feat(ai): expand OpenRouter native support (#39907)

packages/ai/src/cache-policy.ts

@@ -38,7 +38,7 @@ const resolve = (policy: CachePolicy | undefined): CachePolicyObject => {
 // Protocols whose wire format ignores inline cache markers (OpenAI's implicit
 // prefix caching, Gemini's implicit + out-of-band CachedContent). Skip the
 // whole policy pass for these — emitting hints would be harmless but pointless.
-const RESPECTS_INLINE_HINTS = new Set(["anthropic-messages", "bedrock-converse"])
+const RESPECTS_INLINE_HINTS = new Set(["anthropic-messages", "bedrock-converse", "openrouter"])
 
 const makeHint = (ttlSeconds: number | undefined): CacheHint =>
   ttlSeconds !== undefined ? new CacheHint({ type: "ephemeral", ttlSeconds }) : new CacheHint({ type: "ephemeral" })
@@ -133,6 +133,7 @@ const countHints = (request: LLMRequest) =>
 
 export const applyCachePolicy = (request: LLMRequest): LLMRequest => {
   if (!RESPECTS_INLINE_HINTS.has(request.model.route.id)) return request
+  if (request.model.route.id === "openrouter" && (request.cache === undefined || request.cache === "auto")) return request
   const policy = resolve(request.cache)
   if (!policy.tools && !policy.system && !policy.messages) return request
 

packages/ai/src/protocols/openai-chat.ts

@@ -11,6 +11,7 @@ import {
   Usage,
   type FinishReason,
   type FinishReasonDetails,
+  type CacheHint,
   type JsonSchema,
   type LLMRequest,
   type MediaPart,
@@ -38,6 +39,11 @@ export const PATH = "/chat/completions"
 // The body schema is the provider-native JSON body. `fromRequest` below builds
 // this shape from the common `LLMRequest`, then `Route.make` validates and
 // JSON-encodes it before transport.
+const OpenAIChatCacheControl = Schema.Struct({
+  type: Schema.Literal("ephemeral"),
+  ttl: Schema.optional(Schema.String),
+})
+
 const OpenAIChatFunction = Schema.Struct({
   name: Schema.String,
   description: Schema.String,
@@ -47,6 +53,7 @@ const OpenAIChatFunction = Schema.Struct({
 const OpenAIChatTool = Schema.Struct({
   type: Schema.tag("function"),
   function: OpenAIChatFunction,
+  cache_control: Schema.optional(OpenAIChatCacheControl),
 })
 type OpenAIChatTool = Schema.Schema.Type<typeof OpenAIChatTool>
 
@@ -61,7 +68,11 @@ const OpenAIChatAssistantToolCall = Schema.Struct({
 type OpenAIChatAssistantToolCall = Schema.Schema.Type<typeof OpenAIChatAssistantToolCall>
 
 const OpenAIChatUserContent = Schema.Union([
-  Schema.Struct({ type: Schema.Literal("text"), text: Schema.String }),
+  Schema.Struct({
+    type: Schema.Literal("text"),
+    text: Schema.String,
+    cache_control: Schema.optional(OpenAIChatCacheControl),
+  }),
   Schema.Struct({
     type: Schema.Literal("image_url"),
     image_url: Schema.Struct({ url: Schema.String }),
@@ -69,7 +80,10 @@ const OpenAIChatUserContent = Schema.Union([
 ])
 
 const OpenAIChatMessage = Schema.Union([
-  Schema.Struct({ role: Schema.Literal("system"), content: Schema.String }),
+  Schema.Struct({
+    role: Schema.Literal("system"),
+    content: Schema.Union([Schema.String, Schema.Array(OpenAIChatUserContent)]),
+  }),
   Schema.Struct({
     role: Schema.Literal("user"),
     content: Schema.Union([Schema.String, Schema.Array(OpenAIChatUserContent)]),
@@ -83,10 +97,16 @@ const OpenAIChatMessage = Schema.Union([
       reasoning: Schema.optional(Schema.String),
       reasoning_text: Schema.optional(Schema.String),
       reasoning_details: Schema.optional(Schema.Unknown),
+      cache_control: Schema.optional(OpenAIChatCacheControl),
     }),
     [Schema.Record(Schema.String, Schema.Unknown)],
   ),
-  Schema.Struct({ role: Schema.Literal("tool"), tool_call_id: Schema.String, content: Schema.String }),
+  Schema.Struct({
+    role: Schema.Literal("tool"),
+    tool_call_id: Schema.String,
+    content: Schema.String,
+    cache_control: Schema.optional(OpenAIChatCacheControl),
+  }),
 ]).pipe(Schema.toTaggedUnion("role"))
 type OpenAIChatMessage = Schema.Schema.Type<typeof OpenAIChatMessage>
 
