diff --git a/plugins/admin/public/index.html b/plugins/admin/public/index.html
index 7096c9ad8..e6b3d6f7e 100644
--- a/plugins/admin/public/index.html
+++ b/plugins/admin/public/index.html
@@ -4246,6 +4246,32 @@ <h2>Ambient behavior</h2>
                   <h2>Models &amp; browsing</h2>
                   <p>The models, browser runtime, and organization context available on future turns.</p>
                 </div>
+                <section class="card setting-row hidden" id="card-interactive-fast-mode">
+                  <div class="head">
+                    <h2>Fast mode for interactive turns</h2>
+                    <p>
+                      Org-wide, default off. When on, human turns run in fast mode on fast-capable models unless the
+                      turn asks otherwise. Requires fast-mode quota with the provider.
+                    </p>
+                  </div>
+                  <div class="body">
+                    <label class="setting-toggle">
+                      <input type="checkbox" id="interactive-fast-mode" />
+                      <span class="setting-switch" aria-hidden="true"></span>
+                      <span class="setting-copy"
+                        ><strong>Default interactive turns to fast mode</strong
+                        ><small
+                          >A turn that picks its own fast-mode setting (for example the web UI toggle) still
+                          wins.</small
+                        ></span
+                      >
+                    </label>
+                  </div>
+                  <div class="foot">
+                    <button class="primary" data-save="interactive-fast-mode">Apply</button
+                    ><span class="status" id="st-interactive-fast-mode"></span>
+                  </div>
+                </section>
                 <section class="card setting-row hidden" id="card-base-model">
                   <div class="head">
                     <h2>Default harness and model</h2>
@@ -6212,6 +6238,9 @@ <h2 id="governance-review-title">Confirm governance change</h2>
         const showOrgAmbient = scope.startsWith("org:") && "orgAmbient" in r.data;
         $("card-org-ambient").classList.toggle("hidden", !showOrgAmbient);
         if (showOrgAmbient) $("org-ambient").checked = r.data.orgAmbient !== false;
+        const showInteractiveFastMode = scope.startsWith("org:") && "interactiveFastMode" in r.data;
+        $("card-interactive-fast-mode").classList.toggle("hidden", !showInteractiveFastMode);
+        if (showInteractiveFastMode) $("interactive-fast-mode").checked = r.data.interactiveFastMode === true;
 
         const opts = r.data.baseModelOptions || [];
         const dflt = r.data.baseModelDefault || "";
@@ -7694,6 +7723,7 @@ <h2 id="governance-review-title">Confirm governance change</h2>
         egress: () => collectEgress(),
         "external-slack-participants": () => ({ on: $("external-slack-participants").checked }),
         "org-ambient": () => ({ on: $("org-ambient").checked }),
+        "interactive-fast-mode": () => ({ on: $("interactive-fast-mode").checked }),
         runtime: () => ({ harnessId: $("base-harness").value, modelId: $("base-model").value }),
         "approved-harnesses": () => ({
           ids: Array.from(document.querySelectorAll("#approved-harnesses-list input[type=checkbox]:checked")).map(
@@ -7727,6 +7757,7 @@ <h2 id="governance-review-title">Confirm governance change</h2>
