feat(subagent): thread explicit parent effort to workers

src/exec/runner.ts

@@ -714,7 +714,12 @@ export async function runExec(config: Config): Promise<ExecResult> {
     });
 
     const liveSubAgentProvider: { current: SubAgentProvider } = {
-      current: buildSubAgentProvider(config),
+      current: buildSubAgentProvider({
+        ...config,
+        ...(config.reasoningEffort !== undefined
+          ? { explicitReasoningEffort: true }
+          : {}),
+      }),
     };
     const fleetSessions = createSubAgentSessionStore({
       admission: getProcessAdmissionQueue(),

src/provider/reasoning-effort.test.ts

@@ -379,6 +379,61 @@ describe("pickEffortFromCascade (precedence table)", () => {
       }),
     ).toBeUndefined();
   });
+
+  test("6. explicit parent outranks role default (CL-10227)", () => {
+    expect(
+      pickEffortFromCascade({
+        roleDefault: "medium",
+        parentEffort: "none",
+        explicitParentEffort: true,
+        supported: ["none", "low", "medium", "high"],
+      }),
+    ).toBe("none");
+  });
+
+  test("6b. explicit parent wins even when role default is supported", () => {
+    expect(
+      pickEffortFromCascade({
+        roleDefault: "medium",
+        parentEffort: "high",
+        explicitParentEffort: true,
+        supported: ["low", "medium", "high"],
+      }),
+    ).toBe("high");
+  });
+
+  test("6c. unsupported explicit parent is clamped onto supported", () => {
+    expect(
+      pickEffortFromCascade({
+        roleDefault: "medium",
+        parentEffort: "xhigh",
+        explicitParentEffort: true,
+        supported: ["low", "medium", "high"],
+      }),
+    ).toBe("high");
+  });
+
+  test("7. explicit pin still wins over explicit parent", () => {
+    expect(
+      pickEffortFromCascade({
+        pin: "low",
+        roleDefault: "medium",
+        parentEffort: "xhigh",
+        explicitParentEffort: true,
+        supported: ["low", "medium", "high"],
+      }),
+    ).toBe("low");
+  });
+
+  test("8. unset explicitParentEffort keeps role default above parent (CL-5162)", () => {
+    expect(
+      pickEffortFromCascade({
+        roleDefault: "medium",
+        parentEffort: "high",
+        supported: ["low", "medium", "high"],
+      }),
+    ).toBe("medium");
+  });
 });
 
 describe("resolveEffortForRole", () => {
@@ -455,6 +510,50 @@ describe("resolveEffortForRole", () => {
       }),
     ).toBe("high");
   });
+
+  test("explicit parent none wins over leaf role default (CL-10227)", () => {
+    expect(
+      resolveEffortForRole({
+        orchestrator: false,
+        parentEffort: "none",
+        explicitParentEffort: true,
+        model: "gpt-5.1",
+      }),
+    ).toBe("none");
+  });
+
+  test("explicit parent overrides orchestrator high default", () => {
+    expect(
+      resolveEffortForRole({
+        orchestrator: true,
+        parentEffort: "low",
+        explicitParentEffort: true,
+        model: "gpt-5",
+      }),
+    ).toBe("low");
+  });
+
+  test("unset parent keeps leaf role default (CL-5162)", () => {
+    expect(
+      resolveEffortForRole({
+        orchestrator: false,
+        parentEffort: "high",
+        model: "gpt-5",
+      }),
+    ).toBe("medium");
+  });
+
+  test("explicit pin wins over explicit parent", () => {
+    expect(
+      resolveEffortForRole({
+        orchestrator: false,
+        pin: "low",
+        parentEffort: "high",
+        explicitParentEffort: true,
+        model: "gpt-5",
+      }),
+    ).toBe("low");
+  });
 });
 
