feat(core): expose config changes stream (#39131)

packages/core/src/config.ts

@@ -159,6 +159,12 @@ export function latest<K extends keyof Info>(entries: readonly Entry[], key: K):
 export interface Interface {
   /** Returns location config documents and discovery sources from lowest to highest priority. */
   readonly entries: () => Effect.Effect<Entry[]>
+  /**
+   * Streams raw filesystem updates under config roots. Config owns root
+   * topology and watch reconciliation; domain owners filter this feed for the
+   * source files they parse and rebuild their own state.
+   */
+  readonly changes: () => Stream.Stream<Watcher.Update>
 }
 
 export const Options = Schema.Struct({
@@ -430,6 +436,7 @@ export const layer = (options?: Options) => Layer.effect(
       entries: Effect.fn("Config.entries")(function* () {
         return configs
       }),
+      changes: () => Stream.fromPubSub(updates),
     })
   }),
 )

packages/core/test/config/agent.test.ts

@@ -1,7 +1,7 @@
 import { describe, expect, test } from "bun:test"
 import fs from "fs/promises"
 import path from "path"
-import { Effect, Schema } from "effect"
+import { Effect, Schema, Stream } from "effect"
 import { Agent } from "@opencode-ai/core/agent"
 import { Config } from "@opencode-ai/core/config"
 import { ConfigAgentPlugin } from "@opencode-ai/core/config/plugin/agent"
@@ -67,6 +67,7 @@ describe("ConfigAgentPlugin.Plugin", () => {
       )
 
       const config = Config.Service.of({
+        changes: () => Stream.empty,
         entries: () =>
           Effect.succeed([
             new Config.Document({
@@ -152,6 +153,7 @@ describe("ConfigAgentPlugin.Plugin", () => {
     Effect.gen(function* () {
       const agents = yield* Agent.Service
       const config = Config.Service.of({
+        changes: () => Stream.empty,
         entries: () =>
           Effect.succeed([
             new Config.Document({
@@ -220,6 +222,7 @@ describe("ConfigAgentPlugin.Plugin", () => {
       yield* agents.transform((editor) => editor.update(build, () => {}))
 
       const config = Config.Service.of({
+        changes: () => Stream.empty,
         entries: () =>
           Effect.succeed([
             new Config.Document({
@@ -279,6 +282,7 @@ Use native v2 fields.`,
           })
           const agents = yield* Agent.Service
           const config = Config.Service.of({
+            changes: () => Stream.empty,
             entries: () =>
               Effect.succeed([
                 new Config.Document({
@@ -320,6 +324,7 @@ function loadHomePermissions(home: string) {
     const build = Agent.ID.make("build")
     yield* agents.transform((editor) => editor.update(build, () => {}))
     const config = Config.Service.of({
+      changes: () => Stream.empty,
       entries: () =>
         Effect.succeed([
           new Config.Document({

packages/core/test/config/command.test.ts

@@ -71,6 +71,7 @@ Review files`,
             Effect.provideService(
               Config.Service,
               Config.Service.of({
+                changes: () => Stream.empty,
                 entries: () =>
                   Effect.succeed([
                     new Config.Document({

packages/core/test/config/config.test.ts

@@ -215,6 +215,45 @@ describe("Config", () => {
     ),
   )
 
+  it.live("exposes filesystem updates under config roots through changes", () =>
+    Effect.acquireRelease(
+      Effect.promise(() => tmpdir()),
+      (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
+    ).pipe(
+      Effect.flatMap((tmp) =>
+        Effect.gen(function* () {
+          const global = path.join(tmp.path, "global")
+          const project = path.join(tmp.path, "project")
+          yield* Effect.promise(async () => {
+            await fs.mkdir(path.join(global, "commands"), { recursive: true })
+            await fs.mkdir(project, { recursive: true })
+          })
+          const updates = yield* PubSub.unbounded<Watcher.Update>()
+          const watcher = Layer.succeed(
+            Watcher.Service,
+            Watcher.Service.of({
+              subscribe: () => Stream.fromPubSub(updates),
+            }),
+          )
+
+          return yield* Effect.gen(function* () {
+            const config = yield* Config.Service
+            const received = yield* config
+              .changes()
+              .pipe(Stream.take(1), Stream.runCollect, Effect.forkScoped({ startImmediately: true }))
+            yield* Effect.sleep("10 millis")
+
+            const file = path.join(global, "commands", "review.md")
+            yield* PubSub.publish(updates, { type: "update", path: file } satisfies Watcher.Update)
+
+            const collected = yield* Fiber.join(received).pipe(Effect.timeout("1 second"))
+            expect(Array.from(collected)).toEqual([{ type: "update", path: file }])
+          }).pipe(Effect.provide(testLayer(project, global, project, undefined, watcher)))
+        }),
+      ),
+    ),
+  )
+
   it.effect("returns the latest defined scalar from priority-ordered documents", () =>
     Effect.sync(() => {
       const entries = [

