fix(protocol): keep internal events off SSE (#35378)

packages/client/src/promise/generated/types.ts

@@ -5402,14 +5402,6 @@ export type EventSubscribeOutput =
       readonly location?: { readonly directory: string; readonly workspaceID?: string }
       readonly data: { readonly branch?: string }
     }
-  | {
-      readonly id: string
-      readonly created: number
-      readonly metadata?: { readonly [x: string]: unknown }
-      readonly type: "mcp.tools.changed"
-      readonly location?: { readonly directory: string; readonly workspaceID?: string }
-      readonly data: { readonly server: string }
-    }
   | {
       readonly id: string
       readonly created: number

packages/core/src/event.ts

@@ -160,15 +160,22 @@ export interface Interface {
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/Event") {}
 
-export const liveBounded = (events: Interface, capacity: number) =>
+export const liveBounded = (
+  events: Interface,
+  options: { readonly capacity: number; readonly accept?: (event: Payload) => boolean },
+) =>
   Effect.gen(function* () {
-    const queue = yield* Queue.dropping<Payload, SubscriberOverflowError>(capacity)
+    const queue = yield* Queue.dropping<Payload, SubscriberOverflowError>(options.capacity)
     const unsubscribe = yield* events.listen((event) =>
-      Queue.offer(queue, event).pipe(
-        Effect.flatMap((accepted) =>
-          accepted ? Effect.void : Queue.fail(queue, new SubscriberOverflowError({ capacity })).pipe(Effect.asVoid),
-        ),
-      ),
+      options.accept && !options.accept(event)
+        ? Effect.void
+        : Queue.offer(queue, event).pipe(
+            Effect.flatMap((accepted) =>
+              accepted
+                ? Effect.void
+                : Queue.fail(queue, new SubscriberOverflowError({ capacity: options.capacity })).pipe(Effect.asVoid),
+            ),
+          ),
     )
     yield* Effect.addFinalizer(() => unsubscribe.pipe(Effect.andThen(Queue.shutdown(queue)), Effect.asVoid))
     return Stream.fromQueue(queue)

packages/core/src/plugin/host.ts

@@ -23,8 +23,6 @@ import { ToolHooks } from "../tool/hooks"
 import { WorkspaceV2 } from "../workspace"
 
 const mutable = <T>(value: T) => value as DeepMutable<T>
-const isEvent = Schema.is(Schema.Union(EventManifest.ServerDefinitions))
-
 export const make = Effect.fn("PluginHost.make")(function* (plugin: PluginV2.Interface) {
   const agents = yield* AgentV2.Service
   const aisdk = yield* AISDK.Service
@@ -160,7 +158,7 @@ export const make = Effect.fn("PluginHost.make")(function* (plugin: PluginV2.Int
         }),
     },
     event: {
-      subscribe: () => events.live().pipe(Stream.filter(isEvent)),
+      subscribe: () => events.live().pipe(Stream.filter(EventManifest.isServer)),
     },
     integration: {
       list: () => response(integration.list()),

packages/core/test/event.test.ts

@@ -2,6 +2,8 @@ import { describe, expect } from "bun:test"
 import { Cause, DateTime, Deferred, Effect, Exit, Fiber, Layer, Option, Ref, Schema, Stream } from "effect"
 import { EventV2 } from "@opencode-ai/core/event"
 import { Event } from "@opencode-ai/schema/event"
+import { EventManifest } from "@opencode-ai/schema/event-manifest"
+import { McpEvent } from "@opencode-ai/schema/mcp-event"
 import { Session } from "@opencode-ai/schema/session"
 import { SessionEvent } from "@opencode-ai/schema/session-event"
 import { SessionV1 } from "@opencode-ai/schema/session-v1"
@@ -329,8 +331,8 @@ describe("EventV2", () => {
       const events = yield* EventV2.Service
       const consuming = yield* Deferred.make<void>()
       const release = yield* Deferred.make<void>()
-      const slowStream = yield* EventV2.liveBounded(events, 1)
-      const fastStream = yield* EventV2.liveBounded(events, 8)
+      const slowStream = yield* EventV2.liveBounded(events, { capacity: 1 })
+      const fastStream = yield* EventV2.liveBounded(events, { capacity: 8 })
       const slow = yield* slowStream.pipe(
         Stream.runForEach(() => Deferred.succeed(consuming, undefined).pipe(Effect.andThen(Deferred.await(release)))),
         Effect.forkScoped,
@@ -355,6 +357,20 @@ describe("EventV2", () => {
     }),
   )
 
+  it.effect("filters internal events before they enter a bounded server stream", () =>
+    Effect.gen(function* () {
+      const events = yield* EventV2.Service
+      const stream = yield* EventV2.liveBounded(events, { capacity: 1, accept: EventManifest.isServer })
+      const received = yield* stream.pipe(Stream.take(1), Stream.runCollect, Effect.forkScoped)
+
+      yield* events.publish(McpEvent.ToolsChanged, { server: "one" })
+      yield* events.publish(McpEvent.ToolsChanged, { server: "two" })
+      const published = yield* events.publish(McpEvent.StatusChanged, { server: "example" })
+
+      expect(Array.from(yield* Fiber.join(received))).toEqual([published])
+    }),
+  )
+
   it.effect("preserves observer interruption", () =>
     Effect.gen(function* () {
       const events = yield* EventV2.Service