         egress: "st-egress",
         "external-slack-participants": "st-external-slack-participants",
         "org-ambient": "st-org-ambient",
+        "interactive-fast-mode": "st-interactive-fast-mode",
         runtime: "st-runtime",
         "approved-harnesses": "st-approved-harnesses",
         "webui-models": "st-webui-models",
diff --git a/plugins/web-ui/src/chat.ts b/plugins/web-ui/src/chat.ts
index 170e67350..44a3c1826 100644
--- a/plugins/web-ui/src/chat.ts
+++ b/plugins/web-ui/src/chat.ts
@@ -346,7 +346,9 @@ function currentTurnOptions(): TurnOptions {
   const { harnessId: harness } = currentModelOption();
   return {
     ...(harnessSupportsEffort(harness) ? { effortLevel: composerState.effortLevel } : {}),
-    ...(harnessSupportsFastMode(harness) ? { fastMode: composerState.fastMode } : {}),
+    ...(harnessSupportsFastMode(harness) && typeof composerState.fastMode === "boolean"
+      ? { fastMode: composerState.fastMode }
+      : {}),
     harness,
     scopeId: chatState.scopeId,
     channelName: chatState.contextName,
diff --git a/plugins/web-ui/src/composer.ts b/plugins/web-ui/src/composer.ts
index 51080c2c5..03fe4fe5a 100644
--- a/plugins/web-ui/src/composer.ts
+++ b/plugins/web-ui/src/composer.ts
@@ -118,7 +118,7 @@ function modelOptionFor(value: ModelOptionValue): ModelOption {
   );
 }
 
-function loadStoredFastMode(): boolean {
+function loadStoredFastMode(): boolean | undefined {
   try {
     const stored = localStorage.getItem(FAST_MODE_STORAGE_KEY);
     if (stored === "0") return false;
@@ -126,7 +126,7 @@ function loadStoredFastMode(): boolean {
   } catch {
     void 0;
   }
-  return true;
+  return undefined;
 }
 
 function loadStoredEffort(fallback: EffortLevel): EffortLevel {
@@ -209,6 +209,11 @@ let dragDepth = 0;
 let skillsLoading = false;
 let slashActiveIndex = 0;
 let fastModeCharging = false;
+let orgFastModeDefault = false;
+
+function effectiveFastMode(): boolean {
+  return composerState.fastMode ?? orgFastModeDefault;
+}
 let fastModeChargeTimer: ReturnType<typeof setTimeout> | null = null;
 
 export function resetComposer(): void {
@@ -242,6 +247,7 @@ export async function refreshRuntimeSelection(scopeId: string | null, agent?: Ag
   }
   activeRuntimeConfig = config;
   setFastModeModelIds(config.fastModeModelIds);
+  orgFastModeDefault = config.interactiveFastMode === true;
   applyRuntimeOptions(config.approvedHarnesses, config.modelsByHarness, config.effective, config.modelCatalog);
   if (agent && (!chatState.threadRef || !threadModelPicks.has(chatState.threadRef)))
     agent.state.model = currentModelOption().model;
@@ -260,6 +266,7 @@ async function changeScopeRuntime(
     if (request !== runtimeRequest || scopeId !== chatState.scopeId) return;
     activeRuntimeConfig = config;
     setFastModeModelIds(config.fastModeModelIds);
+    orgFastModeDefault = config.interactiveFastMode === true;
     applyRuntimeOptions(config.approvedHarnesses, config.modelsByHarness, config.effective, config.modelCatalog);
     if (!chatState.threadRef || !threadModelPicks.has(chatState.threadRef))
       agent.state.model = currentModelOption().model;
@@ -285,7 +292,7 @@ export function composerForm(agent: Agent): TemplateResult {
   const effortAvailable = harnessSupportsEffort(selectedModel.harnessId);
   const fastSupported = harnessSupportsFastMode(selectedModel.harnessId);
