diff --git a/src/adapters/openai-chat/reasoning-wire.ts b/src/adapters/openai-chat/reasoning-wire.ts
index eb1f0afd3c9..cd92ba3bc77 100644
--- a/src/adapters/openai-chat/reasoning-wire.ts
+++ b/src/adapters/openai-chat/reasoning-wire.ts
@@ -44,7 +44,12 @@ export function declaresIndependentChatReasoningControls(provider: OcxProviderCo
 export function nativeChatUltraWireEffort(provider: OcxProviderConfig, modelId: string): string | undefined {
   const ladder = configuredReasoningEfforts(provider, modelId);
   if (ladder?.includes("ultra")) return "ultra";
-  if (declaresThinkingToggleWire(provider, modelId)) return ladder ? resolveEffortAtOrBelow("max", ladder) ?? "max" : "max";
+  if (declaresThinkingToggleWire(provider, modelId)) {
+    // Keep the original alias for the independent policy to omit effort and select thinking.
+    if (declaresIndependentChatReasoningEffort(provider, modelId)
+      && isReasoningEffortOmitted(reasoningEffortMapFor(provider, modelId)?.max)) return "max";
+    return ladder ? resolveEffortAtOrBelow("max", ladder) ?? "max" : "max";
+  }
   return mapReasoningEffort(provider, modelId, "ultra");
 }
 
diff --git a/structure/providers/chat-compat.md b/structure/providers/chat-compat.md
index ad45d9b8cc9..9978e04874f 100644
--- a/structure/providers/chat-compat.md
+++ b/structure/providers/chat-compat.md
@@ -112,7 +112,7 @@ Passthrough and routed-compaction raw-body repairs emit it as a user turn (`exte
 Stateful developer-guidance injection reuses that validator for its raw insertion
 boundary, so parsed messages and stored raw history retain the same task/guidance order.
 
-Native Chat passthrough and translated Chat share `src/adapters/openai-chat/reasoning-wire.ts` after provider resolution. Explicit reasoning/effort false declarations and empty strength ladders remove unsupported effort; toggle false removes the switch without declaring an unknown strength axis unsupported. A declared toggle wire serializes the independent thinking choice without treating enabled/disabled/adaptive discriminators as strengths. On a dual-control wire, an explicit `__omit__` effort alias removes the strength while the caller's effort still selects the thinking switch. Dual-control requests still pass through gateway-object projection and tool-bearing effort omission; a legacy toggle configuration gains a second serialized control only with explicit effort support; unknown declarations preserve legacy raw forwarding. Native passthrough also sanitizes routed reasoning history so `reasoning` input items do not send
+Native Chat passthrough and translated Chat share `src/adapters/openai-chat/reasoning-wire.ts` after provider resolution. Explicit reasoning/effort false declarations and empty strength ladders remove unsupported effort; toggle false removes the switch without declaring an unknown strength axis unsupported. A declared toggle wire serializes the independent thinking choice without treating enabled/disabled/adaptive discriminators as strengths. On a dual-control wire, an explicit `__omit__` effort alias removes the strength while the caller's effort still selects the thinking switch. Native `ultra` honors the `max` omission alias before ladder clamping, unless the declared ladder supports native `ultra` itself. Dual-control requests still pass through gateway-object projection and tool-bearing effort omission; a legacy toggle configuration gains a second serialized control only with explicit effort support; unknown declarations preserve legacy raw forwarding. Native passthrough also sanitizes routed reasoning history so `reasoning` input items do not send
 non-empty `content` arrays to upstream models that reject them. Chat Completions bridging repairs
 orphan `toolResult` messages by inserting a synthetic assistant `tool_call` before tool messages.
 It also repairs the opposite direction (260718): an assistant `tool_calls` round left dangling —
diff --git a/tests/adapters/openai/openai-chat-reasoning-wire-policy.test.ts b/tests/adapters/openai/openai-chat-reasoning-wire-policy.test.ts
index 0a0b17c8f64..597b32f54ac 100644
--- a/tests/adapters/openai/openai-chat-reasoning-wire-policy.test.ts
+++ b/tests/adapters/openai/openai-chat-reasoning-wire-policy.test.ts
@@ -316,6 +316,56 @@ describe("toggle-only Chat reasoning capability", () => {
     }
   });
 
