diff --git a/Cargo.lock b/Cargo.lock
index 8e40b59..f9e01e9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -154,8 +154,13 @@ checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
 name = "cube"
 version = "0.1.0"
 dependencies = [
+ "axum",
  "cube-core",
+ "reqwest",
+ "serde",
+ "serde_json",
  "tokio",
+ "tracing",
 ]
 
 [[package]]
diff --git a/apps/cube/Cargo.toml b/apps/cube/Cargo.toml
index 7d772a8..8395de3 100644
--- a/apps/cube/Cargo.toml
+++ b/apps/cube/Cargo.toml
@@ -8,4 +8,9 @@ description = "cube.famzheng.me — cube 平台入口门户（app #0）"
 
 [dependencies]
 cube-core = { path = "../../crates/cube-core" }
+axum = { workspace = true }
 tokio = { workspace = true }
+tracing = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }
+reqwest = { workspace = true }
diff --git a/apps/cube/frontend/src/App.vue b/apps/cube/frontend/src/App.vue
index 0481a02..817bda6 100644
--- a/apps/cube/frontend/src/App.vue
+++ b/apps/cube/frontend/src/App.vue
@@ -1,5 +1,6 @@
 <script setup lang="ts">
 import AppCard from './components/AppCard.vue'
+import Chatbot from './components/Chatbot.vue'
 import { apps } from './apps'
 </script>
 
@@ -33,6 +34,8 @@ import { apps } from './apps'
       <span>cube · monorepo at</span>
       <a href="https://famzheng.me/gitea/fam/cube" target="_blank" rel="noopener">famzheng.me/gitea/fam/cube</a>
     </footer>
+
+    <Chatbot />
   </main>
 </template>
 
diff --git a/apps/cube/frontend/src/components/Chatbot.vue b/apps/cube/frontend/src/components/Chatbot.vue
new file mode 100644
index 0000000..fa0091a
--- /dev/null
+++ b/apps/cube/frontend/src/components/Chatbot.vue
@@ -0,0 +1,292 @@
+<script setup lang="ts">
+import { computed, nextTick, ref, watch } from 'vue'
+
+interface Msg {
+  role: 'user' | 'assistant'
+  content: string
+  issue?: { number: number; url: string; title: string }
+}
+
+const open = ref(false)
+const messages = ref<Msg[]>([])
+const input = ref('')
+const busy = ref(false)
+const error = ref<string | null>(null)
+const scrollEl = ref<HTMLElement | null>(null)
+
+const canSend = computed(() => !busy.value && input.value.trim().length > 0)
+
+watch(messages, async () => {
+  await nextTick()
+  scrollEl.value?.scrollTo({ top: scrollEl.value.scrollHeight, behavior: 'smooth' })
+}, { deep: true })
+
+async function send() {
+  if (!canSend.value) return
+  const text = input.value.trim()
+  input.value = ''
+  error.value = null
+  messages.value.push({ role: 'user', content: text })
+  busy.value = true
+  try {
+    const payload = {
+      messages: messages.value.map((m) => ({ role: m.role, content: m.content })),
+    }
+    const res = await fetch('/api/chat', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(payload),
+    })
+    if (!res.ok) {
+      const body = await res.text()
+      throw new Error(body || `HTTP ${res.status}`)
+    }
+    const data = (await res.json()) as {
+      reply: string
+      created_issue: { number: number; url: string; title: string } | null
+    }
+    messages.value.push({
+      role: 'assistant',
+      content: data.reply,
+      issue: data.created_issue ?? undefined,
+    })
+  } catch (e) {
+    const msg = (e as Error).message
+    error.value = msg
+    messages.value.push({ role: 'assistant', content: `（出错了：${msg}）` })
+  } finally {
+    busy.value = false
+  }
+}
+
+function onKeydown(e: KeyboardEvent) {
+  if (e.key === 'Enter' && !e.shiftKey) {
+    e.preventDefault()
+    send()
+  }
+}
+
+function reset() {
