feat(core): strip unsupported sampling params via model capability registry

Some models (claude-opus-4-7, gpt-5-pro) reject temperature/topP/topK
with a 400. The model router now checks the capability registry before
dispatching and silently strips unsupported sampling parameters.

Extends the existing attachment-only capability system to a generic
multi-dimension registry. The temperature dimension is populated from
models.dev data and auto-updated by the CI regeneration workflow.

Closes #16247

Author: intojhanurag

.changeset/twelve-candles-love.md

@@ -0,0 +1,15 @@
+---
+'@mastra/core': minor
+---
+
+Agents using models that dropped support for `temperature`, `topP`, or `topK` (such as `claude-opus-4-7` or `gpt-5-pro`) no longer crash with a 400 error. The model router now automatically strips unsupported sampling parameters before the request is sent — no configuration or processors needed.
+
+```ts
+const agent = new Agent({
+  model: 'anthropic/claude-opus-4-7',
+  instructions: 'You are a helpful assistant.',
+});
+
+// temperature is stripped automatically — no 400 error
+await agent.generate('hello', { modelSettings: { temperature: 0.7 } });
+```

packages/core/scripts/generate-providers.ts

@@ -10,7 +10,8 @@ const __dirname = path.dirname(__filename);
 
 async function generateProviderRegistry(gateways: MastraModelGateway[]) {
   // Fetch providers from all gateways
-  const { providers, models, attachmentCapabilities, failedGateways } = await fetchProvidersFromGateways(gateways);
+  const { providers, models, attachmentCapabilities, temperatureCapabilities, failedGateways } =
+    await fetchProvidersFromGateways(gateways);
 
   if (failedGateways.length > 0) {
     console.warn(
@@ -23,12 +24,26 @@ async function generateProviderRegistry(gateways: MastraModelGateway[]) {
   const srcDir = path.join(__dirname, '..', 'src', 'llm', 'model');
   const srcJsonPath = path.join(srcDir, 'provider-registry.json');
   const srcTypesPath = path.join(srcDir, 'provider-types.generated.d.ts');
-  await writeRegistryFiles(srcJsonPath, srcTypesPath, providers, models, attachmentCapabilities);
+  await writeRegistryFiles(
+    srcJsonPath,
+    srcTypesPath,
+    providers,
+    models,
+    attachmentCapabilities,
+    temperatureCapabilities,
+  );
 
   // Write registry files to dist/ (for build output)
   const distJsonPath = path.join(__dirname, '..', 'dist', 'provider-registry.json');
   const distTypesPath = path.join(__dirname, '..', 'dist', 'llm', 'model', 'provider-types.generated.d.ts');
-  await writeRegistryFiles(distJsonPath, distTypesPath, providers, models, attachmentCapabilities);
+  await writeRegistryFiles(
+    distJsonPath,
+    distTypesPath,
+    providers,
+    models,
+    attachmentCapabilities,
+    temperatureCapabilities,
+  );
 
   // Log summary
   console.info(`\nRegistered providers:`);
@@ -38,6 +53,9 @@ async function generateProviderRegistry(gateways: MastraModelGateway[]) {
   const capProviderCount = Object.keys(attachmentCapabilities).length;
   const capModelCount = Object.values(attachmentCapabilities).reduce((sum, models) => sum + models.length, 0);
   console.info(`\nAttachment-capable: ${capModelCount} models across ${capProviderCount} providers`);
+  const tempProviderCount = Object.keys(temperatureCapabilities).length;
+  const tempModelCount = Object.values(temperatureCapabilities).reduce((sum, models) => sum + models.length, 0);
+  console.info(`Temperature-capable: ${tempModelCount} models across ${tempProviderCount} providers`);
 }
 
