth");
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("validateProviderApiKey returns valid for 200 response (bailian-coding-plan)", async () => {
+  const originalFetch = globalThis.fetch;
+
+  globalThis.fetch = async () =>
+    new Response(JSON.stringify({ model: "qwen3-coder-plus" }), {
+      status: 200,
+      headers: { "content-type": "application/json" },
+    });
+
+  try {
+    const result = await validateProviderApiKey({
+      provider: "bailian-coding-plan",
+      apiKey: "valid-key",
+      providerSpecificData: {
+        baseUrl: "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1",
+      },
+    });
+
+    assert.equal(result.valid, true, "Should return valid for 200");
+    assert.equal(result.error, null, "Error should be null for valid auth");
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("validateProviderApiKey returns invalid for 500 response (bailian-coding-plan)", async () => {
+  const originalFetch = globalThis.fetch;
+
+  globalThis.fetch = async () =>
+    new Response(JSON.stringify({ error: "upstream unavailable" }), {
+      status: 500,
+      headers: { "content-type": "application/json" },
+    });
+
+  try {
+    const result = await validateProviderApiKey({
+      provider: "bailian-coding-plan",
+      apiKey: "bad-key",
+      providerSpecificData: {
+        baseUrl: "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1",
+      },
+    });
+
+    assert.equal(result.valid, false, "Should return invalid for 500");
+    assert.equal(result.error, "Validation failed: 500");
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("validateProviderApiKey avoids double /messages suffix for bailian-coding-plan", async () => {
+  const originalFetch = globalThis.fetch;
+  const urls = [];
+
+  globalThis.fetch = async (url) => {
+    urls.push(String(url));
+    return new Response(JSON.stringify({ error: "invalid request" }), {
+      status: 400,
+      headers: { "content-type": "application/json" },
+    });
+  };
+
+  try {
+    const result = await validateProviderApiKey({
+      provider: "bailian-coding-plan",
+      apiKey: "valid-key",
+      providerSpecificData: {
+        baseUrl: "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1/messages",
+      },
+    });
+
+    assert.equal(result.valid, true);
+    assert.equal(urls.length, 1);
+    assert.equal(
+      urls[0],
+      "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1/messages",
+      "Should probe exactly one /messages suffix"
+    );
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+// ============================================================================
+// SCENARIO A TESTS: POST /api/providers create flow validation
+// These test that the schema (used by POST route) accepts valid bailian data
+// ============================================================================
+
+test("POST /api/providers validation: bailian-coding-plan with baseUrl passes schema", () => {
+  const validation = validateBody(createProviderSchema, {
+    provider: "bailian-coding-plan",
+    apiKey: "sk-placeholder-key",
+    name: "Test Bailian Provider",
+    providerSpecificData: {
+      baseUrl: "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1",
+    },
+  });
+
+  assert.equal(validation.success, true, "Schema should accept valid bailian-coding-plan payload");
+  if (validation.success) {
+    assert.equal(validation.data.provider, "bailian-coding-plan");
+    assert.equal(
+      validation.data.providerSpecificData?.baseUrl,
+      "https://coding-intl.dashscope.aliyuncs.com/apps/anthropic/v1"
+    );
+  }
+});
+
+test("POST /api/providers validation: bailian-coding-plan with custom baseUrl passes schema", () => {
+  const customUrl = "https://custom.dashscope.aliyuncs.com/apps/anthropic/v1";
+
+  const validation = validateBody(createProviderSchema, {
+    provider: "bailian-coding-plan",
+    apiKey: "sk-another-placeholder",
+    name: "Custom Bailian",
+    providerSpecificData: {
+      baseUrl: customUrl,
+    },
+  });
+
+  assert.equal(validation.success, true, "Schema should accept custom baseUrl");
+  if (validation.success) {
+    assert.equal(validation.data.providerSpecificData?.baseUrl, customUrl);
+  }
+});
+
+test("POST /api/providers validation rejects non-http(s) baseUrl", () => {
+  const validation = validateBody(createProviderSchema, {
