Add experimental background agents

packages/core/src/flag/flag.ts

@@ -72,6 +72,8 @@ export const Flag = {
   OPENCODE_EXPERIMENTAL_LSP_TOOL: OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_LSP_TOOL"),
   OPENCODE_EXPERIMENTAL_PLAN_MODE: OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_PLAN_MODE"),
   OPENCODE_EXPERIMENTAL_SCOUT: OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_SCOUT"),
+  OPENCODE_EXPERIMENTAL_BACKGROUND_AGENTS:
+    OPENCODE_EXPERIMENTAL || truthy("OPENCODE_EXPERIMENTAL_BACKGROUND_AGENTS"),
   OPENCODE_EXPERIMENTAL_MARKDOWN: !falsy("OPENCODE_EXPERIMENTAL_MARKDOWN"),
   OPENCODE_ENABLE_PARALLEL: truthy("OPENCODE_ENABLE_PARALLEL") || truthy("OPENCODE_EXPERIMENTAL_PARALLEL"),
   OPENCODE_MODELS_URL: process.env["OPENCODE_MODELS_URL"],

packages/opencode/src/cli/cmd/tui/routes/session/index.tsx

@@ -2028,7 +2028,9 @@ function Task(props: ToolProps<typeof TaskTool>) {
 
   const content = createMemo(() => {
     if (!props.input.description) return ""
-    let content = [`${Locale.titlecase(props.input.subagent_type ?? "General")} Task — ${props.input.description}`]
+    const description =
+      props.metadata.background === true ? `${props.input.description} (background)` : props.input.description
+    let content = [`${Locale.titlecase(props.input.subagent_type ?? "General")} Task — ${description}`]
 
     if (isRunning() && tools().length > 0) {
       // content[0] += ` · ${tools().length} toolcalls`
@@ -2040,7 +2042,11 @@ function Task(props: ToolProps<typeof TaskTool>) {
     }
 
     if (props.part.state.status === "completed") {
-      content.push(`└ ${tools().length} toolcalls · ${Locale.duration(duration())}`)
+      content.push(
+        props.metadata.background === true
+          ? `└ ${tools().length} toolcalls`
+          : `└ ${tools().length} toolcalls · ${Locale.duration(duration())}`,
+      )
     }
 
     return content.join("\n")

packages/opencode/src/session/prompt.ts

@@ -210,6 +210,7 @@ export const layer = Layer.effect(
         cancel: (sessionID: SessionID) => cancel(sessionID),
         resolvePromptParts: (template: string) => resolvePromptParts(template),
         prompt: (input: PromptInput) => prompt(input),
+        loop: (input: LoopInput) => loop(input),
       } satisfies TaskPromptOps
     })
 

packages/opencode/src/session/run-state.ts

@@ -1,5 +1,6 @@
 import { InstanceState } from "@/effect/instance-state"
 import { Runner } from "@/effect/runner"
+import { BackgroundJob } from "@/background/job"
 import { Effect, Latch, Layer, Scope, Context } from "effect"
 import * as Session from "./session"
 import { MessageV2 } from "./message-v2"
@@ -27,6 +28,7 @@ export class Service extends Context.Service<Service, Interface>()("@opencode/Se
 export const layer = Layer.effect(
   Service,
   Effect.gen(function* () {
+    const background = yield* BackgroundJob.Service
     const status = yield* SessionStatus.Service
 
     const state = yield* InstanceState.make(
@@ -75,6 +77,7 @@ export const layer = Layer.effect(
     })
 
     const cancel = Effect.fn("SessionRunState.cancel")(function* (sessionID: SessionID) {
+      yield* cancelBackgroundJobs(background, sessionID)
       const data = yield* InstanceState.get(state)
       const existing = data.runners.get(sessionID)
       if (!existing || !existing.busy) {
@@ -105,6 +108,40 @@ export const layer = Layer.effect(
   }),
 )
 