+  test.each([
+    [undefined, undefined], [undefined, false], [undefined, true],
+    ["gateway-object", undefined], ["gateway-object", false], ["gateway-object", true],
+  ] as const)("dual-axis %s omits ultra before ladder clamping with thinking override %s", (reasoningWireFormat, thinkingEnabled) => {
+    const target: OcxProviderConfig = {
+      ...toggleProvider, reasoningWireFormat,
+      modelCapabilities: { [toggleModel]: { supportsThinkingToggle: true, supportsReasoningEffort: true } },
+      modelReasoningEfforts: { [toggleModel]: ["low", "high"] },
+      modelReasoningEffortMap: { [toggleModel]: { max: "__omit__" } },
+    };
+    for (const effort of ["max", "ultra"]) {
+      for (const body of Object.values(finalToggleBodies(request(effort), target, toggleModel, thinkingEnabled))) {
+        expect(body.thinking).toEqual({ type: thinkingEnabled === false ? "disabled" : "enabled" });
+        expect(body.reasoning_effort).toBeUndefined();
+        expect(body.reasoning).toBeUndefined();
+      }
+    }
+  });
+
+  test.each([undefined, "gateway-object"] as const)("dual-axis %s still clamps ultra when max has no omission alias", reasoningWireFormat => {
+    const target: OcxProviderConfig = {
+      ...toggleProvider, reasoningWireFormat,
+      modelCapabilities: { [toggleModel]: { supportsThinkingToggle: true, supportsReasoningEffort: true } },
+      modelReasoningEfforts: { [toggleModel]: ["low", "high"] },
+    };
+    for (const thinkingEnabled of [undefined, false, true]) {
+      for (const body of Object.values(finalToggleBodies(request("ultra"), target, toggleModel, thinkingEnabled))) {
+        expect(body.thinking).toEqual({ type: thinkingEnabled === false ? "disabled" : "enabled" });
+        expect(body.reasoning_effort).toBe(reasoningWireFormat ? undefined : "high");
+        expect(body.reasoning).toEqual(reasoningWireFormat ? { enabled: thinkingEnabled !== false, effort: "high" } : undefined);
+      }
+    }
+  });
+
+  test.each([undefined, "gateway-object"] as const)("disabled toggle omits aliased ultra on %s", reasoningWireFormat => {
+    const target: OcxProviderConfig = {
+      ...toggleProvider, reasoningWireFormat,
+      modelCapabilities: { [toggleModel]: { supportsThinkingToggle: false, supportsReasoningEffort: true } },
+      modelReasoningEfforts: { [toggleModel]: ["low", "high"] },
+      modelReasoningEffortMap: { [toggleModel]: { max: "__omit__" } },
+    };
+    for (const thinkingEnabled of [undefined, false, true]) {
+      for (const body of Object.values(finalToggleBodies(request("ultra"), target, toggleModel, thinkingEnabled))) {
+        expect(body.thinking).toBeUndefined();
+        expect(body.reasoning_effort).toBeUndefined();
+        expect(body.reasoning).toBeUndefined();
+      }
+    }
+  });
+
   test("native dual-axis wire preserves explicitly supported ultra despite the max omission alias", () => {
     const target: OcxProviderConfig = {
       ...toggleProvider,
@@ -323,9 +373,15 @@ describe("toggle-only Chat reasoning capability", () => {
       modelReasoningEfforts: { [toggleModel]: ["high", "max", "ultra"] },
       modelReasoningEffortMap: { [toggleModel]: { max: "__omit__" } },
     };
-    const body = JSON.parse(buildOpenAIChatPassthroughRequest(target, request("ultra"), toggleModel, false).body);
-    expect(body.reasoning_effort).toBe("ultra");
-    expect(body.thinking).toEqual({ type: "enabled" });
+    for (const thinkingEnabled of [undefined, false, true]) {
+      const bodies = finalToggleBodies(request("ultra"), target, toggleModel, thinkingEnabled);
+      expect(bodies.native.reasoning_effort).toBe("ultra");
+      expect(bodies.translated.reasoning_effort).toBeUndefined();
+      for (const body of Object.values(bodies)) {
+        expect(body.thinking).toEqual({ type: thinkingEnabled === false ? "disabled" : "enabled" });
+        expect(body.reasoning).toBeUndefined();
+      }
+    }
   });
 
   test.each([