diff --git a/.changeset/openrouter-combined-tools-and-schema.md b/.changeset/openrouter-combined-tools-and-schema.md
new file mode 100644
index 0000000000..953df9f5fc
--- /dev/null
+++ b/.changeset/openrouter-combined-tools-and-schema.md
@@ -0,0 +1,7 @@
+---
+'@tanstack/ai-openrouter': minor
+---
+
+Add native combined tools + `outputSchema` mode to both OpenRouter text adapters (chat-completions and Responses). When the resolved upstream model supports emitting a schema-constrained final answer alongside tool calls in a single pass, `chat({ outputSchema, tools, stream: true })` now wires the JSON Schema into the same streaming request as the tools and harvests the final-turn JSON, skipping the separate finalization round-trip.
+
+Because OpenRouter is a routing layer, capability is keyed per resolved upstream model via the new `OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS` set, exported from `@tanstack/ai-openrouter/model-meta`, which both adapters consult from `supportsCombinedToolsAndSchema()`. The set is derived from each upstream provider's combined-mode gate (Anthropic 4.5+, Gemini 3.x, OpenAI's strict `json_schema` era, Grok 4.x) rather than the broader catalog `responseFormat` flag, so models that advertise structured output but predate native combined mode stay on the legacy finalization path.
diff --git a/docs/adapters/openrouter.md b/docs/adapters/openrouter.md
index 3060bff5f4..91ffdb9dc8 100644
--- a/docs/adapters/openrouter.md
+++ b/docs/adapters/openrouter.md
@@ -112,6 +112,135 @@ export async function POST(request: Request) {
 }
 ```
 
+## Tools and structured output together
+
+You can pass both `tools` and `outputSchema` on one `chat()` call. For some
+upstream models OpenRouter can return the typed object in that same streaming
+request, so the engine does not make a second finalization call.
+
+That happens only when **every** model that can receive the request is in
+`OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS`. The set is the upstream models
+that already support this combined mode:
+
+- Anthropic Claude 4.5 and later
+- Gemini 3.x text models
+- Grok 4.x (not the multi-agent variant)
+- OpenAI models from the `gpt-4o-2024-08-06` strict JSON Schema era onward
+  (the unpinned `openai/gpt-4o-mini` alias is included; the dated pin
+  `openai/gpt-4o-mini-2024-07-18` is not)
+
+If any fallback in `modelOptions.models` is outside that set, OpenRouter keeps
+the two-call path. Routing suffixes such as `:nitro` do not change the gate.
+
+Import the set from `@tanstack/ai-openrouter/model-meta` if you need to check a
+model before you send:
+
+```typescript
+import { OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS } from "@tanstack/ai-openrouter/model-meta";
+
+OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS.has("openai/gpt-5.5");
+```
+
+Chat Completions (`openRouterText`) and Responses (`openRouterResponsesText`)
+both attach the schema on this path. The client does not change: `useChat({
+outputSchema })` still reads `partial` and `final`.
+
+Server (Chat Completions):
+
+```typescript
+import { chat, toServerSentEventsResponse, toolDefinition } from "@tanstack/ai";
+import { openRouterText } from "@tanstack/ai-openrouter";
+import { z } from "zod";
+
+const getWeather = toolDefinition({
+  name: "get_weather",
+  description: "Get the current weather",
+  inputSchema: z.object({ location: z.string() }),
+}).server(async ({ location }) => {
+  return { temperature: 72, conditions: "sunny", location };
+});
+
+const AnswerSchema = z.object({
+  summary: z.string(),
+  location: z.string(),
+});
+
+export async function POST(request: Request) {
+  const { messages } = await request.json();
+
+  const stream = chat({
+    adapter: openRouterText("openai/gpt-5.5"),
+    messages,
+    tools: [getWeather],
+    outputSchema: AnswerSchema,
+    stream: true,
+  });
+
+  return toServerSentEventsResponse(stream);
+}
+```
+
+Server (Responses). Same `tools` and `outputSchema` as the Chat Completions
+example, with `openRouterResponsesText`:
+
+```typescript
+import { chat, toServerSentEventsResponse, toolDefinition } from "@tanstack/ai";
+import { openRouterResponsesText } from "@tanstack/ai-openrouter";
+import { z } from "zod";
+
+const getWeather = toolDefinition({
+  name: "get_weather",
+  description: "Get the current weather",
+  inputSchema: z.object({ location: z.string() }),
+}).server(async ({ location }) => {
+  return { temperature: 72, conditions: "sunny", location };
+});
+
+const AnswerSchema = z.object({
+  summary: z.string(),
+  location: z.string(),
+});
+
+export async function POST(request: Request) {
+  const { messages } = await request.json();
+
+  const stream = chat({
+    adapter: openRouterResponsesText("openai/gpt-5.5"),
+    messages,
+    tools: [getWeather],
+    outputSchema: AnswerSchema,
+    stream: true,
+  });
+
+  return toServerSentEventsResponse(stream);
+}
+```
+
+Client:
+
+```tsx
+import { useChat, fetchServerSentEvents } from "@tanstack/ai-react";
+import { z } from "zod";
+
+const AnswerSchema = z.object({
+  summary: z.string(),
+  location: z.string(),
+});
+
+const { sendMessage, partial, final } = useChat({
+  connection: fetchServerSentEvents("/api/chat"),
+  outputSchema: AnswerSchema,
+});
+```
+
+See [Structured Outputs with tools](../structured-outputs/with-tools) for the
+event order, and [Middleware](../advanced/middleware) for how
+`structuredOutput` phase behaves on this path.
+
+To try this in a browser, run `examples/ts-react-chat` and open
+`/generations/openrouter-combined`. The page shows the tool call, the typed
+object, and the adapter call counts. `structuredOutputStream` must stay at 0.
+
 ## Environment Variables
 
 Set your API key in environment variables:
diff --git a/docs/advanced/middleware.md b/docs/advanced/middleware.md
index 80fe5fed46..334bb3ead2 100644
--- a/docs/advanced/middleware.md
+++ b/docs/advanced/middleware.md
@@ -102,7 +102,7 @@ The context's `phase` field tracks where you are in the lifecycle:
 | `modelStream` | While adapter streams chunks | `onChunk`, `onUsage` |
 | `beforeTools` | Before tool execution | `onBeforeToolCall` |
 | `afterTools` | After tool execution | `onAfterToolCall` |
-| `structuredOutput` | During the final structured-output adapter call (when `outputSchema` is set **and** the adapter does not declare `supportsCombinedToolsAndSchema()`). Chunks from `adapter.structuredOutputStream` (or the synthesized non-streaming fallback) flow through `onChunk` with this phase, and `onUsage` fires for the final call's tokens. **Does not fire** for adapters that natively combine tools + schema in one streaming call (modern OpenAI Chat Completions, OpenAI Responses, Claude 4.5+, Gemini 3.x, Grok 4.x family — see issue #605); on that path middleware observes the run through `beforeModel` / `modelStream` as usual. | `onStructuredOutputConfig`, `onConfig`, `onChunk`, `onUsage` |
+| `structuredOutput` | During the final structured-output adapter call (when `outputSchema` is set **and** the adapter does not declare `supportsCombinedToolsAndSchema()`). Chunks from `adapter.structuredOutputStream` (or the synthesized non-streaming fallback) flow through `onChunk` with this phase, and `onUsage` fires for the final call's tokens. **Does not fire** for adapters that natively combine tools + schema in one streaming call (modern OpenAI Chat Completions, OpenAI Responses, Claude 4.5+, Gemini 3.x, Grok 4.x family, and OpenRouter when every routed model is in `OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS`; see issue #605). On that path middleware observes the run through `beforeModel` / `modelStream` as usual. | `onStructuredOutputConfig`, `onConfig`, `onChunk`, `onUsage` |
 
 ## Hooks Reference
 
diff --git a/docs/config.json b/docs/config.json
index 6ab97268ed..ca435a0054 100644
--- a/docs/config.json
+++ b/docs/config.json
@@ -337,7 +337,7 @@
           "label": "Overview",
           "to": "structured-outputs/overview",
           "addedAt": "2026-05-19",
-          "updatedAt": "2026-08-18"
+          "updatedAt": "2026-08-19"
         },
         {
           "label": "One-Shot Extraction",
@@ -360,7 +360,7 @@
           "label": "With Tools",
           "to": "structured-outputs/with-tools",
           "addedAt": "2026-05-19",
-          "updatedAt": "2026-08-14"
+          "updatedAt": "2026-08-19"
         },
         {
           "label": "Harness Agents",
@@ -490,7 +490,7 @@
           "label": "Middleware",
           "to": "advanced/middleware",
           "addedAt": "2026-04-15",
-          "updatedAt": "2026-07-21"
+          "updatedAt": "2026-08-19"
         },
         {
           "label": "Built-in Middleware",
@@ -857,7 +857,7 @@
           "label": "OpenRouter Adapter",
           "to": "adapters/openrouter",
           "addedAt": "2026-04-15",
-          "updatedAt": "2026-08-13"
+          "updatedAt": "2026-08-19"
         },
         {
           "label": "Perplexity Search",
diff --git a/docs/structured-outputs/overview.md b/docs/structured-outputs/overview.md
index 79d1ad1c3f..dba56fe729 100644
--- a/docs/structured-outputs/overview.md
+++ b/docs/structured-outputs/overview.md
@@ -113,10 +113,14 @@ exactly once at the end of the entire run.
 > - Anthropic Claude 4.5+
 > - Gemini 3.x
 > - Grok 4.x family
+> - OpenRouter, when every routed model is in
+>   `OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS` (see the
+>   [OpenRouter adapter](../adapters/openrouter.md#tools-and-structured-output-together))
 >
 > **Adapters without native combined-mode support** (Anthropic 4.4-, Gemini
-> 2.x, Grok 2/3, Groq, Ollama, OpenRouter) keep the legacy finalization
-> path and the `'structuredOutput'` phase fires as before.
+> 2.x, Grok 2/3, Groq, Ollama, and OpenRouter models outside that set) keep
+> the legacy finalization path and the `'structuredOutput'` phase fires as
+> before.
