diff --git a/BLOCKED.md b/BLOCKED.md
index 27e7d7c9..0e8f4b4b 100644
--- a/BLOCKED.md
+++ b/BLOCKED.md
@@ -1,5 +1,10 @@
 # BLOCKED
 
+## TASK-answer-effort-ab-20261013：答题步推理强度的真实 A/B（2026-10-15）
+
+- **A/B 未跑：缺模型 key。** 本机没有 `DS_KEY` 或 `BACKTEST_MODEL_KEY`。供应商是否接受 `low` / `medium` / `high` / `max`、推理 token 和耗时有没有下降，都没测。不得把请求体拦截写成「A/B 通过」。
+- 开关默认不设，请求体与改前一致。默认值等有 key 的验收跑完再由产品拍板，本单不改部署。
+
 ## TASK-consult-prep-parallel-20261013：审核真实延迟、Postgres 中位数、多领域镜像（2026-10-14）
 
 - **阿里云审核**：本机没有审核密钥。1500 毫秒挡首帧的结论来自测试里的假等待，不是真实供应商。开关 `CONSULT_PREP_PARALLEL` 保持关闭。
diff --git a/docs/BUG_HISTORY.md b/docs/BUG_HISTORY.md
index deb92593..fa95654e 100644
--- a/docs/BUG_HISTORY.md
+++ b/docs/BUG_HISTORY.md
@@ -36131,3 +36131,19 @@
 - 相关记录：BUG-203（锁文件，不是这一条）、BUG-1063（人物表列级读取权）、BUG-1348。
 - 复发自：无。
 - 修复版本：分支 `codex/release-path-production-20261014`。编号接在 BUG-1349 之后。
+
+## BUG-1351 | 低强度推理设置写在嵌套字段里，供应商收不到
+
+- 状态：investigating
+- 首次发现 / 最近更新：2026-10-13 / 2026-10-15
+- 来源：issue #65。任务书 `docs/tasks/TASK-answer-effort-ab-20261013.md`。请求体拦截见 `docs/testing/answer-effort-ab-20261013.md`。
+- 现象：代码里有一处把推理强度写成 `low`，但真正发出去的请求没有 `reasoning_effort` 这个字段。强度被包在 `thinking` 里面。
+- 触发条件：调用 `consultationSliceGenerationSettings`。产品代码里没有调用方，线上对话不受影响。
+- 根因：兼容通道只认供应商选项最外层的 `reasoningEffort`，并把它写成 `reasoning_effort`。嵌在 `thinking` 里的同名键会原样送出去，供应商不把它当强度。
+- 修复：本单不改这处形状，也不改它的两条断言。答题步的新开关写在最外层。要不要删掉或改掉这处旧形状，等产品拍板。
+- 验证：`frontend/scripts/research/answer-effort-probe.mts --dry-run`。这处设置的请求体是 `thinking.reasoningEffort = "low"`，`reasoning_effort` 为空。新开关设成 `low` 时，答题步请求体有 `reasoning_effort: "low"`。
+- 防复发：新测试锁住「开关不设时请求体与改前一致」，并锁住新强度出现在最外层。
+- 相关记录：BUG-148、BUG-1142。
+- 复发自：无。
+- 修复版本：未修。分支 `codex/answer-effort-ab-20261013` 只记录。编号接在 BUG-1350 之后。
+
diff --git a/docs/tasks/PROGRESS-answer-effort-ab-20261013.md b/docs/tasks/PROGRESS-answer-effort-ab-20261013.md
new file mode 100644
index 00000000..ac86d009
--- /dev/null
+++ b/docs/tasks/PROGRESS-answer-effort-ab-20261013.md
@@ -0,0 +1,43 @@
+# PROGRESS · 答题步推理强度开关（2026-10-15）
+
+- 分支：`codex/answer-effort-ab-20261013`
+- 实际基线：`origin/staging` `9274491681f6fcacbc87e3797441d2c5221de874`
+- 前置 `consult-prep-parallel` 已在 `origin/staging` 上（`git merge-base --is-ancestor` 退出码 0）
+- 默认行为不变。没有模型钥匙，A/B 未跑。
+
+## 做了什么
+
+1. 新环境变量 `CONSULT_ANSWER_REASONING_EFFORT`。`low` / `medium` / `high` / `max` 才生效。空着或没设，请求体与改前一致。非法值 `console.warn` 一次，然后当作没设。
+2. `agentGenerationSettings` 增加 `providerReasoningEffort`。它写在供应商选项的最外层，兼容通道据此发出 `reasoning_effort`。原来的 `reasoningEffort` 仍嵌在 `thinking` 里，切片那两条断言不用改。
+3. 答题步才带这个字段。判据与答案时钟相同：计算结果已经在手（`answerReady`），或者公开日历从第一步就是答题（`answerFromStart`）。主循环第 0 步计算结果还没到，不带。重试是新的一轮，步号从 0 重新计，但计算结果已经在手，所以重试的第 0 步也带。续写仍是关闭思考，不带这个字段。
+4. Mastra 的 `prepareStep` 会按步合并 `providerOptions`（`mergeObjects`）。答题步返回的强度会并进这一步，不会整轮都带。本单按步生效，没有改成整轮。
+5. 生平回测脚本增加 `--cases figure:domain,…` 和 `--efforts unset,low,medium`。每行记下端到端秒数、第 0 / 1 步秒数和推理 token、输出 token、结束原因、是否空答、是否截断、正文字数。摘要记下当次强度。
+
+## 自测
+
+| 检查 | 命令 | 结果 |
+| --- | --- | --- |
+| 请求体拦截 | `node node_modules/tsx/dist/cli.mjs scripts/research/answer-effort-probe.mts --dry-run` | 退出码 0。数字见 `docs/testing/answer-effort-ab-20261013.md` |
+| 本单测试与任务书点名的四份 | `node node_modules/tsx/dist/cli.mjs --test` 后接 `answer-effort-switch-20261013`、`consultation-agentic-runtime`、`consultation-workflow-contract`、`consult-answer-clock-20261001`、`consult-latency-timing-20261005` | 114 pass，0 fail，0 cancelled |
+| 类型检查 | 在 `frontend` 下 `.\node_modules\.bin\tsc --noEmit -p .` | 退出码 0 |
+| lint | 在 `frontend` 下 `npm run lint` | 退出码 0，0 error，123 条原有 warning。探针里多出来的 1 条未使用变量已去掉，改过的文件再跑 eslint 是 0 |
+
+开关不设时，两步请求体与改前保存的整份 JSON 逐字节一致。设 `low` 时只有答题步出现 `reasoning_effort: "low"`，第 0 步没有；续写仍是 `thinking: disabled` 且没有 `reasoning_effort`。
+
+## 改既有断言
+
+| 原值 | 新值 | 原因 |
+| --- | --- | --- |
+| `await streamWithOverflowRetry(agent)` | `await streamWithOverflowRetry(agent, generalStreamOptions)` | 公开日历从第一步就是答题。不传选项就没有 `prepareStep`，强度加不上去。开关不设时这些选项不改请求体。答案时钟的断言还在。 |
+
+切片的嵌套形状和它的两条断言没有改。
+
+## 需拍板
+
