diff --git a/packages/cloud-agents/src/server/fast-agent/__tests__/fast-agent-integration-broker.test.ts b/packages/cloud-agents/src/server/fast-agent/__tests__/fast-agent-integration-broker.test.ts
index dda3fc8dd..599d7194c 100644
--- a/packages/cloud-agents/src/server/fast-agent/__tests__/fast-agent-integration-broker.test.ts
+++ b/packages/cloud-agents/src/server/fast-agent/__tests__/fast-agent-integration-broker.test.ts
@@ -376,6 +376,85 @@ describe('fast-agent integration broker', () => {
     });
   });
 
+  it('defaults Brain query controls and preserves the native result', async () => {
+    const nativeResult = [
+      {
+        slug: 'tasks/example',
+        page_id: 42,
+        title: 'Example',
+        chunk_text: 'Full native result',
+        score: 0.9,
+      },
+    ];
+    mocks.callMcpTool.mockResolvedValue(nativeResult);
+
+    const result = await callFastAgentIntegration(
+      auditContext,
+      [
+        {
+          id: 'gbrain',
+          name: 'Brain',
+          description: 'Shared memory',
+          tools: [{ name: 'query' }],
+        },
+      ],
+      {
+        integrationId: 'gbrain',
+        toolName: 'query',
+        args: { query: 'fast mode' },
+      },
+    );
+
+    expect(mocks.callMcpTool).toHaveBeenCalledWith(
+      expect.objectContaining({
+        args: {
+          query: 'fast mode',
+          detail: 'low',
+          adaptive_return: true,
+          limit: 6,
+        },
+      }),
+    );
+    expect(result).toBe(nativeResult);
+  });
+
+  it('preserves explicit Brain query detail controls', async () => {
+    mocks.callMcpTool.mockResolvedValue([]);
+
+    await callFastAgentIntegration(
+      auditContext,
+      [
+        {
+          id: 'gbrain',
+          name: 'Brain',
+          description: 'Shared memory',
+          tools: [{ name: 'query' }],
+        },
+      ],
+      {
+        integrationId: 'gbrain',
+        toolName: 'query',
+        args: {
+          query: 'all context',
+          detail: 'high',
+          adaptive_return: false,
+          limit: 20,
+        },
+      },
+    );
+
+    expect(mocks.callMcpTool).toHaveBeenCalledWith(
+      expect.objectContaining({
+        args: {
+          query: 'all context',
+          detail: 'high',
+          adaptive_return: false,
+          limit: 20,
+        },
+      }),
+    );
+  });
+
   it('does not execute a tool when its durable audit cannot be created', async () => {
     mocks.beginIntegrationCall.mockRejectedValue(new Error('database offline'));
 
diff --git a/packages/cloud-agents/src/server/fast-agent/fast-agent-integration-broker.ts b/packages/cloud-agents/src/server/fast-agent/fast-agent-integration-broker.ts
index 8faad1283..cc1c5d81b 100644
--- a/packages/cloud-agents/src/server/fast-agent/fast-agent-integration-broker.ts
+++ b/packages/cloud-agents/src/server/fast-agent/fast-agent-integration-broker.ts
@@ -58,6 +58,7 @@ const FAST_AGENT_INTEGRATION_TOOL_CACHE_TTL_MS = 5 * 60_000;
 const FAST_AGENT_INTEGRATION_TOOL_CACHE_RETRY_MS = 30_000;
 const FAST_AGENT_INTEGRATION_DISCOVERY_TIMEOUT_MS = 10_000;
 const FAST_AGENT_INTEGRATION_CALL_TIMEOUT_MS = 60_000;
+const FAST_AGENT_BRAIN_QUERY_DEFAULT_LIMIT = 6;
 
 type IntegrationToolCacheEntry = {
   expiresAt: number;
@@ -329,20 +330,28 @@ export async function callFastAgentIntegration(
 
   try {
     const { apiBaseUrl, authToken } = await resolveBrokerAuth(context);
+    const effectiveArgs =
+      integration.id === BRAIN_MCP_ID && request.toolName === 'query'
+        ? {
+            ...request.args,
+            detail: request.args.detail ?? 'low',
+            adaptive_return: request.args.adaptive_return ?? true,
+            limit: request.args.limit ?? FAST_AGENT_BRAIN_QUERY_DEFAULT_LIMIT,
+          }
+        : request.args;
     const result = await withFastIntegrationTimeout(
       (signal) =>
         callMcpTool({
           url: integrationProxyUrl(apiBaseUrl, integration.id),
           headers: { Authorization: `Bearer ${authToken}` },
           toolName: request.toolName,
-          args: request.args,
+          args: effectiveArgs,
           toolCallId: `fast:${audit.id}:${integration.id}:${request.toolName}`,
           signal,
         }),
       FAST_AGENT_INTEGRATION_CALL_TIMEOUT_MS,
       `Fast ${integration.id}/${request.toolName} integration call`,
     );
-
     try {
       await completeSlackFastIntegrationCall({
         id: audit.id,