fix(plugin): reload late SDK plugins (#35576)

packages/core/src/plugin/host.ts

@@ -18,6 +18,7 @@ import { ProviderV2 } from "../provider"
 import { Reference } from "../reference"
 import { AbsolutePath, type DeepMutable } from "../schema"
 import { SkillV2 } from "../skill"
+import { Tool } from "../tool/tool"
 import { Tools } from "../tool/tools"
 import { ToolHooks } from "../tool/hooks"
 import { WorkspaceV2 } from "../workspace"
@@ -298,7 +299,26 @@ export const make = Effect.fn("PluginHost.make")(function* (plugin: PluginV2.Int
         }),
     },
     tool: {
-      register: (input, options) => tools.register(input, options),
+      transform: (callback) =>
+        Effect.gen(function* () {
+          const registrations: Array<{
+            readonly name: string
+            readonly tool: Tool.AnyTool
+            readonly options?: Tool.RegisterOptions
+          }> = []
+          yield* Effect.sync(() =>
+            callback({
+              add: (name, tool, options) => {
+                registrations.push({ name, tool, ...(options ? { options } : {}) })
+              },
+            }),
+          )
+          yield* Effect.forEach(
+            registrations,
+            (registration) => tools.register({ [registration.name]: registration.tool }, registration.options),
+            { discard: true },
+          )
+        }),
       execute: {
         before: (callback) =>
           toolHooks.hook.before((event) => {

packages/core/src/plugin/sdk.ts

@@ -3,6 +3,9 @@ export * as SdkPlugins from "./sdk"
 import type { Plugin } from "@opencode-ai/plugin/v2/effect"
 import { Context, Effect, Layer } from "effect"
 import { makeGlobalNode } from "../effect/app-node"
+import { EventV2 } from "../event"
+
+export const Updated = EventV2.ephemeral({ type: "sdk.plugin.updated", schema: {} })
 
 export interface Store {
   readonly plugins: Map<string, Plugin>
@@ -16,9 +19,8 @@ const defaultStore = makeStore()
  * Holds the plugins an embedder (the `@opencode-ai/sdk-next` host) contributes,
  * so `PluginSupervisor` can add them on every Location boot through the ordinary
  * generation path that `PluginSupervisor` uses for plugins discovered from
- * config. A plugin registered after a Location has booted only
- * applies to Locations booted afterward, matching config-plugin timing;
- * embedders register at startup before creating Sessions.
+ * config. Registration publishes an unlocated update so every booted Location
+ * reloads its plugin generation from the shared store.
  *
  * The store is shared explicitly between the SDK construction graph and the
  * embedded route graph because `LocationServiceMap` builds Location layers lazily
@@ -36,6 +38,7 @@ export const layerWithStore = (store: Store) =>
   Layer.effect(
     Service,
     Effect.gen(function* () {
+      const events = yield* EventV2.Service
       yield* Effect.addFinalizer(() =>
         Effect.sync(() => {
           store.plugins.clear()
@@ -45,7 +48,7 @@ export const layerWithStore = (store: Store) =>
         register: (plugin) =>
           Effect.sync(() => {
             store.plugins.set(plugin.id, plugin)
-          }),
+          }).pipe(Effect.andThen(events.publish(Updated, {})), Effect.asVoid),
         all: () => [...store.plugins.values()],
       })
     }),
@@ -53,4 +56,4 @@ export const layerWithStore = (store: Store) =>
 
 export const layer = layerWithStore(defaultStore)
 
-export const node = makeGlobalNode({ service: Service, layer, deps: [] })
+export const node = makeGlobalNode({ service: Service, layer, deps: [EventV2.node] })

packages/core/src/plugin/supervisor.ts

@@ -276,7 +276,7 @@ const layer = Layer.effect(
         }),
       ),
     )
-    yield* events.subscribe(Event.Updated).pipe(
+    yield* events.subscribe([Event.Updated, SdkPlugins.Updated]).pipe(
       Stream.runForEach(() =>
         reload().pipe(Effect.catchCause((cause) => Effect.logError("failed to reload plugins", { cause }))),
       ),