+- 默认强度。本单不改。有钥匙的验收按任务书 T3 出数之后，再决定设不设、设哪一档。部署默认写在哪里也留到那次。
+- `consultationSliceGenerationSettings` 删掉还是改成最外层。它没有调用方。本单不改。见 BUG-1351。
+- 若供应商不接受降档，对照组 D（答题步关思考）只供参考，采用与否另说。本机没跑。
+
+## 环境缺口
+
+A/B 未跑：缺模型 key。没有 `DS_KEY`，也没有 `BACKTEST_MODEL_KEY`。
diff --git a/docs/tasks/README.md b/docs/tasks/README.md
index 3c8a8cdf..5b5eaa7c 100644
--- a/docs/tasks/README.md
+++ b/docs/tasks/README.md
@@ -483,7 +483,7 @@
 | `TASK-frontend-dead-code-20261013.md` | `PROGRESS-frontend-dead-code-20261013.md` | 前端死代码 17 文件与无调用方接口删除，含未登录重计算接口（BUG-1342） | 待验收 | `codex/frontend-dead-code-20261013` |
 | `TASK-frontend-dead-code-fix-20261014.md` | `PROGRESS-frontend-dead-code-20261013.md` | **#63 第 1 次打回**：类名白名单去掉已删组件留下的条目 | 待验收 | `codex/frontend-dead-code-20261013` |
 | `TASK-api-chart-subprocess-gate-20261013.md` | — | 合盘不带 skip 串行排盘、报告无效子进程、名额轻重混用（只模拟）（BUG-1333～1334，A/B） | 待领取（排队：api-disk-cache-retention + report-reference-perf） | `codex/api-chart-subprocess-gate-20261013` |
-| `TASK-answer-effort-ab-20261013.md` | — | 答题步推理强度开关 + A/B（需模型 key） | 待领取（排队：consult-prep-parallel） | `codex/answer-effort-ab-20261013` |
+| `TASK-answer-effort-ab-20261013.md` | `PROGRESS-answer-effort-ab-20261013.md` | 答题步推理强度开关 + A/B（需模型 key） | 待验收 | `codex/answer-effort-ab-20261013` |
 | `TASK-consult-route-split-20261013.md` | — | consult POST 拆分第一阶段：开流前加载 + 计费结算 | 待领取（排队：consult-prep-parallel、answer-effort-ab） | `codex/consult-route-split-20261013` |
 | `TASK-pl9-render-split-20261013.md` | — | render_pl9_markdown 第一阶段：搬出无依赖内部函数 | 待领取（排队：api-chart-subprocess-gate） | `codex/pl9-render-split-20261013` |
 | `TASK-python-hygiene-20261013.md` | — | 免费层排队开关报反、静默吞异常、功能吉凶兜底合一、测试专用脚本归位（BUG-1340） | 待领取（排队：pl9-render-split） | `codex/python-hygiene-20261013` |
diff --git a/docs/testing/answer-effort-ab-20261013.md b/docs/testing/answer-effort-ab-20261013.md
new file mode 100644
index 00000000..3b57a2a2
--- /dev/null
+++ b/docs/testing/answer-effort-ab-20261013.md
@@ -0,0 +1,43 @@
+# 答题步推理强度（2026-10-15）
+
+没有模型钥匙。下面只是本机拦截到的请求体，不是供应商的接受度，也不是耗时和质量。A/B 未跑。
+
+命令：在 `frontend` 目录执行 `node node_modules/tsx/dist/cli.mjs scripts/research/answer-effort-probe.mts --dry-run`。假请求不离开这台机器。模型对象与产品相同：`providerId: deepseek`，`modelId: deepseek-flash`，带 `url` 和假的 `apiKey`。
+
+## 请求体里实际有什么
+
+| 形状 | thinking | reasoning_effort | max_tokens |
+| --- | --- | --- | --- |
+| 今天的答题设置，第 0 步和第 1 步 | `{ type: enabled }` | 无 | 24576 |
+| 旧的低强度设置（没有产品调用方） | `{ type: enabled, reasoningEffort: low }` | 无 | 10240 |
+| 新开关 `low` / `medium` / `high` / `max`（只在答题步） | `{ type: enabled }` | 与开关相同 | 24576 |
+| 续写 | `{ type: disabled }` | 无 | 16384 |
+
+旧的低强度写在 `thinking` 里面，请求体没有 `reasoning_effort`。这证实了任务书 §2.3。记为 BUG-1351，状态 investigating。线上不用这处设置。
+
+新开关写在供应商选项的最外层。兼容通道把它写成 `reasoning_effort`。开关不设时，两步请求体与改前逐字节一致，样本在 `frontend/tests/fixtures/answer-effort-switch-20261013.json`。
+
+## 供应商接受度
+
+未跑。没有 `DS_KEY` / `BACKTEST_MODEL_KEY`。`low`、`medium`、`high`、`max` 哪几档能用，要等验收时用临时钥匙跑探针的后半段。
+
+## 固定 10 题
+
+脚本已能按 `--cases` 跑下面这 10 题，并能按 `--efforts unset,low,medium` 把同一题的几档挨着跑。多档同时跑时并发降为 1，因为强度读的是进程里的环境变量，并行会串档。本机没有钥匙，这 10 题没有跑。
+
+| # | 盘 | 领域 |
+| --- | --- | --- |
+| 1 | steve_jobs | career |
+| 2 | barack_obama | parents |
+| 3 | elizabeth_taylor | marriage |
+| 4 | marilyn_monroe | parents |
+| 5 | judy_garland | health |
+| 6 | edith_piaf | marriage |
+| 7 | frida_kahlo | health |
+| 8 | george_w_bush | career |
+| 9 | zinedine_zidane | career |
+| 10 | marilyn_monroe | marriage |
+
+## 耗时与质量
+
+没有数。空答、截断、rubric、人工四项都没做。默认值维持不设。
diff --git a/frontend/scripts/research/answer-effort-probe.mts b/frontend/scripts/research/answer-effort-probe.mts
new file mode 100644
index 00000000..fbd1ca4e
--- /dev/null
+++ b/frontend/scripts/research/answer-effort-probe.mts
@@ -0,0 +1,203 @@
+/**
+ * Request-body probe for issue #65.
+ *
+ * --dry-run needs no model key. It sends one agent.stream per shape through
+ * Mastra's OpenAI-compatible channel and prints the thinking / reasoning_effort
+ * / max_tokens fields of each request. A fake fetch never leaves the machine.