@@ -210,13 +230,20 @@ export interface ParserState {
 // Lowering is the only place that knows how common LLM messages map onto the
 // OpenAI Chat wire format. Keep provider quirks here instead of leaking native
 // fields into `LLMRequest`.
-const lowerTool = (tool: ToolDefinition, inputSchema: JsonSchema): OpenAIChatTool => ({
+interface LoweringOptions {
+  readonly cacheControl?: (
+    cache: CacheHint | undefined,
+  ) => Schema.Schema.Type<typeof OpenAIChatCacheControl> | undefined
+}
+
+const lowerTool = (tool: ToolDefinition, inputSchema: JsonSchema, options: LoweringOptions): OpenAIChatTool => ({
   type: "function",
   function: {
     name: tool.name,
     description: tool.description,
     parameters: ToolSchemaProjection.openAI(inputSchema),
   },
+  cache_control: options.cacheControl?.(tool.cache),
 })
 
 const lowerToolChoice = (toolChoice: NonNullable<LLMRequest["toolChoice"]>) =>
@@ -258,11 +285,14 @@ const reasoningDetails = (parts: ReadonlyArray<ReasoningPart>, native: unknown)
   if (isRecord(native) && Array.isArray(native.reasoning_details)) return native.reasoning_details
 }
 
-const lowerUserMessage = Effect.fn("OpenAIChat.lowerUserMessage")(function* (message: OpenAIChatRequestMessage) {
+const lowerUserMessage = Effect.fn("OpenAIChat.lowerUserMessage")(function* (
+  message: OpenAIChatRequestMessage,
+  options: LoweringOptions,
+) {
   const content: Array<Schema.Schema.Type<typeof OpenAIChatUserContent>> = []
   for (const part of message.content) {
     if (part.type === "text") {
-      content.push({ type: "text", text: part.text })
+      content.push({ type: "text", text: part.text, cache_control: options.cacheControl?.(part.cache) })
       continue
     }
     if (part.type === "media") {
@@ -271,14 +301,18 @@ const lowerUserMessage = Effect.fn("OpenAIChat.lowerUserMessage")(function* (mes
     }
     return yield* ProviderShared.unsupportedContent("OpenAI Chat", "user", ["text", "media"])
   }
-  if (content.every((part) => part.type === "text"))
-    return { role: "user" as const, content: content.map((part) => part.text).join("") }
+  if (content.every((part) => part.type === "text" && part.cache_control === undefined))
+    return {
+      role: "user" as const,
+      content: content.map((part) => (part.type === "text" ? part.text : "")).join(""),
+    }
   return { role: "user" as const, content }
 })
 
 const lowerAssistantMessage = Effect.fn("OpenAIChat.lowerAssistantMessage")(function* (
   message: OpenAIChatRequestMessage,
   configuredField?: string,
+  options: LoweringOptions = {},
 ) {
   const content: TextPart[] = []
   const reasoning: ReasoningPart[] = []
@@ -316,29 +350,44 @@ const lowerAssistantMessage = Effect.fn("OpenAIChat.lowerAssistantMessage")(func
     if (reasoning.length === 0) return nativeReasoning
     return text
   })()
+  const cached = message.content.findLast((part) => "cache" in part && part.cache !== undefined)
   const result = {
     role: "assistant" as const,
     content: content.length === 0 ? null : ProviderShared.joinText(content),
     tool_calls: toolCalls.length === 0 ? undefined : toolCalls,
     reasoning_details: details,
+    cache_control: options.cacheControl?.(cached && "cache" in cached ? cached.cache : undefined),
   }
   if (field === undefined || reasoningText === undefined) return result
   return { ...result, [field]: reasoningText }
 })
 
-const lowerToolMessages = Effect.fn("OpenAIChat.lowerToolMessages")(function* (message: OpenAIChatRequestMessage) {
+const lowerToolMessages = Effect.fn("OpenAIChat.lowerToolMessages")(function* (
+  message: OpenAIChatRequestMessage,
+  options: LoweringOptions,
+) {
   const messages: OpenAIChatMessage[] = []
   const images: Array<Schema.Schema.Type<typeof OpenAIChatUserContent>> = []
   for (const part of message.content) {
     if (!ProviderShared.supportsContent(part, ["tool-result"]))
       return yield* ProviderShared.unsupportedContent("OpenAI Chat", "tool", ["tool-result"])
     if (part.result.type !== "content") {
-      messages.push({ role: "tool", tool_call_id: part.id, content: ProviderShared.toolResultText(part) })
+      messages.push({
+        role: "tool",
+        tool_call_id: part.id,
+        content: ProviderShared.toolResultText(part),
+        cache_control: options.cacheControl?.(part.cache),
+      })
       continue
     }
     const content: ReadonlyArray<Tool.Content> = part.result.value
     const text = content.filter((item) => item.type === "text").map((item) => item.text)
-    messages.push({ role: "tool", tool_call_id: part.id, content: text.join("\n") })
+    messages.push({
+      role: "tool",
+      tool_call_id: part.id,
+      content: text.join("\n"),
+      cache_control: options.cacheControl?.(part.cache),
+    })
     const files = content.filter((item) => item.type === "file")
     images.push(
       ...(yield* Effect.forEach(files, (item) =>
@@ -352,15 +401,29 @@ const lowerToolMessages = Effect.fn("OpenAIChat.lowerToolMessages")(function* (m
 const lowerMessage = Effect.fn("OpenAIChat.lowerMessage")(function* (
   message: OpenAIChatRequestMessage,
   reasoningField?: string,
+  options: LoweringOptions = {},
 ) {
-  if (message.role === "user") return [yield* lowerUserMessage(message)]
-  if (message.role === "assistant") return [yield* lowerAssistantMessage(message, reasoningField)]
-  return (yield* lowerToolMessages(message)).messages
+  if (message.role === "user") return [yield* lowerUserMessage(message, options)]
+  if (message.role === "assistant") return [yield* lowerAssistantMessage(message, reasoningField, options)]
+  return (yield* lowerToolMessages(message, options)).messages
 })
 