 // Main execution

packages/core/src/llm/index.ts

@@ -83,6 +83,7 @@ export {
   parseModelString,
   getProviderConfig,
   modelSupportsAttachments,
+  modelSupportsTemperature,
 } from './model/provider-registry.js';
 export type {
   ModelRouterModelId,

packages/core/src/llm/model/capabilities/anthropic.json

@@ -17,5 +17,21 @@
     "claude-sonnet-4-5",
     "claude-sonnet-4-5-20250929",
     "claude-sonnet-4-6"
+  ],
+  "temperature": [
+    "claude-haiku-4-5",
+    "claude-haiku-4-5-20251001",
+    "claude-opus-4-0",
+    "claude-opus-4-1",
+    "claude-opus-4-1-20250805",
+    "claude-opus-4-20250514",
+    "claude-opus-4-5",
+    "claude-opus-4-5-20251101",
+    "claude-opus-4-6",
+    "claude-sonnet-4-0",
+    "claude-sonnet-4-20250514",
+    "claude-sonnet-4-5",
+    "claude-sonnet-4-5-20250929",
+    "claude-sonnet-4-6"
   ]
 }

packages/core/src/llm/model/capabilities/openai.json

@@ -45,5 +45,20 @@
     "o3-pro",
     "o4-mini",
     "o4-mini-deep-research"
+  ],
+  "temperature": [
+    "gpt-3.5-turbo",
+    "gpt-4",
+    "gpt-4-turbo",
+    "gpt-4.1",
+    "gpt-4.1-mini",
+    "gpt-4.1-nano",
+    "gpt-4o",
+    "gpt-4o-2024-05-13",
+    "gpt-4o-2024-08-06",
+    "gpt-4o-2024-11-20",
+    "gpt-4o-mini",
+    "gpt-5-chat-latest",
+    "gpt-5.3-chat-latest"
   ]
 }

packages/core/src/llm/model/gateways/base.ts

@@ -22,9 +22,10 @@ export interface ProviderConfig {
 
 /**
  * Compact capability data collected from gateways during generation.
- * Each provider maps to a list of model IDs that support attachments.
+ * Each provider maps to a list of model IDs that support a capability.
  */
 export type AttachmentCapabilities = Record<string, string[]>;
+export type TemperatureCapabilities = Record<string, string[]>;
 
 /**
  * Union type for language models that can be returned by gateways.

packages/core/src/llm/model/gateways/models-dev.ts

@@ -15,7 +15,7 @@ import { createGateway } from '@internal/ai-v6';
 import { createOpenRouter } from '@openrouter/ai-sdk-provider-v5';
 import { parseModelRouterId } from '../gateway-resolver.js';
 import { MastraModelGateway } from './base.js';
-import type { AttachmentCapabilities, GatewayLanguageModel, ProviderConfig } from './base.js';
+import type { AttachmentCapabilities, GatewayLanguageModel, ProviderConfig, TemperatureCapabilities } from './base.js';
 import { EXCLUDED_PROVIDERS, MASTRA_USER_AGENT, PROVIDERS_WITH_INSTALLED_PACKAGES } from './constants.js';
 
 interface ModelsDevModelInfo {
@@ -24,6 +24,7 @@ interface ModelsDevModelInfo {
   status?: string;
   modalities?: { input?: string[]; output?: string[] };
   attachment?: boolean;
+  temperature?: boolean;
   [key: string]: unknown;
 }
 
@@ -110,6 +111,7 @@ export class ModelsDevGateway extends MastraModelGateway {
 
   private providerConfigs: Record<string, ProviderConfig> = {};
   private attachmentCapabilities: AttachmentCapabilities = {};
+  private temperatureCapabilities: TemperatureCapabilities = {};
 
   constructor(providerConfigs?: Record<string, ProviderConfig>) {
     super();
@@ -124,6 +126,10 @@ export class ModelsDevGateway extends MastraModelGateway {
 
     const data = (await response.json()) as ModelsDevResponse;
 
+    // Reset capability maps so removed providers/models are not retained across syncs
+    this.attachmentCapabilities = {};
+    this.temperatureCapabilities = {};
+
     const providerConfigs: Record<string, ProviderConfig> = {};
 
     for (const [providerId, providerInfo] of Object.entries(data)) {
@@ -161,6 +167,12 @@ export class ModelsDevGateway extends MastraModelGateway {
           .map(([modelId]) => modelId)
           .sort();
 
