feat(ai): add Vertex Mistral route (#54058)

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

@@ -125,7 +125,7 @@ export type ProviderOptionsInput = {
   readonly [key: string]: unknown
 }
 
-const MistralBody = Schema.Struct({
+export const MistralBody = Schema.Struct({
   model: Schema.String,
   messages: Schema.Array(MistralMessage),
   tools: optionalArray(MistralTool),

packages/ai/src/providers/google-vertex-mistral.ts

@@ -0,0 +1,109 @@
+import { Effect, Schema, Struct } from "effect"
+import type { ProviderPackage } from "../provider-package.js"
+import { MistralChat } from "../protocols/mistral-chat.js"
+import { Auth } from "../route/auth.js"
+import { Route, type RouteDefaultsInput } from "../route/client.js"
+import { Endpoint } from "../route/endpoint.js"
+import { Protocol } from "../route/protocol.js"
+import { HttpTransport } from "../route/transport/index.js"
+import { ProviderConfigurationError, ProviderID, type ModelID } from "../schema/index.js"
+import { GoogleVertexShared } from "./google-vertex-shared.js"
+
+export const id = ProviderID.make("google-vertex")
+
+export type Config = RouteDefaultsInput &
+  GoogleVertexShared.OAuthOptions & {
+    readonly baseURL?: string
+    readonly location?: string
+    readonly project?: string
+    readonly providerOptions?: MistralChat.ProviderOptionsInput
+  }
+
+export type Settings = ProviderPackage.Settings &
+  MistralChat.ProviderOptionsInput & {
+    readonly accessToken?: string
+    readonly apiKey?: never
+    readonly baseURL?: string
+    readonly location?: string
+    readonly project?: string
+  }
+
+type Body = Omit<MistralChat.MistralBody, "prompt_cache_key">
+
+// Mistral on Vertex takes the Mistral chat body, model included, through the publisher's streamRawPredict method.
+// Vertex validates the body strictly and rejects prompt_cache_key, which Mistral's own API accepts.
+const route = Route.make({
+  id: "google-vertex-mistral",
+  provider: id,
+  providerMetadataKey: "vertex",
+  protocol: Protocol.make({
+    id: MistralChat.protocol.id,
+    body: {
+      schema: Schema.Struct(Struct.omit(MistralChat.MistralBody.fields, ["prompt_cache_key"])),
+      from: (request) =>
+        MistralChat.protocol.body.from(request).pipe(Effect.map((body) => Struct.omit(body, ["prompt_cache_key"]))),
+    },
+    stream: MistralChat.protocol.stream,
+  }),
+  endpoint: Endpoint.path(({ request }) => `/${request.model.id}:streamRawPredict`),
+  auth: Auth.none,
+  transport: HttpTransport.sseJson.with<Body>().with({ framing: MistralChat.framing }),
+})
+
+export const routes = [route]
+
+const configuredRoute = (input: Config) => {
+  if ("apiKey" in input && input.apiKey !== undefined)
+    throw new ProviderConfigurationError({ provider: id, message: "Google Vertex Mistral does not support API keys" })
+  const {
+    accessToken: _accessToken,
+    auth: _auth,
+    baseURL,
+    location: inputLocation,
+    project: inputProject,
+    ...rest
+  } = input
+  // Mistral is served from regional endpoints only; the global endpoint returns 404.
+  const location = GoogleVertexShared.location(inputLocation, "us-central1")
+  const project = GoogleVertexShared.project(inputProject)
+  return route.with({
+    ...rest,
+    endpoint: {
+      baseURL:
+        baseURL ??
+        `https://${GoogleVertexShared.host(location)}/v1/projects/${GoogleVertexShared.requireProject(project)}/locations/${location}/publishers/mistralai/models`,
+    },
+    auth: GoogleVertexShared.oauth(input, project),
+  })
+}
+
+export const configure = (input: Config = {}) => {
+  const route = configuredRoute(input)
+  return {
+    id,
+    model: (modelID: string | ModelID) => route.model<MistralChat.ProviderOptionsInput>({ id: modelID }),
+    configure,
+  }
+}
+
+export const provider = {
+  id,
+  configure,
+}
+
+export const model: ProviderPackage.Definition<Settings, MistralChat.ProviderOptionsInput>["model"] = (
+  modelID,
+  { accessToken, apiKey, baseURL, body, headers, location, project, ...providerOptions },
+) => {
+  if (apiKey !== undefined)
+    throw new ProviderConfigurationError({ provider: id, message: "Google Vertex Mistral does not support API keys" })
+  return configure({
+    accessToken,
+    baseURL,
+    headers,
+    http: body === undefined ? undefined : { body },
+    location,
+    project,
+    providerOptions,
+  }).model(modelID)
+}

