diff --git a/apps/web/src/lib/ai-gateway/providers/anthropic.constants.ts b/apps/web/src/lib/ai-gateway/providers/anthropic.constants.ts
index d552681efa..33c29c147f 100644
--- a/apps/web/src/lib/ai-gateway/providers/anthropic.constants.ts
+++ b/apps/web/src/lib/ai-gateway/providers/anthropic.constants.ts
@@ -120,5 +120,13 @@ export function isClaudeModel(requestedModel: string) {
 }
 
 export function isFableModel(requestedModel: string) {
-  return requestedModel.includes('claude-fable');
+  return isClaudeModel(requestedModel) && requestedModel.includes('fable');
+}
+
+export function isOpusFastModel(requestedModel: string) {
+  return (
+    isClaudeModel(requestedModel) &&
+    requestedModel.includes('opus') &&
+    requestedModel.includes('fast')
+  );
 }
diff --git a/apps/web/src/lib/ai-gateway/providers/openai.ts b/apps/web/src/lib/ai-gateway/providers/openai.ts
index 0439c84670..6bca5daf16 100644
--- a/apps/web/src/lib/ai-gateway/providers/openai.ts
+++ b/apps/web/src/lib/ai-gateway/providers/openai.ts
@@ -5,6 +5,10 @@ export function isOpenAiModel(requestedModel: string) {
   );
 }
 
+export function isOpenAiProModel(requestedModel: string) {
+  return isOpenAiModel(requestedModel) && requestedModel.includes('pro');
+}
+
 export function isGptOssModel(requestedModel: string) {
   return requestedModel.includes('gpt-oss');
 }
diff --git a/apps/web/src/lib/ai-gateway/providers/openrouter/types.ts b/apps/web/src/lib/ai-gateway/providers/openrouter/types.ts
index 00ad400ef4..88229d23e1 100644
--- a/apps/web/src/lib/ai-gateway/providers/openrouter/types.ts
+++ b/apps/web/src/lib/ai-gateway/providers/openrouter/types.ts
@@ -4,6 +4,7 @@ import type { AnthropicProviderOptions } from '@ai-sdk/anthropic';
 import type { ReasoningDetailUnion } from '@/lib/ai-gateway/custom-llm/reasoning-details';
 import type { AwsCredentials } from '@/lib/ai-gateway/providers/openrouter/inference-provider-id';
 import type Anthropic from '@anthropic-ai/sdk';
+import type { OpenAILanguageModelResponsesOptions } from '@ai-sdk/openai';
 
 // Base types for OpenRouter API that don't depend on other lib files
 // This breaks circular dependencies with mistral.ts, minimax.ts, etc.
@@ -28,6 +29,7 @@ export type VercelProviderConfig = {
     byok?: Record<string, VercelInferenceProviderConfig[]>;
   };
   anthropic?: AnthropicProviderOptions;
+  openai?: OpenAILanguageModelResponsesOptions;
 };
 
 export function isDataCollectionExplicitlyDisallowed(
diff --git a/apps/web/src/lib/ai-gateway/providers/vercel/index.test.ts b/apps/web/src/lib/ai-gateway/providers/vercel/index.test.ts
index e0877f1bc0..267974f4e7 100644
--- a/apps/web/src/lib/ai-gateway/providers/vercel/index.test.ts
+++ b/apps/web/src/lib/ai-gateway/providers/vercel/index.test.ts
@@ -1,7 +1,8 @@
 import { describe, it, expect } from '@jest/globals';
 import {
+  getAnthropicProviderOptions,
+  getOpenAIProviderOptions,
   convertProviderOptions,
-  getAnthropicProviderOptionsForVercel,
   getVercelInferenceProvidersExcludingIgnored,
   hasCompatibleVercelInferenceProvider,
   passesVercelRoutingPercentage,
@@ -9,7 +10,7 @@ import {
 import { getRandomNumber } from '@/lib/ai-gateway/getRandomNumber';
 import type { GatewayRequest } from '@/lib/ai-gateway/providers/openrouter/types';
 
-describe('getAnthropicProviderOptionsForVercel', () => {
+describe('getAnthropicProviderOptions', () => {
   it('maps chat completion verbosity to Anthropic effort', () => {
     const request: GatewayRequest = {
       kind: 'chat_completions',
@@ -20,7 +21,7 @@ describe('getAnthropicProviderOptionsForVercel', () => {
       },
     };
 
-    expect(getAnthropicProviderOptionsForVercel(request)).toEqual({
+    expect(getAnthropicProviderOptions(request.body.model, request)).toEqual({
       effort: 'high',
     });
   });
@@ -35,7 +36,7 @@ describe('getAnthropicProviderOptionsForVercel', () => {
       },
     };
 