+  messages.value = []
+  error.value = null
+}
+</script>
+
+<template>
+  <button v-if="!open" class="fab" @click="open = true" aria-label="打开聊天">
+    <svg viewBox="0 0 24 24" width="22" height="22" fill="none" stroke="currentColor" stroke-width="2.4" stroke-linecap="round" stroke-linejoin="round">
+      <path d="M21 11.5a8.38 8.38 0 0 1-.9 3.8 8.5 8.5 0 0 1-7.6 4.7 8.38 8.38 0 0 1-3.8-.9L3 21l1.9-5.7a8.38 8.38 0 0 1-.9-3.8 8.5 8.5 0 0 1 4.7-7.6 8.38 8.38 0 0 1 3.8-.9h.5a8.48 8.48 0 0 1 8 8z" />
+    </svg>
+    <span>反馈 / 提问</span>
+  </button>
+
+  <div v-else class="panel">
+    <header>
+      <div class="title">
+        <span class="dot" />
+        <strong>cube · chat</strong>
+      </div>
+      <div class="actions">
+        <button class="icon" @click="reset" title="清空对话">↺</button>
+        <button class="icon" @click="open = false" title="收起">✕</button>
+      </div>
+    </header>
+
+    <div class="thread" ref="scrollEl">
+      <div v-if="messages.length === 0" class="hint">
+        <p>问 cube 平台的事，或反馈 bug / 想法 — 我会帮你提到 <code>fam/cube</code> issue。</p>
+      </div>
+
+      <div v-for="(m, i) in messages" :key="i" :class="['bubble', m.role]">
+        <div class="content">{{ m.content }}</div>
+        <a v-if="m.issue" :href="m.issue.url" target="_blank" rel="noopener" class="issue-link">
+          已建 issue #{{ m.issue.number }} →
+        </a>
+      </div>
+
+      <div v-if="busy" class="bubble assistant typing">
+        <span /><span /><span />
+      </div>
+    </div>
+
+    <footer>
+      <textarea
+        v-model="input"
+        :disabled="busy"
+        @keydown="onKeydown"
+        rows="2"
+        placeholder="说点什么...（Enter 发送，Shift+Enter 换行）"
+      />
+      <button class="send" :disabled="!canSend" @click="send">发送</button>
+    </footer>
+  </div>
+</template>
+
+<style scoped>
+.fab {
+  position: fixed;
+  right: 20px;
+  bottom: 20px;
+  z-index: 1000;
+  background: linear-gradient(135deg, #7c3aed, #06b6d4);
+  color: white;
+  border: none;
+  padding: 12px 18px;
+  border-radius: 999px;
+  font-size: 0.95rem;
+  font-weight: 600;
+  cursor: pointer;
+  display: inline-flex;
+  align-items: center;
+  gap: 8px;
+  box-shadow: 0 8px 24px rgba(124, 58, 237, 0.35);
+  transition: transform 0.15s, box-shadow 0.15s;
+}
+.fab:hover { transform: translateY(-2px); box-shadow: 0 12px 28px rgba(124, 58, 237, 0.45); }
+
+.panel {
+  position: fixed;
+  right: 20px;
+  bottom: 20px;
+  z-index: 1000;
+  width: min(380px, calc(100vw - 32px));
+  height: min(560px, calc(100vh - 40px));
+  background: var(--bg-soft, rgba(20, 20, 30, 0.95));
+  backdrop-filter: blur(12px);
+  border: 1px solid var(--border, rgba(255, 255, 255, 0.15));
+  border-radius: 14px;
+  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.55);
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+  color: var(--fg, rgba(255, 255, 255, 0.92));
+}
+
+header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 10px 14px;
+  border-bottom: 1px solid var(--border, rgba(255, 255, 255, 0.15));
+}
+.title { display: flex; align-items: center; gap: 8px; }
+.dot {
+  width: 9px;
+  height: 9px;
+  border-radius: 50%;
+  background: #4ade80;
+  box-shadow: 0 0 8px rgba(74, 222, 128, 0.7);
+}
+.actions { display: flex; gap: 4px; }
+.icon {
+  width: 28px;
+  height: 28px;
+  background: transparent;
+  border: 1px solid var(--border, rgba(255, 255, 255, 0.15));
+  color: inherit;
+  border-radius: 6px;
+  cursor: pointer;
+  font-size: 0.9rem;
