fix(core): route Copilot Claude through plugin

packages/core/src/plugin/provider/github-copilot.ts

@@ -202,7 +202,12 @@ export const GithubCopilotPlugin = define({
           if (!loaded.models.has(Model.ID.make(id))) evt.model.remove(item.provider.id, id)
         }
         for (const [id, model] of loaded.models) {
-          evt.model.update(item.provider.id, id, (draft) => Object.assign(draft, structuredClone(model)))
+          evt.model.update(item.provider.id, id, (draft) => {
+            Object.assign(draft, structuredClone(model))
+            if (Provider.packageName(draft.package) === "@ai-sdk/anthropic") {
+              draft.package = Provider.aisdk("@ai-sdk/github-copilot")
+            }
+          })
         }
       } else if (loaded.baseURL) {
         for (const id of item.models.keys()) {
@@ -230,14 +235,15 @@ export const GithubCopilotPlugin = define({
       "sdk",
       Effect.fn(function* (evt) {
         if (evt.model.providerID !== Provider.ID.githubCopilot) return
-        if (evt.package !== "@ai-sdk/github-copilot" && evt.package !== "@ai-sdk/anthropic") return
+        if (evt.package !== "@ai-sdk/github-copilot") return
+        const anthropic = evt.options.endpoint === "messages"
         evt.options.fetch = copilotFetch(
           typeof evt.options.apiKey === "string" ? evt.options.apiKey : undefined,
           evt.options.fetch,
-          evt.package === "@ai-sdk/anthropic",
+          anthropic,
           ctx.app,
         )
-        if (evt.package === "@ai-sdk/anthropic") {
+        if (anthropic) {
           evt.options.headers = {
             ...evt.options.headers,
             "anthropic-beta": "interleaved-thinking-2025-05-14",

packages/core/test/plugin/provider-github-copilot.test.ts

@@ -118,7 +118,7 @@ describe("GithubCopilotPlugin", () => {
     }),
   )
 
-  it.effect("creates the bundled Copilot SDK for the GitHub Copilot package", () =>
+  it.effect("creates the Copilot SDK for OpenAI and Anthropic endpoints", () =>
     Effect.gen(function* () {
       const plugin = yield* Plugin.Service
       const aisdk = yield* AISDK.Service
@@ -141,8 +141,18 @@ describe("GithubCopilotPlugin", () => {
         package: "@ai-sdk/github-copilot",
         options: { name: "github-copilot" },
       })
+      const messages = yield* aisdk.runSDK({
+        model: Model.Info.make({
+          ...Model.Info.default(Provider.ID.make("github-copilot"), Model.ID.make("claude-haiku-4.5")),
+          modelID: Model.ID.make("claude-haiku-4.5"),
+          package: Provider.aisdk("@ai-sdk/github-copilot"),
+        }),
+        package: "@ai-sdk/github-copilot",
+        options: { name: "github-copilot", endpoint: "messages" },
+      })
       expect(ignored.sdk).toBeUndefined()
       expect(result.sdk).toBeDefined()
+      expect(messages.sdk).toBeDefined()
     }),
   )