fix(kimi-coding): disable reasoning for Roo Code-based clients (#2839)

* fix(kimi-coding): disable reasoning for Roo Code-based clients

Kimi Code's `thinking` parameter was enabled by default for all BYOK
requests, which fails for older Roo Code-based clients that don't expect
reasoning output. Detect those clients via the incoming user-agent and
force `thinking.type = 'disabled'` for them.

Threads fraudHeaders through the transformRequest context so providers
can inspect the originating client.

* refactor: rename fraudHeaders context field to originalHeaders

---------

Co-authored-by: kiloconnect[bot] <240665456+kiloconnect[bot]@users.noreply.github.com>

Author: kilo-code-bot[bot]

apps/web/src/app/api/openrouter/[...path]/route.ts

@@ -530,7 +530,8 @@ export async function POST(request: NextRequest): Promise<NextResponseType<unkno
     originalModelIdLowerCased,
     requestBodyParsed,
     extraHeaders,
-    userByok
+    userByok,
+    fraudHeaders
   );
 
   const response = await openRouterRequest({

apps/web/src/lib/ai-gateway/providers/direct-byok/kimi-coding.ts

@@ -4,15 +4,19 @@ import {
 } from '@/lib/ai-gateway/providers/direct-byok/types';
 import { REASONING_VARIANTS_MINIMAL_LOW_MEDIUM_HIGH } from '@/lib/ai-gateway/providers/model-settings';
 import { isReasoningExplicitlyDisabled } from '@/lib/ai-gateway/providers/openrouter/request-helpers';
+import { isRooCodeBasedClient } from '@/lib/utils';
 
 export default {
   id: 'kimi-coding',
   name: 'Kimi Code',
   base_url: 'https://api.kimi.com/coding/v1',
   ai_sdk_provider: 'openai-compatible',
   transformRequest(context) {
+    const reasoningDisabled =
+      isRooCodeBasedClient(context.originalHeaders) ||
+      isReasoningExplicitlyDisabled(context.request);
     context.request.body.thinking = {
-      type: isReasoningExplicitlyDisabled(context.request) ? 'disabled' : 'enabled',
+      type: reasoningDisabled ? 'disabled' : 'enabled',
     };
     context.extraHeaders['user-agent'] = COMPATIBLE_USER_AGENT;
   },

apps/web/src/lib/ai-gateway/providers/index.ts

@@ -47,6 +47,7 @@ import {
   injectReasoningIntoContent,
 } from '@/lib/ai-gateway/providers/openrouter/request-helpers';
 import { isStepFunModel } from '@/lib/ai-gateway/providers/stepfun';
+import type { FraudDetectionHeaders } from '@/lib/utils';
 
 function inferSupportedChatApis(
   aiSdkProvider: CustomLlmProvider | undefined,
@@ -291,7 +292,8 @@ export function applyProviderSpecificLogic(
   requestedModel: string,
   requestToMutate: GatewayRequest,
   extraHeaders: Record<string, string>,
-  userByok: BYOKResult[] | null
+  userByok: BYOKResult[] | null,
+  originalHeaders: FraudDetectionHeaders
 ) {
   const kiloExclusiveModel = kiloExclusiveModels.find(m => m.public_id === requestedModel);
   if (kiloExclusiveModel) {
@@ -334,6 +336,7 @@ export function applyProviderSpecificLogic(
   provider.transformRequest({
     model: requestedModel,
     request: requestToMutate,
+    originalHeaders,
     extraHeaders,
     userByok,
   });

apps/web/src/lib/ai-gateway/providers/types.ts

@@ -1,5 +1,6 @@
 import type { UserByokProviderId } from '@/lib/ai-gateway/providers/openrouter/inference-provider-id';
 import type { GatewayRequest } from '@/lib/ai-gateway/providers/openrouter/types';
+import type { FraudDetectionHeaders } from '@/lib/utils';
 
 export type ProviderId =
   | 'openrouter'
@@ -22,6 +23,7 @@ export type BYOKResult = {
 export type TransformRequestContext = {
   model: string;
   request: GatewayRequest;
+  originalHeaders: FraudDetectionHeaders;
   extraHeaders: Record<string, string>;
   userByok: BYOKResult[] | null;
 };