diff --git a/open-sse/executors/opencode.js b/open-sse/executors/opencode.js
index 531c5df5..507c3718 100644
--- a/open-sse/executors/opencode.js
+++ b/open-sse/executors/opencode.js
@@ -24,6 +24,68 @@ export const OPENCODE_SESSION_RE = /^ses_[0-9a-f]{12}[0-9A-Za-z]{14}$/;
 export const OPENCODE_REQUEST_RE = /^msg_[0-9a-f]{12}[0-9A-Za-z]{14}$/;
 const BASE62_CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 
+// OpenCode free tier requires both 'bash' and 'read' in tools payload.
+// Injected as cloaked decoy tools so external CLI tools (e.g. Claude Code's Bash/Read)
+// take precedence while satisfying upstream verification.
+const OPENCODE_DECOY_CHAT_TOOLS = [
+  {
+    type: "function",
+    function: {
+      name: "bash",
+      description: "This tool is currently unavailable and must not be used.",
+      parameters: { type: "object", properties: {} },
+    },
+  },
+  {
+    type: "function",
+    function: {
+      name: "read",
+      description: "This tool is currently unavailable and must not be used.",
+      parameters: { type: "object", properties: {} },
+    },
+  },
+];
+
+const OPENCODE_DECOY_RESPONSES_TOOLS = [
+  {
+    type: "function",
+    name: "bash",
+    description: "This tool is currently unavailable and must not be used.",
+    parameters: { type: "object", properties: {} },
+  },
+  {
+    type: "function",
+    name: "read",
+    description: "This tool is currently unavailable and must not be used.",
+    parameters: { type: "object", properties: {} },
+  },
+];
+
+function cloakOpencodeTools(body, isResponses) {
+  if (!body || typeof body !== "object") return;
+  if (isResponses) {
+    if (!Array.isArray(body.tools)) body.tools = [];
+    const names = new Set(body.tools.map((t) => t.name || t.function?.name));
+    for (const tool of OPENCODE_DECOY_RESPONSES_TOOLS) {
+      if (!names.has(tool.name)) body.tools.push({ ...tool });
+    }
+    if (!body.tool_choice) body.tool_choice = "auto";
+  } else {
+    const hasTools = Array.isArray(body.tools) && body.tools.length > 0;
+    if (!hasTools) {
+      body.tools = OPENCODE_DECOY_CHAT_TOOLS.map((t) => ({ ...t, function: { ...t.function } }));
+      if (!body.tool_choice) body.tool_choice = "none";
+    } else {
+      const names = new Set(body.tools.map((t) => t.function?.name || t.name));
+      for (const tool of OPENCODE_DECOY_CHAT_TOOLS) {
+        if (!names.has(tool.function.name)) {
+          body.tools.push({ ...tool, function: { ...tool.function } });
+        }
+      }
+    }
+  }
+}
+
 function hasValidOpencodeVersion(ua) {
   const m = String(ua || "").match(/opencode\/(\d+)\.(\d+)(?:\.(\d+))?/i);
   if (!m) return false;
@@ -410,6 +472,9 @@ export class OpenCodeExecutor extends BaseExecutor {
 
   transformRequest(model, body, stream, credentials) {
     if (body && typeof body === "object" && model && !body.model) body.model = model;
+    // Zen rejects non-streaming requests on free models with 403 FreeTierError;
+    // always stream upstream and let the handler layer aggregate for non-stream clients.
+    if (body && typeof body === "object") body.stream = true;
     if (isResponsesModel(model || body?.model) && body && typeof body === "object") {
       // ponytail: chỉ model đã xác nhận auto-only; mở allowlist khi có bằng chứng.
       if ("tool_choice" in body && body.tool_choice !== "auto"
@@ -434,6 +499,11 @@ export class OpenCodeExecutor extends BaseExecutor {
       body.store = false;
       normalizeResponsesTools(body);
       sanitizeResponsesItems(body);
+      if (!Array.isArray(body.tools) || body.tools.length === 0) {
+        cloakOpencodeTools(body, true);
+      }
+    } else if (body && typeof body === "object") {
+      cloakOpencodeTools(body, false);
     }
     return injectReasoningContent({ provider: this.provider, model, body });
   }
diff --git a/src/app/(dashboard)/dashboard/providers/[id]/page.js b/src/app/(dashboard)/dashboard/providers/[id]/page.js
index 437214e2..bae6ff05 100644
--- a/src/app/(dashboard)/dashboard/providers/[id]/page.js
+++ b/src/app/(dashboard)/dashboard/providers/[id]/page.js
@@ -1783,7 +1783,33 @@ export default function ProviderDetailPage() {
           })()}
         </div>
         {!!modelsTestError && (
-          <p className="text-xs text-red-500 mb-3 break-words">{modelsTestError}</p>
+          <div className="mb-3">
+            <p className="text-xs text-red-500 break-words">{modelsTestError}</p>
+            {/RegionError|hosted in China|regionNotAllowed/i.test(modelsTestError) && (() => {
+              const str = typeof modelsTestError === "string" ? modelsTestError : JSON.stringify(modelsTestError);
+              const linkMatch = str.match(/https:\/\/opencode\.ai\/workspace\/[^\s"')]+/);
+              const wrkMatch = str.match(/wrk_[0-9A-Za-z]+/);
+              const targetUrl = linkMatch
+                ? (linkMatch[0].endsWith("/go") ? linkMatch[0] : `${linkMatch[0]}/go`)
+                : wrkMatch
+                  ? `https://opencode.ai/workspace/${wrkMatch[0]}/go`
+                  : "https://opencode.ai";
+
+              return (
+                <div className="mt-1.5">
+                  <a
+                    href={targetUrl}
+                    target="_blank"
+                    rel="noreferrer"
+                    className="inline-flex items-center gap-1 rounded-md bg-amber-500/10 px-2 py-0.5 text-xs font-medium text-amber-600 hover:bg-amber-500/20 dark:text-amber-400 transition-colors"
+                  >
+                    <span>Allow China-hosted models</span>
+                    <span className="material-symbols-outlined text-[13px]">open_in_new</span>
+                  </a>
+                </div>
+              );
+            })()}
+          </div>
         )}
         {providerId === "zed" && !!liveModelsError && (
           <p className="text-xs text-red-500 mb-3 break-words">{liveModelsError}</p>
diff --git a/src/app/api/models/test/ping.js b/src/app/api/models/test/ping.js
index 273aff47..a5c882d5 100644
--- a/src/app/api/models/test/ping.js
+++ b/src/app/api/models/test/ping.js
@@ -160,7 +160,7 @@ export async function pingModelByKind(model, kind, baseUrl = `http://127.0.0.1:$
 