packages/core/test/config/policy.test.ts

@@ -7,7 +7,7 @@ import { Bus } from "@opencode-ai/core/bus"
 import { Plugin } from "@opencode-ai/core/plugin"
 import { PluginHost } from "@opencode-ai/core/plugin/host"
 import { Provider } from "@opencode-ai/core/provider"
-import { Effect, Schema } from "effect"
+import { Effect, Schema, Stream } from "effect"
 import { testEffect } from "../lib/effect"
 import { PluginTestLayer } from "../plugin/fixture"
 
@@ -28,7 +28,10 @@ const addPlugin = Effect.fn(function* (entries: () => Config.Entry[]) {
   const plugin = yield* Plugin.Service
   const host = yield* PluginHost.make(plugin)
   yield* ConfigPolicyPlugin.Plugin.effect(host).pipe(
-    Effect.provideService(Config.Service, Config.Service.of({ entries: () => Effect.sync(entries) })),
+    Effect.provideService(
+      Config.Service,
+      Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.sync(entries) }),
+    ),
   )
 })
 

packages/core/test/config/provider.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect } from "bun:test"
 import { Money } from "@opencode-ai/schema/money"
-import { Effect, Schema } from "effect"
+import { Effect, Schema, Stream } from "effect"
 import { Catalog } from "@opencode-ai/core/catalog"
 import { Config } from "@opencode-ai/core/config"
 import { ConfigProviderPlugin } from "@opencode-ai/core/config/plugin/provider"
@@ -55,6 +55,7 @@ describe("ConfigProviderPlugin.Plugin", () => {
       const providerID = Provider.ID.make("custom")
       const modelID = Model.ID.make("chat")
       const config = Config.Service.of({
+        changes: () => Stream.empty,
         entries: () =>
           Effect.succeed([
             new Config.Document({
@@ -93,6 +94,7 @@ describe("ConfigProviderPlugin.Plugin", () => {
         })
       })
       const config = Config.Service.of({
+        changes: () => Stream.empty,
         entries: () =>
           Effect.succeed([
             new Config.Document({
@@ -135,6 +137,7 @@ describe("ConfigProviderPlugin.Plugin", () => {
       const providerID = Provider.ID.opencode
       const modelID = Model.ID.make("alpha-gpt-next")
       const config = Config.Service.of({
+        changes: () => Stream.empty,
         entries: () =>
           Effect.succeed([
             new Config.Document({
@@ -187,6 +190,7 @@ describe("ConfigProviderPlugin.Plugin", () => {
       const providerID = Provider.ID.opencode
       const modelID = Model.ID.make("alpha-gpt-next")
       const config = Config.Service.of({
+        changes: () => Stream.empty,
         entries: () =>
           Effect.succeed([
             new Config.Document({
@@ -235,6 +239,7 @@ describe("ConfigProviderPlugin.Plugin", () => {
         const providerID = Provider.ID.make("custom")
         const modelID = Model.ID.make("chat")
         const config = Config.Service.of({
+          changes: () => Stream.empty,
           entries: () =>
             Effect.succeed([
               new Config.Document({

packages/core/test/config/reload.test.ts

@@ -17,7 +17,7 @@ import { PluginHost } from "@opencode-ai/core/plugin/host"
 import { Provider } from "@opencode-ai/core/provider"
 import { Reference } from "@opencode-ai/core/reference"
 import { Skill } from "@opencode-ai/core/skill"
-import { Effect, Schema } from "effect"
+import { Effect, Schema, Stream } from "effect"
 import { testEffect } from "../lib/effect"
 import { PluginTestLayer } from "../plugin/fixture"
 
@@ -37,7 +37,7 @@ describe("config plugin reloads", () => {
       const skills = yield* Skill.Service
       const host = yield* PluginHost.make(plugins)
       let entries: Config.Entry[] = [config("first")]
-      const service = Config.Service.of({ entries: () => Effect.sync(() => entries) })
+      const service = Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.sync(() => entries) })
       const setup = <R>(effect: Effect.Effect<void, never, R>) =>
         effect.pipe(Effect.provideService(Config.Service, service))
 