packages/ai/src/providers/google-vertex/mistral.ts

@@ -0,0 +1,2 @@
+export { model } from "../google-vertex-mistral.js"
+export type { Settings } from "../google-vertex-mistral.js"

packages/ai/src/providers/index.ts

@@ -23,6 +23,7 @@ export * as Google from "./google.js"
 export * as GoogleVertex from "./google-vertex.js"
 export * as GoogleVertexChat from "./google-vertex-chat.js"
 export * as GoogleVertexMessages from "./google-vertex-messages.js"
+export * as GoogleVertexMistral from "./google-vertex-mistral.js"
 export * as GoogleVertexResponses from "./google-vertex-responses.js"
 export * as Groq from "./groq.js"
 export * as Meta from "./meta.js"

packages/core/src/aisdk-native.ts

@@ -104,7 +104,10 @@ const HOSTS: Readonly<Record<string, Readonly<Record<string, string>>>> = {
   deepseek: { "@ai-sdk/openai-compatible": "@opencode/ai/providers/deepseek" },
   digitalocean: { "@ai-sdk/openai-compatible": "@opencode/ai/providers/digitalocean" },
   "fireworks-ai": { "@ai-sdk/openai-compatible": "@opencode/ai/providers/fireworks" },
-  "google-vertex": { "@ai-sdk/openai-compatible": "@opencode/ai/providers/google-vertex/chat" },
+  "google-vertex": {
+    "@ai-sdk/openai-compatible": "@opencode/ai/providers/google-vertex/chat",
+    "@ai-sdk/mistral": "@opencode/ai/providers/google-vertex/mistral",
+  },
   "kimi-for-coding": protocols("moonshot"),
   meta: protocols("meta"),
   minimax: protocols("minimax"),
@@ -149,8 +152,7 @@ function resolve(specifier: string, context: Context & { readonly settings?: Pro
   if (Provider.isAISDK(specifier) || npm in PACKAGES || npm in (HOSTS[context.providerID] ?? {}))
     return native(npm, context)
   if (npm === "@opencode/ai/providers/amazon-bedrock/mantle") return mantle(context.modelID)
-  if (npm === "@opencode/ai/providers/azure/responses" && azureChat(context))
-    return "@opencode/ai/providers/azure/chat"
+  if (npm === "@opencode/ai/providers/azure/responses" && azureChat(context)) return "@opencode/ai/providers/azure/chat"
   return NATIVE.has(npm) ? npm : undefined
 }
 

packages/core/src/provider.ts

@@ -81,6 +81,7 @@ const builtins = new Map<string, () => Promise<unknown>>([
   ["@opencode/ai/providers/google-vertex/chat", () => import("@opencode/ai/providers/google-vertex/chat")],
   ["@opencode/ai/providers/google-vertex/responses", () => import("@opencode/ai/providers/google-vertex/responses")],
   ["@opencode/ai/providers/google-vertex/messages", () => import("@opencode/ai/providers/google-vertex/messages")],
+  ["@opencode/ai/providers/google-vertex/mistral", () => import("@opencode/ai/providers/google-vertex/mistral")],
   ["@opencode/ai/providers/groq", () => import("@opencode/ai/providers/groq")],
   ["@opencode/ai/providers/meta/chat", () => import("@opencode/ai/providers/meta/chat")],
   ["@opencode/ai/providers/meta/messages", () => import("@opencode/ai/providers/meta/messages")],

packages/core/src/variant.ts

@@ -610,6 +610,7 @@ const PROTOCOLS: Readonly<Record<string, Protocol>> = {
 
   "@opencode/ai/providers/anthropic": anthropicMessages,
   "@opencode/ai/providers/google-vertex/messages": anthropicMessages,
+  "@opencode/ai/providers/google-vertex/mistral": openaiChat,
   "@opencode/ai/providers/alibaba/messages": alibabaMessages,
   "@opencode/ai/providers/meta/messages": anthropicMessages,
   "@opencode/ai/providers/minimax/messages": minimaxMessages,