diff --git a/CHANGELOG.md b/CHANGELOG.md
index 475f11d3..c70d05d7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # 印度占星 Skill 更新日志
 
+## 2026-10-29 — 咨询回答快约三分之一
+
+- 咨询里写回答那一步，模型的思考量默认改为「低」：对比测试里思考量少约一半，一轮回答从约 34 秒降到约 22 秒，回答质量逐份并排读过没有变差（issue #134，产品选 A）。
+- 只影响写回答那一步；排盘、查资料那几步不变。
+- 需要退回时，在服务器设 `CONSULT_ANSWER_REASONING_EFFORT=off` 即恢复原来的请求。
+
 ## 2026-10-28 — 切换人物时看得出是谁的盘
 
 - 「当前星盘」按钮上写名字、出生日期时间和城市；名单每行写关系和出生时间、城市。
diff --git a/docs/tasks/README.md b/docs/tasks/README.md
index 3a980050..6cdbceaa 100644
--- a/docs/tasks/README.md
+++ b/docs/tasks/README.md
@@ -546,3 +546,4 @@
 | `TASK-home-crash-saved-people-20261027.md` | `PROGRESS-home-crash-saved-people-20261027.md` | **#115 首页崩溃**：存过别人的账户一进首页就「页面出错了」——人物列表的资料缺两个字段，启程引导一读就报错；入口补齐默认值（BUG-1464） | 待验收 | `codex/home-crash-saved-people-20261027` |
 | `TASK-upstream-sync9-20261028.md` | `PROGRESS-upstream-sync9-20261028.md` | **第 1 次打回（快速门 1 败：Darakaraka 旧测试锁错值，见 `TASK-upstream-sync9-fix-20261028.md`）** · **#141 上游同步第九轮**：甲批九项已做完并推 `codex/upstream-sync9-20261028`；校正 20 条和 900 条与上一份回放逐条相同；乙批仍等 #137 | 待验收 | `codex/upstream-sync9-20261028` |
 | `TASK-upstream-sync9b-20261028.md` | `PROGRESS-upstream-sync9b-20261028.md` | **第 1 次打回（冻结契约排除清单删了第八轮两条，见 `TASK-upstream-sync9b-fix-20261028.md`）** · **#159 上游同步第九轮乙批（产品选 A）**：Sarpa Drekkana 补成五段、第 22 号 Drekkana 改为 D3 第 8 宫；改冻结文件 `varga.py`，校正 20 + 900 与上一份逐条相同后按 ERR-110 重新冻结。Narayana 小运强度口径（B2）不做，另问产品 | 待验收 | `codex/upstream-sync9b-20261028` |
+| — | — | **#134 咨询答题默认低思考量（产品选 A）**：`CONSULT_ANSWER_REASONING_EFFORT` 不设时默认 `low`，设 `off` 恢复原请求体（Claude 直接执行） | 已推 staging | `codex/answer-effort-default-20261029` |
diff --git a/docs/testing/answer-effort-default-20261029.md b/docs/testing/answer-effort-default-20261029.md
new file mode 100644
index 00000000..1555318b
--- /dev/null
+++ b/docs/testing/answer-effort-default-20261029.md
@@ -0,0 +1,7 @@
+# 真机走查 · 咨询回答默认低思考量（issue #134）
+
+| # | 操作 | 应该看到 |
+| --- | --- | --- |
+| 1 | 用一张星盘问一个具体问题（如「今年事业怎么样」） | 回答正常出来，比以前快一截（以前常要半分钟以上） |
+| 2 | 连问两三个追问 | 每轮都正常回答，引用的宫位、大运和以前一样具体 |
+| 3 | 问一个时间段（如「明年上半年」） | 照常出时段分析，没有空答或中途断掉 |
diff --git a/frontend/src/mastra/consultation-tools.ts b/frontend/src/mastra/consultation-tools.ts
index 6613c877..965a0dcf 100644
--- a/frontend/src/mastra/consultation-tools.ts
+++ b/frontend/src/mastra/consultation-tools.ts
@@ -177,22 +177,26 @@ export const MAX_EVIDENCE_LOOKUPS_PER_TURN = 3;
 export const CONSULTATION_WINDOW_CALC_TOOL_ID = "run-jyotish-window-consultation";
 