packages/core/test/config/skill.test.ts

@@ -1,6 +1,6 @@
 import path from "path"
 import { describe, expect } from "bun:test"
-import { Effect, Layer, Schema } from "effect"
+import { Effect, Layer, Schema, Stream } from "effect"
 import { Config } from "@opencode-ai/core/config"
 import { ConfigSkillPlugin } from "@opencode-ai/core/config/plugin/skill"
 import { Global } from "@opencode-ai/util/global"
@@ -44,6 +44,7 @@ describe("ConfigSkillPlugin.Plugin", () => {
         Effect.provideService(
           Config.Service,
           Config.Service.of({
+            changes: () => Stream.empty,
             entries: () =>
               Effect.succeed([
                 new Config.ClaudeDirectory({ type: "claude", path: AbsolutePath.make("/repo/.claude") }),

packages/core/test/filesystem/watcher.test.ts

@@ -25,9 +25,7 @@ const it = testEffect(AppNodeBuilder.build(LayerNode.group([FSUtil.node, Bus.nod
 
 const configLayer = Layer.succeed(
   Config.Service,
-  Config.Service.of({
-    entries: () => Effect.succeed([]),
-  }),
+  Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.succeed([]) }),
 )
 
 function provide(directory: string, vcs?: Location.Interface["vcs"]) {

packages/core/test/fixture/mcp.ts

@@ -1,4 +1,4 @@
-import { Effect, Layer } from "effect"
+import { Effect, Layer, Stream } from "effect"
 import { Config } from "@opencode-ai/core/config"
 import { Location } from "@opencode-ai/core/location"
 import { MCP } from "@opencode-ai/core/mcp/index"
@@ -23,7 +23,10 @@ export const emptyMcpLayer = Layer.succeed(
   }),
 )
 
-export const emptyConfigLayer = Layer.succeed(Config.Service, Config.Service.of({ entries: () => Effect.succeed([]) }))
+export const emptyConfigLayer = Layer.succeed(
+  Config.Service,
+  Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.succeed([]) }),
+)
 
 export const testLocationLayer = Layer.succeed(
   Location.Service,

packages/core/test/mcp.test.ts

@@ -163,6 +163,7 @@ function resourceMcpLayer(
         Layer.succeed(
           Config.Service,
           Config.Service.of({
+            changes: () => Stream.empty,
             entries: () =>
               Effect.succeed([
                 new Config.Document({

packages/core/test/plugin/fixture.ts

@@ -21,7 +21,7 @@ import { Reference } from "@opencode-ai/core/reference"
 import { Skill } from "@opencode-ai/core/skill"
 import { Tool } from "@opencode-ai/core/tool"
 import { WebSearch } from "@opencode-ai/core/websearch"
-import { Effect, Layer } from "effect"
+import { Effect, Layer, Stream } from "effect"
 import { tempLocationLayer } from "../fixture/location"
 
 const npmLayer = Layer.succeed(
@@ -60,6 +60,12 @@ export const PluginTestLayer = AppNodeBuilder.build(
   [
     [Location.node, tempLocationLayer],
     [Npm.node, npmLayer],
-    [Config.node, Layer.succeed(Config.Service, Config.Service.of({ entries: () => Effect.succeed([]) }))],
+    [
+      Config.node,
+      Layer.succeed(
+        Config.Service,
+        Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.succeed([]) }),
+      ),
+    ],
   ],
 ) as unknown as Layer.Layer<unknown, never>

packages/core/test/plugin/skill.test.ts

@@ -4,7 +4,7 @@ import { Config } from "@opencode-ai/core/config"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { FSUtil } from "@opencode-ai/util/fs-util"
 import { Location } from "@opencode-ai/core/location"
-import { Effect } from "effect"
+import { Effect, Stream } from "effect"
 import { SkillPlugin } from "@opencode-ai/core/plugin/skill"
 import { AbsolutePath } from "@opencode-ai/core/schema"
 import { Skill } from "@opencode-ai/core/skill"
@@ -28,7 +28,10 @@ describe("SkillPlugin.Plugin", () => {
           },
         }),
       ).pipe(
-        Effect.provideService(Config.Service, Config.Service.of({ entries: () => Effect.succeed([]) })),
+        Effect.provideService(
+          Config.Service,
+          Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.succeed([]) }),
+        ),
         Effect.provideService(
           Location.Service,
           Location.Service.of(location({ directory: AbsolutePath.make(import.meta.dir) })),

packages/core/test/plugin/websearch-fixture.ts

@@ -1,4 +1,4 @@
-import { Effect, Layer } from "effect"
+import { Effect, Layer, Stream } from "effect"
 import { HttpClient, HttpClientResponse } from "effect/unstable/http"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
@@ -43,7 +43,15 @@ export const webSearchIntegrationTest = testEffect(
   Layer.merge(
     AppNodeBuilder.build(
       LayerNode.group([Integration.node, Credential.node, Bus.node, Form.node, WebSearch.node]),
-      [[Config.node, Layer.succeed(Config.Service, Config.Service.of({ entries: () => Effect.succeed([]) }))]],
+      [
+        [
+          Config.node,
+          Layer.succeed(
+            Config.Service,
+            Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.succeed([]) }),
+          ),
+        ],
+      ],
     ),
     http,
   ),