+}
+.icon:hover { background: rgba(255, 255, 255, 0.06); }
+
+.thread {
+  flex: 1;
+  overflow-y: auto;
+  padding: 14px;
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+}
+.hint { color: var(--fg-dim, rgba(255, 255, 255, 0.6)); font-size: 0.9rem; }
+.hint code {
+  background: rgba(255, 255, 255, 0.08);
+  padding: 1px 5px;
+  border-radius: 4px;
+  font-size: 0.85em;
+}
+
+.bubble {
+  max-width: 85%;
+  padding: 10px 13px;
+  border-radius: 12px;
+  line-height: 1.4;
+  font-size: 0.92rem;
+  white-space: pre-wrap;
+  word-wrap: break-word;
+}
+.bubble.user {
+  align-self: flex-end;
+  background: linear-gradient(135deg, #7c3aed, #4f46e5);
+  color: white;
+}
+.bubble.assistant {
+  align-self: flex-start;
+  background: rgba(255, 255, 255, 0.08);
+  border: 1px solid var(--border, rgba(255, 255, 255, 0.15));
+}
+.issue-link {
+  display: inline-block;
+  margin-top: 8px;
+  color: #4ea7f7;
+  font-size: 0.85rem;
+  text-decoration: none;
+  border-top: 1px dashed rgba(255, 255, 255, 0.15);
+  padding-top: 8px;
+}
+.issue-link:hover { color: #80c2ff; }
+
+.bubble.typing {
+  display: inline-flex;
+  gap: 4px;
+  padding: 12px 14px;
+}
+.bubble.typing span {
+  width: 6px;
+  height: 6px;
+  border-radius: 50%;
+  background: rgba(255, 255, 255, 0.45);
+  animation: bounce 1.2s ease-in-out infinite;
+}
+.bubble.typing span:nth-child(2) { animation-delay: 0.15s; }
+.bubble.typing span:nth-child(3) { animation-delay: 0.3s; }
+@keyframes bounce {
+  0%, 60%, 100% { transform: translateY(0); opacity: 0.45; }
+  30%           { transform: translateY(-5px); opacity: 1; }
+}
+
+footer {
+  padding: 10px 12px 12px;
+  border-top: 1px solid var(--border, rgba(255, 255, 255, 0.15));
+  display: flex;
+  gap: 8px;
+  align-items: flex-end;
+}
+textarea {
+  flex: 1;
+  resize: none;
+  background: rgba(255, 255, 255, 0.06);
+  border: 1px solid var(--border, rgba(255, 255, 255, 0.15));
+  border-radius: 8px;
+  padding: 8px 10px;
+  font-family: inherit;
+  font-size: 0.92rem;
+  color: inherit;
+  line-height: 1.4;
+}
+textarea:focus { outline: 2px solid #7c3aed; outline-offset: -1px; }
+.send {
+  background: linear-gradient(135deg, #7c3aed, #06b6d4);
+  color: white;
+  border: none;
+  padding: 10px 16px;
+  border-radius: 8px;
+  font-weight: 600;
+  cursor: pointer;
+}
+.send:disabled { background: rgba(255, 255, 255, 0.1); color: rgba(255, 255, 255, 0.4); cursor: not-allowed; }
+
+@media (max-width: 420px) {
+  .panel { right: 12px; bottom: 12px; width: calc(100vw - 24px); height: calc(100vh - 24px); }
+}
+</style>
diff --git a/apps/cube/frontend/tsconfig.tsbuildinfo b/apps/cube/frontend/tsconfig.tsbuildinfo
deleted file mode 100644
index 6c1949f..0000000
--- a/apps/cube/frontend/tsconfig.tsbuildinfo
+++ /dev/null
@@ -1 +0,0 @@
-{"root":["./src/apps.ts","./src/main.ts","./src/App.vue","./src/components/AppCard.vue","./vite-env.d.ts"],"version":"5.7.3"}
\ No newline at end of file
diff --git a/apps/cube/k8s/all.yaml b/apps/cube/k8s/all.yaml
index 4fcc49c..2cb907c 100644
--- a/apps/cube/k8s/all.yaml
+++ b/apps/cube/k8s/all.yaml
@@ -30,6 +30,20 @@ spec:
           ports:
             - containerPort: 8080
               name: http
+          envFrom:
+            # secret `chat-credentials` (LLM_API_TOKEN + GITEA_TOKEN) 由 kubectl 手工创建，
+            # 不在 git manifest 里。kubectl apply -f all.yaml 不会动它。
+            - secretRef:
+                name: chat-credentials
+          env:
+            - name: LLM_GATEWAY