-const lowerMessages = Effect.fn("OpenAIChat.lowerMessages")(function* (request: LLMRequest) {
+const lowerMessages = Effect.fn("OpenAIChat.lowerMessages")(function* (request: LLMRequest, options: LoweringOptions) {
   const system: OpenAIChatMessage[] =
-    request.system.length === 0 ? [] : [{ role: "system", content: ProviderShared.joinText(request.system) }]
+    request.system.length === 0
+      ? []
+      : request.system.some((part) => part.cache !== undefined) && options.cacheControl !== undefined
+        ? [
+            {
+              role: "system",
+              content: request.system.map((part) => ({
+                type: "text",
+                text: part.text,
+                cache_control: options.cacheControl?.(part.cache),
+              })),
+            },
+          ]
+        : [{ role: "system", content: ProviderShared.joinText(request.system) }]
   const messages = [...system]
   const pendingImages: Array<Schema.Schema.Type<typeof OpenAIChatUserContent>> = []
   const flushImages = () => {
@@ -371,28 +434,53 @@ const lowerMessages = Effect.fn("OpenAIChat.lowerMessages")(function* (request:
     if (message.role === "system") {
       const part = yield* ProviderShared.wrappedSystemUpdate("OpenAI Chat", message)
       if (pendingImages.length > 0) {
-        messages.push({ role: "user", content: [...pendingImages.splice(0), { type: "text", text: part.text }] })
+        messages.push({
+          role: "user",
+          content: [
+            ...pendingImages.splice(0),
+            { type: "text", text: part.text, cache_control: options.cacheControl?.(part.cache) },
+          ],
+        })
         continue
       }
       const previous = messages.at(-1)
       if (previous?.role === "user" && typeof previous.content === "string")
-        messages[messages.length - 1] = { role: "user", content: `${previous.content}\n${part.text}` }
+        messages[messages.length - 1] = options.cacheControl?.(part.cache)
+          ? {
+              role: "user",
+              content: [
+                { type: "text", text: previous.content },
+                { type: "text", text: part.text, cache_control: options.cacheControl(part.cache) },
+              ],
+            }
+          : { role: "user", content: `${previous.content}\n${part.text}` }
       else if (previous?.role === "user" && Array.isArray(previous.content))
         messages[messages.length - 1] = {
           role: "user",
-          content: [...previous.content, { type: "text", text: part.text }],
+          content: [
+            ...previous.content,
+            { type: "text", text: part.text, cache_control: options.cacheControl?.(part.cache) },
+          ],
         }
-      else messages.push({ role: "user", content: part.text })
+      else
+        messages.push(
+          options.cacheControl?.(part.cache)
+            ? {
+                role: "user",
+                content: [{ type: "text", text: part.text, cache_control: options.cacheControl(part.cache) }],
+              }
+            : { role: "user", content: part.text },
+        )
       continue
     }
     if (message.role === "tool") {
-      const lowered = yield* lowerToolMessages(message)
+      const lowered = yield* lowerToolMessages(message, options)
       messages.push(...lowered.messages)
       pendingImages.push(...lowered.images)
       continue
     }
     flushImages()
-    messages.push(...(yield* lowerMessage(message, request.model.compatibility?.reasoningField)))
+    messages.push(...(yield* lowerMessage(message, request.model.compatibility?.reasoningField, options)))
   }
   flushImages()
   return messages
@@ -406,7 +494,10 @@ const lowerOptions = (request: LLMRequest) => {
   }
 }
 
-const fromRequest = Effect.fn("OpenAIChat.fromRequest")(function* (request: LLMRequest) {
+export const fromRequest = Effect.fn("OpenAIChat.fromRequest")(function* (
+  request: LLMRequest,
+  options: LoweringOptions = {},
+) {
   // `fromRequest` returns the provider body only. Endpoint, auth, framing,
   // validation, and HTTP execution are composed by `Route.make`.
   const reasoningField = request.model.compatibility?.reasoningField
@@ -419,12 +510,16 @@ const fromRequest = Effect.fn("OpenAIChat.fromRequest")(function* (request: LLMR
   const maxTokensField = request.model.compatibility?.maxTokensField ?? "max_tokens"
   return {
     model: request.model.id,
-    messages: yield* lowerMessages(request),
+    messages: yield* lowerMessages(request, options),
     tools:
       request.tools.length === 0
         ? undefined
         : request.tools.map((tool) =>
-            lowerTool(tool, ToolSchemaProjection.modelCompatibility(tool.inputSchema, toolSchemaCompatibility)),
+            lowerTool(
+              tool,
+              ToolSchemaProjection.modelCompatibility(tool.inputSchema, toolSchemaCompatibility),
+              options,
+            ),
           ),
     tool_choice: request.toolChoice ? yield* lowerToolChoice(request.toolChoice) : undefined,
     stream: true as const,

