diff --git a/src/services/ai/providers/base-provider.ts b/src/services/ai/providers/base-provider.ts
index 0a76e68..3d30a53 100644
--- a/src/services/ai/providers/base-provider.ts
+++ b/src/services/ai/providers/base-provider.ts
@@ -25,6 +25,7 @@ const PROTECTED_KEYS = new Set([
   "input",
   "instructions",
   "conversation",
+  "stream",
 ]);
 
 export function applySafeExtraParams(
diff --git a/src/services/user-profile/ai-cleanup.ts b/src/services/user-profile/ai-cleanup.ts
index 527b229..d81dc55 100644
--- a/src/services/user-profile/ai-cleanup.ts
+++ b/src/services/user-profile/ai-cleanup.ts
@@ -6,6 +6,7 @@ import {
   EXTERNAL_PROFILE_CLEANUP_TIMEOUT_MS,
   OPENCODE_PROFILE_CLEANUP_TIMEOUT_MS,
 } from "../request-timeouts.js";
+import { applySafeExtraParams } from "../ai/providers/base-provider.js";
 
 export interface AICleanupResult {
   cleaned: UserProfileData;
@@ -242,21 +243,30 @@ async function callViaExternalAPI(
   const systemPrompt =
     "You are a user profile cleanup assistant. Merge duplicate entries and return only JSON.";
 
+  const requestBody: Record<string, unknown> = {};
+  if (CONFIG.memoryExtraParams) {
+    applySafeExtraParams(requestBody, CONFIG.memoryExtraParams);
+  }
+
+  // Cleanup relies on these fields for deterministic JSON output. Assign them after optional
+  // provider parameters so callers cannot replace cleanup semantics through extra params.
+  Object.assign(requestBody, {
+    model: CONFIG.memoryModel,
+    messages: [
+      { role: "system", content: systemPrompt },
+      { role: "user", content: prompt },
+    ],
+    temperature: 0.3,
+    response_format: { type: "json_object" },
+  });
+
   const response = await fetch(`${CONFIG.memoryApiUrl}/chat/completions`, {
     method: "POST",
     headers: {
       "Content-Type": "application/json",
       Authorization: `Bearer ${CONFIG.memoryApiKey}`,
     },
-    body: JSON.stringify({
-      model: CONFIG.memoryModel,
-      messages: [
-        { role: "system", content: systemPrompt },
-        { role: "user", content: prompt },
-      ],
-      temperature: 0.3,
-      response_format: { type: "json_object" },
-    }),
+    body: JSON.stringify(requestBody),
     signal: AbortSignal.timeout(EXTERNAL_PROFILE_CLEANUP_TIMEOUT_MS),
   });
 
diff --git a/tests/ai-cleanup.test.ts b/tests/ai-cleanup.test.ts
index 5a990ba..fbaa5a6 100644
--- a/tests/ai-cleanup.test.ts
+++ b/tests/ai-cleanup.test.ts
@@ -88,6 +88,7 @@ import { mock } from "bun:test";
 const promptCalls = [];
 const deleteCalls = [];
 let externalFetchCalled = false;
+let externalRequestBody = null;
 
 const cleanupJson = JSON.stringify({
   preferences: [{ id: "pref_0", category: "style", description: "Prefer concise answers" }],
@@ -107,6 +108,15 @@ mock.module(${JSON.stringify(configUrl)}, () => ({
     memoryModel: ${withExternalApi ? '"gpt-ext"' : "undefined"},
     memoryApiUrl: ${withExternalApi ? '"http://example.test/v1"' : "undefined"},
     memoryApiKey: "test-key",
+    memoryExtraParams: {
+      enable_thinking: false,
+      top_p: 0.7,
+      stream: true,
+      model: "must-not-override",
+      messages: [{ role: "user", content: "must-not-override" }],
+      temperature: 0.9,
+      response_format: { type: "text" },
+    },
   },
 }));
 
@@ -141,8 +151,9 @@ mock.module(${JSON.stringify(opencodeProviderLoaderUrl)}, () => ({
 }));
 
 if (${withExternalApi}) {
-  globalThis.fetch = async () => {
+  globalThis.fetch = async (_url, init) => {
     externalFetchCalled = true;
+    externalRequestBody = JSON.parse(String(init?.body));
     return {
       ok: true,
       status: 200,
@@ -178,6 +189,7 @@ console.log(
     promptCalls,
     deleteCalls,
     externalFetchCalled,
+    externalRequestBody,
     kept: result?.diff?.kept ?? null,
     removed: result?.diff?.removed?.map((r) => r.id) ?? null,
     noReply: promptCalls[0]?.noReply,
@@ -243,5 +255,14 @@ describe("AI cleanup opencode provider path (#177)", () => {
     expect(result.parsed?.errorMessage).toBeNull();
     expect(result.parsed?.externalFetchCalled).toBe(true);
     expect(result.parsed?.kept).toEqual(["Prefer concise answers"]);
+    expect(result.parsed?.externalRequestBody).toMatchObject({
+      model: "gpt-ext",
+      temperature: 0.3,
+      response_format: { type: "json_object" },
+      enable_thinking: false,
+      top_p: 0.7,
+    });
+    expect(result.parsed?.externalRequestBody?.stream).toBeUndefined();
+    expect(result.parsed?.externalRequestBody?.messages).toHaveLength(2);
   });
 });
diff --git a/tests/ai-provider-config.test.ts b/tests/ai-provider-config.test.ts
index 32f664d..6b55310 100644
--- a/tests/ai-provider-config.test.ts
+++ b/tests/ai-provider-config.test.ts
@@ -3,6 +3,7 @@ import { existsSync, mkdtempSync, readFileSync, rmSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { buildMemoryProviderConfig } from "../src/services/ai/provider-config.js";
+import { applySafeExtraParams } from "../src/services/ai/providers/base-provider.js";
 import { OpenAIChatCompletionProvider } from "../src/services/ai/providers/openai-chat-completion.js";
 import { OpenAIResponsesProvider } from "../src/services/ai/providers/openai-responses.js";
 import type { ChatCompletionTool } from "../src/services/ai/tools/tool-schema.js";
@@ -292,4 +293,46 @@ describe("AI provider config", () => {
     expect(capturedBody).toBeDefined();
     expect(capturedBody?.temperature).toBeUndefined();
   });
+
+  describe("applySafeExtraParams", () => {
+    it("copies allowable extra parameters to request body", () => {
+      const body: Record<string, unknown> = { model: "gpt-5-nano" };
+      applySafeExtraParams(body, {
+        top_p: 0.8,
+        enable_thinking: false,
+        custom_header: "val",
+      });
+
+      expect(body).toEqual({
+        model: "gpt-5-nano",
+        top_p: 0.8,
+        enable_thinking: false,
+        custom_header: "val",
+      });
+    });
+
+    it("blocks protected keys from overriding core request structure", () => {
+      const body: Record<string, unknown> = {
+        model: "gpt-5-nano",
+        messages: [{ role: "system", content: "hi" }],
+      };
+      applySafeExtraParams(body, {
+        model: "override-model",
+        messages: [{ role: "user", content: "override" }],
+        tools: ["fake-tool"],
+        tool_choice: "none",
+        temperature: 0.9,
+        input: "override-input",
+        instructions: "override-instructions",
+        conversation: "override-convo",
+        stream: true,
+      });
+
+      expect(body).toEqual({
+        model: "gpt-5-nano",
+        messages: [{ role: "system", content: "hi" }],
+      });
+      expect(body.stream).toBeUndefined();
+    });
+  });
 });