+ *
+ * Shapes:
+ *   (a) consultationGenerationSettings (today's answer settings)
+ *   (b) consultationSliceGenerationSettings (nested reasoningEffort, no caller)
+ *   (c) providerReasoningEffort low / medium / high / max at the top level
+ *
+ * With DS_KEY or BACKTEST_MODEL_KEY, the same file can ask the provider which
+ * efforts it accepts. This checkout does not run that half.
+ */
+import { writeFileSync } from "node:fs";
+
+import { Agent } from "@mastra/core/agent";
+import { createTool } from "@mastra/core/tools";
+import { z } from "zod";
+
+import { agentGenerationSettings } from "../../src/lib/agent-generation-settings.ts";
+import {
+  consultationContinueGenerationSettings,
+  consultationGenerationSettings,
+  consultationNatalPrepareStep,
+  consultationSliceGenerationSettings,
+} from "../../src/mastra/consultation-tools.ts";
+
+const MODEL = {
+  providerId: "deepseek",
+  modelId: "deepseek-flash",
+  url: "http://127.0.0.1:9/v1",
+  apiKey: "dummy",
+};
+
+const markTool = createTool({
+  id: "run-jyotish-consultation",
+  description: "Mark the calculation done.",
+  inputSchema: z.object({}).strict(),
+  execute: async () => ({ ok: true }),
+});
+
+function sse(chunks: unknown[]) {
+  const body = `${chunks.map((chunk) => `data: ${JSON.stringify(chunk)}\n\n`).join("")}data: [DONE]\n\n`;
+  return new Response(body, {
+    status: 200,
+    headers: { "content-type": "text/event-stream" },
+  });
+}
+
+function toolCallChunk() {
+  return sse([
+    {
+      id: "chatcmpl-tool",
+      object: "chat.completion.chunk",
+      choices: [{
+        index: 0,
+        delta: {
+          role: "assistant",
+          tool_calls: [{
+            index: 0,
+            id: "call_1",
+            type: "function",
+            function: { name: "run-jyotish-consultation", arguments: "" },
+          }],
+        },
+        finish_reason: null,
+      }],
+    },
+    {
+      id: "chatcmpl-tool",
+      object: "chat.completion.chunk",
+      choices: [{
+        index: 0,
+        delta: { tool_calls: [{ index: 0, function: { arguments: "{}" } }] },
+        finish_reason: null,
+      }],
+    },
+    {
+      id: "chatcmpl-tool",
+      object: "chat.completion.chunk",
+      choices: [{ index: 0, delta: {}, finish_reason: "tool_calls" }],
+    },
+  ]);
+}
+
+function textChunk() {
+  return sse([
+    {
+      id: "chatcmpl-text",
+      object: "chat.completion.chunk",
+      choices: [{ index: 0, delta: { role: "assistant", content: "ok" }, finish_reason: null }],
+    },
+    {
+      id: "chatcmpl-text",
+      object: "chat.completion.chunk",
+      choices: [{ index: 0, delta: {}, finish_reason: "stop" }],
+      usage: { prompt_tokens: 1, completion_tokens: 1, completion_tokens_details: { reasoning_tokens: 0 } },
+    },
+  ]);
+}
+
+export function requestFields(body: unknown) {
+  const record = body && typeof body === "object" ? body as Record<string, unknown> : {};
+  return {
+    thinking: record.thinking ?? null,
+    reasoning_effort: record.reasoning_effort ?? null,
+    max_tokens: record.max_tokens ?? null,
+  };
+}
+
+export async function captureStreamBodies(input: {
+  settings: ReturnType<typeof consultationGenerationSettings>;
+  prepareStep?: (step: { stepNumber: number }) => { toolChoice?: "auto"; activeTools?: string[]; providerOptions?: unknown };
+  steps: 1 | 2;
+}): Promise<unknown[]> {
+  const bodies: unknown[] = [];
+  const previous = globalThis.fetch;
+  globalThis.fetch = async (_url, init) => {
+    const raw = init?.body;
+    bodies.push(JSON.parse(typeof raw === "string" ? raw : "{}"));
+    return bodies.length === 1 && input.steps === 2 ? toolCallChunk() : textChunk();
+  };
+  try {
+    const agent = new Agent({
+      id: `answer-effort-probe-${bodies.length}-${Date.now()}`,
+      name: "answer-effort-probe",
+      instructions: "Reply ok.",
+      model: MODEL,
+      tools: { "run-jyotish-consultation": markTool },
+    });
+    const result = await agent.stream([{ role: "user", content: "ping" }], {
+      maxSteps: input.steps,
+      ...input.settings,
+      ...(input.prepareStep ? { prepareStep: input.prepareStep } : {}),
+    } as never);
+    const drained: unknown[] = [];
+    for await (const chunk of result.fullStream) drained.push(chunk);
+    if (drained.length === 0) throw new Error("probe stream produced no chunks");
+  } finally {
+    globalThis.fetch = previous;
+  }
+  return bodies;
+}
+
+async function main() {
+  if (!process.argv.includes("--dry-run")) {
+    console.log("A/B 未跑：缺模型 key。只做请求体拦截时加上 --dry-run。");
+    return;
+  }
+  const model = MODEL;
+  const natal = await captureStreamBodies({
+    settings: consultationGenerationSettings(model),
+    prepareStep: (input) => consultationNatalPrepareStep({
+      stepNumber: input.stepNumber,
+      answerReady: input.stepNumber >= 1,
+    }),
+    steps: 2,
+  });
+  const slice = await captureStreamBodies({
+    settings: consultationSliceGenerationSettings(model),
+    steps: 1,
+  });
+  const topLevel = [];
+  for (const effort of ["low", "medium", "high", "max"] as const) {
+    const bodies = await captureStreamBodies({
+      settings: agentGenerationSettings(model, { thinking: "enabled", providerReasoningEffort: effort }),
+      steps: 1,
+    });
+    topLevel.push({ effort, fields: requestFields(bodies[0]) });
+  }
+  const continued = await captureStreamBodies({
+    settings: consultationContinueGenerationSettings(model),
+    steps: 1,
+  });
+  const report = {
+    fixtureProvenance: "frontend/scripts/research/answer-effort-probe.mts --dry-run",
+    a_consultationGenerationSettings: natal.map(requestFields),
+    b_consultationSliceGenerationSettings: slice.map(requestFields),
+    c_providerReasoningEffort: topLevel,
+    continue: continued.map(requestFields),
+  };
+  console.log(JSON.stringify(report, null, 2));
+  if (process.argv.includes("--save-baseline")) {
+    const file = new URL("../../tests/fixtures/answer-effort-switch-20261013.json", import.meta.url);
+    writeFileSync(file, `${JSON.stringify({
+      fixtureProvenance: "node node_modules/tsx/dist/cli.mjs scripts/research/answer-effort-probe.mts --dry-run --save-baseline（开关尚未读取环境变量时的整份请求体）",
+      natal: natal,