+        // Collect model IDs that support temperature sampling
+        const temperatureModels = activeModels
+          .filter(([, modelInfo]) => modelInfo?.temperature === true)
+          .map(([modelId]) => modelId)
+          .sort();
+
         // Get the API URL - overrides take priority over models.dev data
         const url = PROVIDER_OVERRIDES[normalizedId]?.url || providerInfo.api;
 
@@ -203,6 +215,9 @@ export class ModelsDevGateway extends MastraModelGateway {
         if (attachmentModels.length > 0) {
           this.attachmentCapabilities[normalizedId] = attachmentModels;
         }
+        if (temperatureModels.length > 0) {
+          this.temperatureCapabilities[normalizedId] = temperatureModels;
+        }
       }
     }
 
@@ -220,6 +235,10 @@ export class ModelsDevGateway extends MastraModelGateway {
     return this.attachmentCapabilities;
   }
 
+  getTemperatureCapabilities(): TemperatureCapabilities {
+    return this.temperatureCapabilities;
+  }
+
   buildUrl(routerId: string, envVars?: typeof process.env): string | undefined {
     const { providerId } = parseModelRouterId(routerId);
 

packages/core/src/llm/model/index.ts

@@ -6,6 +6,7 @@ export {
   type ModelForProvider,
   type AttachmentCapabilities,
   modelSupportsAttachments,
+  modelSupportsTemperature,
 } from './provider-registry.js';
 export { resolveModelConfig, isOpenAICompatibleObjectConfig } from './resolve-model';
 export { resolveModelAuth, type ResolveModelAuthArgs } from './model-auth-resolver';

packages/core/src/llm/model/provider-registry.test.ts

@@ -6,10 +6,16 @@ import type { ProviderConfig } from './gateways/base.js';
 import { MastraGateway } from './gateways/mastra.js';
 import { ModelsDevGateway } from './gateways/models-dev.js';
 import { NetlifyGateway } from './gateways/netlify.js';
-import { GatewayRegistry, modelSupportsAttachments } from './provider-registry.js';
+import {
+  GatewayRegistry,
+  modelSupportsAttachments,
+  modelSupportsTemperature,
+  _resetCapabilityCaches,
+} from './provider-registry.js';
 
 describe('modelSupportsAttachments', () => {
   afterEach(() => {
+    _resetCapabilityCaches();
     vi.restoreAllMocks();
   });
 
@@ -35,6 +41,35 @@ describe('modelSupportsAttachments', () => {
   });
 });
 
+describe('modelSupportsTemperature', () => {
+  beforeEach(() => {
+    _resetCapabilityCaches();
+  });
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('returns true for models listed in the temperature capability', () => {
+    expect(modelSupportsTemperature('openai/gpt-4o')).toBe(true);
+    expect(modelSupportsTemperature('anthropic/claude-sonnet-4-6')).toBe(true);
+  });
+
+  it('returns false for models whose provider is known but model is not in temperature list', () => {
+    // gpt-5-pro is in the openai attachment list but NOT in the temperature list
+    expect(modelSupportsTemperature('openai/gpt-5-pro')).toBe(false);
+  });
+
+  it('returns undefined for unknown providers', () => {
+    expect(modelSupportsTemperature('unknown-provider/some-model')).toBeUndefined();
+  });
+
+  it('resolves nested provider model IDs through the fallback path', () => {
+    // openrouter/anthropic/claude-sonnet-4-6 should resolve via the nested provider fallback
+    expect(modelSupportsTemperature('openrouter/anthropic/claude-sonnet-4-6')).toBe(true);
+    expect(modelSupportsTemperature('openrouter/openai/gpt-5-pro')).toBe(false);
+  });
+});
+
 describe('GatewayRegistry Auto-Refresh', () => {
   const CACHE_DIR = path.join(os.homedir(), '.cache', 'mastra');
   const CACHE_FILE = path.join(CACHE_DIR, 'gateway-refresh-time');