packages/protocol/src/groups/event.ts

@@ -67,3 +67,5 @@ export const EventGroup = event.group
 export const OpenCodeEvent = event.schema
 export type OpenCodeEvent = typeof OpenCodeEvent.Type
 export type OpenCodeEventEncoded = typeof OpenCodeEvent.Encoded
+export const isOpenCodeEvent = (event: { readonly type: string }): event is OpenCodeEvent =>
+  event.type === "server.connected" || EventManifest.isServer(event)

packages/protocol/test/event.test.ts

@@ -1,23 +1,8 @@
 import { expect, test } from "bun:test"
-import { Event } from "@opencode-ai/schema/event"
-import { AbsolutePath } from "@opencode-ai/schema/schema"
-import { DateTime, Schema } from "effect"
-import { OpenCodeEvent } from "../src/groups/event.js"
+import { isOpenCodeEvent } from "../src/groups/event.js"
 
-test("encodes MCP tool changes emitted by the server", () => {
-  expect(
-    Schema.encodeSync(OpenCodeEvent)({
-      id: Event.ID.make("evt_test"),
-      created: DateTime.makeUnsafe(0),
-      type: "mcp.tools.changed",
-      location: { directory: AbsolutePath.make("/tmp") },
-      data: { server: "example" },
-    }),
-  ).toEqual({
-    id: "evt_test",
-    created: 0,
-    type: "mcp.tools.changed",
-    location: { directory: "/tmp" },
-    data: { server: "example" },
-  })
+test("classifies public events by type", () => {
+  expect(isOpenCodeEvent({ type: "server.connected" })).toBe(true)
+  expect(isOpenCodeEvent({ type: "mcp.status.changed" })).toBe(true)
+  expect(isOpenCodeEvent({ type: "mcp.tools.changed" })).toBe(false)
 })

packages/schema/src/event-manifest.ts

@@ -1,5 +1,6 @@
 export * as EventManifest from "./event-manifest.js"
 
+import { Schema } from "effect"
 import { Agent } from "./agent.js"
 import { Catalog } from "./catalog.js"
 import { Command } from "./command.js"
@@ -78,7 +79,7 @@ export const ServerDefinitions = Event.inventory(
   ...TuiEvent.Definitions,
   ...InstallationEvent.Definitions,
   ...VcsEvent.Definitions,
-  ...McpEvent.Definitions,
+  McpEvent.StatusChanged,
   // Shared transitional: V1 contracts the current TUI still consumes during
   // the migration (permission.asked/replied, question.asked, session.error).
   // Remove when the TUI moves to the current permission/question surfaces.
@@ -86,6 +87,9 @@ export const ServerDefinitions = Event.inventory(
   ...QuestionV1.Event.Definitions,
   SessionV1.Error,
 )
+export const Server = Event.latest(ServerDefinitions)
+export type ServerEvent = Schema.Schema.Type<(typeof ServerDefinitions)[number]>
+export const isServer = (event: { readonly type: string }): event is ServerEvent => Server.has(event.type)
 
 export const Definitions = Event.inventory(
   ...foundationDefinitions,

packages/schema/test/event-manifest.test.ts

@@ -27,7 +27,6 @@ describe("public event manifest", () => {
       Agent.Event.Updated,
     ])
     expect(EventManifest.Definitions).toContain(Agent.Event.Updated)
-    expect(EventManifest.ServerDefinitions).toContain(McpEvent.ToolsChanged)
     expect(EventManifest.Definitions.filter((definition) => definition.type === "agent.updated")).toEqual([
       Agent.Event.Updated,
     ])
@@ -47,6 +46,8 @@ describe("public event manifest", () => {
       EventManifest.Definitions.map((definition) => definition.type),
     )
     expect(EventManifest.Latest.get("agent.updated")).toBe(Agent.Event.Updated)
+    expect(EventManifest.Server.get("mcp.status.changed")).toBe(McpEvent.StatusChanged)
+    expect(EventManifest.Server.has("mcp.tools.changed")).toBe(false)
     expect(Agent.Event.Updated.durable).toBeUndefined()
     expect(EventManifest.Durable.has("agent.updated")).toBe(false)
   })

packages/server/src/handlers/event.ts

@@ -1,5 +1,5 @@
 import { EventV2 } from "@opencode-ai/core/event"
-import { OpenCodeEvent } from "@opencode-ai/protocol/groups/event"
+import { isOpenCodeEvent, OpenCodeEvent } from "@opencode-ai/protocol/groups/event"
 import { Effect, Schema, Stream } from "effect"
 import { Sse } from "effect/unstable/encoding"
 import { HttpServerResponse } from "effect/unstable/http"
@@ -35,7 +35,10 @@ export const EventHandler = HttpApiBuilder.group(Api, "server.event", (handlers)
           const output = Stream.unwrap(
             Effect.gen(function* () {
               // Acquiring the bounded stream installs its listener before readiness is observable.
-              const live = yield* EventV2.liveBounded(events, subscriberCapacity)
+              const live = yield* EventV2.liveBounded(events, {
+                capacity: subscriberCapacity,
+                accept: isOpenCodeEvent,
+              })
               return Stream.make(connected).pipe(Stream.concat(live))
             }),
           ).pipe(Stream.map(eventData), Stream.pipeThroughChannel(Sse.encode()))