+      continue: continued,
+    }, null, 2)}\n`);
+  }
+}
+
+const invoked = process.argv[1]
+  ? new URL(`file:///${process.argv[1].replace(/\\/g, "/")}`).href === import.meta.url
+  : false;
+if (invoked) {
+  main().catch((error) => {
+    console.error(error);
+    process.exitCode = 1;
+  });
+}
diff --git a/frontend/scripts/research/consult-biography-backtest.mts b/frontend/scripts/research/consult-biography-backtest.mts
index 2083df7f..56ed30bd 100644
--- a/frontend/scripts/research/consult-biography-backtest.mts
+++ b/frontend/scripts/research/consult-biography-backtest.mts
@@ -27,6 +27,7 @@
  * Usage (from frontend/, Node 22):
  *   DS_KEY=... ./node_modules/.bin/tsx scripts/research/consult-biography-backtest.mts \
  *     [--out <dir>] [--repeats 2] [--figures a,b] [--domains parents,marriage,health,career] \
+ *     [--cases steve_jobs:career,barack_obama:parents] [--efforts unset,low,medium] \
  *     [--model deepseek-flash] [--base-url https://api.deepseek.com] [--concurrency 4] [--dump-cards]
  *     [--correction barack_obama,marilyn_monroe] [--correction-text 我爸其实没怎么管过我]
  *     [--correction-domain career] [--correction-texts "zinedine_zidane=我是足球运动员|barack_obama=我是政治家"]
@@ -142,6 +143,8 @@ function parseArgs(argv: readonly string[]) {
       const at = pair.indexOf("=");
       return [pair.slice(0, at), pair.slice(at + 1)];
     })) as Record<string, string>,
+    cases: value("cases")?.split(",").map((item) => item.trim()).filter(Boolean) ?? null,
+    efforts: value("efforts")?.split(",").map((item) => item.trim()).filter(Boolean) ?? null,
   };
 }
 
@@ -270,7 +273,15 @@ function model(args: ReturnType<typeof parseArgs>, apiKey: string): ResolvedLang
 
 /** A follow-up turn in the same session: the earlier question and answer are the history. */
 type FollowUp = { priorQuestion: string; priorAnswer: string };
-type Job = { figure: GoldenFigure; domain: string; question: string; run: number; followUp?: FollowUp };
+type Job = {
+  figure: GoldenFigure;
+  domain: string;
+  question: string;
+  run: number;
+  followUp?: FollowUp;
+  /** When set, this job overrides CONSULT_ANSWER_REASONING_EFFORT for its own stream. */
+  effort?: string;
+};
 
 type Usage = { inputTokens?: number; outputTokens?: number; reasoningTokens?: number; cachedInputTokens?: number };
 
@@ -316,6 +327,22 @@ function userTurn(question: string, followUp?: FollowUp) {
 }
 
 async function runJob(job: Job, resolved: ResolvedLanguageModel) {
+  const previousEffort = process.env.CONSULT_ANSWER_REASONING_EFFORT;
+  if (job.effort !== undefined) {
+    if (job.effort === "unset" || job.effort === "") delete process.env.CONSULT_ANSWER_REASONING_EFFORT;
+    else process.env.CONSULT_ANSWER_REASONING_EFFORT = job.effort;
+  }
+  try {
+    return await runJobOnce(job, resolved);
+  } finally {
+    if (job.effort !== undefined) {
+      if (previousEffort === undefined) delete process.env.CONSULT_ANSWER_REASONING_EFFORT;
+      else process.env.CONSULT_ANSWER_REASONING_EFFORT = previousEffort;
+    }
+  }
+}
+
+async function runJobOnce(job: Job, resolved: ResolvedLanguageModel) {
   const state = createConsultationRuntimeState();
   const executed: string[] = [];
   const ctx = agentContext(job, state, executed);
@@ -333,7 +360,14 @@ async function runJob(job: Job, resolved: ResolvedLanguageModel) {
     maxSteps: AGENT_MAX_STEPS,
     ...consultationGenerationSettings(resolved.model),
   };
-  const natalStreamOptions = { ...streamOptions, prepareStep: consultationNatalPrepareStep };
+  const natalStreamOptions = {
+    ...streamOptions,
+    prepareStep: (input: { stepNumber: number }) => consultationNatalPrepareStep({
+      stepNumber: input.stepNumber,
+      answerReady: state.consultationToolCompleted,
+      model: resolved.model,
+    }),
+  };
   const usages: Promise<unknown>[] = [];
   const startedAt = Date.now();
   let output: string | null = null;
@@ -417,6 +451,17 @@ async function runJob(job: Job, resolved: ResolvedLanguageModel) {
     methodologySections: state.methodologySectionCount,
     lookups: state.evidenceLookupCallCount,
     finish: state.composeFinishReason ?? state.modelFinishReason ?? null,
+    effort: process.env.CONSULT_ANSWER_REASONING_EFFORT?.trim() || null,
+    answerReasoningMs: state.answerReasoningMs ?? null,
+    steps: [0, 1].map((index) => {
+      const step = state.modelStepTimings?.find((item) => item.index === index);
+      return {
+        index,
+        seconds: step?.durationMs == null ? null : step.durationMs / 1000,
+        reasoningTokens: step?.reasoningTokens ?? null,
+        outputTokens: step?.outputTokens ?? null,
+      };
+    }),
   };
 }
 
@@ -477,7 +522,18 @@ console.info = (...items: unknown[]) => {
   productInfo(...items);
 };
 
-type Row = { figure: string; domain: string; run: number; chars: number; seconds: number; checks: ReturnType<typeof deterministicChecks> };
+type Row = {
+  figure: string;
+  domain: string;
+  run: number;
+  chars: number;
+  seconds: number;
+  checks: ReturnType<typeof deterministicChecks>;
+  empty?: boolean;
+  truncated?: boolean;
+  finish?: string | null;
+  steps?: { seconds: number | null; reasoningTokens: number | null; outputTokens: number | null }[];
+};
 
 function writeSummary(out: string, summary: Json & { rows: Row[] }, modelId: string) {
   const rows = summary.rows;
@@ -488,13 +544,13 @@ function writeSummary(out: string, summary: Json & { rows: Row[] }, modelId: str
   writeFileSync(join(out, "summary.md"), [
     `# 名人生平回测 · ${modelId}`,
     "",
-    `开始 ${summary.started_at}，${rows.length} 份，墙钟 ${Number(summary.wall_seconds).toFixed(0)} s，失败 ${summary.failures} 份。`,
+    `开始 ${summary.started_at}，${rows.length} 份，墙钟 ${Number(summary.wall_seconds).toFixed(0)} s，失败 ${summary.failures} 份。推理强度：${String(summary.reasoning_effort ?? "不设")}。`,
     `用量合计：${JSON.stringify(summary.usage)}`,
     `确定性检查：禁句 ${summary.banned_hits}，性别代词（婚恋/子女）${summary.pronoun_hits}，must_not 原文 ${summary.must_not_literal_hits}。判断类评分需逐份阅读。`,
     "",
-    "| 名人 | 领域 | run | 字数 | 秒 | 禁句 | 代词 | must_not |",
-    "| --- | --- | --- | --- | --- | --- | --- | --- |",
-    ...rows.map((row) => `| ${row.figure} | ${row.domain} | ${row.run} | ${row.chars} | ${row.seconds.toFixed(0)} | ${row.checks.banned.length} | ${row.checks.pronouns.length} | ${row.checks.literalHits.length} |`),