 
 ### Observing structured-output chunks
 
diff --git a/docs/structured-outputs/with-tools.md b/docs/structured-outputs/with-tools.md
index 7ac8aec506..8e64503f52 100644
--- a/docs/structured-outputs/with-tools.md
+++ b/docs/structured-outputs/with-tools.md
@@ -17,6 +17,10 @@ You want the agent to use tools to gather information, then return a structured
 
 This page covers the combined `outputSchema` + `tools` shape, including the pause/resume points (server-tool approval prompts, client-tool invocations) that can land mid-run before the structured object arrives.
 
+On adapters that support native combined mode (modern OpenAI, Claude 4.5+, Gemini 3.x, Grok 4.x, and [OpenRouter on those same upstream models](../adapters/openrouter.md#tools-and-structured-output-together)), `chat({ tools, outputSchema, stream: true })` is one streaming request. The extra finalization call does not run.
+
+The React chat example has a live OpenRouter page at `/generations/openrouter-combined`.
+
 > **Note:** If you're not yet familiar with how tools work in TanStack AI, read [Tool Architecture](../tools/tool-architecture) and [Server Tools](../tools/server-tools) first. The patterns here build on the regular agent-loop flow — `outputSchema` just adds a final terminal event.
 
 ## Non-streaming: tools first, then structured object
diff --git a/examples/ts-react-chat/src/components/Header.tsx b/examples/ts-react-chat/src/components/Header.tsx
index 8660905a3c..aba382f7a3 100644
--- a/examples/ts-react-chat/src/components/Header.tsx
+++ b/examples/ts-react-chat/src/components/Header.tsx
@@ -204,6 +204,19 @@ export default function Header() {
             <span className="font-medium">Structured Output</span>
           </Link>
 
+          <Link
+            to="/generations/openrouter-combined"
+            onClick={() => setIsOpen(false)}
+            className="flex items-center gap-3 p-3 rounded-lg hover:bg-gray-800 transition-colors mb-1"
+            activeProps={{
+              className:
+                'flex items-center gap-3 p-3 rounded-lg bg-cyan-600 hover:bg-cyan-700 transition-colors mb-1',
+            }}
+          >
+            <Layers size={20} />
+            <span className="font-medium">OpenRouter Combined</span>
+          </Link>
+
           <Link
             to="/repo-report"
             onClick={() => setIsOpen(false)}
diff --git a/examples/ts-react-chat/src/routeTree.gen.ts b/examples/ts-react-chat/src/routeTree.gen.ts
index e42124b47d..bc690e9d93 100644
--- a/examples/ts-react-chat/src/routeTree.gen.ts
+++ b/examples/ts-react-chat/src/routeTree.gen.ts
@@ -35,6 +35,7 @@ import { Route as GenerationsStructuredOutputRouteImport } from './routes/genera
 import { Route as GenerationsStructuredChatRouteImport } from './routes/generations.structured-chat'
 import { Route as GenerationsSpeechRouteImport } from './routes/generations.speech'
 import { Route as GenerationsPersistentGenerationRouteImport } from './routes/generations.persistent-generation'
+import { Route as GenerationsOpenrouterCombinedRouteImport } from './routes/generations.openrouter-combined'
 import { Route as GenerationsImageRouteImport } from './routes/generations.image'
 import { Route as GenerationsAudioRouteImport } from './routes/generations.audio'
 import { Route as ExampleRuntimeContextRouteImport } from './routes/example.runtime-context'
@@ -48,6 +49,7 @@ import { Route as ApiSandboxTriageRouteImport } from './routes/api.sandbox-triag
 import { Route as ApiSandboxRepoReportRouteImport } from './routes/api.sandbox-repo-report'
 import { Route as ApiResumableRouteImport } from './routes/api.resumable'
 import { Route as ApiPersistentChatRouteImport } from './routes/api.persistent-chat'
+import { Route as ApiOpenrouterCombinedRouteImport } from './routes/api.openrouter-combined'
 import { Route as ApiMcpStatusRouteImport } from './routes/api.mcp-status'
 import { Route as ApiMcpPoolRouteImport } from './routes/api.mcp-pool'
 import { Route as ApiMcpManualRouteImport } from './routes/api.mcp-manual'
@@ -203,6 +205,12 @@ const GenerationsPersistentGenerationRoute =
     path: '/generations/persistent-generation',
     getParentRoute: () => rootRouteImport,
   } as any)
+const GenerationsOpenrouterCombinedRoute =
+  GenerationsOpenrouterCombinedRouteImport.update({
+    id: '/generations/openrouter-combined',
+    path: '/generations/openrouter-combined',
+    getParentRoute: () => rootRouteImport,
+  } as any)
 const GenerationsImageRoute = GenerationsImageRouteImport.update({
   id: '/generations/image',
   path: '/generations/image',
@@ -268,6 +276,11 @@ const ApiPersistentChatRoute = ApiPersistentChatRouteImport.update({
   path: '/api/persistent-chat',
   getParentRoute: () => rootRouteImport,
 } as any)
+const ApiOpenrouterCombinedRoute = ApiOpenrouterCombinedRouteImport.update({
+  id: '/api/openrouter-combined',
+  path: '/api/openrouter-combined',
+  getParentRoute: () => rootRouteImport,
+} as any)
 const ApiMcpStatusRoute = ApiMcpStatusRouteImport.update({
   id: '/api/mcp-status',
   path: '/api/mcp-status',
@@ -403,6 +416,7 @@ export interface FileRoutesByFullPath {
   '/api/mcp-manual': typeof ApiMcpManualRoute
   '/api/mcp-pool': typeof ApiMcpPoolRoute
   '/api/mcp-status': typeof ApiMcpStatusRoute
+  '/api/openrouter-combined': typeof ApiOpenrouterCombinedRoute
   '/api/persistent-chat': typeof ApiPersistentChatRoute
   '/api/resumable': typeof ApiResumableRoute
   '/api/sandbox-repo-report': typeof ApiSandboxRepoReportRoute
@@ -416,6 +430,7 @@ export interface FileRoutesByFullPath {
   '/example/runtime-context': typeof ExampleRuntimeContextRoute
   '/generations/audio': typeof GenerationsAudioRoute
   '/generations/image': typeof GenerationsImageRoute
+  '/generations/openrouter-combined': typeof GenerationsOpenrouterCombinedRoute
   '/generations/persistent-generation': typeof GenerationsPersistentGenerationRoute
   '/generations/speech': typeof GenerationsSpeechRoute
   '/generations/structured-chat': typeof GenerationsStructuredChatRoute
@@ -464,6 +479,7 @@ export interface FileRoutesByTo {
   '/api/mcp-manual': typeof ApiMcpManualRoute
   '/api/mcp-pool': typeof ApiMcpPoolRoute
   '/api/mcp-status': typeof ApiMcpStatusRoute
+  '/api/openrouter-combined': typeof ApiOpenrouterCombinedRoute
   '/api/persistent-chat': typeof ApiPersistentChatRoute
   '/api/resumable': typeof ApiResumableRoute
   '/api/sandbox-repo-report': typeof ApiSandboxRepoReportRoute
@@ -477,6 +493,7 @@ export interface FileRoutesByTo {
   '/example/runtime-context': typeof ExampleRuntimeContextRoute
   '/generations/audio': typeof GenerationsAudioRoute
   '/generations/image': typeof GenerationsImageRoute
+  '/generations/openrouter-combined': typeof GenerationsOpenrouterCombinedRoute
   '/generations/persistent-generation': typeof GenerationsPersistentGenerationRoute
   '/generations/speech': typeof GenerationsSpeechRoute
   '/generations/structured-chat': typeof GenerationsStructuredChatRoute
@@ -526,6 +543,7 @@ export interface FileRoutesById {
   '/api/mcp-manual': typeof ApiMcpManualRoute
   '/api/mcp-pool': typeof ApiMcpPoolRoute
   '/api/mcp-status': typeof ApiMcpStatusRoute
+  '/api/openrouter-combined': typeof ApiOpenrouterCombinedRoute
   '/api/persistent-chat': typeof ApiPersistentChatRoute
   '/api/resumable': typeof ApiResumableRoute
   '/api/sandbox-repo-report': typeof ApiSandboxRepoReportRoute
@@ -539,6 +557,7 @@ export interface FileRoutesById {
   '/example/runtime-context': typeof ExampleRuntimeContextRoute
   '/generations/audio': typeof GenerationsAudioRoute
   '/generations/image': typeof GenerationsImageRoute
+  '/generations/openrouter-combined': typeof GenerationsOpenrouterCombinedRoute
   '/generations/persistent-generation': typeof GenerationsPersistentGenerationRoute
   '/generations/speech': typeof GenerationsSpeechRoute
   '/generations/structured-chat': typeof GenerationsStructuredChatRoute
@@ -589,6 +608,7 @@ export interface FileRouteTypes {
     | '/api/mcp-manual'
     | '/api/mcp-pool'
     | '/api/mcp-status'
+    | '/api/openrouter-combined'
     | '/api/persistent-chat'
     | '/api/resumable'
     | '/api/sandbox-repo-report'
@@ -602,6 +622,7 @@ export interface FileRouteTypes {
     | '/example/runtime-context'
     | '/generations/audio'
     | '/generations/image'
+    | '/generations/openrouter-combined'
     | '/generations/persistent-generation'
     | '/generations/speech'
     | '/generations/structured-chat'
@@ -650,6 +671,7 @@ export interface FileRouteTypes {
     | '/api/mcp-manual'
     | '/api/mcp-pool'
     | '/api/mcp-status'
+    | '/api/openrouter-combined'
     | '/api/persistent-chat'
     | '/api/resumable'
     | '/api/sandbox-repo-report'
@@ -663,6 +685,7 @@ export interface FileRouteTypes {
     | '/example/runtime-context'
     | '/generations/audio'
     | '/generations/image'
+    | '/generations/openrouter-combined'
     | '/generations/persistent-generation'
     | '/generations/speech'
     | '/generations/structured-chat'
@@ -711,6 +734,7 @@ export interface FileRouteTypes {
     | '/api/mcp-manual'
     | '/api/mcp-pool'
     | '/api/mcp-status'
+    | '/api/openrouter-combined'
     | '/api/persistent-chat'
     | '/api/resumable'
     | '/api/sandbox-repo-report'
@@ -724,6 +748,7 @@ export interface FileRouteTypes {
     | '/example/runtime-context'
     | '/generations/audio'
     | '/generations/image'
+    | '/generations/openrouter-combined'
     | '/generations/persistent-generation'
     | '/generations/speech'
     | '/generations/structured-chat'
@@ -773,6 +798,7 @@ export interface RootRouteChildren {
   ApiMcpManualRoute: typeof ApiMcpManualRoute
   ApiMcpPoolRoute: typeof ApiMcpPoolRoute
   ApiMcpStatusRoute: typeof ApiMcpStatusRoute
+  ApiOpenrouterCombinedRoute: typeof ApiOpenrouterCombinedRoute
   ApiPersistentChatRoute: typeof ApiPersistentChatRoute
   ApiResumableRoute: typeof ApiResumableRoute
   ApiSandboxRepoReportRoute: typeof ApiSandboxRepoReportRoute
@@ -786,6 +812,7 @@ export interface RootRouteChildren {
   ExampleRuntimeContextRoute: typeof ExampleRuntimeContextRoute