+              value: "http://3.135.65.204:8848/v1"
+            - name: LLM_MODEL
+              value: "gemma-4-31b-it"
+            - name: GITEA_URL
+              value: "https://famzheng.me/gitea"
+            - name: ISSUE_REPO
+              value: "fam/cube"
           readinessProbe:
             httpGet:
               path: /healthz
@@ -48,7 +62,7 @@ spec:
               memory: 16Mi
             limits:
               cpu: 200m
-              memory: 64Mi
+              memory: 128Mi
 ---
 apiVersion: v1
 kind: Service
diff --git a/apps/cube/src/chat.rs b/apps/cube/src/chat.rs
new file mode 100644
index 0000000..086c12e
--- /dev/null
+++ b/apps/cube/src/chat.rs
@@ -0,0 +1,381 @@
+//! `/api/chat` — 浏览器 ↔ LLM gateway 中转 + `create_issue` 工具调用。
+//!
+//! 单步 tool calling：拿到用户消息 → 调一次 LLM with tools → 如果 LLM 决定调
+//! `create_issue` 就同步建 issue，把结果（issue 编号 + URL）当作 reply 返回给前端。
+//! 不做 agent loop，不递归把工具结果喂回 LLM（重新调一次是浪费，issue 已经建好，
+//! 直接告诉用户就行）。
+
+use std::sync::Arc;
+
+use axum::{extract::State, http::StatusCode, response::IntoResponse, Json};
+use serde::{Deserialize, Serialize};
+use serde_json::{json, Value};
+
+#[derive(Clone)]
+pub struct Config {
+    pub gateway: String,    // http://3.135.65.204:8848/v1
+    pub llm_token: String,  // Bearer for LLM gateway
+    pub llm_model: String,  // gemma-4-31b-it
+    pub gitea_url: String,  // https://famzheng.me/gitea
+    pub gitea_token: String,
+    pub issue_repo: String, // fam/cube
+}
+
+impl Config {
+    pub fn from_env() -> Self {
+        Self {
+            gateway: env_or("LLM_GATEWAY", "http://3.135.65.204:8848/v1"),
+            llm_token: env_or("LLM_API_TOKEN", ""),
+            llm_model: env_or("LLM_MODEL", "gemma-4-31b-it"),
+            gitea_url: env_or("GITEA_URL", "https://famzheng.me/gitea"),
+            gitea_token: env_or("GITEA_TOKEN", ""),
+            issue_repo: env_or("ISSUE_REPO", "fam/cube"),
+        }
+    }
+}
+
+fn env_or(key: &str, fallback: &str) -> String {
+    std::env::var(key).unwrap_or_else(|_| fallback.to_string())
+}
+
+#[derive(Deserialize, Serialize, Clone, Debug)]
+pub struct ChatMessage {
+    pub role: String, // "user" | "assistant" | "system" | "tool"
+    pub content: String,
+}
+
+#[derive(Deserialize)]
+pub struct ChatRequest {
+    pub messages: Vec<ChatMessage>,
+}
+
+#[derive(Serialize)]
+pub struct CreatedIssue {
+    pub number: u64,
+    pub url: String,
+    pub title: String,
+}
+
+#[derive(Serialize)]
+pub struct ChatResponse {
+    pub reply: String,
+    pub created_issue: Option<CreatedIssue>,
+}
+
+pub enum ChatError {
+    UpstreamLlm(String),
+    UpstreamGitea(String),
+    Empty,
+}
+
+impl IntoResponse for ChatError {
+    fn into_response(self) -> axum::response::Response {
+        match self {
+            Self::UpstreamLlm(msg) => {
+                tracing::error!(%msg, "llm upstream failed");
+                (StatusCode::BAD_GATEWAY, format!("LLM upstream error: {msg}")).into_response()
+            }
+            Self::UpstreamGitea(msg) => {
+                tracing::error!(%msg, "gitea upstream failed");
+                (StatusCode::BAD_GATEWAY, format!("Gitea upstream error: {msg}")).into_response()
+            }
+            Self::Empty => (StatusCode::BAD_REQUEST, "messages 不能为空").into_response(),
+        }
+    }
+}
+
+pub fn system_prompt(repo: &str) -> String {
+    format!(
+        "你是 cube 平台（cube.famzheng.me，Fam 的小 app 平台）入口页上的聊天助手。\n\
+         你可以做两件事：\n\