+    "| 名人 | 领域 | run | 字数 | 秒 | 空答 | 截断 | 第0步秒 | 第1步秒 | 第1步推理token | 结束 |",
+    "| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |",
+    ...rows.map((row) => `| ${row.figure} | ${row.domain} | ${row.run} | ${row.chars} | ${row.seconds.toFixed(0)} | ${row.empty ? "是" : ""} | ${row.truncated ? "是" : ""} | ${row.steps?.[0]?.seconds ?? ""} | ${row.steps?.[1]?.seconds ?? ""} | ${row.steps?.[1]?.reasoningTokens ?? ""} | ${row.finish ?? ""} |`),
     "",
     "## must_not 原文命中",
     "",
@@ -529,11 +585,28 @@ async function main() {
   }
   const questions = new Map(golden.routes.map((route) => [route.domain, route.question]));
   const figures = golden.figures.filter((figure) => !args.figures || args.figures.includes(figure.id));
-  const jobs: Job[] = figures.flatMap((figure) => args.domains.flatMap((domain) => {
-    const question = questions.get(domain);
-    if (!question) throw new Error(`no golden question for domain ${domain}`);
-    return Array.from({ length: args.repeats }, (_, index) => ({ figure, domain, question, run: index + 1 }));
-  }));
+  const pairs = args.cases
+    ? args.cases.map((spec) => {
+      const splitAt = spec.indexOf(":");
+      const figureId = spec.slice(0, splitAt);
+      const domain = spec.slice(splitAt + 1);
+      const figure = golden.figures.find((item) => item.id === figureId);
+      const question = questions.get(domain);
+      if (!figure || !question) throw new Error(`unknown case ${spec}`);
+      return { figure, domain, question };
+    })
+    : figures.flatMap((figure) => args.domains.flatMap((domain) => {
+      const question = questions.get(domain);
+      if (!question) throw new Error(`no golden question for domain ${domain}`);
+      return [{ figure, domain, question }];
+    }));
+  const efforts = args.efforts;
+  const jobs: Job[] = pairs.flatMap((pair) => Array.from({ length: args.repeats }, (_, index) => {
+    const run = index + 1;
+    if (!efforts) return [{ ...pair, run }];
+    return efforts.map((effort) => ({ ...pair, run, effort }));
+  }).flat());
+  const concurrency = efforts && efforts.length > 1 ? 1 : args.concurrency;
   mkdirSync(args.out, { recursive: true });
   if (args.dumpCards) {
     await dumpCards(jobs, args.out);
@@ -543,12 +616,12 @@ async function main() {
   if (!apiKey) throw new Error("Set DS_KEY (or BACKTEST_MODEL_KEY); without a key the backtest is an environment gap.");
   const resolved = model(args, apiKey);
   const started = Date.now();
-  const rows = await pool(jobs, args.concurrency, async (job) => {
+  const rows = await pool(jobs, concurrency, async (job) => {
     let result: Awaited<ReturnType<typeof runJob>>;
     try {
       result = await runJob(job, resolved);
     } catch (error) {
-      result = { output: "", failure: error instanceof Error ? error.message : String(error), executed: [], seconds: 0, usage: {}, cardChars: null, visibleChars: null, methodologySections: 0, lookups: 0, finish: null };
+      result = { output: "", failure: error instanceof Error ? error.message : String(error), executed: [], seconds: 0, usage: {}, cardChars: null, visibleChars: null, methodologySections: 0, lookups: 0, finish: null, effort: job.effort ?? null, answerReasoningMs: null, steps: [{ index: 0, seconds: null, reasoningTokens: null, outputTokens: null }, { index: 1, seconds: null, reasoningTokens: null, outputTokens: null }] };
     }
     const mustNot = rubric.figures.find((item) => item.id === job.figure.id)?.domains[job.domain]?.must_not ?? [];
     const checks = deterministicChecks(result.output, job.domain, mustNot);
@@ -573,7 +646,18 @@ async function main() {
       "",
     ].join("\n"));
     console.log(`${job.figure.id} ${job.domain} run${job.run}: ${result.output.length} chars, ${result.seconds.toFixed(0)} s${result.failure ? `, FAILED ${result.failure}` : ""}`);
-    return { figure: job.figure.id, domain: job.domain, run: job.run, chars: result.output.length, ...result, output: undefined, checks };
+    return {
+      figure: job.figure.id,
+      domain: job.domain,
+      run: job.run,
+      chars: result.output.length,
+      empty: result.output.trim() === "",
+      truncated: result.finish === "length" || (result.failure ?? "").includes("answer_truncated"),
+      outputTokens: result.usage.outputTokens ?? null,
+      ...result,
+      output: undefined,
+      checks,
+    };
   });
   const corrections = await pool(
     jobs.filter((job) => args.correctionDomains.includes(job.domain)
@@ -589,7 +673,7 @@ async function main() {
       try {
         result = await runJob(job, resolved);
       } catch (error) {
-        result = { output: "", failure: error instanceof Error ? error.message : String(error), executed: [], seconds: 0, usage: {}, cardChars: null, visibleChars: null, methodologySections: 0, lookups: 0, finish: null };
+        result = { output: "", failure: error instanceof Error ? error.message : String(error), executed: [], seconds: 0, usage: {}, cardChars: null, visibleChars: null, methodologySections: 0, lookups: 0, finish: null, effort: job.effort ?? null, answerReasoningMs: null, steps: [{ index: 0, seconds: null, reasoningTokens: null, outputTokens: null }, { index: 1, seconds: null, reasoningTokens: null, outputTokens: null }] };
       }
       const file = join(args.out, job.figure.id, `${job.domain}-correction-run${job.run}.md`);
       writeFileSync(file, [
@@ -619,6 +703,9 @@ async function main() {
     jobs: rows.length,
     failures: rows.filter((row) => row.failure || row.chars === 0).length,
     usage: total,
+    reasoning_effort: process.env.CONSULT_ANSWER_REASONING_EFFORT?.trim() || null,
+    efforts: args.efforts,
+    concurrency,
     gaps: GAPS,
     rows,
     corrections,
diff --git a/frontend/src/app/api/consult/route.ts b/frontend/src/app/api/consult/route.ts
index e9e6a056..db0478b4 100644
--- a/frontend/src/app/api/consult/route.ts
+++ b/frontend/src/app/api/consult/route.ts
@@ -75,6 +75,8 @@ import {
   createConsultationRunClock,
   consultationContinueGenerationSettings,
   consultationGenerationSettings,
+  consultationGeneralPrepareStep,
+  consultAnswerEffortProviderOptions,