   GenerationsAudioRoute: typeof GenerationsAudioRoute
   GenerationsImageRoute: typeof GenerationsImageRoute
+  GenerationsOpenrouterCombinedRoute: typeof GenerationsOpenrouterCombinedRoute
   GenerationsPersistentGenerationRoute: typeof GenerationsPersistentGenerationRoute
   GenerationsSpeechRoute: typeof GenerationsSpeechRoute
   GenerationsStructuredChatRoute: typeof GenerationsStructuredChatRoute
@@ -985,6 +1012,13 @@ declare module '@tanstack/react-router' {
       preLoaderRoute: typeof GenerationsPersistentGenerationRouteImport
       parentRoute: typeof rootRouteImport
     }
+    '/generations/openrouter-combined': {
+      id: '/generations/openrouter-combined'
+      path: '/generations/openrouter-combined'
+      fullPath: '/generations/openrouter-combined'
+      preLoaderRoute: typeof GenerationsOpenrouterCombinedRouteImport
+      parentRoute: typeof rootRouteImport
+    }
     '/generations/image': {
       id: '/generations/image'
       path: '/generations/image'
@@ -1076,6 +1110,13 @@ declare module '@tanstack/react-router' {
       preLoaderRoute: typeof ApiPersistentChatRouteImport
       parentRoute: typeof rootRouteImport
     }
+    '/api/openrouter-combined': {
+      id: '/api/openrouter-combined'
+      path: '/api/openrouter-combined'
+      fullPath: '/api/openrouter-combined'
+      preLoaderRoute: typeof ApiOpenrouterCombinedRouteImport
+      parentRoute: typeof rootRouteImport
+    }
     '/api/mcp-status': {
       id: '/api/mcp-status'
       path: '/api/mcp-status'
@@ -1263,6 +1304,7 @@ const rootRouteChildren: RootRouteChildren = {
   ApiMcpManualRoute: ApiMcpManualRoute,
   ApiMcpPoolRoute: ApiMcpPoolRoute,
   ApiMcpStatusRoute: ApiMcpStatusRoute,
+  ApiOpenrouterCombinedRoute: ApiOpenrouterCombinedRoute,
   ApiPersistentChatRoute: ApiPersistentChatRoute,
   ApiResumableRoute: ApiResumableRoute,
   ApiSandboxRepoReportRoute: ApiSandboxRepoReportRoute,
@@ -1276,6 +1318,7 @@ const rootRouteChildren: RootRouteChildren = {
   ExampleRuntimeContextRoute: ExampleRuntimeContextRoute,
   GenerationsAudioRoute: GenerationsAudioRoute,
   GenerationsImageRoute: GenerationsImageRoute,
+  GenerationsOpenrouterCombinedRoute: GenerationsOpenrouterCombinedRoute,
   GenerationsPersistentGenerationRoute: GenerationsPersistentGenerationRoute,
   GenerationsSpeechRoute: GenerationsSpeechRoute,
   GenerationsStructuredChatRoute: GenerationsStructuredChatRoute,
diff --git a/examples/ts-react-chat/src/routes/api.openrouter-combined.ts b/examples/ts-react-chat/src/routes/api.openrouter-combined.ts
new file mode 100644
index 0000000000..1cce943826
--- /dev/null
+++ b/examples/ts-react-chat/src/routes/api.openrouter-combined.ts
@@ -0,0 +1,276 @@
+import { createFileRoute } from '@tanstack/react-router'
+import {
+  chat,
+  chatParamsFromRequestBody,
+  EventType,
+  toServerSentEventsResponse,
+  toolDefinition,
+} from '@tanstack/ai'
+import {
+  openRouterResponsesText,
+  openRouterText,
+} from '@tanstack/ai-openrouter'
+import { z } from 'zod'
+import type { ChatMiddleware, StreamChunk } from '@tanstack/ai'
+
+/**
+ * Live confirmation page for OpenRouter native combined mode:
+ * `chat({ tools, outputSchema, stream: true })` must stay on `chatStream`
+ * and must not call `structuredOutputStream`.
+ */
+
+export const CitySchema = z.object({
+  city: z.string().describe('City name'),
+  code: z.string().describe('Short 3-letter city code from the tool'),
+  summary: z.string().describe('One sentence that uses the city and the code'),
+})
+
+export type CityResult = z.infer<typeof CitySchema>
+
+const lookupCityCode = toolDefinition({
+  name: 'lookup_city_code',
+  description: 'Return a short 3-letter code for a city',
+  inputSchema: z.object({ city: z.string() }),
+  outputSchema: z.object({ code: z.string() }),
+}).server(async ({ city }) => ({
+  code: city.slice(0, 3).toUpperCase(),
+}))
+
+const PROVIDERS = ['openrouter', 'openrouter-responses'] as const
+type Provider = (typeof PROVIDERS)[number]
+
+const MODELS = [
+  'openai/gpt-5.5',
+  'anthropic/claude-sonnet-4.6',
+  'google/gemini-3.5-flash',
+  'x-ai/grok-4.5',
+] as const
+export type CombinedModel = (typeof MODELS)[number]
+
+export const COMBINED_MODELS: ReadonlyArray<{
+  value: CombinedModel
+  label: string
+}> = [
+  { value: 'openai/gpt-5.5', label: 'OpenAI GPT-5.5' },
+  { value: 'anthropic/claude-sonnet-4.6', label: 'Claude Sonnet 4.6' },
+  { value: 'google/gemini-3.5-flash', label: 'Gemini 3.5 Flash' },
+  { value: 'x-ai/grok-4.5', label: 'Grok 4.5' },
+]
+
+function isProvider(value: unknown): value is Provider {
+  return value === 'openrouter' || value === 'openrouter-responses'
+}
+
+function isModel(value: unknown): value is CombinedModel {
+  return typeof value === 'string' && MODELS.some((model) => model === value)
+}
+
+export type CombinedModeStats = {
+  supportsCombined: boolean
+  chatStreamCalls: number
+  chatStreamWithSchema: number
+  structuredOutputStreamCalls: number
+  structuredOutputCalls: number
+  nativeCombined: boolean
+}
+
+/**
+ * Count adapter entry points so the UI can prove native combined mode:
+ * schema rides on `chatStream`, and `structuredOutputStream` stays at 0.
+ *
+ * Infer T from one concrete adapter (Chat Completions or Responses). A union
+ * of those two classes made the wrapper `options` parameter implicit `any`.
+ */
+function instrumentAdapter<
+  T extends {
+    model: string
+    chatStream: (options: never) => AsyncIterable<StreamChunk>
+    structuredOutputStream?: (options: never) => AsyncIterable<StreamChunk>
+    structuredOutput: (options: never) => Promise<unknown>
+    supportsCombinedToolsAndSchema: () => boolean
+  },
+>(adapter: T): { adapter: T; snapshot: () => CombinedModeStats } {
+  const stats = {
+    supportsCombined: adapter.supportsCombinedToolsAndSchema() === true,
+    chatStreamCalls: 0,
+    chatStreamWithSchema: 0,
+    structuredOutputStreamCalls: 0,
+    structuredOutputCalls: 0,
+  }
+
+  const origChatStream = adapter.chatStream.bind(adapter)
+  adapter.chatStream = (options: { outputSchema?: unknown }) => {
+    stats.chatStreamCalls += 1
+    if (options.outputSchema) {
+      stats.chatStreamWithSchema += 1
+    }
+    return origChatStream(options as never)
+  }
+
+  const origStructuredStream = adapter.structuredOutputStream?.bind(adapter)
+  if (origStructuredStream) {
+    adapter.structuredOutputStream = (options: never) => {
+      stats.structuredOutputStreamCalls += 1
+      return origStructuredStream(options)
+    }
+  }
+
+  const origStructured = adapter.structuredOutput.bind(adapter)
+  adapter.structuredOutput = (options: never) => {
+    stats.structuredOutputCalls += 1
+    return origStructured(options)
+  }
+
+  return {
+    adapter,
+    snapshot: () => ({
+      ...stats,
+      nativeCombined:
+        stats.supportsCombined &&
+        stats.structuredOutputStreamCalls === 0 &&
+        stats.structuredOutputCalls === 0 &&
+        stats.chatStreamWithSchema > 0,
+    }),
+  }
+}
+
+function phaseCounterMiddleware(): {
+  middleware: ChatMiddleware
+  snapshot: () => Record<string, number>
+} {
+  const counts: Record<string, number> = {}
+  return {
+    middleware: {
+      name: 'phase-counter',
+      onChunk(ctx) {
+        counts[ctx.phase] = (counts[ctx.phase] ?? 0) + 1
+      },
+    },
+    snapshot: () => ({ ...counts }),
+  }
+}
+
+async function* withTrailingDiagnostics(
+  stream: AsyncIterable<StreamChunk>,
+  combinedSnapshot: () => CombinedModeStats,
+  phaseSnapshot: () => Record<string, number>,
+  model: string,
+): AsyncIterable<StreamChunk> {
+  let yielded = false
+  for await (const chunk of stream) {
+    if (
+      chunk.type === EventType.RUN_FINISHED ||
+      chunk.type === EventType.RUN_ERROR
+    ) {
+      yielded = true
+      yield {
+        type: EventType.CUSTOM,
+        name: 'combined-mode',
+        value: combinedSnapshot(),
+        model,
+        timestamp: Date.now(),
+      }
+      yield {
+        type: EventType.CUSTOM,
+        name: 'phase-counts',
+        value: phaseSnapshot(),
+        model,
+        timestamp: Date.now(),
+      }
+    }
+    yield chunk
+  }
+  if (!yielded) {
+    yield {
+      type: EventType.CUSTOM,
+      name: 'combined-mode',
+      value: combinedSnapshot(),
+      model,
+      timestamp: Date.now(),
+    }
+    yield {
+      type: EventType.CUSTOM,
+      name: 'phase-counts',
+      value: phaseSnapshot(),
+      model,
+      timestamp: Date.now(),
+    }
+  }
+}
+
+export const Route = createFileRoute('/api/openrouter-combined')({
+  server: {
+    handlers: {
+      POST: async ({ request }) => {
+        if (request.signal.aborted) {
+          return new Response(null, { status: 499 })
+        }
+
+        const abortController = new AbortController()
+        const onAbort = () => abortController.abort()
+        request.signal.addEventListener('abort', onAbort, { once: true })
+        if (request.signal.aborted) {
+          onAbort()
+        }
+
+        let params: Awaited<ReturnType<typeof chatParamsFromRequestBody>>
+        try {
+          params = await chatParamsFromRequestBody(await request.json())
+        } catch (error) {
+          return new Response(
+            error instanceof Error ? error.message : 'Bad request',
+            { status: 400 },
+          )
+        }
+
+        try {
+          const provider: Provider = isProvider(params.forwardedProps.provider)
+            ? params.forwardedProps.provider
+            : 'openrouter'
+          const model: CombinedModel = isModel(params.forwardedProps.model)
+            ? params.forwardedProps.model
+            : 'openai/gpt-5.5'
+
+          const { adapter, snapshot: combinedSnapshot } =
+            provider === 'openrouter-responses'
+              ? instrumentAdapter(openRouterResponsesText(model))
+              : instrumentAdapter(openRouterText(model))
+          const counter = phaseCounterMiddleware()
+
+          const streamIterable = chat({
+            adapter,
+            messages: params.messages,
+            tools: [lookupCityCode],