+    provider: "bailian-coding-plan",
+    apiKey: "sk-placeholder-key",
+    name: "Bad URL Scheme",
+    providerSpecificData: {
+      baseUrl: "ftp://example.com/v1",
+    },
+  });
+
+  assert.equal(validation.success, false, "Schema should reject non-http(s) URL schemes");
+});
+
+// ============================================================================
+// SCENARIO B TESTS: PUT /api/providers/{id} update flow validation
+// These test that the schema (used by PUT route) accepts valid baseUrl updates
+// ============================================================================
+
+test("PUT /api/providers/{id} validation: updating baseUrl passes schema", () => {
+  const validation = validateBody(updateProviderConnectionSchema, {
+    providerSpecificData: {
+      baseUrl: "https://updated.dashscope.aliyuncs.com/apps/anthropic/v1",
+    },
+  });
+
+  assert.equal(validation.success, true, "Schema should accept baseUrl update");
+  if (validation.success) {
+    assert.equal(
+      validation.data.providerSpecificData?.baseUrl,
+      "https://updated.dashscope.aliyuncs.com/apps/anthropic/v1"
+    );
+  }
+});
+
+test("PUT /api/providers/{id} validation: baseUrl update with other fields passes schema", () => {
+  const validation = validateBody(updateProviderConnectionSchema, {
+    name: "Updated Bailian Name",
+    priority: 5,
+    providerSpecificData: {
+      baseUrl: "https://new-url.example.com/v1",
+    },
+  });
+
+  assert.equal(
+    validation.success,
+    true,
+    "Schema should accept update with baseUrl and other fields"
+  );
+  if (validation.success) {
+    assert.equal(validation.data.name, "Updated Bailian Name");
+    assert.equal(validation.data.priority, 5);
+    assert.equal(validation.data.providerSpecificData?.baseUrl, "https://new-url.example.com/v1");
+  }
+});
+
+test("PUT /api/providers/{id} validation rejects non-http(s) baseUrl", () => {
+  const validation = validateBody(updateProviderConnectionSchema, {
+    providerSpecificData: {
+      baseUrl: "file:///etc/passwd",
+    },
+  });
+
+  assert.equal(validation.success, false, "Schema should reject non-http(s) URL schemes");
+});
diff --git a/tests/unit/search-provider-validation.test.mjs b/tests/unit/search-provider-validation.test.mjs
index 26ed3e97..453c4635 100644
--- a/tests/unit/search-provider-validation.test.mjs
+++ b/tests/unit/search-provider-validation.test.mjs
@@ -89,3 +89,69 @@ test("kimi-coding-apikey validation uses Kimi Coding messages endpoint", async (
     globalThis.fetch = originalFetch;
   }
 });
+
+test("bailian-coding-plan validation accepts 400 as valid auth path", async () => {
+  const originalFetch = globalThis.fetch;
+
+  globalThis.fetch = async () =>
+    new Response(JSON.stringify({ error: "invalid request" }), {
+      status: 400,
+      headers: { "content-type": "application/json" },
+    });
+
+  try {
+    const result = await validateProviderApiKey({
+      provider: "bailian-coding-plan",
+      apiKey: "valid-bailian-key",
+    });
+
+    assert.equal(result.valid, true);
+    assert.equal(result.error, null);
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("bailian-coding-plan validation rejects 401 as invalid key", async () => {
+  const originalFetch = globalThis.fetch;
+
+  globalThis.fetch = async () =>
+    new Response(JSON.stringify({ error: "Unauthorized" }), {
+      status: 401,
+      headers: { "content-type": "application/json" },
+    });
+
+  try {
+    const result = await validateProviderApiKey({
+      provider: "bailian-coding-plan",
+      apiKey: "bad-bailian-key",
+    });
+
+    assert.equal(result.valid, false);
+    assert.equal(result.error, "Invalid API key");
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test("bailian-coding-plan validation rejects 403 as invalid key", async () => {
+  const originalFetch = globalThis.fetch;
+
+  globalThis.fetch = async () =>
+    new Response(JSON.stringify({ error: "Forbidden" }), {
+      status: 403,
+      headers: { "content-type": "application/json" },
+    });
+
+  try {
+    const result = await validateProviderApiKey({
+      provider: "bailian-coding-plan",
+      apiKey: "bad-bailian-key",
+    });
+
+    assert.equal(result.valid, false);
+    assert.equal(result.error, "Invalid API key");
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});