   const fastAvailable = fastSupported && modelSupportsFastMode(selectedModel.model.id);
-  const fastOn = fastAvailable && composerState.fastMode;
+  const fastOn = fastAvailable && effectiveFastMode();
   const fastCharging = fastModeCharging && fastOn;
   let fastTitle = "Fast mode is only available on Opus models";
   if (fastAvailable) fastTitle = fastOn ? "Fast mode active" : "Fast mode";
@@ -676,7 +683,7 @@ function composerApprovalPanel(approvals: PendingApproval[]): TemplateResult {
 function settingsControl(agent: Agent, selected: ModelOption, disabled: boolean): TemplateResult {
   const open = composerState.openMenu === "settings";
   const fastAvailable = harnessSupportsFastMode(selected.harnessId) && modelSupportsFastMode(selected.model.id);
-  const fastOn = fastAvailable && composerState.fastMode;
+  const fastOn = fastAvailable && effectiveFastMode();
   const summary = `${selected.buttonLabel} · ${effortLabel(composerState.effortLevel)}${fastOn ? " · Fast" : ""}`;
   return html`
     <div class="menu-control settings-control ${open ? "open" : ""}" data-align="right">
@@ -1305,13 +1312,13 @@ function selectEffort(level: EffortLevel, agent: Agent): void {
 function toggleFastMode(agent: Agent): void {
   if (hasUnresolvedApproval() || chatState.resolvingApprovals.size > 0) return;
   if (!modelSupportsFastMode(currentModelOption().model.id)) return;
-  composerState.fastMode = !composerState.fastMode;
+  composerState.fastMode = !effectiveFastMode();
   persistPreference(FAST_MODE_STORAGE_KEY, composerState.fastMode ? "1" : "0");
   if (fastModeChargeTimer) {
     clearTimeout(fastModeChargeTimer);
     fastModeChargeTimer = null;
   }
-  fastModeCharging = composerState.fastMode;
+  fastModeCharging = composerState.fastMode === true;
   drawActiveChat(agent);
   if (fastModeCharging) {
     fastModeChargeTimer = setTimeout(() => {
diff --git a/plugins/web-ui/src/core-bridge.ts b/plugins/web-ui/src/core-bridge.ts
index 6cea6c38e..d06e0e767 100644
--- a/plugins/web-ui/src/core-bridge.ts
+++ b/plugins/web-ui/src/core-bridge.ts
@@ -406,6 +406,7 @@ export interface RuntimeConfig {
   effective: { harnessId: string; modelId: string };
   upgradeAvailable: boolean;
   fastModeModelIds?: string[];
+  interactiveFastMode?: boolean;
 }
 
 export async function fetchRuntimeConfig(scopeId?: string | null): Promise<RuntimeConfig | null> {
diff --git a/src/api/routes/admin-resources.ts b/src/api/routes/admin-resources.ts
index c87c6851b..6d3c2f22f 100644
--- a/src/api/routes/admin-resources.ts
+++ b/src/api/routes/admin-resources.ts
@@ -326,6 +326,23 @@ export const ADMIN_RESOURCES: readonly AdminResource[] = [
       (deps, _scope, on) => deps.config!.setOrgAmbient(on),
     ),
   },
+  {
+    id: "interactive-fast-mode",
+    kind: "boolean",
+    target: "org",
+    label:
+      "Fast mode for interactive turns org-wide: on means human turns run in fast mode on fast-capable models unless the turn asks otherwise. Requires fast-mode quota with the provider.",
+    readKey: "interactiveFastMode",
+    get: (deps, scope) => (parseScopeId(scope).kind === "org" ? deps.config!.getInteractiveFastMode() : undefined),
+    apply: generic<boolean>(
+      (body, { scope }) => {
+        const bad = orgOnly(scope, "the interactive fast-mode switch is org-wide");
+        if (bad) return bad;
+        return boolBody(body);
+      },
+      (deps, _scope, on) => deps.config!.setInteractiveFastMode(on),
+    ),
+  },
   {