+            outputSchema: CitySchema,
+            stream: true,
+            middleware: [counter.middleware],
+            threadId: params.threadId,
+            runId: params.runId,
+            abortController,
+          }) as AsyncIterable<StreamChunk>
+
+          const withDiagnostics = withTrailingDiagnostics(
+            streamIterable,
+            combinedSnapshot,
+            counter.snapshot,
+            adapter.model,
+          )
+
+          return toServerSentEventsResponse(withDiagnostics, {
+            abortController,
+          })
+        } catch (error: unknown) {
+          const message =
+            error instanceof Error ? error.message : 'An error occurred'
+          console.error('[api/openrouter-combined] Error:', error)
+          return new Response(JSON.stringify({ error: message }), {
+            status: 500,
+            headers: { 'Content-Type': 'application/json' },
+          })
+        } finally {
+          request.signal.removeEventListener('abort', onAbort)
+        }
+      },
+    },
+  },
+})
diff --git a/examples/ts-react-chat/src/routes/generations.openrouter-combined.tsx b/examples/ts-react-chat/src/routes/generations.openrouter-combined.tsx
new file mode 100644
index 0000000000..457c15fda3
--- /dev/null
+++ b/examples/ts-react-chat/src/routes/generations.openrouter-combined.tsx
@@ -0,0 +1,394 @@
+import { useId, useState } from 'react'
+import { createFileRoute } from '@tanstack/react-router'
+import { EventType } from '@tanstack/ai'
+import { fetchServerSentEvents, useChat } from '@tanstack/ai-react'
+import { CitySchema, COMBINED_MODELS } from './api.openrouter-combined'
+import type {
+  CityResult,
+  CombinedModeStats,
+  CombinedModel,
+} from './api.openrouter-combined'
+import type { StreamChunk } from '@tanstack/ai'
+
+const SAMPLE_PROMPT =
+  'Call lookup_city_code for Paris, then return the structured object with city, code, and a one-sentence summary.'
+
+type Provider = 'openrouter' | 'openrouter-responses'
+
+function isProvider(value: string): value is Provider {
+  return value === 'openrouter' || value === 'openrouter-responses'
+}
+
+function isCombinedModel(value: string): value is CombinedModel {
+  return COMBINED_MODELS.some((option) => option.value === value)
+}
+
+function isPhaseCounts(value: unknown): value is Record<string, number> {
+  if (typeof value !== 'object' || value === null) return false
+  return Object.values(value).every((item) => typeof item === 'number')
+}
+
+function isCombinedStats(value: unknown): value is CombinedModeStats {
+  if (typeof value !== 'object' || value === null) return false
+  if (
+    !('supportsCombined' in value) ||
+    !('chatStreamCalls' in value) ||
+    !('chatStreamWithSchema' in value) ||
+    !('structuredOutputStreamCalls' in value) ||
+    !('structuredOutputCalls' in value) ||
+    !('nativeCombined' in value)
+  ) {
+    return false
+  }
+  return (
+    typeof value.supportsCombined === 'boolean' &&
+    typeof value.chatStreamCalls === 'number' &&
+    typeof value.chatStreamWithSchema === 'number' &&
+    typeof value.structuredOutputStreamCalls === 'number' &&
+    typeof value.structuredOutputCalls === 'number' &&
+    typeof value.nativeCombined === 'boolean'
+  )
+}
+
+function OpenRouterCombinedPage() {
+  const providerId = useId()
+  const modelId = useId()
+  const promptId = useId()
+  const statusId = useId()
+  const [prompt, setPrompt] = useState(SAMPLE_PROMPT)
+  const [provider, setProvider] = useState<Provider>('openrouter')
+  const [model, setModel] = useState<CombinedModel>('openai/gpt-5.5')
+  const [error, setError] = useState<string | null>(null)
+  const [phaseCounts, setPhaseCounts] = useState<Record<string, number> | null>(
+    null,
+  )
+  const [combined, setCombined] = useState<CombinedModeStats | null>(null)
+
+  const resetLocal = () => {
+    setError(null)
+    setPhaseCounts(null)
+    setCombined(null)
+  }
+
+  const handleChunk = (chunk: StreamChunk) => {
+    if (chunk.type !== EventType.CUSTOM) return
+
+    if (chunk.name === 'combined-mode' && isCombinedStats(chunk.value)) {
+      setCombined(chunk.value)
+    } else if (chunk.name === 'phase-counts' && isPhaseCounts(chunk.value)) {
+      setPhaseCounts(chunk.value)
+    }
+  }
+
+  const chat = useChat({
+    threadId: 'openrouter-combined:useChat',
+    outputSchema: CitySchema,
+    connection: fetchServerSentEvents('/api/openrouter-combined'),
+    forwardedProps: { provider, model },
+    onChunk: handleChunk,
+    onError: (err) => {
+      setError(err.message)
+    },
+  })
+
+  const toolCalls = chat.messages
+    .flatMap((message) => message.parts)
+    .filter((part) => part.type === 'tool-call')
+
+  const result: CityResult | null = chat.final ?? null
+  const isLoading = chat.isLoading
+  const structuredOutputPhase = phaseCounts?.structuredOutput ?? 0
+  const nativeCombined =
+    combined?.nativeCombined === true && structuredOutputPhase === 0
+
+  const handleGenerate = async () => {
+    if (!prompt.trim()) return
+    resetLocal()
+    chat.clear()
+    await chat.sendMessage(prompt.trim())
+  }
+
+  const handleAbort = () => {
+    chat.stop()
+    setError('Aborted')
+  }
+
+  const handleReset = () => {
+    resetLocal()
+    chat.clear()
+  }
+
+  return (
+    <main className="flex flex-col h-[calc(100vh-72px)] bg-gray-900 text-white">
+      <div className="border-b border-orange-500/20 bg-gray-800 px-6 py-4">
+        <h2 className="text-xl font-semibold">OpenRouter combined mode</h2>
+        <p className="text-sm text-gray-400 mt-1 max-w-3xl">
+          This page calls <code className="text-orange-400">chat()</code> with
+          both <code className="text-orange-400">tools</code> and{' '}
+          <code className="text-orange-400">outputSchema</code>. Native combined
+          mode is working when the model calls{' '}
+          <code className="text-orange-400">lookup_city_code</code>, returns a
+          typed object, and{' '}
+          <code className="text-orange-400">structuredOutputStream</code> stays
+          at 0.
+        </p>
+      </div>
+
+      <div className="flex-1 overflow-y-auto p-6">
+        <div className="max-w-2xl mx-auto space-y-6">
+          <div className="grid grid-cols-2 gap-3">
+            <div className="space-y-2">
+              <label htmlFor={providerId} className="text-sm text-gray-400">
+                OpenRouter endpoint
+              </label>
+              <select
+                id={providerId}
+                value={provider}
+                onChange={(event) => {
+                  const next = event.target.value
+                  if (isProvider(next)) setProvider(next)
+                }}
+                disabled={isLoading}
+                className="w-full rounded-lg border border-orange-500/20 bg-gray-800/50 px-3 py-2 text-sm text-white focus:outline-none focus:ring-2 focus:ring-orange-500/50 disabled:opacity-50"
+              >
+                <option value="openrouter">Chat Completions</option>
+                <option value="openrouter-responses">Responses beta</option>
+              </select>
+            </div>
+            <div className="space-y-2">
+              <label htmlFor={modelId} className="text-sm text-gray-400">
+                Model
+              </label>
+              <select
+                id={modelId}
+                value={model}
+                onChange={(event) => {
+                  const next = event.target.value
+                  if (isCombinedModel(next)) setModel(next)
+                }}
+                disabled={isLoading}
+                className="w-full rounded-lg border border-orange-500/20 bg-gray-800/50 px-3 py-2 text-sm text-white focus:outline-none focus:ring-2 focus:ring-orange-500/50 disabled:opacity-50"
+              >
+                {COMBINED_MODELS.map((option) => (
+                  <option key={option.value} value={option.value}>
+                    {option.label}
+                  </option>
+                ))}
+              </select>
+            </div>
+          </div>
+
+          <div className="space-y-2">
+            <label htmlFor={promptId} className="text-sm text-gray-400">
+              Prompt
+            </label>
+            <textarea
+              id={promptId}
+              value={prompt}
+              onChange={(event) => setPrompt(event.target.value)}
+              rows={4}
+              disabled={isLoading}
+              className="w-full rounded-lg border border-orange-500/20 bg-gray-800/50 px-4 py-3 text-sm text-white placeholder-gray-500 focus:outline-none focus:ring-2 focus:ring-orange-500/50 resize-none"
+            />
+          </div>
+
+          <div className="flex gap-3">
+            <button
+              type="button"
+              onClick={handleGenerate}
+              disabled={!prompt.trim() || isLoading}
+              className="px-6 py-2 bg-orange-600 hover:bg-orange-700 disabled:bg-gray-700 disabled:text-gray-500 text-white rounded-lg text-sm font-medium transition-colors"
+            >
+              {isLoading ? 'Running…' : 'Run combined test'}
+            </button>
+            {isLoading && (
+              <button
+                type="button"
+                onClick={handleAbort}
+                className="px-6 py-2 bg-red-600 hover:bg-red-700 text-white rounded-lg text-sm font-medium transition-colors"
+              >
+                Abort
+              </button>
+            )}
+            {(result || toolCalls.length > 0 || combined) && !isLoading && (
+              <button
+                type="button"
+                onClick={handleReset}
+                className="px-6 py-2 bg-gray-700 hover:bg-gray-600 text-white rounded-lg text-sm font-medium transition-colors"
+              >
+                Clear
+              </button>
+            )}
+          </div>
+
+          <p id={statusId} className="text-sm text-gray-400" aria-live="polite">
+            {isLoading
+              ? 'Waiting for the tool call and the typed object. This can take about 30 seconds.'