   consultationNatalPrepareStep,
   consultationWindowPrepareStep,
   createConsultationAgentContext,
@@ -1288,6 +1290,8 @@ export async function POST(request: Request) {
       prepareStep: (input: { stepNumber: number }) => consultationNatalPrepareStep({
         stepNumber: input.stepNumber,
         rectificationOffer: true,
+        answerReady: state.consultationToolCompleted,
+        model: selectedModel.model,
       }),
     };
     const windowStreamOptions = {
@@ -1295,6 +1299,15 @@ export async function POST(request: Request) {
       prepareStep: (input: { stepNumber: number }) => consultationWindowPrepareStep({
         stepNumber: input.stepNumber,
         rectificationOffer: true,
+        answerReady: state.consultationToolCompleted,
+        model: selectedModel.model,
+      }),
+    };
+    const generalStreamOptions = {
+      ...streamOptions,
+      prepareStep: (input: { stepNumber: number }) => consultationGeneralPrepareStep({
+        stepNumber: input.stepNumber,
+        model: selectedModel.model,
       }),
     };
     const answerPhaseSignal = runClock.answerSignal;
@@ -1305,10 +1318,10 @@ export async function POST(request: Request) {
       agent: {
         stream: (
           messages: typeof baseMessages,
-          options: typeof streamOptions | typeof natalStreamOptions | typeof windowStreamOptions,
+          options: typeof streamOptions | typeof natalStreamOptions | typeof windowStreamOptions | typeof generalStreamOptions,
         ) => Promise<{ fullStream: AsyncIterable<unknown> | ReadableStream<unknown>; totalUsage: Promise<Usage> }>;
       },
-      options: typeof streamOptions | typeof natalStreamOptions | typeof windowStreamOptions = streamOptions,
+      options: typeof streamOptions | typeof natalStreamOptions | typeof windowStreamOptions | typeof generalStreamOptions = streamOptions,
     ) {
       try {
         const result = await agent.stream(baseMessages, options);
@@ -1369,14 +1382,14 @@ export async function POST(request: Request) {
     if (usesPublicDailyGeneralAgent(consultationMode, generalDailyContext)) {
       state.workflowReceipt = workflowReceipt;
       const agent = getGeneralJyotishAgent(selectedModel);
-      const result = await streamWithOverflowRetry(agent);
+      const result = await streamWithOverflowRetry(agent, generalStreamOptions);
       // This mode has no calculation to require and no chart method to bind,
       // so there is no contract for a retry to repair.
       const retryForAnswer = async (retryHint?: string) => {
         const retried = await agent.stream([
           ...baseMessages,
           { role: "user" as const, content: `上一轮没有输出任何回答文本。请直接给出这个问题的回答，不要只说明过程。${retryHint ? `\n${retryHint}` : ""}` },
-        ], { ...streamOptions, abortSignal: answerPhaseSignal() });
+        ], { ...generalStreamOptions, abortSignal: answerPhaseSignal() });
         usages.push(retried.totalUsage);
         return retried.fullStream;
       };
@@ -1472,7 +1485,11 @@ export async function POST(request: Request) {
             role: "user" as const,
             content: `服务器窗口计算已经完成，但上一轮没有输出任何回答文本。请重新取回本次计算结果，然后直接给出回答；不要只描述过程或工具调用。${retryHint ? `\n${retryHint}` : ""}`,
           },
-        ], { ...streamOptions, abortSignal: answerPhaseSignal() });
+        ], {
+          ...streamOptions,
+          abortSignal: answerPhaseSignal(),
+          ...consultAnswerEffortProviderOptions(selectedModel.model),
+        });
         usages.push(retried.totalUsage);
         return retried.fullStream;
       };
diff --git a/frontend/src/lib/agent-generation-settings.ts b/frontend/src/lib/agent-generation-settings.ts
index 25488402..7d3de3f6 100644
--- a/frontend/src/lib/agent-generation-settings.ts
+++ b/frontend/src/lib/agent-generation-settings.ts
@@ -16,6 +16,8 @@ export const AGENT_MAX_OUTPUT_TOKENS = AGENT_ANSWER_OUTPUT_TOKENS;
 
 export type ThinkingMode = "enabled" | "disabled";
 export type ReasoningEffort = "low" | "medium" | "high";
+/** Top-level OpenAI-compatible `reasoning_effort`, including DeepSeek's `max`. */
+export type ProviderReasoningEffort = "low" | "medium" | "high" | "max";
 
 export type PromptCacheUsage = Readonly<{
   readTokens: number;
@@ -100,6 +102,8 @@ export function agentGenerationSettings(
     answerTokens?: number;
     thinkingTokens?: number;
     reasoningEffort?: ReasoningEffort;
+    /** Written beside `thinking`, not inside it, so compatible gateways emit `reasoning_effort`. */
+    providerReasoningEffort?: ProviderReasoningEffort;
   } = {},
 ) {
   const thinkingMode: ThinkingMode = options.thinking ?? "disabled";
@@ -110,6 +114,9 @@ export function agentGenerationSettings(
         ? { reasoningEffort: options.reasoningEffort }
         : {}),
     },
+    ...(options.providerReasoningEffort
+      ? { reasoningEffort: options.providerReasoningEffort }
+      : {}),
   };
   const providerId = typeof model === "string"
     ? model
diff --git a/frontend/src/mastra/consultation-tools.ts b/frontend/src/mastra/consultation-tools.ts
index 47d9e899..c5c3fd8f 100644
--- a/frontend/src/mastra/consultation-tools.ts
+++ b/frontend/src/mastra/consultation-tools.ts
@@ -25,7 +25,7 @@ import { createConsultationPlan, type ConsultationPlan } from "../lib/consultati
 import type { TechniqueAuditRow, WorkflowReceipt } from "../lib/consultation-agent-events.ts";
 import { normalizeTechniqueAuditRows } from "../lib/consultation-technique-audit.ts";
 import type { AgentModelFinishReason, EvidenceCardTelemetry } from "../lib/agent-observability.ts";
-import { agentGenerationSettings, AGENT_SLICE_ANSWER_OUTPUT_TOKENS, AGENT_SLICE_THINKING_OUTPUT_TOKENS } from "../lib/agent-generation-settings.ts";
+import { agentGenerationSettings, AGENT_SLICE_ANSWER_OUTPUT_TOKENS, AGENT_SLICE_THINKING_OUTPUT_TOKENS, type ProviderReasoningEffort } from "../lib/agent-generation-settings.ts";
 import { chartCalculationProgressLabel, evidenceLookupActivityLabel } from "../lib/consultation-activity-labels.ts";
 import { consultDomainConcurrency } from "../lib/consult/prep-flags.ts";
 import {
@@ -176,6 +176,45 @@ export const CONSULTATION_EVIDENCE_LOOKUP_TOOL_ID = "read-consultation-evidence"
 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.
