core: expose v2 model listing API (#25821)

packages/opencode/src/server/routes/instance/httpapi/handlers/v2.ts

@@ -1,6 +1,12 @@
+import { Catalog } from "@opencode-ai/core/catalog"
 import { SessionV2 } from "@/v2/session"
 import { Layer } from "effect"
 import { messageHandlers } from "./v2/message"
+import { modelHandlers } from "./v2/model"
+import { providerHandlers } from "./v2/provider"
 import { sessionHandlers } from "./v2/session"
 
-export const v2Handlers = Layer.mergeAll(sessionHandlers, messageHandlers).pipe(Layer.provide(SessionV2.defaultLayer))
+export const v2Handlers = Layer.mergeAll(sessionHandlers, messageHandlers, modelHandlers, providerHandlers).pipe(
+  Layer.provide(Catalog.defaultLayer),
+  Layer.provide(SessionV2.defaultLayer),
+)

packages/opencode/src/server/routes/instance/httpapi/handlers/v2/model.ts

@@ -0,0 +1,12 @@
+import { Catalog } from "@opencode-ai/core/catalog"
+import { Effect } from "effect"
+import { HttpApiBuilder } from "effect/unstable/httpapi"
+import { InstanceHttpApi } from "../../api"
+
+export const modelHandlers = HttpApiBuilder.group(InstanceHttpApi, "v2.model", (handlers) =>
+  Effect.gen(function* () {
+    const catalog = yield* Catalog.Service
+
+    return handlers.handle("models", () => catalog.model.available())
+  }),
+)

packages/opencode/src/server/routes/instance/httpapi/handlers/v2/provider.ts

@@ -0,0 +1,22 @@
+import { Catalog } from "@opencode-ai/core/catalog"
+import { Effect } from "effect"
+import { HttpApiBuilder } from "effect/unstable/httpapi"
+import { InstanceHttpApi } from "../../api"
+import { notFound } from "../../errors"
+
+export const providerHandlers = HttpApiBuilder.group(InstanceHttpApi, "v2.provider", (handlers) =>
+  Effect.gen(function* () {
+    const catalog = yield* Catalog.Service
+
+    return handlers
+      .handle("providers", () => catalog.provider.available())
+      .handle(
+        "provider",
+        Effect.fn(function* (ctx) {
+          return yield* catalog.provider
+            .get(ctx.params.providerID)
+            .pipe(Effect.catchTag("CatalogV2.ProviderNotFound", () => Effect.fail(notFound("Provider not found"))))
+        }),
+      )
+  }),
+)