packages/core/test/session-instructions.test.ts

@@ -1,7 +1,7 @@
 import { describe, expect, test } from "bun:test"
 import fs from "fs/promises"
 import path from "path"
-import { DateTime, Effect, Layer } from "effect"
+import { DateTime, Effect, Layer, Stream } from "effect"
 import { Message } from "@opencode-ai/ai"
 import { Agent } from "@opencode-ai/core/agent"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
@@ -70,7 +70,10 @@ const permission = Layer.succeed(
     list: () => Effect.die("unused"),
   }),
 )
-const config = Layer.succeed(Config.Service, Config.Service.of({ entries: () => Effect.succeed([]) }))
+const config = Layer.succeed(
+  Config.Service,
+  Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.succeed([]) }),
+)
 const imageLayer = AppNodeBuilder.build(Image.node, [[Config.node, config]])
 
 const testLayer = AppNodeBuilder.build(

packages/core/test/session-runner-recorded.test.ts

@@ -40,7 +40,7 @@ import { PluginHooks } from "@opencode-ai/core/plugin/hooks"
 import { SystemPromptPlugin } from "@opencode-ai/core/plugin/system-prompt"
 import { describe, expect } from "bun:test"
 import { eq } from "drizzle-orm"
-import { Effect, Layer } from "effect"
+import { Effect, Layer, Stream } from "effect"
 import path from "node:path"
 import { testEffect } from "./lib/effect"
 import { agentHost, catalogHost, host } from "./plugin/host"
@@ -88,7 +88,10 @@ const referenceInstructions = Layer.mock(ReferenceInstructions.Service, {
   load: () => Effect.succeed(Instructions.empty),
 })
 const mcpInstructions = Layer.mock(McpInstructions.Service, { load: () => Effect.succeed(Instructions.empty) })
-const config = Layer.succeed(Config.Service, Config.Service.of({ entries: () => Effect.succeed([]) }))
+const config = Layer.succeed(
+  Config.Service,
+  Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.succeed([]) }),
+)
 const pluginSupervisor = Layer.succeed(PluginSupervisor.Service, PluginSupervisor.Service.of({ flush: Effect.void }))
 const promptCatalog = Layer.mock(Catalog.Service, {
   provider: {

packages/core/test/session-runner.test.ts

@@ -358,6 +358,7 @@ const mcpInstructions = Layer.mock(McpInstructions.Service, { load: () => Effect
 const config = Layer.succeed(
   Config.Service,
   Config.Service.of({
+    changes: () => Stream.empty,
     entries: () =>
       Effect.succeed([
         new Config.Document({

packages/core/test/tool-read.test.ts

@@ -1,6 +1,6 @@
 import { beforeEach, describe, expect } from "bun:test"
 import path from "path"
-import { Effect, Exit, Layer, PlatformError } from "effect"
+import { Effect, Exit, Layer, PlatformError, Stream } from "effect"
 import { Config } from "@opencode-ai/core/config"
 import { ConfigAttachments } from "@opencode-ai/core/config/attachments"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
@@ -100,7 +100,10 @@ const permission = Layer.succeed(
     list: () => Effect.die("unused"),
   }),
 )
-const config = Layer.succeed(Config.Service, Config.Service.of({ entries: () => Effect.succeed(configEntries) }))
+const config = Layer.succeed(
+  Config.Service,
+  Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.succeed(configEntries) }),
+)
 const imageLayer = AppNodeBuilder.build(Image.node, [[Config.node, config]])
 const testFileSystem = Layer.effect(
   FSUtil.Service,

packages/simulation/test/simulated-provider.test.ts

@@ -701,7 +701,15 @@ const toolLifecycleLayer = (endpoint: string) => {
   })
   return AppNodeBuilder.build(
     LayerNode.group([Database.node, Bus.node, SdkPlugins.node, LocationServiceMap.node, provider]),
-    [[Config.node, Layer.succeed(Config.Service, Config.Service.of({ entries: () => Effect.succeed([]) }))]],
+    [
+      [
+        Config.node,
+        Layer.succeed(
+          Config.Service,
+          Config.Service.of({ changes: () => Stream.empty, entries: () => Effect.succeed([]) }),
+        ),
+      ],
+    ],
   )
 }