+         1. 回答用户关于 cube 上各个 app（werewolf / articulate / karaoke / music / simpleasm 等）的问题，简短直接\n\
+         2. 当用户表达 bug / feature request / feedback / 想反馈给 Fam 时，调用 `create_issue` 工具，\n\
+            把它整理成 issue 创建到 `{repo}`。标题要简洁明确（不超过 60 个字符），body 要包含足够上下文\n\
+            （重现步骤、期望行为、用户原话等）。\n\
+         \n\
+         不要主动鼓励用户提 issue —— 只在他明确表达想反馈时才创建。\n\
+         同一次对话只创建一个 issue。Reply 要简短，不写长段散文。",
+    )
+}
+
+pub fn create_issue_tool_schema() -> Value {
+    json!({
+        "type": "function",
+        "function": {
+            "name": "create_issue",
+            "description": "在 fam/cube 仓库创建一个 issue，用于收集用户反馈、bug 报告或 feature request",
+            "parameters": {
+                "type": "object",
+                "properties": {
+                    "title": {
+                        "type": "string",
+                        "description": "Issue 标题，简洁明确，不超过 60 个字符"
+                    },
+                    "body": {
+                        "type": "string",
+                        "description": "Issue 正文 Markdown，包含重现步骤 / 期望行为 / 用户原话等上下文"
+                    }
+                },
+                "required": ["title", "body"]
+            }
+        }
+    })
+}
+
+pub async fn handle(
+    State(cfg): State<Arc<Config>>,
+    Json(req): Json<ChatRequest>,
+) -> Result<Json<ChatResponse>, ChatError> {
+    if req.messages.is_empty() {
+        return Err(ChatError::Empty);
+    }
+
+    // 拼 messages：注入 system + 用户历史
+    let mut messages: Vec<Value> = vec![json!({
+        "role": "system",
+        "content": system_prompt(&cfg.issue_repo),
+    })];
+    for m in &req.messages {
+        messages.push(json!({ "role": m.role, "content": m.content }));
+    }
+
+    let body = json!({
+        "model": cfg.llm_model,
+        "messages": messages,
+        "tools": [create_issue_tool_schema()],
+        "tool_choice": "auto",
+        "stream": false,
+        "temperature": 0.6,
+    });
+
+    let endpoint = format!("{}/chat/completions", cfg.gateway.trim_end_matches('/'));
+    let client = reqwest::Client::new();
+    let resp = client
+        .post(&endpoint)
+        .bearer_auth(&cfg.llm_token)
+        .json(&body)
+        .send()
+        .await
+        .map_err(|e| ChatError::UpstreamLlm(e.to_string()))?;
+
+    let status = resp.status();
+    let bytes = resp
+        .bytes()
+        .await
+        .map_err(|e| ChatError::UpstreamLlm(e.to_string()))?;
+    if !status.is_success() {
+        let body = String::from_utf8_lossy(&bytes);
+        return Err(ChatError::UpstreamLlm(format!("{status}: {body}")));
+    }
+    let v: Value = serde_json::from_slice(&bytes)
+        .map_err(|e| ChatError::UpstreamLlm(format!("invalid json: {e}")))?;
+
+    let choice = v
+        .pointer("/choices/0/message")
+        .ok_or_else(|| ChatError::UpstreamLlm("no choices/0/message".into()))?;
+
+    // 拿 tool_calls 数组；如果有 create_issue 调用就执行，否则返回 content
+    if let Some(tool_call) = first_create_issue_call(choice) {
+        let (title, body_md) = extract_issue_args(&tool_call).map_err(ChatError::UpstreamLlm)?;
+        let created = create_gitea_issue(&cfg, &title, &body_md).await?;
+        let llm_text = choice
+            .get("content")
+            .and_then(Value::as_str)
+            .unwrap_or("")
+            .trim();
+        let reply = if llm_text.is_empty() {
+            format!("已记下 → issue #{}: {}", created.number, created.title)
+        } else {