packages/ai/src/providers/openrouter.ts

@@ -4,21 +4,72 @@ import { Endpoint } from "../route/endpoint"
 import { Framing } from "../route/framing"
 import { Protocol } from "../route/protocol"
 import { AuthOptions, type ProviderAuthOption } from "../route/auth-options"
-import { ProviderID, type ModelID, type ProviderOptions } from "../schema"
+import { ProviderID, type CacheHint, type ModelID, type ProviderOptions } from "../schema"
 import type { ProviderPackage } from "../provider-package"
 import * as OpenAICompatibleProfiles from "./openai-compatible-profile"
 import * as OpenAIChat from "../protocols/openai-chat"
+import { newBreakpoints, ttlBucket } from "../protocols/utils/cache"
 import { isRecord } from "../protocols/shared"
 
 export const profile = OpenAICompatibleProfiles.profiles.openrouter
 export const id = ProviderID.make(profile.provider)
 const ADAPTER = "openrouter"
 
+type OpenRouterString<Known extends string> = Known | (string & {})
+
+export interface OpenRouterProviderRouting {
+  readonly [key: string]: unknown
+  readonly order?: ReadonlyArray<string>
+  readonly allow_fallbacks?: boolean
+  readonly require_parameters?: boolean
+  readonly data_collection?: OpenRouterString<"allow" | "deny">
+  readonly only?: ReadonlyArray<string>
+  readonly ignore?: ReadonlyArray<string>
+  readonly quantizations?: ReadonlyArray<string>
+  readonly sort?: OpenRouterString<"price" | "throughput" | "latency">
+  readonly max_price?: Readonly<{
+    prompt?: number | string
+    completion?: number | string
+    image?: number | string
+    audio?: number | string
+    request?: number | string
+  }>
+  readonly zdr?: boolean
+}
+
+export type OpenRouterPlugin =
+  | Readonly<{
+      id: "web"
+      max_results?: number
+      search_prompt?: string
+      engine?: OpenRouterString<"native" | "exa">
+    }>
+  | Readonly<{ id: "file-parser"; max_files?: number; pdf?: { engine?: string } }>
+  | Readonly<{ id: "moderation" }>
+  | Readonly<{ id: "response-healing" }>
+  | Readonly<{ id: "auto-router"; allowed_models?: ReadonlyArray<string> }>
+  | Readonly<{ id: string & {}; [key: string]: unknown }>
+
 export interface OpenRouterOptions {
   readonly [key: string]: unknown
-  readonly usage?: boolean | Record<string, unknown>
-  readonly reasoning?: Record<string, unknown>
+  readonly debug?: Readonly<{ echo_upstream_body?: boolean }>
+  readonly models?: ReadonlyArray<string>
+  readonly plugins?: ReadonlyArray<OpenRouterPlugin>
   readonly promptCacheKey?: string
+  readonly provider?: OpenRouterProviderRouting
+  readonly reasoning?: Readonly<{
+    enabled?: boolean
+    exclude?: boolean
+    effort?: OpenRouterString<"none" | "minimal" | "low" | "medium" | "high" | "xhigh" | "max">
+    max_tokens?: number
+  }>
+  readonly usage?: boolean | Readonly<{ include: boolean }>
+  readonly user?: string
+  readonly web_search_options?: Readonly<{
+    max_results?: number
+    search_prompt?: string
+    engine?: OpenRouterString<"native" | "exa">
+  }>
 }
 
 export type OpenRouterProviderOptionsInput = ProviderOptions & {
@@ -47,7 +98,7 @@ export const protocol = Protocol.make({
   body: {
     schema: OpenRouterBody,
     from: (request) =>
-      OpenAIChat.protocol.body.from(request).pipe(
+      OpenAIChat.fromRequest(request, { cacheControl: cacheControl() }).pipe(
         Effect.map((body) => {
           const sourceAssistants = request.messages.filter((message) => message.role === "assistant")
           let assistantIndex = 0
@@ -78,16 +129,38 @@ export const protocol = Protocol.make({
   stream: OpenAIChat.protocol.stream,
 })
 
+const cacheControl = () => {
+  const breakpoints = newBreakpoints(4)
+  return (cache: CacheHint | undefined) => {
+    if (cache === undefined || breakpoints.remaining === 0) return undefined
+    breakpoints.remaining -= 1
+    return {
+      type: "ephemeral" as const,
+      ...(ttlBucket(cache.ttlSeconds) === "1h" ? { ttl: "1h" } : {}),
+    }
+  }
+}
+
 const bodyOptions = (input: unknown) => {
   const openrouter = isRecord(input) ? input : {}
+  const { promptCacheKey, ...options } = openrouter
   return {
-    ...(openrouter.usage === true
+    ...options,
+    ...(openrouter.usage === undefined || openrouter.usage === true
       ? { usage: { include: true } }
-      : isRecord(openrouter.usage)
-        ? { usage: openrouter.usage }
-        : {}),
+      : openrouter.usage === false
+        ? { usage: { include: false } }
+        : isRecord(openrouter.usage)
+          ? { usage: openrouter.usage }
+          : {}),
+    ...(Array.isArray(openrouter.models) ? { models: openrouter.models } : {}),
+    ...(isRecord(openrouter.provider) ? { provider: openrouter.provider } : {}),
+    ...(Array.isArray(openrouter.plugins) ? { plugins: openrouter.plugins } : {}),
+    ...(isRecord(openrouter.web_search_options) ? { web_search_options: openrouter.web_search_options } : {}),
+    ...(isRecord(openrouter.debug) ? { debug: openrouter.debug } : {}),
+    ...(typeof openrouter.user === "string" ? { user: openrouter.user } : {}),
     ...(isRecord(openrouter.reasoning) ? { reasoning: openrouter.reasoning } : {}),
-    ...(typeof openrouter.promptCacheKey === "string" ? { prompt_cache_key: openrouter.promptCacheKey } : {}),
+    ...(typeof promptCacheKey === "string" ? { prompt_cache_key: promptCacheKey } : {}),
   }
 }
 

