diff --git a/open-sse/handlers/chatCore.ts b/open-sse/handlers/chatCore.ts
index f024da8dbb..fc78182c61 100644
--- a/open-sse/handlers/chatCore.ts
+++ b/open-sse/handlers/chatCore.ts
@@ -106,7 +106,11 @@ import {
   isFallbackDecision,
   EMERGENCY_FALLBACK_CONFIG,
 } from "../services/emergencyFallback.ts";
-import { resolveStreamFlag, stripMarkdownCodeFence } from "../utils/aiSdkCompat.ts";
+import {
+  resolveExplicitStreamAlias,
+  resolveStreamFlag,
+  stripMarkdownCodeFence,
+} from "../utils/aiSdkCompat.ts";
 import { generateRequestId } from "@/shared/utils/requestId";
 import { normalizePayloadForLog } from "@/lib/logPayloads";
 import { extractFacts } from "@/lib/memory/extraction";
@@ -782,6 +786,22 @@ export async function handleChatCore({
       ? clientRawRequest.headers.get("accept") || clientRawRequest.headers.get("Accept")
       : (clientRawRequest?.headers || {})["accept"] || (clientRawRequest?.headers || {})["Accept"];
 
+  const explicitStreamAlias = resolveExplicitStreamAlias(body);
+
+  // Remove non-standard non-stream aliases before provider translation/execution.
+  // They are accepted for compatibility at the OmniRoute API boundary only.
+  if (body && typeof body === "object") {
+    const b = body as Record<string, unknown>;
+    if (explicitStreamAlias !== undefined) {
+      b.stream = explicitStreamAlias;
+    }
+
+    delete b.non_stream;
+    delete b.disable_stream;
+    delete b.disable_streaming;
+    delete b.streaming;
+  }
+
   const stream = resolveStreamFlag(body?.stream, acceptHeader);
 
   // ── Phase 9.1: Semantic cache check (non-streaming, temp=0 only) ──
diff --git a/open-sse/utils/aiSdkCompat.ts b/open-sse/utils/aiSdkCompat.ts
index a439ae928e..91d284bfc1 100644
--- a/open-sse/utils/aiSdkCompat.ts
+++ b/open-sse/utils/aiSdkCompat.ts
@@ -26,6 +26,33 @@ export function resolveStreamFlag(bodyStream: unknown, acceptHeader: unknown): b
   return !clientWantsJsonResponse(acceptHeader);
 }
 
+/**
+ * Resolves explicit stream aliases used by non-standard clients.
+ * Returns:
+ * - `true`  -> explicit streaming intent
+ * - `false` -> explicit non-stream intent
+ * - `undefined` -> no explicit alias present
+ */
+export function resolveExplicitStreamAlias(body: unknown): boolean | undefined {
+  if (!body || typeof body !== "object") return undefined;
+  const b = body as Record<string, unknown>;
+
+  if (b.streaming === true) return true;
+  if (b.streaming === false) return false;
+  if (b.non_stream === true) return false;
+  if (b.disable_stream === true) return false;
+  if (b.disable_streaming === true) return false;
+
+  return undefined;
+}
+
+/**
+ * Backward-compatible helper used by tests/legacy call sites.
+ */
+export function hasExplicitNoStreamParam(body: unknown): boolean {
+  return resolveExplicitStreamAlias(body) === false;
+}
+
 /**
  * Removes surrounding markdown code fences when Claude wraps JSON payloads.
  * Example: ```json\n{"ok":true}\n``` -> {"ok":true}
diff --git a/tests/unit/t26-ai-sdk-accept-header-compat.test.mjs b/tests/unit/t26-ai-sdk-accept-header-compat.test.mjs
index c4f9b1ba0f..4b2b398316 100644
--- a/tests/unit/t26-ai-sdk-accept-header-compat.test.mjs
+++ b/tests/unit/t26-ai-sdk-accept-header-compat.test.mjs
@@ -1,8 +1,13 @@
 import test from "node:test";
 import assert from "node:assert/strict";
 
-const { clientWantsJsonResponse, resolveStreamFlag, stripMarkdownCodeFence } =
-  await import("../../open-sse/utils/aiSdkCompat.ts");
+const {
+  clientWantsJsonResponse,
+  resolveStreamFlag,
+  resolveExplicitStreamAlias,
+  hasExplicitNoStreamParam,
+  stripMarkdownCodeFence,
+} = await import("../../open-sse/utils/aiSdkCompat.ts");
 
 test("T26: explicit stream:true takes priority over Accept application/json (#656)", () => {
   assert.equal(clientWantsJsonResponse("application/json"), true);
@@ -42,3 +47,20 @@ test("T26: explicit stream:false always prevents streaming", () => {
   assert.equal(resolveStreamFlag(false, "text/event-stream"), false);
   assert.equal(resolveStreamFlag(false, undefined), false);
 });
+
+test("T26: explicit non-stream aliases are detected", () => {
+  assert.equal(hasExplicitNoStreamParam({ non_stream: true }), true);
+  assert.equal(hasExplicitNoStreamParam({ disable_stream: true }), true);
+  assert.equal(hasExplicitNoStreamParam({ disable_streaming: true }), true);
+  assert.equal(hasExplicitNoStreamParam({ streaming: false }), true);
+  assert.equal(hasExplicitNoStreamParam({ streaming: true }), false);
+  assert.equal(hasExplicitNoStreamParam({ stream: false }), false);
+  assert.equal(hasExplicitNoStreamParam({}), false);
+});
+
+test("T26: explicit stream aliases resolve true/false correctly", () => {
+  assert.equal(resolveExplicitStreamAlias({ streaming: true }), true);
+  assert.equal(resolveExplicitStreamAlias({ streaming: false }), false);
+  assert.equal(resolveExplicitStreamAlias({ disable_streaming: true }), false);
+  assert.equal(resolveExplicitStreamAlias({}), undefined);
+});