+ */
+const CONSULT_ANSWER_REASONING_EFFORTS = ["low", "medium", "high", "max"] as const;
+let consultAnswerReasoningEffortWarned = false;
+
+export function consultAnswerReasoningEffort(): ProviderReasoningEffort | undefined {
+  const raw = process.env.CONSULT_ANSWER_REASONING_EFFORT;
+  if (raw === undefined || raw.trim() === "") return undefined;
+  const value = raw.trim();
+  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.`);
+  }
+  return undefined;
+}
+
+type AnswerEffortInput = {
+  answerReady?: boolean;
+  answerFromStart?: boolean;
+  model?: unknown;
+};
+
+function answerEffortOptions(input: AnswerEffortInput) {
+  const effort = consultAnswerReasoningEffort();
+  const answerStep = input.answerFromStart === true || input.answerReady === true;
+  if (!effort || !answerStep) return {};
+  return {
+    providerOptions: agentGenerationSettings(input.model, {
+      thinking: "enabled",
+      providerReasoningEffort: effort,
+    }).providerOptions,
+  };
+}
+
 /**
  * Step 0 narrows with activeTools and leaves toolChoice auto. Thinking-mode
  * providers reject named and required toolChoice (BUG-282, BUG-937).
@@ -185,35 +224,77 @@ export const CONSULTATION_WINDOW_CALC_TOOL_ID = "run-jyotish-window-consultation
  * Later steps stay auto.
  *
  * Window and general agents must not share the natal hook.
+ *
+ * The answer step is any step that already holds a calculation (`answerReady`,
+ * the same flag as the answer clock) or a no-tool public-daily turn
+ * (`answerFromStart`). A retry starts a new stream at step 0 with the
+ * calculation already in hand, so the step number is not part of the check.
+ * The main loop's step 0 still has `answerReady` false.
  */
-export function consultationNatalPrepareStep(input: { stepNumber: number; rectificationOffer?: boolean }) {
-  if (input.stepNumber !== 0) return { toolChoice: "auto" as const };
+type ConsultPrepareInput = {
+  rectificationOffer?: boolean;
+  answerReady?: boolean;
+  answerFromStart?: boolean;
+  model?: unknown;
+};
+
+export function consultationNatalPrepareStep(input: { stepNumber: 0 } & ConsultPrepareInput): {
+  activeTools: string[];
+  toolChoice: "auto";
+};
+export function consultationNatalPrepareStep(input: { stepNumber: number } & ConsultPrepareInput): {
+  toolChoice: "auto";
+  activeTools?: string[];
+};
+export function consultationNatalPrepareStep(input: { stepNumber: number } & ConsultPrepareInput) {
+  const effort = answerEffortOptions(input);
+  if (input.stepNumber !== 0) return { toolChoice: "auto" as const, ...effort };
   if (!input.rectificationOffer) {
     return {
       activeTools: [CONSULTATION_NATAL_CALC_TOOL_ID],
       toolChoice: "auto" as const,
+      ...effort,
     };
   }
   return {
     activeTools: [CONSULTATION_NATAL_CALC_TOOL_ID, RECTIFICATION_OFFER_TOOL_ID],
     toolChoice: "auto" as const,
+    ...effort,
   };
 }
 
-export function consultationWindowPrepareStep(input: { stepNumber: number; rectificationOffer?: boolean }) {
-  if (input.stepNumber !== 0) return { toolChoice: "auto" as const };
+export function consultationWindowPrepareStep(input: {
+  stepNumber: number;
+  rectificationOffer?: boolean;
+  answerReady?: boolean;
+  answerFromStart?: boolean;
+  model?: unknown;
+}) {
+  const effort = answerEffortOptions(input);
+  if (input.stepNumber !== 0) return { toolChoice: "auto" as const, ...effort };
   if (!input.rectificationOffer) {
     return {
       activeTools: [CONSULTATION_WINDOW_CALC_TOOL_ID],
       toolChoice: "auto" as const,
+      ...effort,
     };
   }
   return {
     activeTools: [CONSULTATION_WINDOW_CALC_TOOL_ID, RECTIFICATION_OFFER_TOOL_ID],
     toolChoice: "auto" as const,
+    ...effort,
   };
 }
 
+export function consultAnswerEffortProviderOptions(model?: unknown) {
+  return answerEffortOptions({ answerReady: true, model });
+}
+
+/** Public daily has no chart tool. Its first step is already the answer. */
+export function consultationGeneralPrepareStep(input: { stepNumber: number; model?: unknown }) {
+  return answerEffortOptions({ ...input, answerFromStart: true });
+}
+
 const CONSULTATION_DOMAIN_DURATION_MS = 31_000;
 const CONSULTATION_ANSWER_RESERVE_MS = 45_000;
 export const CONSULTATION_DOMAIN_WALL_CLOCK_MS = AGENT_TIMEOUT_MS - CONSULTATION_ANSWER_RESERVE_MS;
diff --git a/frontend/tests/answer-effort-switch-20261013.test.ts b/frontend/tests/answer-effort-switch-20261013.test.ts
new file mode 100644
index 00000000..56611113
--- /dev/null
+++ b/frontend/tests/answer-effort-switch-20261013.test.ts
@@ -0,0 +1,111 @@
+/**
+ * Answer-step reasoning effort (issue #65).