     id: "base-model",
     kind: "enum",
diff --git a/src/api/routes/surface.ts b/src/api/routes/surface.ts
index ae2120bf6..9ddc0d194 100644
--- a/src/api/routes/surface.ts
+++ b/src/api/routes/surface.ts
@@ -1004,6 +1004,7 @@ async function runtimeConfigBody(ctx: ApiCtx, scope: ScopeId): Promise<Record<st
     effective: { harnessId: effective.harnessId, modelId: effective.modelId },
     upgradeAvailable: Boolean(scopeOverride && scopeOverride.orgRevision !== orgDefault.revision),
     fastModeModelIds: FAST_MODE_MODEL_IDS,
+    interactiveFastMode: await config.getInteractiveFastModeDurable(),
   };
 }
 
diff --git a/src/core/orchestrator.ts b/src/core/orchestrator.ts
index e37a21f3b..0e9802b2b 100644
--- a/src/core/orchestrator.ts
+++ b/src/core/orchestrator.ts
@@ -12,6 +12,7 @@ import type {
 } from "../types.ts";
 import { scopeId as toScopeId, personalScope } from "../types.ts";
 import { turnOriginRequestFields } from "./turn-origin.ts";
+import { resolveTurnFastMode } from "./turn-options.ts";
 import { orgId } from "../config.ts";
 import { renderGatewayContext } from "./gateway-context.ts";
 import { deriveTurnOutcome, approvalBlocksInput } from "./turn-outcome.ts";
@@ -2032,6 +2033,9 @@ export function createOrchestrator(deps: OrchestratorDeps): Orchestrator {
               ? Math.min(requestedTurnWallClockMs, configuredTurnWallClockMs)
               : requestedTurnWallClockMs;
         }
+        const wantsOrgFastMode =
+          typeof input.fastMode !== "boolean" && humanTurn && (await deps.config?.getInteractiveFastModeDurable());
+        const effectiveFastMode = resolveTurnFastMode(input.fastMode, humanTurn, wantsOrgFastMode === true);
         const runHarnessTurn = (
           harnessInput: string,
           extras: {
@@ -2069,7 +2073,7 @@ export function createOrchestrator(deps: OrchestratorDeps): Orchestrator {
             ...(input.harness ? { harness: input.harness } : {}),
             ...(input.model ? { model: input.model } : {}),
             ...(input.thinkingLevel ? { thinkingLevel: input.thinkingLevel } : {}),
-            ...(typeof input.fastMode === "boolean" ? { fastMode: input.fastMode } : {}),
+            ...(typeof effectiveFastMode === "boolean" ? { fastMode: effectiveFastMode } : {}),
             ...(strictReadOnly ? { readOnly: true } : {}),
             ...(input.surfaceTools && surfaceToolDeps
               ? {
diff --git a/src/core/turn-options.ts b/src/core/turn-options.ts
index 984dc3029..850688bf0 100644
--- a/src/core/turn-options.ts
+++ b/src/core/turn-options.ts
@@ -11,6 +11,15 @@ import {
 export const NON_INTERACTIVE_THINKING_LEVEL = "xhigh";
 export const NON_INTERACTIVE_FAST_MODE = false;
 
+export function resolveTurnFastMode(
+  requested: boolean | undefined,
+  humanTurn: boolean,
+  interactiveDefault: boolean,
+): boolean | undefined {
+  if (typeof requested === "boolean") return requested;
+  return humanTurn && interactiveDefault ? true : undefined;
+}
+
 export function turnModelOptions(input: { triggered?: boolean; thinkingLevel?: string; fastMode?: boolean }): {
   thinkingLevel?: string;
   fastMode?: boolean;
diff --git a/src/resolution/config-store.ts b/src/resolution/config-store.ts
index 2b33efb89..cba1a0e04 100644
--- a/src/resolution/config-store.ts
+++ b/src/resolution/config-store.ts
@@ -168,6 +168,9 @@ export interface ScopedConfigStore {
   getOrgAmbient(): boolean;
   setOrgAmbient(on: boolean): void;
