diff --git a/packages/core/types/index.ts b/packages/core/types/index.ts
index d5dcd0045b..a5fa932c44 100644
--- a/packages/core/types/index.ts
+++ b/packages/core/types/index.ts
@@ -36,6 +36,8 @@ export type {
   RuntimeUpdate,
   RuntimeUpdateStatus,
   RuntimeModel,
+  RuntimeModelThinking,
+  RuntimeModelThinkingLevel,
   RuntimeModelListRequest,
   RuntimeModelListStatus,
   RuntimeModelsResult,
diff --git a/packages/views/agents/components/agent-detail-inspector.tsx b/packages/views/agents/components/agent-detail-inspector.tsx
index 103ad86d9b..f796960a63 100644
--- a/packages/views/agents/components/agent-detail-inspector.tsx
+++ b/packages/views/agents/components/agent-detail-inspector.tsx
@@ -8,10 +8,12 @@ import {
 } from "react";
 import { Camera, Loader2, Pencil } from "lucide-react";
 import { toast } from "sonner";
+import { useQuery } from "@tanstack/react-query";
 import type {
   Agent,
   AgentRuntime,
   MemberWithUser,
+  RuntimeModel,
 } from "@multica/core/types";
 import {
   AGENT_DESCRIPTION_MAX_LENGTH,
@@ -19,6 +21,7 @@ import {
 } from "@multica/core/agents";
 import { api } from "@multica/core/api";
 import { useFileUpload } from "@multica/core/hooks/use-file-upload";
+import { runtimeModelsOptions } from "@multica/core/runtimes";
 import { isImeComposing, timeAgo } from "@multica/core/utils";
 import { Button } from "@multica/ui/components/ui/button";
 import { ActorAvatar } from "../../common/actor-avatar";
@@ -43,6 +46,7 @@ import { ConcurrencyPicker } from "./inspector/concurrency-picker";
 import { ModelPicker } from "./inspector/model-picker";
 import { RuntimePicker } from "./inspector/runtime-picker";
 import { SkillAttach } from "./inspector/skill-attach";
+import { ThinkingPicker } from "./inspector/thinking-picker";
 import { VisibilityPicker } from "./inspector/visibility-picker";
 
 interface InspectorProps {
@@ -130,6 +134,14 @@ export function AgentDetailInspector({
             onChange={(m) => update({ model: m })}
           />
         </PropRow>
+        <ThinkingPropRow
+          runtimeId={agent.runtime_id}
+          runtimeOnline={!!isOnline}
+          model={agent.model ?? ""}
+          value={agent.thinking_level ?? ""}
+          canEdit={canEdit}
+          onChange={(v) => update({ thinking_level: v })}
+        />
         <PropRow label={t(($) => $.inspector.prop_visibility)} interactive={false}>
           <VisibilityPicker
             value={agent.visibility}
@@ -221,6 +233,59 @@ function Section({
   );
 }
 
+// ---------------------------------------------------------------------------
+// Thinking row — hidden entirely when the active model has no
+// `supported_levels` advertised. Reuses the shared runtime-models query so
+// it hits the same 60s cache as the model picker; no extra round-trip on
+// the inspector's hot path.