+            format!("{llm_text}\n\n→ issue #{}: {}", created.number, created.title)
+        };
+        return Ok(Json(ChatResponse {
+            reply,
+            created_issue: Some(created),
+        }));
+    }
+
+    // 没工具调用 — 普通回复
+    let text = choice
+        .get("content")
+        .and_then(Value::as_str)
+        .unwrap_or("")
+        .trim()
+        .to_string();
+    Ok(Json(ChatResponse {
+        reply: if text.is_empty() {
+            "嗯？没听清，再说一遍？".to_string()
+        } else {
+            text
+        },
+        created_issue: None,
+    }))
+}
+
+/// 从 LLM 返回的 message 里挑第一个 `create_issue` tool_call。
+pub fn first_create_issue_call(message: &Value) -> Option<Value> {
+    let arr = message.get("tool_calls")?.as_array()?;
+    arr.iter()
+        .find(|tc| {
+            tc.pointer("/function/name").and_then(Value::as_str) == Some("create_issue")
+        })
+        .cloned()
+}
+
+/// arguments 是 JSON 字符串（OpenAI 协议），需要二次解析。
+pub fn extract_issue_args(tool_call: &Value) -> Result<(String, String), String> {
+    let args_raw = tool_call
+        .pointer("/function/arguments")
+        .and_then(Value::as_str)
+        .ok_or_else(|| "tool_call 缺少 arguments".to_string())?;
+    let args: Value = serde_json::from_str(args_raw)
+        .map_err(|e| format!("arguments 不是合法 JSON: {e}"))?;
+    let title = args
+        .get("title")
+        .and_then(Value::as_str)
+        .ok_or_else(|| "tool 调用缺少 title".to_string())?
+        .trim()
+        .to_string();
+    let body = args
+        .get("body")
+        .and_then(Value::as_str)
+        .ok_or_else(|| "tool 调用缺少 body".to_string())?
+        .trim()
+        .to_string();
+    if title.is_empty() {
+        return Err("title 为空".to_string());
+    }
+    Ok((title, body))
+}
+
+async fn create_gitea_issue(
+    cfg: &Config,
+    title: &str,
+    body: &str,
+) -> Result<CreatedIssue, ChatError> {
+    let url = format!(
+        "{}/api/v1/repos/{}/issues",
+        cfg.gitea_url.trim_end_matches('/'),
+        cfg.issue_repo
+    );
+    let body_md = format!(
+        "{body}\n\n---\n_via cube portal chatbot · cube.famzheng.me_"
+    );
+    let payload = json!({
+        "title": title,
+        "body": body_md,
+        "labels": ["chatbot"],
+    });
+    let client = reqwest::Client::new();
+    let resp = client
+        .post(&url)
+        .header("Authorization", format!("token {}", cfg.gitea_token))
+        .json(&payload)
+        .send()
+        .await
+        .map_err(|e| ChatError::UpstreamGitea(e.to_string()))?;
+    let status = resp.status();
+    let bytes = resp
+        .bytes()
+        .await
+        .map_err(|e| ChatError::UpstreamGitea(e.to_string()))?;
+    if !status.is_success() {
+        return Err(ChatError::UpstreamGitea(format!(
+            "{status}: {}",
+            String::from_utf8_lossy(&bytes)
+        )));
+    }
+    let issue: Value = serde_json::from_slice(&bytes)
+        .map_err(|e| ChatError::UpstreamGitea(format!("invalid json: {e}")))?;
+    Ok(CreatedIssue {
+        number: issue.get("number").and_then(Value::as_u64).unwrap_or(0),
+        url: issue
+            .get("html_url")
+            .and_then(Value::as_str)
+            .unwrap_or("")
+            .to_string(),
+        title: issue
+            .get("title")
+            .and_then(Value::as_str)
+            .unwrap_or(title)
+            .to_string(),
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn system_prompt_includes_repo() {