 /**
- * Answer-step reasoning effort. Unset or blank keeps today's request body.
- * An illegal value warns once and is treated as unset.
+ * Answer-step reasoning effort. Unset or blank means "low" (issue #134: the
+ * A/B halved reasoning tokens and cut answer time ~37% with no quality loss).
+ * "off" sends no reasoning_effort, i.e. the pre-#134 request body.
+ * An illegal value warns once and is treated as "off".
  */
 const CONSULT_ANSWER_REASONING_EFFORTS = ["low", "medium", "high", "max"] as const;
+export const CONSULT_ANSWER_REASONING_EFFORT_DEFAULT: ProviderReasoningEffort = "low";
 let consultAnswerReasoningEffortWarned = false;
 
 export function consultAnswerReasoningEffort(): ProviderReasoningEffort | undefined {
   const raw = process.env.CONSULT_ANSWER_REASONING_EFFORT;
-  if (raw === undefined || raw.trim() === "") return undefined;
+  if (raw === undefined || raw.trim() === "") return CONSULT_ANSWER_REASONING_EFFORT_DEFAULT;
   const value = raw.trim();
+  if (value === "off") return undefined;
   if ((CONSULT_ANSWER_REASONING_EFFORTS as readonly string[]).includes(value)) {
     return value as ProviderReasoningEffort;
   }
   if (!consultAnswerReasoningEffortWarned) {
     consultAnswerReasoningEffortWarned = true;
-    console.warn(`CONSULT_ANSWER_REASONING_EFFORT=${value} is not low, medium, high, or max; leaving reasoning effort unset.`);
+    console.warn(`CONSULT_ANSWER_REASONING_EFFORT=${value} is not off, low, medium, high, or max; leaving reasoning effort unset.`);
   }
   return undefined;
 }
diff --git a/frontend/tests/answer-effort-switch-20261013.test.ts b/frontend/tests/answer-effort-switch-20261013.test.ts
index 20589d37..d8ab7f66 100644
--- a/frontend/tests/answer-effort-switch-20261013.test.ts
+++ b/frontend/tests/answer-effort-switch-20261013.test.ts
@@ -51,9 +51,12 @@ test("an illegal effort warns once and stays unset", () => {
   }
 });
 
-test("unset effort keeps the pre-change request bodies", async () => {
+// 原值: 不设环境变量时请求体与改动前逐字节相同
+// 新值: 设成 "off" 时请求体与改动前逐字节相同；不设时默认 "low"（见下一条）
+// 原因: issue #134 产品选 A，答题步默认低思考量；"off" 是一行回退
+test("off keeps the pre-change request bodies", async () => {
   const previous = process.env.CONSULT_ANSWER_REASONING_EFFORT;
-  delete process.env.CONSULT_ANSWER_REASONING_EFFORT;
+  process.env.CONSULT_ANSWER_REASONING_EFFORT = "off";
   try {
     const natal = await captureStreamBodies({
       settings: consultationGenerationSettings(MODEL),
@@ -76,6 +79,43 @@ test("unset effort keeps the pre-change request bodies", async () => {
   }
 });
 
+test("unset or blank effort defaults to low", () => {
+  const previous = process.env.CONSULT_ANSWER_REASONING_EFFORT;
+  try {
+    delete process.env.CONSULT_ANSWER_REASONING_EFFORT;
+    assert.equal(consultAnswerReasoningEffort(), "low");
+    process.env.CONSULT_ANSWER_REASONING_EFFORT = "  ";
+    assert.equal(consultAnswerReasoningEffort(), "low");
+    process.env.CONSULT_ANSWER_REASONING_EFFORT = "off";
+    assert.equal(consultAnswerReasoningEffort(), undefined);
+  } finally {
+    if (previous === undefined) delete process.env.CONSULT_ANSWER_REASONING_EFFORT;
+    else process.env.CONSULT_ANSWER_REASONING_EFFORT = previous;
+  }
+});
+
+test("unset effort puts low on the answer step only", async () => {
+  const previous = process.env.CONSULT_ANSWER_REASONING_EFFORT;
+  delete process.env.CONSULT_ANSWER_REASONING_EFFORT;
+  try {
+    const natal = await captureStreamBodies({
+      settings: consultationGenerationSettings(MODEL),
+      prepareStep: (input) => consultationNatalPrepareStep({
+        stepNumber: input.stepNumber,
+        answerReady: input.stepNumber >= 1,
+        model: MODEL,
+      }),
+      steps: 2,
+    }) as Record<string, unknown>[];
+    assert.deepEqual(natal[0], fixture.natal[0]);
+    assert.equal(natal[1]?.reasoning_effort, "low");
+    assert.deepEqual(withoutEffort(natal[1]), fixture.natal[1]);
+  } finally {
+    if (previous === undefined) delete process.env.CONSULT_ANSWER_REASONING_EFFORT;
+    else process.env.CONSULT_ANSWER_REASONING_EFFORT = previous;
+  }
+});
+
 test("low effort is only on the answer step", async () => {
   const previous = process.env.CONSULT_ANSWER_REASONING_EFFORT;
   process.env.CONSULT_ANSWER_REASONING_EFFORT = "low";