packages/ai/src/schema/messages.ts

@@ -124,6 +124,7 @@ export const ToolCallPart = Object.assign(
     name: Schema.String,
     input: Schema.Unknown,
     providerExecuted: Schema.optional(Schema.Boolean),
+    cache: Schema.optional(CacheHint),
     metadata: Schema.optional(Schema.Record(Schema.String, Schema.Unknown)),
     providerMetadata: Schema.optional(ProviderMetadata),
   }).annotate({ identifier: "LLM.Content.ToolCall" }),
@@ -168,6 +169,7 @@ export const ReasoningPart = Schema.Struct({
   type: Schema.Literal("reasoning"),
   text: Schema.String,
   encrypted: Schema.optional(Schema.String),
+  cache: Schema.optional(CacheHint),
   metadata: Schema.optional(Schema.Record(Schema.String, Schema.Unknown)),
   providerMetadata: Schema.optional(ProviderMetadata),
 }).annotate({ identifier: "LLM.Content.Reasoning" })

packages/ai/test/provider-options/openrouter.types.ts

@@ -5,6 +5,28 @@ const model = OpenRouter.provider.model("anthropic/claude-sonnet-4.5")
 
 LLM.request({ model, prompt: "Hello", providerOptions: { openrouter: { usage: true } } })
 
+LLM.request({
+  model,
+  prompt: "Hello",
+  providerOptions: {
+    openrouter: {
+      models: ["google/gemini-3.1-pro"],
+      provider: {
+        order: ["anthropic"],
+        require_parameters: true,
+        data_collection: "future-policy",
+        sort: "future-sort",
+        max_price: { prompt: "0.50" },
+      },
+      reasoning: { effort: "future-effort", exclude: false },
+      plugins: [{ id: "future-plugin", enabled: true }],
+      web_search_options: { engine: "future-engine" },
+      debug: { echo_upstream_body: true },
+      user: "user_123",
+    },
+  },
+})
+
 LLM.request({
   model,
   prompt: "Hello",

packages/ai/test/provider/openrouter.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect } from "bun:test"
 import { Effect } from "effect"
-import { LLM, Message } from "../../src"
+import { CacheHint, LLM, Message } from "../../src"
 import { LLMClient } from "../../src/route"
 import { compileRequest } from "../../src/route/client"
 import * as OpenRouter from "../../src/providers/openrouter"
@@ -27,10 +27,131 @@ describe("OpenRouter", () => {
         model: "openai/gpt-4o-mini",
         messages: [{ role: "user", content: "Say hello." }],
         stream: true,
+        usage: { include: true },
+      })
+    }),
+  )
+
+  it.effect("lowers the native cache policy to OpenRouter cache controls", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model: OpenRouter.configure({ apiKey: "test-key" }).model("anthropic/claude-sonnet-4.6"),
+          system: [
+            { type: "text", text: "Base agent", cache: new CacheHint({ type: "ephemeral", ttlSeconds: 3_600 }) },
+            { type: "text", text: "Project instructions" },
+          ],
+          tools: [{ name: "lookup", description: "Lookup", inputSchema: { type: "object", properties: {} } }],
+          prompt: "Hello",
+          cache: { tools: true, system: true, messages: { tail: 1 } },
+        }),
+      )
+
+      expect(prepared.body).toMatchObject({
+        tools: [{ cache_control: { type: "ephemeral" } }],
+        messages: [
+          {
+            role: "system",
+            content: [
+              { text: "Base agent", cache_control: { type: "ephemeral", ttl: "1h" } },
+              { text: "Project instructions", cache_control: { type: "ephemeral" } },
+            ],
+          },
+          {
+            role: "user",
+            content: [{ text: "Hello", cache_control: { type: "ephemeral" } }],
+          },
+        ],
       })
     }),
   )
 