+              : nativeCombined
+                ? 'Native combined mode is on. structuredOutputStream stayed at 0.'
+                : combined
+                  ? 'Legacy path ran. structuredOutputStream or the structuredOutput phase was used.'
+                  : 'Ready. Use the sample prompt, then click Run combined test.'}
+          </p>
+
+          {error && (
+            <div
+              role="alert"
+              className="p-4 bg-red-500/10 border border-red-500/20 rounded-lg"
+            >
+              <p className="text-red-400 text-sm">{error}</p>
+            </div>
+          )}
+
+          {toolCalls.length > 0 && (
+            <section
+              aria-labelledby="tool-calls-heading"
+              className="p-4 bg-cyan-500/5 border border-cyan-500/20 rounded-lg space-y-3"
+            >
+              <h3 id="tool-calls-heading" className="text-sm font-semibold">
+                Tool calls
+              </h3>
+              <ul className="space-y-3">
+                {toolCalls.map((part) => (
+                  <li
+                    key={part.id}
+                    className="rounded-lg border border-cyan-500/20 bg-gray-900/40 p-3"
+                  >
+                    <p className="font-mono text-sm text-cyan-300">
+                      {part.name}{' '}
+                      <span className="text-gray-400">({part.state})</span>
+                    </p>
+                    <pre className="mt-2 overflow-x-auto text-xs text-gray-300 whitespace-pre-wrap">
+                      {JSON.stringify(
+                        {
+                          input: part.input,
+                          output: part.output,
+                        },
+                        null,
+                        2,
+                      )}
+                    </pre>
+                  </li>
+                ))}
+              </ul>
+            </section>
+          )}
+
+          {(result || chat.partial.city || chat.partial.code) && (
+            <section
+              aria-labelledby="result-heading"
+              aria-busy={isLoading}
+              className="p-4 bg-gray-800/50 border border-gray-700 rounded-lg space-y-2"
+            >
+              <h3 id="result-heading" className="text-sm font-semibold">
+                Typed object
+              </h3>
+              <dl className="grid grid-cols-[auto_1fr] gap-x-4 gap-y-1 text-sm">
+                <dt className="text-gray-400">city</dt>
+                <dd>{result?.city ?? chat.partial.city ?? '…'}</dd>
+                <dt className="text-gray-400">code</dt>
+                <dd className="font-mono">
+                  {result?.code ?? chat.partial.code ?? '…'}
+                </dd>
+                <dt className="text-gray-400">summary</dt>
+                <dd>{result?.summary ?? chat.partial.summary ?? '…'}</dd>
+              </dl>
+            </section>
+          )}
+
+          {combined && (
+            <section
+              aria-labelledby="verdict-heading"
+              className={`p-4 border rounded-lg ${
+                nativeCombined
+                  ? 'bg-emerald-900/20 border-emerald-700/50'
+                  : 'bg-amber-900/20 border-amber-700/50'
+              }`}
+            >
+              <h3 id="verdict-heading" className="text-sm font-semibold mb-3">
+                {nativeCombined
+                  ? 'Native combined mode'
+                  : 'Legacy two-call path'}
+              </h3>
+              <table className="w-full text-xs font-mono">
+                <caption className="sr-only">
+                  Adapter call counts for this run
+                </caption>
+                <thead>
+                  <tr className="text-left text-gray-400">
+                    <th scope="col" className="py-1 pr-4 font-medium">
+                      Check
+                    </th>
+                    <th scope="col" className="py-1 font-medium">
+                      Value
+                    </th>
+                  </tr>
+                </thead>
+                <tbody className="text-gray-200">
+                  <tr>
+                    <th scope="row" className="py-1 pr-4 font-normal">
+                      supportsCombinedToolsAndSchema
+                    </th>
+                    <td>{combined.supportsCombined ? 'true' : 'false'}</td>
+                  </tr>
+                  <tr>
+                    <th scope="row" className="py-1 pr-4 font-normal">
+                      chatStream calls
+                    </th>
+                    <td>{combined.chatStreamCalls}</td>
+                  </tr>
+                  <tr>
+                    <th scope="row" className="py-1 pr-4 font-normal">
+                      chatStream with outputSchema
+                    </th>
+                    <td>{combined.chatStreamWithSchema}</td>
+                  </tr>
+                  <tr>
+                    <th scope="row" className="py-1 pr-4 font-normal">
+                      structuredOutputStream calls
+                    </th>
+                    <td>{combined.structuredOutputStreamCalls}</td>
+                  </tr>
+                  <tr>
+                    <th scope="row" className="py-1 pr-4 font-normal">
+                      structuredOutput calls
+                    </th>
+                    <td>{combined.structuredOutputCalls}</td>
+                  </tr>
+                  <tr>
+                    <th scope="row" className="py-1 pr-4 font-normal">
+                      structuredOutput phase chunks
+                    </th>
+                    <td>{structuredOutputPhase}</td>
+                  </tr>
+                </tbody>
+              </table>
+              <p className="text-xs text-gray-400 mt-3">
+                Two <code>chatStream</code> calls is the agent loop (tool, then
+                final answer). That is not the legacy extra call. The extra call
+                is <code>structuredOutputStream</code> and must stay at 0.
+              </p>
+              {phaseCounts && (
+                <ul className="text-xs font-mono mt-3 space-y-1">
+                  {Object.entries(phaseCounts).map(([phase, count]) => (
+                    <li key={phase}>
+                      <span className="text-cyan-300">{phase}</span>
+                      {': '}
+                      <span className="text-gray-300">
+                        {count} chunk{count === 1 ? '' : 's'}
+                      </span>
+                    </li>
+                  ))}
+                </ul>
+              )}
+            </section>
+          )}
+        </div>
+      </div>
+    </main>
+  )
+}
+
+export const Route = createFileRoute('/generations/openrouter-combined')({
+  component: OpenRouterCombinedPage,
+})
diff --git a/examples/ts-react-chat/src/routes/index.tsx b/examples/ts-react-chat/src/routes/index.tsx
index fac7e8aa3d..fa268abd21 100644
--- a/examples/ts-react-chat/src/routes/index.tsx
+++ b/examples/ts-react-chat/src/routes/index.tsx
@@ -9,6 +9,7 @@ import {
   Github,
   Image,
   ImagePlus,
+  Layers,
   Mic,
   Music,
   PauseCircle,
@@ -202,6 +203,13 @@ function Messages({
               <Braces size={24} className="text-orange-400" />
               <span className="text-sm text-gray-300">Structured Chat</span>
             </Link>
+            <Link
+              to="/generations/openrouter-combined"
+              className="flex flex-col items-center gap-2 p-4 bg-gray-800/50 border border-gray-700 rounded-lg hover:border-orange-500/40 hover:bg-gray-800 transition-colors"
+            >
+              <Layers size={24} className="text-orange-400" />
+              <span className="text-sm text-gray-300">OpenRouter Combined</span>
+            </Link>
             <Link
               to="/typesafe-tools"
               className="flex flex-col items-center gap-2 p-4 bg-gray-800/50 border border-gray-700 rounded-lg hover:border-orange-500/40 hover:bg-gray-800 transition-colors"
diff --git a/packages/ai-openrouter/package.json b/packages/ai-openrouter/package.json
index aaefe951cc..0b239cea76 100644
--- a/packages/ai-openrouter/package.json
+++ b/packages/ai-openrouter/package.json
@@ -25,6 +25,10 @@
       "types": "./dist/esm/index.d.ts",
       "import": "./dist/esm/index.js"
     },
+    "./model-meta": {
+      "types": "./dist/esm/model-meta.d.ts",
+      "import": "./dist/esm/model-meta.js"
+    },
     "./tools": {
       "types": "./dist/esm/tools/index.d.ts",
       "import": "./dist/esm/tools/index.js"
diff --git a/packages/ai-openrouter/src/adapters/responses-text.ts b/packages/ai-openrouter/src/adapters/responses-text.ts
index 35538ef762..930760d5c5 100644
--- a/packages/ai-openrouter/src/adapters/responses-text.ts
+++ b/packages/ai-openrouter/src/adapters/responses-text.ts
@@ -7,6 +7,7 @@ import {
 } from '@tanstack/ai/adapter-internals'
 import { generateId } from '@tanstack/ai-utils'
 import { extractRequestOptions } from '../internal/request-options'
+import { openRouterSupportsCombinedToolsAndSchema } from '../internal/combined-tools-and-schema'
 import { makeStructuredOutputCompatible } from '../internal/schema-converter'
 import { convertFunctionToolToResponsesFormat } from '../internal/responses-tool-converter'
 import { isWebSearchTool } from '../tools/web-search-tool'
@@ -29,6 +30,7 @@ import type {
 } from '@tanstack/ai/adapters'
 import type {
   ContentPart,
+  JSONSchema,
   ModelMessage,
   StreamChunk,
   TextOptions,
@@ -1605,6 +1607,18 @@ export class OpenRouterResponsesTextAdapter<
         )
       : undefined
 
+    // Attach text.format json_schema only when outputSchema is set and every
+    // routed model is in the combined-capable set.