-    expect(getAnthropicProviderOptionsForVercel(request)).toEqual({
+    expect(getAnthropicProviderOptions('anthropic/claude-sonnet-4.5', request)).toEqual({
       effort: 'low',
     });
   });
@@ -49,7 +50,33 @@ describe('getAnthropicProviderOptionsForVercel', () => {
       },
     };
 
-    expect(getAnthropicProviderOptionsForVercel(request)).toBe(undefined);
+    expect(getAnthropicProviderOptions(request.body.model, request)).toBe(undefined);
+  });
+
+  it('enables fast mode for fast Opus models', () => {
+    const request: GatewayRequest = {
+      kind: 'chat_completions',
+      body: {
+        model: 'anthropic/claude-opus-4.6-fast',
+        messages: [{ role: 'user', content: 'hello' }],
+      },
+    };
+
+    expect(getAnthropicProviderOptions(request.body.model, request)).toEqual({
+      speed: 'fast',
+    });
+  });
+});
+
+describe('getOpenAIProviderOptions', () => {
+  it('enables pro reasoning mode for GPT Pro models', () => {
+    expect(getOpenAIProviderOptions('openai/gpt-5.4-pro')).toEqual({
+      reasoningMode: 'pro',
+    });
+  });
+
+  it('returns undefined for other models', () => {
+    expect(getOpenAIProviderOptions('openai/gpt-5.4')).toBe(undefined);
   });
 });
 
diff --git a/apps/web/src/lib/ai-gateway/providers/vercel/index.ts b/apps/web/src/lib/ai-gateway/providers/vercel/index.ts
index c9676d8038..650d42a883 100644
--- a/apps/web/src/lib/ai-gateway/providers/vercel/index.ts
+++ b/apps/web/src/lib/ai-gateway/providers/vercel/index.ts
@@ -27,6 +27,9 @@ import {
 import type { AnthropicProviderOptions } from '@ai-sdk/anthropic';
 import { isDeepseekModel } from '@/lib/ai-gateway/providers/deepseek';
 import type { KiloExclusiveModel } from '@/lib/ai-gateway/providers/kilo-exclusive-model';
+import type { OpenAILanguageModelResponsesOptions } from '@ai-sdk/openai';
+import { isOpenAiProModel } from '@/lib/ai-gateway/providers/openai';
+import { isOpusFastModel } from '@/lib/ai-gateway/providers/anthropic.constants';
 
 const getVercelRoutingPercentage = createCachedFetch(
   async () => {
@@ -179,23 +182,44 @@ function parseAwsCredentials(input: string) {
   }
 }
 
-export function getAnthropicProviderOptionsForVercel(
+export function getAnthropicProviderOptions(
+  requestedModel: string,
   request: GatewayRequest
 ): AnthropicProviderOptions | undefined {
-  const anthropicOptions: AnthropicProviderOptions = {};
+  const options: AnthropicProviderOptions = {};
 
   if (request.kind === 'chat_completions' && request.body.verbosity) {
-    anthropicOptions.effort = request.body.verbosity;
+    options.effort = request.body.verbosity;
   }
   if (request.kind === 'responses' && request.body.text?.verbosity) {
-    anthropicOptions.effort = request.body.text.verbosity;
+    options.effort = request.body.text.verbosity;
+  }
+
+  if (isOpusFastModel(requestedModel)) {
+    options.speed = 'fast';
   }
 
-  if (Object.keys(anthropicOptions).length === 0) {
+  if (Object.keys(options).length === 0) {
     return undefined;
   }
 
-  return anthropicOptions;
+  return options;
+}
+
+export function getOpenAIProviderOptions(
+  requestedModel: string
+): OpenAILanguageModelResponsesOptions | undefined {
+  const options: OpenAILanguageModelResponsesOptions = {};
+
+  if (isOpenAiProModel(requestedModel)) {
+    options.reasoningMode = 'pro';
+  }
+
+  if (Object.keys(options).length === 0) {
+    return undefined;
+  }
+
+  return options;
 }
 
 export function getVercelInferenceProviderConfigForUserByok(
@@ -264,10 +288,11 @@ export async function applyVercelSettings(
   }
 
   if (requestToMutate.body.providerOptions) {
-    const anthropicOptions = getAnthropicProviderOptionsForVercel(requestToMutate);
-    if (anthropicOptions) {
-      requestToMutate.body.providerOptions.anthropic = anthropicOptions;
-    }
+    requestToMutate.body.providerOptions.anthropic = getAnthropicProviderOptions(
+      requestedModel,
+      requestToMutate
+    );
+    requestToMutate.body.providerOptions.openai = getOpenAIProviderOptions(requestedModel);
   }
 
   delete requestToMutate.body.provider;