+ * The unset bodies were captured before this switch read the environment:
+ * node node_modules/tsx/dist/cli.mjs scripts/research/answer-effort-probe.mts --dry-run --save-baseline
+ */
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import test from "node:test";
+
+import {
+  consultAnswerReasoningEffort,
+  consultationContinueGenerationSettings,
+  consultationGeneralPrepareStep,
+  consultationGenerationSettings,
+  consultationNatalPrepareStep,
+} from "../src/mastra/consultation-tools.ts";
+import { captureStreamBodies } from "../scripts/research/answer-effort-probe.mts";
+
+const MODEL = {
+  providerId: "deepseek",
+  modelId: "deepseek-flash",
+  url: "http://127.0.0.1:9/v1",
+  apiKey: "dummy",
+};
+
+const fixture = JSON.parse(readFileSync(new URL("./fixtures/answer-effort-switch-20261013.json", import.meta.url), "utf8")) as {
+  natal: unknown[];
+  continue: unknown[];
+};
+
+function withoutEffort(body: unknown) {
+  const copy = { ...(body as Record<string, unknown>) };
+  delete copy.reasoning_effort;
+  return copy;
+}
+
+test("an illegal effort warns once and stays unset", () => {
+  const previous = process.env.CONSULT_ANSWER_REASONING_EFFORT;
+  const seen: unknown[][] = [];
+  const warn = console.warn;
+  console.warn = (...args: unknown[]) => { seen.push(args); };
+  process.env.CONSULT_ANSWER_REASONING_EFFORT = "turbo";
+  try {
+    assert.equal(consultAnswerReasoningEffort(), undefined);
+    assert.equal(consultAnswerReasoningEffort(), undefined);
+    assert.equal(seen.length, 1);
+  } finally {
+    console.warn = warn;
+    if (previous === undefined) delete process.env.CONSULT_ANSWER_REASONING_EFFORT;
+    else process.env.CONSULT_ANSWER_REASONING_EFFORT = previous;
+  }
+});
+
+test("unset effort keeps the pre-change request bodies", 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,
+    });
+    const continued = await captureStreamBodies({
+      settings: consultationContinueGenerationSettings(MODEL),
+      steps: 1,
+    });
+    assert.deepEqual(natal, fixture.natal);
+    assert.deepEqual(continued, fixture.continue);
+  } 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";
+  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.equal(natal[0]?.reasoning_effort, undefined);
+    assert.deepEqual(natal[0], fixture.natal[0]);
+    assert.equal(natal[1]?.reasoning_effort, "low");
+    assert.deepEqual(withoutEffort(natal[1]), fixture.natal[1]);
+    const continued = await captureStreamBodies({
+      settings: consultationContinueGenerationSettings(MODEL),
+      steps: 1,
+    });
+    assert.deepEqual(continued, fixture.continue);
+    const daily = await captureStreamBodies({
+      settings: consultationGenerationSettings(MODEL),
+      prepareStep: (input) => consultationGeneralPrepareStep({ stepNumber: input.stepNumber, model: MODEL }),
+      steps: 1,
+    }) as Record<string, unknown>[];
+    assert.equal(daily[0]?.reasoning_effort, "low");
+  } finally {
+    if (previous === undefined) delete process.env.CONSULT_ANSWER_REASONING_EFFORT;
+    else process.env.CONSULT_ANSWER_REASONING_EFFORT = previous;
+  }
+});
diff --git a/frontend/tests/consult-answer-clock-20261001.test.ts b/frontend/tests/consult-answer-clock-20261001.test.ts
index 4e567a49..8cac8b56 100644
--- a/frontend/tests/consult-answer-clock-20261001.test.ts
+++ b/frontend/tests/consult-answer-clock-20261001.test.ts
@@ -50,6 +50,9 @@ test("the consult route starts the general / no-birth-minute loop on the answer
   );
   // That branch still streams on the shared loop signal and keeps its traces.
   const general = route.match(/if \(usesPublicDailyGeneralAgent\(consultationMode, generalDailyContext\)\) \{[\s\S]*?\n {4}\}\n/)?.[0] ?? "";
-  assert.match(general, /await streamWithOverflowRetry\(agent\)/);
+  // 原值：await streamWithOverflowRetry(agent)
+  // 新值：await streamWithOverflowRetry(agent, generalStreamOptions)
+  // 原因：公开日历从第一步就是答题。开关打开时这一步要带推理强度；不传选项就没有 prepareStep，强度加不上去。开关不设时这些选项不改请求体。
+  assert.match(general, /await streamWithOverflowRetry\(agent, generalStreamOptions\)/);
   assert.match(general, /onError: \(error\) => settleRun\(\s*cancel,/);
 });
diff --git a/frontend/tests/fixtures/answer-effort-switch-20261013.json b/frontend/tests/fixtures/answer-effort-switch-20261013.json
new file mode 100644
index 00000000..a78368a3
--- /dev/null
+++ b/frontend/tests/fixtures/answer-effort-switch-20261013.json
@@ -0,0 +1,131 @@
+{
+  "fixtureProvenance": "node node_modules/tsx/dist/cli.mjs scripts/research/answer-effort-probe.mts --dry-run --save-baseline（开关尚未读取环境变量时的整份请求体）",
+  "natal": [
+    {
+      "model": "deepseek-flash",
+      "max_tokens": 24576,
+      "thinking": {
+        "type": "enabled"
+      },
+      "messages": [
+        {
+          "role": "system",
+          "content": "Reply ok."
+        },
+        {
+          "role": "user",
+          "content": "ping"
+        }
+      ],
+      "tools": [
+        {
+          "type": "function",
+          "function": {
+            "name": "run-jyotish-consultation",
+            "description": "Mark the calculation done.",
+            "parameters": {
+              "type": "object",
+              "properties": {},
+              "additionalProperties": false,
+              "$schema": "http://json-schema.org/draft-07/schema#",
+              "required": []
+            }
+          }
+        }
+      ],
+      "tool_choice": "auto",
+      "stream": true
+    },
+    {
+      "model": "deepseek-flash",
+      "max_tokens": 24576,
+      "thinking": {
+        "type": "enabled"
+      },
+      "messages": [
+        {
+          "role": "system",
+          "content": "Reply ok."
+        },
+        {
+          "role": "user",
+          "content": "ping"
+        },
+        {
+          "role": "assistant",
+          "content": "",
+          "tool_calls": [
+            {
+              "id": "call_1",
+              "type": "function",
+              "function": {
+                "name": "run-jyotish-consultation",
+                "arguments": "{}"
+              }
+            }
+          ]
+        },
+        {
+          "role": "tool",
+          "tool_call_id": "call_1",
+          "content": "{\"ok\":true}"
+        }
+      ],
+      "tools": [
+        {
+          "type": "function",
+          "function": {
+            "name": "run-jyotish-consultation",
+            "description": "Mark the calculation done.",
+            "parameters": {
+              "type": "object",
+              "properties": {},
+              "additionalProperties": false,
+              "$schema": "http://json-schema.org/draft-07/schema#",
+              "required": []
+            }
+          }
+        }
+      ],
+      "tool_choice": "auto",
+      "stream": true
+    }
+  ],
+  "continue": [
+    {
+      "model": "deepseek-flash",
+      "max_tokens": 16384,
+      "thinking": {
+        "type": "disabled"
+      },
+      "messages": [
+        {
+          "role": "system",
+          "content": "Reply ok."
+        },
+        {
+          "role": "user",
+          "content": "ping"
+        }
+      ],
+      "tools": [
+        {
+          "type": "function",
+          "function": {
+            "name": "run-jyotish-consultation",
+            "description": "Mark the calculation done.",
+            "parameters": {
+              "type": "object",
+              "properties": {},
+              "additionalProperties": false,
+              "$schema": "http://json-schema.org/draft-07/schema#",
+              "required": []
+            }
+          }
+        }
+      ],
+      "tool_choice": "auto",
+      "stream": true
+    }
+  ]
+}