+    const combinedOutputSchema: JSONSchema | undefined = options.outputSchema
+    const combinedSchema =
+      combinedOutputSchema &&
+      this.supportsCombinedToolsAndSchema(options.modelOptions)
+        ? this.makeStructuredOutputCompatible(
+            combinedOutputSchema,
+            combinedOutputSchema.required,
+          )
+        : undefined
+
     const built: Pick<
       ResponsesRequest,
       | 'model'
@@ -1617,6 +1631,7 @@ export class OpenRouterResponsesTextAdapter<
       | 'tools'
       | 'toolChoice'
       | 'parallelToolCalls'
+      | 'text'
     > = {
       ...modelOptions,
       model: options.model + variantSuffix,
@@ -1635,11 +1650,36 @@ export class OpenRouterResponsesTextAdapter<
         tools.length > 0 && {
           tools,
         }),
+      ...(combinedSchema && {
+        // Merge onto any caller-supplied `text` (spread above via
+        // `...modelOptions`) so sibling fields like `text.verbosity` survive;
+        // only `text.format` is overridden by the combined-mode schema.
+        text: {
+          ...modelOptions.text,
+          format: {
+            type: 'json_schema' as const,
+            name: 'structured_output',
+            schema: combinedSchema,
+            strict: true,
+          },
+        },
+      }),
     }
 
     return built
   }
 
+  /**
+   * Combined mode is safe only when this model and every `modelOptions.models`
+   * fallback are in `OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS`.
+   * `:variant` suffixes are routing directives and do not change the gate.
+   */
+  supportsCombinedToolsAndSchema(
+    modelOptions?: OpenRouterResponsesTextProviderOptions,
+  ): boolean {
+    return openRouterSupportsCombinedToolsAndSchema(this.model, modelOptions)
+  }
+
   /**
    * Convert a list of ModelMessage to OpenRouter's `InputsUnion` array form.
    * Emits camelCase shapes (`callId`, `imageUrl`, `videoUrl`, `fileData`,
diff --git a/packages/ai-openrouter/src/adapters/text.ts b/packages/ai-openrouter/src/adapters/text.ts
index 3fb55f1388..1c48849ca2 100644
--- a/packages/ai-openrouter/src/adapters/text.ts
+++ b/packages/ai-openrouter/src/adapters/text.ts
@@ -8,6 +8,7 @@ import {
 import { generateId } from '@tanstack/ai-utils'
 import { extractRequestOptions } from '../internal/request-options'
 import { makeStructuredOutputCompatible } from '../internal/schema-converter'
+import { openRouterSupportsCombinedToolsAndSchema } from '../internal/combined-tools-and-schema'
 import { convertToolsToProviderFormat } from '../tools'
 import { getOpenRouterApiKeyFromEnv } from '../utils'
 import { buildOpenRouterUsage } from '../usage'
@@ -27,6 +28,7 @@ import type {
 } from '@tanstack/ai/adapters'
 import type {
   ContentPart,
+  JSONSchema,
   ModelMessage,
   StreamChunk,
   TextOptions,
@@ -1189,6 +1191,18 @@ export class OpenRouterTextAdapter<
       ? convertToolsToProviderFormat(options.tools)
       : undefined
 
+    // Attach json_schema only when outputSchema is set and every routed model
+    // is in the combined-capable set.
+    const combinedOutputSchema: JSONSchema | undefined = options.outputSchema
+    const combinedSchema =
+      combinedOutputSchema &&
+      this.supportsCombinedToolsAndSchema(options.modelOptions)
+        ? this.makeStructuredOutputCompatible(
+            combinedOutputSchema,
+            combinedOutputSchema.required,
+          )
+        : undefined
+
     // `modelOptions` is the sole wire surface: callers set provider-native
     // names (`temperature`, `topP`, `maxCompletionTokens`, `metadata`, etc.)
     // there and they flow through the spread below. Root `metadata` is
@@ -1200,10 +1214,31 @@ export class OpenRouterTextAdapter<
       model: options.model + variantSuffix,
       messages,
       ...(tools && tools.length > 0 && { tools }),
+      ...(combinedSchema && {
+        responseFormat: {
+          type: 'json_schema' as const,
+          jsonSchema: {
+            name: 'structured_output',
+            schema: combinedSchema,
+            strict: true,
+          },
+        },
+      }),
     }
     return request
   }
 
+  /**
+   * Combined mode is safe only when this model and every `modelOptions.models`
+   * fallback are in `OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS`.
+   * `:variant` suffixes are routing directives and do not change the gate.
+   */
+  supportsCombinedToolsAndSchema(
+    modelOptions?: ResolveProviderOptions<TModel>,
+  ): boolean {
+    return openRouterSupportsCombinedToolsAndSchema(this.model, modelOptions)
+  }
+
   /**
    * Convert a ModelMessage to OpenRouter's ChatMessages discriminated union
    * (camelCase: `toolCallId`, `toolCalls`).
diff --git a/packages/ai-openrouter/src/index.ts b/packages/ai-openrouter/src/index.ts
index 85b04e88b9..c50bfc7193 100644
--- a/packages/ai-openrouter/src/index.ts
+++ b/packages/ai-openrouter/src/index.ts
@@ -80,6 +80,7 @@ export type {
   OpenRouterModelInputModalitiesByName,
   OpenRouterChatModelToolCapabilitiesByName,
 } from './model-meta'
+export { OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS } from './model-meta'
 export type {
   OpenRouterTextMetadata,
   OpenRouterImageMetadata,
diff --git a/packages/ai-openrouter/src/internal/combined-tools-and-schema.ts b/packages/ai-openrouter/src/internal/combined-tools-and-schema.ts
new file mode 100644
index 0000000000..9892a1ff22
--- /dev/null
+++ b/packages/ai-openrouter/src/internal/combined-tools-and-schema.ts
@@ -0,0 +1,23 @@
+import { OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS } from '../model-meta'
+
+type OpenRouterCombinedModelOptions = {
+  models?: ReadonlyArray<string> | undefined
+}
+
+function stripOpenRouterModelVariant(model: string): string {
+  const variantIndex = model.indexOf(':')
+  return variantIndex === -1 ? model : model.slice(0, variantIndex)
+}
+
+export function openRouterSupportsCombinedToolsAndSchema(
+  model: string,
+  modelOptions?: OpenRouterCombinedModelOptions | undefined,
+): boolean {
+  const candidates = [model, ...(modelOptions?.models ?? [])].map(
+    stripOpenRouterModelVariant,
+  )
+
+  return candidates.every((candidate) =>
+    OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS.has(candidate),
+  )
+}
diff --git a/packages/ai-openrouter/src/model-meta.ts b/packages/ai-openrouter/src/model-meta.ts
index d65379cb9f..7255487790 100644
--- a/packages/ai-openrouter/src/model-meta.ts
+++ b/packages/ai-openrouter/src/model-meta.ts
@@ -19567,3 +19567,123 @@ export const OPENROUTER_IMAGE_MODELS = [
   OPENAI_GPT_5_IMAGE_MINI.id,
   OPENAI_GPT_5_4_IMAGE_2.id,
 ] as const
+
+/**
+ * OpenRouter catalog ids whose resolved upstream model natively supports
+ * strict `json_schema` output **together with** `tools` in a single streaming
+ * request — "combined mode" (issue #612, extends #605). When `chat({
+ * outputSchema, tools, stream: true })` targets one of these, the engine wires
+ * the schema into the regular `chatStream` request alongside `tools` and
+ * harvests the schema-constrained JSON from the agent loop's final-turn text,
+ * skipping the separate finalization round-trip. Ids **not** listed here take
+ * the proven legacy finalization path.
+ *
+ * Membership mirrors the per-provider upstream gates that #605 maintains —
+ * NOT the catalog's `responseFormat` support flag, which is too permissive
+ * (it is also `true` for `claude-opus-4.1`, every `gemini-2.5*`, and `gpt-3.5*`,
+ * all of which the upstream native adapters exclude from combined mode):
+ *   - Anthropic: the Claude 4.5+ ids in the upstream
+ *     `ANTHROPIC_COMBINED_TOOLS_AND_SCHEMA_MODELS` gate (opus/sonnet/haiku);
+ *     newer ids land here only once that gate adds them
+ *   - Google: Gemini 3.x only
+ *   - OpenAI: strict-`json_schema` era (gpt-4o-2024-08-06 and later), gpt-4.1,
+ *     gpt-5*, o-series, and gpt-oss-* — tool-capable text variants only
+ *   - x.ai: Grok 4.x (tool-capable; excludes the multi-agent variant)
+ *
+ * Every entry must also exist in {@link OpenRouterModelOptionsByName} and carry
+ * both `responseFormat` and `toolChoice` capability (guarded by the
+ * `satisfies` check on `OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODEL_IDS`
+ * below), and exist in {@link OPENROUTER_CHAT_MODELS} (guarded by a unit test).
+ */
+type OpenRouterCombinedToolsAndSchemaModelId = {
+  [K in keyof OpenRouterModelOptionsByName]: 'responseFormat' extends keyof OpenRouterModelOptionsByName[K]
+    ? 'toolChoice' extends keyof OpenRouterModelOptionsByName[K]
+      ? K
+      : never
+    : never
+}[keyof OpenRouterModelOptionsByName]
+
+const OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODEL_IDS = [
+  // Anthropic — the Claude 4.5+ ids the upstream gate currently blesses.
+  // Mirrors ANTHROPIC_COMBINED_TOOLS_AND_SCHEMA_MODELS exactly (through the
+  // Claude 5 ids), plus the OpenRouter-only `-fast` variants of gated models.
+  'anthropic/claude-fable-5',
+  'anthropic/claude-haiku-4.5',
+  'anthropic/claude-opus-4.5',
+  'anthropic/claude-opus-4.6',
+  'anthropic/claude-opus-4.7',
+  'anthropic/claude-opus-4.7-fast',
+  'anthropic/claude-opus-4.8',
+  'anthropic/claude-opus-4.8-fast',
+  'anthropic/claude-sonnet-4.5',
+  'anthropic/claude-sonnet-4.6',
+  'anthropic/claude-sonnet-5',
+
+  // Google — Gemini 3.x text models only (image-only ids stay on the legacy path)
+  'google/gemini-3-flash-preview',
+  'google/gemini-3.1-flash-lite',
+  'google/gemini-3.1-flash-lite-preview',
+  'google/gemini-3.1-pro-preview',
+  'google/gemini-3.1-pro-preview-customtools',
+  'google/gemini-3.5-flash',
+  'google/gemini-3.5-flash-lite',
+  'google/gemini-3.6-flash',
+  'google/gemini-3.7-flash',
+
+  // OpenAI — strict-json_schema era, tool-capable text models.