+// ---------------------------------------------------------------------------
+
+function ThinkingPropRow({
+  runtimeId,
+  runtimeOnline,
+  model,
+  value,
+  canEdit,
+  onChange,
+}: {
+  runtimeId: string | null;
+  runtimeOnline: boolean;
+  model: string;
+  value: string;
+  canEdit: boolean;
+  onChange: (next: string) => Promise<void> | void;
+}) {
+  const { t } = useT("agents");
+  const modelsQuery = useQuery(
+    runtimeModelsOptions(runtimeOnline ? runtimeId : null),
+  );
+
+  const models = modelsQuery.data?.models ?? [];
+  const entry = pickModelEntry(models, model);
+  const levels = entry?.thinking?.supported_levels ?? [];
+  if (levels.length === 0) return null;
+
+  return (
+    <PropRow label={t(($) => $.inspector.prop_thinking)} interactive={false}>
+      <ThinkingPicker
+        value={value}
+        levels={levels}
+        defaultLevel={entry?.thinking?.default_level}
+        canEdit={canEdit}
+        onChange={onChange}
+      />
+    </PropRow>
+  );
+}
+
+function pickModelEntry(
+  models: RuntimeModel[],
+  model: string,
+): RuntimeModel | undefined {
+  if (model) return models.find((m) => m.id === model);
+  return models.find((m) => m.default) ?? models[0];
+}
+
 // ---------------------------------------------------------------------------
 // Identity — avatar / name / description editors
 // ---------------------------------------------------------------------------
diff --git a/packages/views/agents/components/inspector/thinking-picker.tsx b/packages/views/agents/components/inspector/thinking-picker.tsx
new file mode 100644
index 0000000000..8c309d4f93
--- /dev/null
+++ b/packages/views/agents/components/inspector/thinking-picker.tsx
@@ -0,0 +1,127 @@
+"use client";
+
+import { useState } from "react";
+import type { RuntimeModelThinkingLevel } from "@multica/core/types";
+import {
+  PickerItem,
+  PropertyPicker,
+} from "../../../issues/components/pickers";
+import { CHIP_CLASS } from "./chip";
+import { useT } from "../../../i18n";
+
+/**
+ * Per-agent reasoning/effort picker (MUL-2339). Renders only when the
+ * current model exposes a non-empty `supported_levels` set — Claude and
+ * Codex today; every other provider gets nothing. The catalog is daemon-
+ * discovered, so the value/label pairs match each CLI's own UI (`Low`,
+ * `Extra high`, …) verbatim; never normalised across providers.
+ *
+ * The empty string is the "use model default" sentinel and renders as
+ * "Default" in the chip, with the discovered `default_level` (when
+ * present) badged inside the popover so the user can see what they'll
+ * get if they clear.
+ */
+export function ThinkingPicker({
+  value,
+  levels,
+  defaultLevel,
+  canEdit = true,
+  onChange,
+}: {
+  /** Persisted thinking_level — "" means "use model default". */
+  value: string;
+  /** Supported levels for the current (runtime, model) pair. Caller has
+   *  already verified the list is non-empty before mounting this picker. */
+  levels: RuntimeModelThinkingLevel[];
+  /** Level the runtime uses when no override is sent. Surfaced as a badge
+   *  in the popover. */
+  defaultLevel?: string;
+  /** When false, render a static read-only display and skip the popover. */
+  canEdit?: boolean;
+  onChange: (next: string) => Promise<void> | void;
+}) {
+  const { t } = useT("agents");
+  const [open, setOpen] = useState(false);
+
+  const selected = value ? levels.find((l) => l.value === value) : undefined;
+  const triggerLabel = selected
+    ? selected.label
+    : t(($) => $.pickers.thinking_default);
+  const triggerTitle = t(($) => $.pickers.thinking_tooltip, {
+    value: triggerLabel,
+  });
+
+  const select = async (next: string) => {
+    setOpen(false);
+    if (next !== value) await onChange(next);
+  };
+
+  if (!canEdit) {
+    return (
+      <span
+        className="min-w-0 truncate px-1.5 py-0.5 font-mono text-[11px] text-muted-foreground"
+        title={triggerTitle}
+      >
+        {triggerLabel}