+  it.effect("lowers manual assistant and tool-result cache hints", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model: OpenRouter.configure({ apiKey: "test-key" }).model("anthropic/claude-sonnet-4.6"),
+          cache: "none",
+          messages: [
+            Message.user("Call the tool"),
+            Message.assistant([
+              { type: "text", text: "Calling", cache: new CacheHint({ type: "ephemeral" }) },
+              { type: "tool-call", id: "call_1", name: "lookup", input: {} },
+            ]),
+            Message.tool({
+              id: "call_1",
+              name: "lookup",
+              result: "Done",
+              cache: new CacheHint({ type: "ephemeral", ttlSeconds: 3_600 }),
+            }),
+          ],
+        }),
+      )
+
+      expect(prepared.body.messages).toMatchObject([
+        { role: "user", content: "Call the tool" },
+        { role: "assistant", content: "Calling", cache_control: { type: "ephemeral" } },
+        { role: "tool", content: '"Done"', cache_control: { type: "ephemeral", ttl: "1h" } },
+      ])
+    }),
+  )
+
+  it.effect("caps manual cache controls at four breakpoints", () =>
+    Effect.gen(function* () {
+      const cache = new CacheHint({ type: "ephemeral" })
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model: OpenRouter.configure({ apiKey: "test-key" }).model("anthropic/claude-sonnet-4.6"),
+          cache: "none",
+          system: [1, 2, 3, 4, 5].map((index) => ({ type: "text" as const, text: `System ${index}`, cache })),
+          prompt: "Hello",
+        }),
+      )
+
+      const system = prepared.body.messages[0]
+      expect(system?.role).toBe("system")
+      expect(
+        system && Array.isArray(system.content)
+          ? system.content.filter((part) => "cache_control" in part && part.cache_control !== undefined)
+          : [],
+      ).toHaveLength(4)
+    }),
+  )
+
+  it.effect("preserves cache policy hints on reasoning-only assistant messages", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model: OpenRouter.configure({ apiKey: "test-key" }).model("anthropic/claude-sonnet-4.6"),
+          cache: { messages: "latest-assistant" },
+          messages: [Message.user("Think"), Message.assistant([{ type: "reasoning", text: "Reasoning" }])],
+        }),
+      )
+
+      expect(prepared.body.messages).toMatchObject([
+        { role: "user", content: "Think" },
+        { role: "assistant", cache_control: { type: "ephemeral" } },
+      ])
+    }),
+  )
+
+  it.effect("allows usage accounting to be disabled explicitly", () =>
+    Effect.gen(function* () {
+      const prepared = yield* compileRequest(
+        LLM.request({
+          model: OpenRouter.configure({
+            apiKey: "test-key",
+            providerOptions: { openrouter: { usage: false } },
+          }).model("openai/gpt-4o-mini"),
+          cache: "none",
+          prompt: "Hello",
+        }),
+      )
+
+      expect(prepared.body.usage).toEqual({ include: false })
+    }),
+  )
+
   it.effect("applies OpenRouter payload options from the model helper", () =>
     Effect.gen(function* () {
       const prepared = yield* compileRequest(
@@ -42,6 +163,13 @@ describe("OpenRouter", () => {
                 usage: true,
                 reasoning: { effort: "high" },
                 promptCacheKey: "session_123",
+                models: ["anthropic/claude-sonnet-4.6", "google/gemini-3.1-pro"],
+                provider: { order: ["anthropic", "google"], require_parameters: true },
+                plugins: [{ id: "response-healing" }],
+                web_search_options: { engine: "native", max_results: 3 },
+                debug: { echo_upstream_body: true },
+                user: "user_123",
+                future_option: { enabled: true },
               },
             },
           }).model("anthropic/claude-3.7-sonnet:thinking"),
@@ -53,6 +181,13 @@ describe("OpenRouter", () => {
         usage: { include: true },
         reasoning: { effort: "high" },
         prompt_cache_key: "session_123",
+        models: ["anthropic/claude-sonnet-4.6", "google/gemini-3.1-pro"],
+        provider: { order: ["anthropic", "google"], require_parameters: true },
+        plugins: [{ id: "response-healing" }],
+        web_search_options: { engine: "native", max_results: 3 },
+        debug: { echo_upstream_body: true },
+        user: "user_123",
+        future_option: { enabled: true },
       })
     }),
   )
@@ -104,6 +239,7 @@ describe("OpenRouter", () => {
       const prepared = yield* compileRequest(
         LLM.request({
           model: OpenRouter.configure({ apiKey: "test-key" }).model("anthropic/claude-sonnet-4.6"),
+          cache: "none",
           messages: [
             Message.assistant([
               {
@@ -137,6 +273,7 @@ describe("OpenRouter", () => {
       const prepared = yield* compileRequest(
         LLM.request({
           model: OpenRouter.configure({ apiKey: "test-key" }).model("anthropic/claude-sonnet-4.6"),
+          cache: "none",
           messages: [
             Message.assistant({
               type: "reasoning",
@@ -162,6 +299,7 @@ describe("OpenRouter", () => {
       const prepared = yield* compileRequest(
         LLM.request({
           model: OpenRouter.configure({ apiKey: "test-key" }).model("anthropic/claude-sonnet-4.6"),
+          cache: "none",
           messages: [
             Message.assistant({
               type: "reasoning",
@@ -183,6 +321,7 @@ describe("OpenRouter", () => {
       const prepared = yield* compileRequest(
         LLM.request({
           model: OpenRouter.configure({ apiKey: "test-key" }).model("anthropic/claude-sonnet-4.6"),
+          cache: "none",
           messages: [Message.assistant({ type: "reasoning", text: "Thinking" })],
         }),
       )

packages/core/src/aisdk-native.ts

@@ -1,10 +1,13 @@
 export * as AISDKNative from "./aisdk-native"
 
 import { isRecord } from "@opencode-ai/ai/utils/record"
+import { Provider } from "./provider"
 