 describe("defaultEffortForModel", () => {

src/provider/reasoning-effort.ts

@@ -382,6 +382,8 @@ export interface ResolveEffortForRoleOpts {
   roleDefault?: ReasoningEffort;
   /** Parent session effort — used only when the role default is not supported. */
   parentEffort?: ReasoningEffort;
+  /** Marker when the parent effort was operator-chosen (see SubAgentProvider). */
+  explicitParentEffort?: true;
   model: string;
   isCodex?: boolean;
   providerEfforts?: readonly ReasoningEffort[];
@@ -393,10 +395,12 @@ export interface ResolveEffortForRoleOpts {
  *
  * Precedence (first match wins):
  * 1. Explicit pin (clamped onto supported when the pin is not in the set)
- * 2. Role default when present in `supported`
- * 3. Parent effort when present in `supported`
- * 4. Clamp of role default onto `supported`
- * 5. undefined when `supported` is empty
+ * 2. Explicit parent effort (operator-chosen fleet pin) when present in
+ *    `supported` — clamped onto the set when not (CL-10227)
+ * 3. Role default when present in `supported`
+ * 4. Parent effort when present in `supported`
+ * 5. Clamp of role default onto `supported`
+ * 6. undefined when `supported` is empty
  *
  * Pins are still highest precedence, but an unsupported pin is clamped so the
  * pure API owns the "never emit an unsupported effort" invariant (callers that
@@ -406,6 +410,7 @@ export function pickEffortFromCascade(opts: {
   pin?: ReasoningEffort;
   roleDefault: ReasoningEffort;
   parentEffort?: ReasoningEffort;
+  explicitParentEffort?: true;
   supported: readonly ReasoningEffort[];
 }): ReasoningEffort | undefined {
   if (opts.supported.length === 0) return undefined;
@@ -414,6 +419,13 @@ export function pickEffortFromCascade(opts: {
       ? opts.pin
       : clampEffort(opts.pin, opts.supported);
   }
+  // An explicit (operator-chosen) parent effort is a fleet-wide pin: it beats
+  // the role default so a primary cycled to none really gives none workers.
+  if (opts.explicitParentEffort === true && opts.parentEffort !== undefined) {
+    return opts.supported.includes(opts.parentEffort)
+      ? opts.parentEffort
+      : clampEffort(opts.parentEffort, opts.supported);
+  }
   if (opts.supported.includes(opts.roleDefault)) return opts.roleDefault;
   if (
     opts.parentEffort !== undefined &&
@@ -427,10 +439,13 @@ export function pickEffortFromCascade(opts: {
 /**
  * Resolve reasoning effort for a sub-agent spawn.
  *
- * Why parent is below role default: a /agent high selection on the primary must
- * not force every leaf onto high — that multiplies the sol+high latency cliff
- * across the fleet. Parent still fills gaps when the role default is not in the
- * model's supported set but the parent effort is.
+ * Precedence: explicit pin > explicit parent (operator-chosen fleet pin) > role
+ * default > derived parent > clamp. An explicit primary effort — including
+ * `none`/off — is fleet-wide, so it beats both the leaf (medium) and the
+ * orchestrator (high) role default. The unset parent case keeps CL-5162: the
+ * role default outranks a derived parent so a /agent high selection on the
+ * primary does not force every leaf onto high (which would multiply the
+ * sol+high latency cliff across the fleet).
  */
 export function resolveEffortForRole(
   opts: ResolveEffortForRoleOpts,
@@ -452,6 +467,9 @@ export function resolveEffortForRole(
     ...(opts.parentEffort !== undefined
       ? { parentEffort: opts.parentEffort }
       : {}),
+    ...(opts.explicitParentEffort === true
+      ? { explicitParentEffort: true }
+      : {}),
     supported,
   });
 }

src/session/runtime-assembly.test.ts

@@ -79,6 +79,42 @@ describe("buildSubAgentProvider", () => {
       bifrostVirtualKey: true,
     });
   });
+
+  test("omits explicitReasoningEffort when not operator-chosen", () => {
+    expect(
+      buildSubAgentProvider({
+        providerName: "openai",
+        baseURL: "https://api.openai.com/v1",
+        model: "gpt-5",
+        reasoningEffort: "medium",
+        providers: [{ name: "openai" }],
+      }),
+    ).toEqual({
+      providerName: "openai",
+      baseURL: "https://api.openai.com/v1",
+      model: "gpt-5",
+      reasoningEffort: "medium",
+    });
+  });
+
+  test("threads explicitReasoningEffort when operator-chosen", () => {
+    expect(
+      buildSubAgentProvider({
+        providerName: "openai",
+        baseURL: "https://api.openai.com/v1",
+        model: "gpt-5",
+        reasoningEffort: "none",
+        explicitReasoningEffort: true,
+        providers: [{ name: "openai" }],
+      }),
+    ).toEqual({
+      providerName: "openai",
+      baseURL: "https://api.openai.com/v1",
+      model: "gpt-5",
+      reasoningEffort: "none",
+      explicitReasoningEffort: true,
+    });
+  });
 });
 
 describe("createLiveSubAgentSources", () => {

src/session/runtime-assembly.ts

@@ -76,6 +76,8 @@ export interface SubAgentProviderConfig {
   apiKey?: string;
   model: string;
   reasoningEffort?: ReasoningEffort;
+  /** Present when operator-chosen — see SubAgentProvider.explicitReasoningEffort. */
+  explicitReasoningEffort?: true;
   providers: readonly Pick<
     ProviderCatalogEntry,
     "name" | "bifrostVirtualKey"
@@ -94,6 +96,9 @@ export function buildSubAgentProvider(
     ...(config.reasoningEffort !== undefined
       ? { reasoningEffort: config.reasoningEffort }
       : {}),
+    ...(config.explicitReasoningEffort === true
+      ? { explicitReasoningEffort: true }
+      : {}),
     ...(config.providers.find((p) => p.name === config.providerName)
       ?.bifrostVirtualKey === true
       ? { bifrostVirtualKey: true }