+        let p = system_prompt("fam/cube");
+        assert!(p.contains("fam/cube"));
+        assert!(p.contains("create_issue"));
+    }
+
+    #[test]
+    fn tool_schema_shape() {
+        let s = create_issue_tool_schema();
+        assert_eq!(s.pointer("/type").and_then(Value::as_str), Some("function"));
+        assert_eq!(
+            s.pointer("/function/name").and_then(Value::as_str),
+            Some("create_issue")
+        );
+        let req = s
+            .pointer("/function/parameters/required")
+            .and_then(Value::as_array)
+            .unwrap();
+        assert!(req.iter().any(|v| v == "title"));
+        assert!(req.iter().any(|v| v == "body"));
+    }
+
+    #[test]
+    fn first_create_issue_call_picks_only_matching_tool() {
+        let m = json!({
+            "tool_calls": [
+                {"id": "x1", "type": "function", "function": {"name": "other_tool", "arguments": "{}"}},
+                {"id": "x2", "type": "function", "function": {"name": "create_issue", "arguments": "{\"title\":\"t\",\"body\":\"b\"}"}}
+            ]
+        });
+        let tc = first_create_issue_call(&m).expect("should find one");
+        assert_eq!(tc.pointer("/function/name").and_then(Value::as_str), Some("create_issue"));
+    }
+
+    #[test]
+    fn first_create_issue_call_returns_none_if_absent() {
+        let m = json!({ "tool_calls": [] });
+        assert!(first_create_issue_call(&m).is_none());
+        let m = json!({});
+        assert!(first_create_issue_call(&m).is_none());
+    }
+
+    #[test]
+    fn extract_issue_args_parses_string_arguments() {
+        let tc = json!({
+            "function": {
+                "name": "create_issue",
+                "arguments": "{\"title\":\"狼人杀: swipe 失灵\",\"body\":\"  iOS Safari 上无法 swipe \"}"
+            }
+        });
+        let (t, b) = extract_issue_args(&tc).unwrap();
+        assert_eq!(t, "狼人杀: swipe 失灵");
+        assert_eq!(b, "iOS Safari 上无法 swipe");
+    }
+
+    #[test]
+    fn extract_issue_args_rejects_empty_title() {
+        let tc = json!({"function": {"arguments": "{\"title\":\"\",\"body\":\"x\"}"}});
+        assert!(extract_issue_args(&tc).is_err());
+    }
+
+    #[test]
+    fn extract_issue_args_rejects_malformed_args() {
+        let tc = json!({"function": {"arguments": "not json"}});
+        assert!(extract_issue_args(&tc).is_err());
+    }
+
+    #[test]
+    fn extract_issue_args_rejects_missing_field() {
+        let tc = json!({"function": {"arguments": "{\"title\":\"x\"}"}});
+        assert!(extract_issue_args(&tc).is_err());
+    }
+}
diff --git a/apps/cube/src/main.rs b/apps/cube/src/main.rs
index 3a4a4e3..8867950 100644
--- a/apps/cube/src/main.rs
+++ b/apps/cube/src/main.rs
@@ -1,9 +1,22 @@
-//! cube.famzheng.me — 入口门户。纯静态 SPA，没有自己的 /api 路由。
+//! cube.famzheng.me — 入口门户 + 反馈聊天助手。
+//!
+//! - 静态 SPA + SPA fallback 由 cube-core::base 处理。
+//! - `POST /api/chat` 转发到 LLM gateway，工具 `create_issue` 直接调 gitea 建 issue。
+
+mod chat;
+
+use std::sync::Arc;
 
 #[tokio::main]
 async fn main() -> std::io::Result<()> {
     cube_core::init_tracing();
     let dist = std::env::var("CUBE_DIST_DIR").unwrap_or_else(|_| "/dist".into());
-    let app = cube_core::base(dist);
+    let cfg = Arc::new(chat::Config::from_env());
+
+    let api = axum::Router::new()
+        .route("/chat", axum::routing::post(chat::handle))
+        .with_state(cfg);
+
+    let app = cube_core::base(dist).nest("/api", api);
     cube_core::serve(app, 8080).await
 }