   if (!res.ok) {
     const detail = parsed?.error?.message || parsed?.msg || parsed?.message || parsed?.error || rawText;
-    return { ok: false, latencyMs, error: `HTTP ${res.status}${detail ? `: ${String(detail).slice(0, 240)}` : ""}`, status: res.status };
+    return { ok: false, latencyMs, error: `HTTP ${res.status}${detail ? `: ${String(detail).slice(0, 500)}` : ""}`, status: res.status };
   }
 
   const providerStatus = parsed?.status;
diff --git a/src/app/api/providers/[id]/test/testUtils.js b/src/app/api/providers/[id]/test/testUtils.js
index 9572e69e..03500da2 100644
--- a/src/app/api/providers/[id]/test/testUtils.js
+++ b/src/app/api/providers/[id]/test/testUtils.js
@@ -751,6 +751,12 @@ async function testApiKeyConnection(connection, effectiveProxy = null) {
         const valid = !!(data && data.user);
         return { valid, error: valid ? null : "Session expired — re-paste cookie" };
       }
+      case "opencode": {
+        const res = await fetchWithConnectionProxy("https://opencode.ai/zen/v1/models", {
+          headers: { Authorization: "Bearer public", "User-Agent": "opencode/1.18.31" },
+        }, effectiveProxy);
+        return { valid: res.ok, error: res.ok ? null : "OpenCode free tier unavailable" };
+      }
       case "opencode-go": {
         const res = await fetchWithConnectionProxy("https://opencode.ai/zen/go/v1/chat/completions", {
           method: "POST",
diff --git a/src/sse/services/auth.js b/src/sse/services/auth.js
index d85c4901..eff83e7c 100644
--- a/src/sse/services/auth.js
+++ b/src/sse/services/auth.js
@@ -263,7 +263,7 @@ export async function markAccountUnavailable(connectionId, status, errorText, pr
   }
   if (!shouldFallback) return { shouldFallback: false, cooldownMs: 0 };
 
-  const reason = typeof errorText === "string" ? errorText.slice(0, 100) : "Provider error";
+  const reason = typeof errorText === "string" ? errorText.slice(0, 200) : "Provider error";
   const lockUpdate = buildModelLockUpdate(githubResetAtMs ? null : model, cooldownMs);
 
   await updateProviderConnection(connectionId, {
diff --git a/tests/unit/opencode-session.test.js b/tests/unit/opencode-session.test.js
index b7651f16..89e06a8f 100644
--- a/tests/unit/opencode-session.test.js
+++ b/tests/unit/opencode-session.test.js
@@ -276,4 +276,39 @@ describe("OpenCode Stable Session Reuse (429 follow-up)", () => {
     expect(first).toMatch(OPENCODE_SESSION_RE);
     expect(second).toBe(first);
   });
+
+  it("cloaks free-tier requests with bash and read decoy tools", () => {
+    const executor = getExecutor("opencode");
+
+    // Case 1: no tools sent by client -> injects bash + read with tool_choice none
+    const chatNoTools = executor.transformRequest("nemotron-3-ultra-free", {
+      messages: [{ role: "user", content: "hi" }],
+    });
+    expect(chatNoTools.stream).toBe(true);
+    expect(chatNoTools.tool_choice).toBe("none");
+    expect(chatNoTools.tools.map((t) => t.function?.name)).toEqual(["bash", "read"]);
+
+    // Case 2: external CLI tools (e.g. Claude Code Bash) -> preserves Bash, appends read
+    const chatWithTools = executor.transformRequest("nemotron-3-ultra-free", {
+      messages: [{ role: "user", content: "hi" }],
+      tools: [{ type: "function", function: { name: "Bash", description: "Claude Code tool" } }],
+      tool_choice: "auto",
+    });
+    expect(chatWithTools.tool_choice).toBe("auto");
+    const names = chatWithTools.tools.map((t) => t.function?.name);
+    expect(names).toContain("Bash");
+    expect(names).toContain("bash");
+    expect(names).toContain("read");
+
+    // Case 3: already has both bash and read -> do not insert anything
+    const chatFull = executor.transformRequest("nemotron-3-ultra-free", {
+      messages: [{ role: "user", content: "hi" }],
+      tools: [
+        { type: "function", function: { name: "bash", description: "existing" } },
+        { type: "function", function: { name: "read", description: "existing" } },
+      ],
+    });
+    expect(chatFull.tools.length).toBe(2);
+    expect(chatFull.tools[0].function.description).toBe("existing");
+  });
 });