+  // Cut is gpt-4o-2024-08-06. The dated pin gpt-4o-mini-2024-07-18 predates
+  // that launch, so it is not listed; the unpinned gpt-4o-mini alias is.
+  'openai/gpt-4o',
+  'openai/gpt-4o-2024-08-06',
+  'openai/gpt-4o-2024-11-20',
+  'openai/gpt-4o-mini',
+  'openai/gpt-4.1',
+  'openai/gpt-4.1-mini',
+  'openai/gpt-4.1-nano',
+  'openai/gpt-5',
+  'openai/gpt-5-mini',
+  'openai/gpt-5-nano',
+  'openai/gpt-5-pro',
+  'openai/gpt-5.1',
+  'openai/gpt-5.1-codex',
+  'openai/gpt-5.1-codex-max',
+  'openai/gpt-5.1-codex-mini',
+  'openai/gpt-5.2',
+  'openai/gpt-5.2-chat',
+  'openai/gpt-5.2-codex',
+  'openai/gpt-5.2-pro',
+  'openai/gpt-5.3-codex',
+  'openai/gpt-5.4',
+  'openai/gpt-5.4-mini',
+  'openai/gpt-5.4-nano',
+  'openai/gpt-5.4-pro',
+  'openai/gpt-5.5',
+  'openai/gpt-5.5-pro',
+  'openai/gpt-5.6-luna',
+  'openai/gpt-5.6-luna-pro',
+  'openai/gpt-5.6-sol',
+  'openai/gpt-5.6-sol-pro',
+  'openai/gpt-5.6-terra',
+  'openai/gpt-5.6-terra-pro',
+  'openai/gpt-chat-latest',
+  'openai/o1',
+  'openai/o3',
+  'openai/o3-mini',
+  'openai/o3-mini-high',
+  'openai/o3-pro',
+  'openai/o4-mini',
+  'openai/o4-mini-high',
+  'openai/gpt-oss-120b',
+  'openai/gpt-oss-20b',
+  'openai/gpt-oss-safeguard-20b',
+
+  // x.ai — Grok 4.x (tool-capable; skip grok-4.20-multi-agent)
+  'x-ai/grok-4.20',
+  'x-ai/grok-4.3',
+  'x-ai/grok-4.5',
+  'x-ai/grok-4.6',
+] as const satisfies ReadonlyArray<OpenRouterCombinedToolsAndSchemaModelId>
+
+export const OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS = new Set<string>(
+  OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODEL_IDS,
+)
diff --git a/packages/ai-openrouter/tests/openrouter-combined-structured-output.test.ts b/packages/ai-openrouter/tests/openrouter-combined-structured-output.test.ts
new file mode 100644
index 0000000000..12a72c0f42
--- /dev/null
+++ b/packages/ai-openrouter/tests/openrouter-combined-structured-output.test.ts
@@ -0,0 +1,462 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { EventType, chat } from '@tanstack/ai'
+import { resolveDebugOption } from '@tanstack/ai/adapter-internals'
+import { z } from 'zod'
+import {
+  OPENROUTER_CHAT_MODELS,
+  OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS,
+} from '../src/model-meta'
+import { openRouterSupportsCombinedToolsAndSchema } from '../src/internal/combined-tools-and-schema'
+import { createOpenRouterResponsesText } from '../src/adapters/responses-text'
+import { createOpenRouterText } from '../src/adapters/text'
+import type { StreamChunk, Tool } from '@tanstack/ai'
+
+// Mock the SDK with a constructor function, not a class. A class field named
+// `chat` collides with the `chat` import when vitest hoists this mock.
+let mockChatSend = vi.fn()
+let mockResponsesSend = vi.fn()
+
+vi.mock('@openrouter/sdk', () => {
+  function OpenRouter(this: {
+    chat: { send: (...args: Array<unknown>) => unknown }
+    beta: { responses: { send: (...args: Array<unknown>) => unknown } }
+  }) {
+    this.chat = {
+      send: (...args: Array<unknown>) => mockChatSend(...args),
+    }
+    this.beta = {
+      responses: {
+        send: (...args: Array<unknown>) => mockResponsesSend(...args),
+      },
+    }
+  }
+  return { OpenRouter }
+})
+
+const AnswerSchema = z.object({ answer: z.string() })
+
+const tools: Array<Tool> = [
+  { name: 'lookup_weather', description: 'Return the forecast for a location' },
+]
+
+const testLogger = resolveDebugOption(false)
+
+function createAsyncIterable<T>(chunks: Array<T>): AsyncIterable<T> {
+  return {
+    [Symbol.asyncIterator]() {
+      let index = 0
+      return {
+        async next(): Promise<IteratorResult<T>> {
+          if (index < chunks.length) {
+            return { value: chunks[index++]!, done: false }
+          }
+          return { done: true, value: undefined }
+        },
+      }
+    },
+  }
+}
+
+function setupChatStream(chunks: Array<Record<string, unknown>>) {
+  mockChatSend = vi
+    .fn()
+    .mockImplementation((params: { chatRequest?: { stream?: boolean } }) => {
+      if (params.chatRequest?.stream) {
+        return Promise.resolve(createAsyncIterable(chunks))
+      }
+      return Promise.resolve({ choices: [{ message: { content: '' } }] })
+    })
+}
+
+function setupResponsesStream(chunks: Array<Record<string, unknown>>) {
+  mockResponsesSend = vi
+    .fn()
+    .mockImplementation(
+      (params: { responsesRequest?: { stream?: boolean } }) => {
+        if (params.responsesRequest?.stream) {
+          return Promise.resolve(createAsyncIterable(chunks))
+        }
+        return Promise.resolve({ output: [] })
+      },
+    )
+}
+
+const jsonStopChunks = [
+  {
+    id: 'chatcmpl-1',
+    model: 'openai/gpt-4o',
+    choices: [{ delta: { content: '{"answer":"ok"}' }, finishReason: null }],
+  },
+  {
+    id: 'chatcmpl-1',
+    model: 'openai/gpt-4o',
+    choices: [{ delta: {}, finishReason: 'stop' }],
+    usage: { promptTokens: 8, completionTokens: 4, totalTokens: 12 },
+  },
+]
+
+const responsesJsonChunks = [
+  {
+    type: 'response.created',
+    sequenceNumber: 0,
+    response: { model: 'openai/gpt-4o', output: [] },
+  },
+  {
+    type: 'response.output_text.delta',
+    sequenceNumber: 1,
+    itemId: 'msg_1',
+    outputIndex: 0,
+    contentIndex: 0,
+    delta: '{"answer":"ok"}',
+  },
+  {
+    type: 'response.completed',
+    sequenceNumber: 2,
+    response: {
+      model: 'openai/gpt-4o',
+      output: [],
+      usage: { inputTokens: 8, outputTokens: 4, totalTokens: 12 },
+    },
+  },
+]
+
+function readCompleteObject(chunks: Array<StreamChunk>): unknown {
+  for (const chunk of chunks) {
+    if (
+      chunk.type === EventType.CUSTOM &&
+      chunk.name === 'structured-output.complete' &&
+      chunk.value &&
+      typeof chunk.value === 'object' &&
+      'object' in chunk.value
+    ) {
+      return chunk.value.object
+    }
+  }
+  throw new Error('missing structured-output.complete')
+}
+
+describe('OpenRouter combined tools + outputSchema', () => {
+  beforeEach(() => {
+    mockChatSend = vi.fn()
+    mockResponsesSend = vi.fn()
+  })
+
+  describe('supportsCombinedToolsAndSchema gate', () => {
+    it('returns true for combined-capable upstream models', () => {
+      expect(
+        createOpenRouterText(
+          'anthropic/claude-sonnet-4.5',
+          'k',
+        ).supportsCombinedToolsAndSchema(),
+      ).toBe(true)
+      expect(
+        createOpenRouterText(
+          'openai/gpt-4o',
+          'k',
+        ).supportsCombinedToolsAndSchema(),
+      ).toBe(true)
+      expect(
+        createOpenRouterText(
+          'x-ai/grok-4.3',
+          'k',
+        ).supportsCombinedToolsAndSchema(),
+      ).toBe(true)
+      expect(
+        createOpenRouterText(
+          'google/gemini-3.6-flash',
+          'k',
+        ).supportsCombinedToolsAndSchema(),
+      ).toBe(true)
+    })
+
+    it('returns false for upstream models the upstream gate excludes', () => {
+      expect(
+        createOpenRouterText(
+          'anthropic/claude-opus-4.1',
+          'k',
+        ).supportsCombinedToolsAndSchema(),
+      ).toBe(false)
+      expect(
+        createOpenRouterText(
+          'openai/gpt-4o-2024-05-13',
+          'k',
+        ).supportsCombinedToolsAndSchema(),
+      ).toBe(false)
+      expect(
+        createOpenRouterText(
+          'openai/gpt-4o-mini-2024-07-18',
+          'k',
+        ).supportsCombinedToolsAndSchema(),
+      ).toBe(false)
+    })
+
+    it('mirrors the gate on the Responses adapter', () => {
+      expect(
+        createOpenRouterResponsesText(
+          'openai/gpt-4o',
+          'k',
+        ).supportsCombinedToolsAndSchema(),
+      ).toBe(true)
+      expect(
+        createOpenRouterResponsesText(
+          'openai/gpt-4o-2024-05-13',
+          'k',
+        ).supportsCombinedToolsAndSchema(),
+      ).toBe(false)
+    })
+
+    it('requires every OpenRouter fallback model to support combined mode', () => {
+      const adapter = createOpenRouterText('openai/gpt-4o', 'k')
+
+      expect(
+        adapter.supportsCombinedToolsAndSchema({
+          models: ['anthropic/claude-sonnet-4.5'],
+        }),
+      ).toBe(true)
+      expect(
+        adapter.supportsCombinedToolsAndSchema({
+          models: ['openai/gpt-4o-2024-05-13'],
+        }),
+      ).toBe(false)
+    })
+
+    it('strips :variant suffixes on the model id and on fallback models', () => {
+      expect(
+        openRouterSupportsCombinedToolsAndSchema('openai/gpt-4o:nitro'),
+      ).toBe(true)
+      expect(
+        openRouterSupportsCombinedToolsAndSchema('openai/gpt-4o', {
+          models: ['openai/gpt-4o:nitro'],
+        }),
+      ).toBe(true)
+      expect(
+        openRouterSupportsCombinedToolsAndSchema('openai/gpt-4o', {
+          models: ['openai/gpt-4o-2024-05-13:nitro'],
+        }),
+      ).toBe(false)
+    })
+  })
+
+  describe('chat-completions request payload', () => {
+    it('attaches responseFormat alongside tools on chatStream', async () => {
+      setupChatStream(jsonStopChunks)