 export interface Mapping {
   readonly package: string
   readonly settings: Readonly<Record<string, unknown>>
+  readonly headers?: Readonly<Record<string, string>>
+  readonly body?: Readonly<Record<string, unknown>>
 }
 
 export function map(packageName: string | undefined, settings: Readonly<Record<string, unknown>>): Mapping | undefined {
@@ -20,14 +23,7 @@ export function map(packageName: string | undefined, settings: Readonly<Record<s
         },
       }
     case "@openrouter/ai-sdk-provider":
-      return {
-        package: "@opencode-ai/ai/providers/openrouter",
-        settings: {
-          ...baseSettings,
-          ...mapAPIKey(settings),
-          ...mapProviderOptions("openrouter", settings),
-        },
-      }
+      return mapOpenRouter(settings, baseSettings)
     case "@ai-sdk/xai":
       return {
         package: "@opencode-ai/ai/providers/xai",
@@ -69,6 +65,61 @@ function mapGoogleOptions(settings: Readonly<Record<string, unknown>>) {
   return { providerOptions: { gemini: options } }
 }
 
+function mapOpenRouter(
+  settings: Readonly<Record<string, unknown>>,
+  baseSettings: Readonly<Record<string, unknown>>,
+): Mapping {
+  const headers =
+    Provider.mergeHeaders(
+      {
+        ...(typeof settings.appName === "string" ? { "X-OpenRouter-Title": settings.appName } : {}),
+        ...(typeof settings.appUrl === "string" ? { "HTTP-Referer": settings.appUrl } : {}),
+        ...(isStringRecord(settings.api_keys) && Object.keys(settings.api_keys).length > 0
+          ? { "X-Provider-API-Keys": JSON.stringify(settings.api_keys) }
+          : {}),
+      },
+      isStringRecord(settings.headers) ? settings.headers : undefined,
+    ) ?? {}
+  return {
+    package: "@opencode-ai/ai/providers/openrouter",
+    settings: {
+      ...baseSettings,
+      ...mapAPIKey(settings),
+      ...mapOpenRouterOptions(settings),
+    },
+    ...(Object.keys(headers).length > 0 ? { headers } : {}),
+    ...(isRecord(settings.extraBody) ? { body: settings.extraBody } : {}),
+  }
+}
+
+function mapOpenRouterOptions(settings: Readonly<Record<string, unknown>>) {
+  const options = Object.fromEntries(
+    Object.entries(settings).filter(
+      ([key]) =>
+        ![
+          "apiKey",
+          "api_keys",
+          "appName",
+          "appUrl",
+          "authToken",
+          "baseURL",
+          "chunkTimeout",
+          "compatibility",
+          "extraBody",
+          "fetch",
+          "headers",
+          "timeout",
+        ].includes(key),
+    ),
+  )
+  if (Object.keys(options).length === 0) return {}
+  return { providerOptions: { openrouter: options } }
+}
+
+function isStringRecord(value: unknown): value is Readonly<Record<string, string>> {
+  return isRecord(value) && Object.values(value).every((item) => typeof item === "string")
+}
+
 function mapXAIOptions(settings: Readonly<Record<string, unknown>>) {
   const options = {
     ...(typeof settings.reasoningEffort === "string" ? { reasoningEffort: settings.reasoningEffort } : {}),
@@ -78,13 +129,3 @@ function mapXAIOptions(settings: Readonly<Record<string, unknown>>) {
   if (Object.keys(options).length === 0) return {}
   return { providerOptions: { xai: options } }
 }
-
-function mapProviderOptions(namespace: string, settings: Readonly<Record<string, unknown>>) {
-  const values = Object.fromEntries(
-    Object.entries(settings).filter(
-      ([key]) => !["apiKey", "authToken", "baseURL", "chunkTimeout", "fetch", "timeout"].includes(key),
-    ),
-  )
-  if (Object.keys(values).length === 0) return {}
-  return { providerOptions: { [namespace]: values } }
-}

packages/core/src/model-resolver.ts

@@ -96,9 +96,7 @@ const providerHeaders = (model: Info) => {
   return Provider.mergeHeaders(generated.size === 0 ? undefined : Object.fromEntries(generated), model.headers)
 }
 
-const providerOptions = (
-  model: Info,
-): { readonly [key: string]: { readonly [key: string]: unknown } } | undefined => {
+const providerOptions = (model: Info): { readonly [key: string]: { readonly [key: string]: unknown } } | undefined => {
   if (!Provider.isAISDK(model.package) || model.settings === undefined) return undefined
   const { apiKey: _, baseURL: _baseURL, ...settings } = model.settings
   if (Object.keys(settings).length === 0) return undefined
@@ -202,8 +200,8 @@ export const fromCatalogModel = (
     const settings = {
       ...(credential ? withoutNativeAuthSettings(mapped) : mapped),
       ...nativeCredentialSettings(specifier, credential),
-      headers: resolved.headers,
-      body: resolved.body,
+      headers: Provider.mergeHeaders(mapping?.headers, resolved.headers),
+      body: Provider.mergeOverlay(mapping?.body, resolved.body),
       limits: { context: resolved.limit.context, input: resolved.limit.input, output: resolved.limit.output },
     }
     return yield* Effect.try({
@@ -266,10 +264,7 @@ export const layer = Layer.effect(
     const integrations = yield* Integration.Service
     const npm = yield* Npm.Service
     const aisdk = yield* AISDK.Service
-    const load = Effect.fn("ModelResolver.resolveModel")(function* (
-      selected: Info,
-      variant?: VariantID,
-    ) {
+    const load = Effect.fn("ModelResolver.resolveModel")(function* (selected: Info, variant?: VariantID) {
       const provider = yield* catalog.provider.get(selected.providerID)
       const connection = yield* integrations.connection.active(
         provider?.integrationID ?? Integration.ID.make(selected.providerID),

