feat(core): add Snowflake Cortex provider (#29901)

Co-authored-by: Cortex Code <noreply@snowflake.com>

packages/core/src/plugin/provider.ts

@@ -19,6 +19,7 @@ import { LLMGatewayPlugin } from "./provider/llmgateway"
 import { MistralPlugin } from "./provider/mistral"
 import { NvidiaPlugin } from "./provider/nvidia"
 import { OpenAIPlugin } from "./provider/openai"
+import { SnowflakeCortexPlugin } from "./provider/snowflake-cortex"
 import { OpenAICompatiblePlugin } from "./provider/openai-compatible"
 import { OpencodePlugin } from "./provider/opencode"
 import { OpenRouterPlugin } from "./provider/openrouter"
@@ -53,6 +54,7 @@ export const ProviderPlugins = [
   MistralPlugin,
   NvidiaPlugin,
   OpencodePlugin,
+  SnowflakeCortexPlugin,
   OpenAICompatiblePlugin,
   OpenAIPlugin,
   OpenRouterPlugin,

packages/core/src/plugin/provider/snowflake-cortex.ts

@@ -0,0 +1,81 @@
+import { Effect } from "effect"
+import { PluginV2 } from "../../plugin"
+import { ProviderV2 } from "../../provider"
+
+type FetchLike = (url: string | URL | Request, init?: RequestInit) => Promise<Response>
+
+// Exported for testing: intercepts Cortex-specific request/response quirks.
+export function cortexFetch(upstream: FetchLike = fetch) {
+  return async (url: string | URL | Request, init?: RequestInit): Promise<Response> => {
+    if (init?.body && typeof init.body === "string") {
+      try {
+        const body = JSON.parse(init.body)
+        if ("max_tokens" in body) {
+          body.max_completion_tokens = body.max_tokens
+          delete body.max_tokens
+          init = { ...init, body: JSON.stringify(body) }
+        }
+      } catch {}
+    }
+
+    const response = await upstream(url, init)
+
+    // Cortex returns 400 "conversation complete" as a normal stop condition
+    if (!response.ok && response.status === 400) {
+      try {
+        const errorData = (await response.clone().json()) as Record<string, unknown>
+        if (String(errorData.message || errorData.error || "").toLowerCase().includes("conversation complete")) {
+          return new Response(
+            JSON.stringify({ choices: [{ finish_reason: "stop", message: { content: "", role: "assistant" } }] }),
+            { status: 200, headers: new Headers({ "content-type": "application/json" }) },
+          )
+        }
+      } catch {}
+    }
+
+    // Cortex returns role:"" in streaming deltas; the AI SDK schema requires "assistant"
+    if (response.body && response.headers.get("content-type")?.includes("text/event-stream")) {
+      const reader = response.body.getReader()
+      const encoder = new TextEncoder()
+      const decoder = new TextDecoder()
+      const stream = new ReadableStream({
+        async pull(ctrl) {
+          const { done, value } = await reader.read()
+          if (done) {
+            ctrl.close()
+            return
+          }
+          ctrl.enqueue(encoder.encode(decoder.decode(value, { stream: true }).replace(/"role"\s*:\s*""/g, '"role":"assistant"')))
+        },
+        cancel() {
+          reader.cancel()
+        },
+      })
+      return new Response(stream, { headers: response.headers, status: response.status })
+    }
+
+    return response
+  }
+}
+
+export const SnowflakeCortexPlugin = PluginV2.define({
+  id: PluginV2.ID.make("snowflake-cortex"),
+  effect: Effect.gen(function* () {
+    return {
+      "aisdk.sdk": Effect.fn(function* (evt) {
+        if (evt.model.providerID !== ProviderV2.ID.make("snowflake-cortex")) return
+        const pat =
+          process.env.SNOWFLAKE_CORTEX_PAT ??
+          (typeof evt.options.apiKey === "string" ? evt.options.apiKey : undefined)
+        const upstream = typeof evt.options.fetch === "function" ? (evt.options.fetch as FetchLike) : undefined
+        if (evt.options.includeUsage !== false) evt.options.includeUsage = true
+        const mod = yield* Effect.promise(() => import("@ai-sdk/openai-compatible"))
+        evt.sdk = mod.createOpenAICompatible({
+          ...evt.options,
+          ...(pat ? { apiKey: pat } : {}),
+          fetch: cortexFetch(upstream) as typeof fetch,
+        } as any)
+      }),
+    }
+  }),
+})