+      const adapter = createOpenRouterText('openai/gpt-4o', 'k')
+
+      for await (const _ of adapter.chatStream({
+        logger: testLogger,
+        model: 'openai/gpt-4o',
+        messages: [{ role: 'user', content: 'hi' }],
+        tools,
+        outputSchema: {
+          type: 'object',
+          properties: { answer: { type: 'string' } },
+          required: ['answer'],
+        },
+      })) {
+        // drain
+      }
+
+      expect(mockChatSend).toHaveBeenCalledTimes(1)
+      const params = mockChatSend.mock.calls[0]![0].chatRequest
+      expect(params.tools?.length).toBeGreaterThan(0)
+      expect(params.responseFormat).toEqual({
+        type: 'json_schema',
+        jsonSchema: {
+          name: 'structured_output',
+          schema: expect.any(Object),
+          strict: true,
+        },
+      })
+    })
+
+    it('omits responseFormat for an unsupported model on the agent-loop call', async () => {
+      setupChatStream(jsonStopChunks)
+      const adapter = createOpenRouterText('anthropic/claude-opus-4.1', 'k')
+
+      for await (const _ of chat({
+        adapter,
+        messages: [{ role: 'user', content: 'hi' }],
+        tools,
+        outputSchema: AnswerSchema,
+        stream: true,
+      })) {
+        // drain
+      }
+
+      expect(mockChatSend.mock.calls.length).toBeGreaterThan(0)
+      const first = mockChatSend.mock.calls[0]![0].chatRequest
+      expect(first.tools).toBeDefined()
+      expect(first.responseFormat).toBeUndefined()
+    })
+
+    it('omits responseFormat when any fallback model is unsupported', async () => {
+      setupChatStream(jsonStopChunks)
+      const adapter = createOpenRouterText('openai/gpt-4o', 'k')
+
+      for await (const _ of adapter.chatStream({
+        logger: testLogger,
+        model: 'openai/gpt-4o',
+        messages: [{ role: 'user', content: 'hi' }],
+        tools,
+        outputSchema: {
+          type: 'object',
+          properties: { answer: { type: 'string' } },
+          required: ['answer'],
+        },
+        modelOptions: { models: ['openai/gpt-4o-2024-05-13'] },
+      })) {
+        // drain
+      }
+
+      const params = mockChatSend.mock.calls[0]![0].chatRequest
+      expect(params.responseFormat).toBeUndefined()
+      expect(params.models).toEqual(['openai/gpt-4o-2024-05-13'])
+      expect(params.tools).toBeDefined()
+    })
+  })
+
+  describe('Responses request payload', () => {
+    it('attaches text.format alongside tools on chatStream', async () => {
+      setupResponsesStream(responsesJsonChunks)
+      const adapter = createOpenRouterResponsesText('openai/gpt-4o', 'k')
+
+      for await (const _ of adapter.chatStream({
+        logger: testLogger,
+        model: 'openai/gpt-4o',
+        messages: [{ role: 'user', content: 'hi' }],
+        tools,
+        outputSchema: {
+          type: 'object',
+          properties: { answer: { type: 'string' } },
+          required: ['answer'],
+        },
+      })) {
+        // drain
+      }
+
+      expect(mockResponsesSend).toHaveBeenCalledTimes(1)
+      const params = mockResponsesSend.mock.calls[0]![0].responsesRequest
+      expect(params.tools).toBeDefined()
+      expect(params.text).toEqual({
+        format: {
+          type: 'json_schema',
+          name: 'structured_output',
+          schema: expect.any(Object),
+          strict: true,
+        },
+      })
+    })
+
+    it('preserves caller-supplied text.* fields when attaching the schema format', async () => {
+      setupResponsesStream(responsesJsonChunks)
+      const adapter = createOpenRouterResponsesText('openai/gpt-4o', 'k')
+
+      for await (const _ of adapter.chatStream({
+        logger: testLogger,
+        model: 'openai/gpt-4o',
+        messages: [{ role: 'user', content: 'hi' }],
+        tools,
+        outputSchema: {
+          type: 'object',
+          properties: { answer: { type: 'string' } },
+          required: ['answer'],
+        },
+        modelOptions: { text: { verbosity: 'low' } },
+      })) {
+        // drain
+      }
+
+      const params = mockResponsesSend.mock.calls[0]![0].responsesRequest
+      expect(params.text?.verbosity).toBe('low')
+      expect(params.text?.format).toMatchObject({
+        type: 'json_schema',
+        name: 'structured_output',
+        strict: true,
+      })
+    })
+  })
+
+  describe('engine harvest', () => {
+    it('parses final-turn JSON from chat({ tools, outputSchema, stream: true }) in one request', async () => {
+      setupChatStream(jsonStopChunks)
+      const adapter = createOpenRouterText('openai/gpt-4o', 'k')
+      const chunks: Array<StreamChunk> = []
+
+      for await (const chunk of chat({
+        adapter,
+        messages: [{ role: 'user', content: 'hi' }],
+        tools,
+        outputSchema: AnswerSchema,
+        stream: true,
+      })) {
+        chunks.push(chunk)
+      }
+
+      expect(mockChatSend).toHaveBeenCalledTimes(1)
+      const params = mockChatSend.mock.calls[0]![0].chatRequest
+      expect(params.tools?.length).toBeGreaterThan(0)
+      expect(params.responseFormat?.type).toBe('json_schema')
+
+      expect(readCompleteObject(chunks)).toEqual({ answer: 'ok' })
+    })
+
+    it('parses final-turn JSON from the Responses adapter on the combined path', async () => {
+      setupResponsesStream(responsesJsonChunks)
+      const adapter = createOpenRouterResponsesText('openai/gpt-4o', 'k')
+      const chunks: Array<StreamChunk> = []
+
+      for await (const chunk of chat({
+        adapter,
+        messages: [{ role: 'user', content: 'hi' }],
+        tools,
+        outputSchema: AnswerSchema,
+        stream: true,
+      })) {
+        chunks.push(chunk)
+      }
+
+      expect(mockResponsesSend).toHaveBeenCalledTimes(1)
+      const params = mockResponsesSend.mock.calls[0]![0].responsesRequest
+      expect(params.tools).toBeDefined()
+      expect(params.text?.format?.type).toBe('json_schema')
+
+      expect(readCompleteObject(chunks)).toEqual({ answer: 'ok' })
+    })
+  })
+
+  describe('set integrity', () => {
+    const catalog = new Set<string>(OPENROUTER_CHAT_MODELS)
+
+    it('every combined-mode id exists in the OpenRouter catalog', () => {
+      for (const id of OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS) {
+        expect(catalog.has(id), `${id} is not in OPENROUTER_CHAT_MODELS`).toBe(
+          true,
+        )
+      }
+    })
+
+    it('every Gemini 3.x text catalog id is in the combined set', () => {
+      for (const id of OPENROUTER_CHAT_MODELS) {
+        if (!id.startsWith('google/gemini-3')) continue
+        if (id.includes(':')) continue
+        if (id.includes('-image')) continue
+        expect(
+          OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS.has(id),
+          `${id} is a Gemini 3.x text catalog id missing from the combined set`,
+        ).toBe(true)
+      }
+    })
+
+    it('every Grok 4.x tool-capable catalog id is in the combined set', () => {
+      for (const id of OPENROUTER_CHAT_MODELS) {
+        if (!id.startsWith('x-ai/grok-4')) continue
+        if (id.includes(':')) continue
+        if (id.includes('multi-agent')) continue
+        expect(
+          OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS.has(id),
+          `${id} is a Grok 4.x catalog id missing from the combined set`,
+        ).toBe(true)
+      }
+    })
+  })
+})
diff --git a/packages/ai-openrouter/vite.config.ts b/packages/ai-openrouter/vite.config.ts
index 0e7e7eaea6..fab574d16d 100644
--- a/packages/ai-openrouter/vite.config.ts
+++ b/packages/ai-openrouter/vite.config.ts
@@ -9,7 +9,7 @@ const config = defineConfig({
     watch: false,
     globals: true,
     environment: 'node',
-    include: ['tests/**/*.test.ts'],
+    include: ['tests/**/*.test.ts', 'src/**/*.test.ts'],
     coverage: {
       provider: 'v8',
       reporter: ['text', 'json', 'html', 'lcov'],
@@ -29,7 +29,7 @@ const config = defineConfig({
 export default mergeConfig(
   config,
   tanstackViteConfig({
-    entry: ['./src/index.ts', './src/tools/index.ts'],
+    entry: ['./src/index.ts', './src/model-meta.ts', './src/tools/index.ts'],
     srcDir: './src',
     cjs: false,
   }),
diff --git a/testing/e2e/src/lib/feature-support.ts b/testing/e2e/src/lib/feature-support.ts
index f0f7926e8f..c9d9234200 100644
--- a/testing/e2e/src/lib/feature-support.ts
+++ b/testing/e2e/src/lib/feature-support.ts
@@ -199,11 +199,15 @@ export const matrix: Record<Feature, Set<Provider>> = {
   // (or per-feature override in `features.ts`) must opt into combined mode
   // — otherwise the engine takes the legacy finalization path, which makes
   // an extra request that this feature's fixture doesn't model.
+  // openrouter and openrouter-responses both default to openai/gpt-4o,
+  // which is in OPENROUTER_COMBINED_TOOLS_AND_SCHEMA_MODELS.
   'agentic-structured-stream': new Set([
     'openai',
     'anthropic',
     'gemini',
     'grok',
+    'openrouter',
+    'openrouter-responses',
     'byteplus',
   ]),
   // Bedrock excluded: the default e2e model (openai.gpt-oss-120b) is text-only