packages/core/src/session/generate-node.ts

@@ -71,7 +71,10 @@ export const layer = Layer.effect(
           LLM.request({
             model: model.model,
             http: { headers: SessionModelHeaders.make(selection.session, app) },
-            providerOptions: { openai: { promptCacheKey } },
+            providerOptions:
+              model.model.route.id === "openrouter"
+                ? { openrouter: { promptCacheKey } }
+                : { openai: { promptCacheKey } },
             system: contextEvent.system,
             messages: contextEvent.messages,
             tools: hookedTools,

packages/core/src/session/model-request.ts

@@ -158,7 +158,10 @@ export const layer = Layer.effect(
         http: {
           headers: SessionModelHeaders.make(session, app),
         },
-        providerOptions: { openai: { promptCacheKey } },
+        providerOptions:
+          model.route.id === "openrouter"
+            ? { openrouter: { promptCacheKey } }
+            : { openai: { promptCacheKey } },
         system: contextEvent.system,
         messages: unsupportedParts(contextEvent.messages, resolved.capabilities),
         tools: hookedTools,

packages/core/test/aisdk-native.test.ts

@@ -2,6 +2,42 @@ import { describe, expect, test } from "bun:test"
 import { AISDKNative } from "@opencode-ai/core/aisdk-native"
 
 describe("AISDKNative", () => {
+  test("maps OpenRouter settings to native destinations", () => {
+    expect(
+      AISDKNative.map("@openrouter/ai-sdk-provider", {
+        appName: "OpenCode",
+        appUrl: "https://opencode.ai",
+        headers: { "x-openrouter-title": "Configured", "x-provider-api-keys": "Configured BYOK" },
+        api_keys: { anthropic: "provider-key" },
+        extraBody: { transforms: ["middle-out"] },
+        models: ["anthropic/claude-sonnet-4.6"],
+        provider: { only: ["anthropic"], require_parameters: true },
+        reasoning: { effort: "high" },
+        promptCacheKey: "session_123",
+        future_option: { enabled: true },
+      }),
+    ).toEqual({
+      package: "@opencode-ai/ai/providers/openrouter",
+      settings: {
+        providerOptions: {
+          openrouter: {
+            models: ["anthropic/claude-sonnet-4.6"],
+            provider: { only: ["anthropic"], require_parameters: true },
+            reasoning: { effort: "high" },
+            promptCacheKey: "session_123",
+            future_option: { enabled: true },
+          },
+        },
+      },
+      headers: {
+        "x-openrouter-title": "Configured",
+        "HTTP-Referer": "https://opencode.ai",
+        "x-provider-api-keys": "Configured BYOK",
+      },
+      body: { transforms: ["middle-out"] },
+    })
+  })
+
   test("maps every Google thinking setting", () => {
     expect(
       AISDKNative.map("@ai-sdk/google", {

packages/core/test/model-resolver.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect } from "bun:test"
 import { LLM, Model } from "@opencode-ai/ai"
+import { OpenAIChat } from "@opencode-ai/ai/protocols"
 import { compileRequest } from "@opencode-ai/ai/route/client"
 import { Effect } from "effect"
 import { Headers } from "effect/unstable/http"
@@ -546,6 +547,37 @@ describe("ModelResolver", () => {
     }),
   )
 
+  it.effect("merges mapped OpenRouter headers and body with catalog overlays", () =>
+    ModelResolver.fromCatalogModel(
+      model(Provider.aisdk("@openrouter/ai-sdk-provider"), {
+        settings: {
+          appName: "OpenCode",
+          appUrl: "https://opencode.ai",
+          extraBody: { transforms: ["middle-out"], provider: { sort: "price" } },
+        },
+        headers: { "X-OpenRouter-Title": "Custom" },
+        body: { provider: { only: ["anthropic"] } },
+      }),
+      undefined,
+      {
+        loadPackage: () =>
+          Effect.succeed({
+            model: (modelID, settings) => {
+              expect(settings.headers).toEqual({
+                "HTTP-Referer": "https://opencode.ai",
+                "X-OpenRouter-Title": "Custom",
+              })
+              expect(settings.body).toEqual({
+                transforms: ["middle-out"],
+                provider: { sort: "price", only: ["anthropic"] },
+              })
+              return Model.make({ id: modelID, provider: "openrouter", route: OpenAIChat.route })
+            },
+          }),
+      },
+    ),
+  )
+
   it.effect("loads supported AISDK catalog packages as native routes", () =>
     Effect.gen(function* () {
       const google = yield* ModelResolver.fromCatalogModel(