   getOrgAmbientDurable(): Promise<boolean>;
+  getInteractiveFastMode(): boolean;
+  setInteractiveFastMode(on: boolean): void;
+  getInteractiveFastModeDurable(): Promise<boolean>;
   getBaseModelOwnDurable(id: ScopeId): Promise<string | null>;
   getWebuiModels(id: ScopeId): string[] | null;
   setWebuiModels(id: ScopeId, ids: string[] | null): void;
@@ -209,6 +212,7 @@ export function createMemoryConfigStore(
     baseModels?: DurableMap<PersistedBaseModel>;
     approvedHarnesses?: DurableMap<PersistedApprovedHarnesses>;
     orgAmbient?: DurableMap<PersistedScopedFlag>;
+    interactiveFastMode?: DurableMap<PersistedScopedFlag>;
     webuiModels?: DurableMap<PersistedWebuiModels>;
     peopleDirectoryUrls?: DurableMap<PersistedPeopleDirectoryUrl>;
     branding?: DurableMap<PersistedBranding>;
@@ -232,6 +236,7 @@ export function createMemoryConfigStore(
   const baseModels = new Map<ScopeId, PersistedBaseModel>();
   let approvedHarnesses: string[] | null = null;
   let orgAmbient = true;
+  let interactiveFastMode = false;
   const webuiModels = new Map<ScopeId, string[]>();
   const peopleDirectoryUrls = new Map<ScopeId, string>();
   const branding = new Map<ScopeId, OrgBranding>();
@@ -249,6 +254,7 @@ export function createMemoryConfigStore(
   const baseModelStore = opts.baseModels ?? createMemoryMap<PersistedBaseModel>();
   const approvedHarnessStore = opts.approvedHarnesses ?? createMemoryMap<PersistedApprovedHarnesses>();
   const orgAmbientStore = opts.orgAmbient ?? createMemoryMap<PersistedScopedFlag>();
+  const interactiveFastModeStore = opts.interactiveFastMode ?? createMemoryMap<PersistedScopedFlag>();
   const webuiModelStore = opts.webuiModels ?? createMemoryMap<PersistedWebuiModels>();
   const peopleDirectoryUrlStore = opts.peopleDirectoryUrls ?? createMemoryMap<PersistedPeopleDirectoryUrl>();
   const brandingStore = opts.branding ?? createMemoryMap<PersistedBranding>();
@@ -377,6 +383,7 @@ export function createMemoryConfigStore(
           for (const r of await baseModelStore.all()) baseModels.set(r.scopeId, r);
           approvedHarnesses = (await approvedHarnessStore.get(org))?.ids ?? null;
           orgAmbient = (await orgAmbientStore.get(org))?.on ?? true;
+          interactiveFastMode = (await interactiveFastModeStore.get(org))?.on ?? false;
           for (const r of await webuiModelStore.all()) webuiModels.set(r.scopeId, r.ids);
           for (const r of await peopleDirectoryUrlStore.all()) peopleDirectoryUrls.set(r.scopeId, r.url);
           for (const r of await brandingStore.all()) branding.set(r.scopeId, r.branding);
@@ -712,6 +719,14 @@ export function createMemoryConfigStore(
       persist(`orgAmbient:${org}`, "org ambient switch", () => orgAmbientStore.put(org, { scopeId: org, on }));
     },
     getOrgAmbientDurable: async () => (await orgAmbientStore.get(org))?.on ?? true,
+    getInteractiveFastMode: () => interactiveFastMode,
+    setInteractiveFastMode(on) {
+      interactiveFastMode = on;
+      persist(`interactiveFastMode:${org}`, "interactive fast mode switch", () =>
+        interactiveFastModeStore.put(org, { scopeId: org, on }),
+      );
+    },
+    getInteractiveFastModeDurable: async () => (await interactiveFastModeStore.get(org))?.on ?? false,
     getBaseModelOwnDurable: async (id) => (await baseModelStore.get(id))?.modelId ?? null,
     getBaseModelDurable: async (id) =>
       (await baseModelStore.get(id))?.modelId ??