+      </span>
+    );
+  }
+
+  return (
+    <PropertyPicker
+      open={open}
+      onOpenChange={setOpen}
+      width="w-auto min-w-[14rem] max-w-md"
+      align="start"
+      tooltip={triggerTitle}
+      triggerRender={
+        <button
+          type="button"
+          className={CHIP_CLASS}
+          aria-label={triggerTitle}
+        />
+      }
+      trigger={
+        <span className="min-w-0 truncate font-mono text-[11px]">
+          {triggerLabel}
+        </span>
+      }
+    >
+      {levels.map((l) => (
+        <PickerItem
+          key={l.value}
+          selected={l.value === value}
+          onClick={() => void select(l.value)}
+          tooltip={l.description || (l.label !== l.value ? `${l.label} · ${l.value}` : l.value)}
+        >
+          <div className="min-w-0 flex-1">
+            <div className="flex items-center gap-1.5">
+              <span className="truncate font-medium">{l.label}</span>
+              {l.value === defaultLevel && (
+                <span className="shrink-0 rounded bg-primary/10 px-1 text-[10px] font-medium text-primary">
+                  {t(($) => $.pickers.thinking_default_badge)}
+                </span>
+              )}
+            </div>
+            {l.description && (
+              <div className="truncate text-[10px] text-muted-foreground">
+                {l.description}
+              </div>
+            )}
+          </div>
+        </PickerItem>
+      ))}
+
+      {value && (
+        <button
+          type="button"
+          onClick={() => void select("")}
+          className="mt-1 flex w-full items-center border-t px-3 py-2 text-left text-xs text-muted-foreground transition-colors hover:bg-accent/50"
+          title={t(($) => $.pickers.thinking_clear_title)}
+        >
+          {t(($) => $.pickers.thinking_clear)}
+        </button>
+      )}
+    </PropertyPicker>
+  );
+}
diff --git a/packages/views/locales/en/agents.json b/packages/views/locales/en/agents.json
index 4a7917fe50..5c657073f9 100644
--- a/packages/views/locales/en/agents.json
+++ b/packages/views/locales/en/agents.json
@@ -130,6 +130,7 @@
     "section_skills": "Skills",
     "prop_runtime": "Runtime",
     "prop_model": "Model",
+    "prop_thinking": "Thinking",
     "prop_visibility": "Visibility",
     "prop_concurrency": "Concurrency",
     "prop_owner": "Owner",
@@ -172,7 +173,12 @@
     "model_custom_tooltip": "Use \"{{value}}\" as a custom model id",
     "model_custom_use": "Use \"{{value}}\"",
     "model_clear": "Clear (use provider default)",
-    "model_clear_title": "Clear and fall back to the runtime's provider default"
+    "model_clear_title": "Clear and fall back to the runtime's provider default",
+    "thinking_default": "Default",
+    "thinking_tooltip": "Thinking · {{value}}",
+    "thinking_default_badge": "default",
+    "thinking_clear": "Use model default",
+    "thinking_clear_title": "Clear and fall back to this model's default reasoning level"
   },
   "model_dropdown": {
     "label": "Model",
diff --git a/packages/views/locales/zh-Hans/agents.json b/packages/views/locales/zh-Hans/agents.json
index 793ca12277..db84c0a456 100644
--- a/packages/views/locales/zh-Hans/agents.json
+++ b/packages/views/locales/zh-Hans/agents.json
@@ -126,6 +126,7 @@
     "section_skills": "skill",
     "prop_runtime": "运行时",
     "prop_model": "模型",
+    "prop_thinking": "思考",
     "prop_visibility": "可见性",
     "prop_concurrency": "并发",
     "prop_owner": "所有者",
@@ -168,7 +169,12 @@
     "model_custom_tooltip": "使用\"{{value}}\"作为自定义模型 ID",
     "model_custom_use": "使用\"{{value}}\"",
     "model_clear": "清除（使用提供方默认）",
-    "model_clear_title": "清除并回退到运行时的提供方默认"
+    "model_clear_title": "清除并回退到运行时的提供方默认",
+    "thinking_default": "默认",
+    "thinking_tooltip": "思考 · {{value}}",
+    "thinking_default_badge": "默认",
+    "thinking_clear": "使用模型默认",
+    "thinking_clear_title": "清除并回退到该模型的默认推理级别"
   },
   "model_dropdown": {
     "label": "模型",