@@ -859,6 +874,7 @@ export function createMemoryConfigStore(
         approved,
         brandingRow,
         orgAmbientRow,
+        interactiveFastModeRow,
       ] = await Promise.all([
         soulStore.get(id),
         commandPolicyStore.get(id),
@@ -871,6 +887,7 @@ export function createMemoryConfigStore(
         id === org ? approvedHarnessStore.get(org) : null,
         brandingStore.get(id),
         id === org ? orgAmbientStore.get(org) : null,
+        id === org ? interactiveFastModeStore.get(org) : null,
       ]);
       let refreshedSoul = soul;
       const legacyHistory = legacySoulHistory.get(id) ?? [];
@@ -908,6 +925,7 @@ export function createMemoryConfigStore(
       else baseModels.delete(id);
       if (id === org) approvedHarnesses = approved?.ids ?? null;
       if (id === org) orgAmbient = orgAmbientRow?.on ?? true;
+      if (id === org) interactiveFastMode = interactiveFastModeRow?.on ?? false;
       if (brandingRow) branding.set(id, brandingRow.branding);
       else branding.delete(id);
     },
@@ -922,7 +940,7 @@ export function createMemoryConfigStore(
         `model:${id}`,
         `turnWallClock:${id}`,
         `branding:${id}`,
-        ...(id === org ? [`approvedHarnesses:${org}`, `orgAmbient:${org}`] : []),
+        ...(id === org ? [`approvedHarnesses:${org}`, `orgAmbient:${org}`, `interactiveFastMode:${org}`] : []),
       ];
       await Promise.all(
         keys.map(async (key) => {
diff --git a/src/wiring.ts b/src/wiring.ts
index f78e98bdd..684365420 100644
--- a/src/wiring.ts
+++ b/src/wiring.ts
@@ -424,6 +424,7 @@ export function buildApp(
     baseModels: artifactMap<PersistedBaseModel>("base_model_configs"),
     approvedHarnesses: artifactMap<PersistedApprovedHarnesses>("approved_harness_configs"),
     orgAmbient: artifactMap<PersistedScopedFlag>("org_ambient_flag"),
+    interactiveFastMode: artifactMap<PersistedScopedFlag>("interactive_fast_mode_flag"),
     webuiModels: artifactMap<PersistedWebuiModels>("webui_model_configs"),
     peopleDirectoryUrls: artifactMap<PersistedPeopleDirectoryUrl>("people_directory_urls"),
     branding: artifactMap<PersistedBranding>("branding_configs"),
diff --git a/test/interactive-fast-mode.test.ts b/test/interactive-fast-mode.test.ts
new file mode 100644
index 000000000..151ddd38f
--- /dev/null
+++ b/test/interactive-fast-mode.test.ts
@@ -0,0 +1,41 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { createMemoryMap } from "../src/persistence/durable-map.ts";
+import { createMemoryConfigStore, type PersistedScopedFlag } from "../src/resolution/config-store.ts";
+import { scopeId } from "../src/types.ts";
+import { resolveTurnFastMode } from "../src/core/turn-options.ts";
+
+test("interactive fast mode defaults off and persists across instances", async () => {
+  const interactiveFastMode = createMemoryMap<PersistedScopedFlag>();
+  const first = createMemoryConfigStore("org", { interactiveFastMode });
+  await first.hydrate!();
+  assert.equal(first.getInteractiveFastMode(), false);
+  assert.equal(await first.getInteractiveFastModeDurable(), false);
+
+  first.setInteractiveFastMode(true);
+  assert.equal(first.getInteractiveFastMode(), true);
+  await first.flushScope(scopeId("org", "org"));
+
+  const second = createMemoryConfigStore("org", { interactiveFastMode });
+  await second.hydrate!();
+  assert.equal(second.getInteractiveFastMode(), true);
+  assert.equal(await second.getInteractiveFastModeDurable(), true);
+});
+
+test("the org default reaches only human turns that expressed no preference", () => {
+  assert.equal(resolveTurnFastMode(undefined, true, true), true);
+  assert.equal(resolveTurnFastMode(undefined, true, false), undefined);
+  assert.equal(resolveTurnFastMode(undefined, false, true), undefined);
+  assert.equal(resolveTurnFastMode(false, true, true), false);
+  assert.equal(resolveTurnFastMode(true, false, false), true);
+});
+
+test("refreshScope picks up an interactive fast mode change written elsewhere", async () => {
+  const interactiveFastMode = createMemoryMap<PersistedScopedFlag>();
+  const store = createMemoryConfigStore("org", { interactiveFastMode });
+  await store.hydrate!();
+  const org = scopeId("org", "org");
+  await interactiveFastMode.put(org, { scopeId: org, on: true });
+  await store.refreshScope(org);
+  assert.equal(store.getInteractiveFastMode(), true);
+});