-export const defaultLayer = layer.pipe(Layer.provide(SessionStatus.defaultLayer))
+export const defaultLayer = layer.pipe(Layer.provide(BackgroundJob.defaultLayer), Layer.provide(SessionStatus.defaultLayer))
+
+const cancelBackgroundJobs = Effect.fn("SessionRunState.cancelBackgroundJobs")(function* (
+  background: BackgroundJob.Interface,
+  sessionID: SessionID,
+) {
+  const jobs = yield* background.list()
+  const pending = new Set<string>([sessionID])
+  const cancelled = new Set<string>()
+  const matches = (job: BackgroundJob.Info) => {
+    if (job.status !== "running") return false
+    if (cancelled.has(job.id)) return false
+    if (pending.has(job.id)) return true
+    if (typeof job.metadata?.sessionId === "string" && pending.has(job.metadata.sessionId)) return true
+    return typeof job.metadata?.parentSessionId === "string" && pending.has(job.metadata.parentSessionId)
+  }
+  let batch = jobs.filter(matches)
+  while (batch.length > 0) {
+    yield* Effect.forEach(
+      batch,
+      (job) =>
+        background.cancel(job.id).pipe(
+          Effect.tap(() =>
+            Effect.sync(() => {
+              cancelled.add(job.id)
+              pending.add(job.id)
+              if (typeof job.metadata?.sessionId === "string") pending.add(job.metadata.sessionId)
+            }),
+          ),
+        ),
+      { concurrency: "unbounded", discard: true },
+    )
+    batch = jobs.filter(matches)
+  }
+})
 
 export * as SessionRunState from "./run-state"

packages/opencode/src/session/session.ts

@@ -1,5 +1,6 @@
 import { Slug } from "@opencode-ai/core/util/slug"
 import path from "path"
+import { BackgroundJob } from "@/background/job"
 import { BusEvent } from "@/bus/bus-event"
 import { Bus } from "@/bus"
 import { Decimal } from "decimal.js"
@@ -503,9 +504,10 @@ export type Patch = Types.DeepMutable<SyncEvent.Event<typeof Event.Updated>["dat
 const db = <T>(fn: (d: Parameters<typeof Database.use>[0] extends (trx: infer D) => any ? D : never) => T) =>
   Effect.sync(() => Database.use(fn))
 
-export const layer: Layer.Layer<Service, never, Bus.Service | Storage.Service | SyncEvent.Service> = Layer.effect(
+export const layer: Layer.Layer<Service, never, BackgroundJob.Service | Bus.Service | Storage.Service | SyncEvent.Service> = Layer.effect(
   Service,
   Effect.gen(function* () {
+    const background = yield* BackgroundJob.Service
     const bus = yield* Bus.Service
     const storage = yield* Storage.Service
     const sync = yield* SyncEvent.Service
@@ -583,6 +585,7 @@ export const layer: Layer.Layer<Service, never, Bus.Service | Storage.Service |
     const remove: Interface["remove"] = Effect.fnUntraced(function* (sessionID: SessionID) {
       const session = yield* get(sessionID)
       try {
+        yield* cancelBackgroundJobs(background, sessionID)
         const kids = yield* children(sessionID)
         for (const child of kids) {
           yield* remove(child.id)
@@ -833,11 +836,29 @@ export const layer: Layer.Layer<Service, never, Bus.Service | Storage.Service |
 )
 
 export const defaultLayer = layer.pipe(
+  Layer.provide(BackgroundJob.defaultLayer),
   Layer.provide(Bus.layer),
   Layer.provide(Storage.defaultLayer),
   Layer.provide(SyncEvent.defaultLayer),
 )
 
+const cancelBackgroundJobs = Effect.fn("Session.cancelBackgroundJobs")(function* (
+  background: BackgroundJob.Interface,
+  sessionID: SessionID,
+) {
+  const jobs = yield* background.list()
+  yield* Effect.forEach(
+    jobs.filter((job) => {
+      if (job.status !== "running") return false
+      if (job.id === sessionID) return true
+      if (job.metadata?.sessionId === sessionID) return true
+      return job.metadata?.parentSessionId === sessionID
+    }),
+    (job) => background.cancel(job.id),
+    { concurrency: "unbounded", discard: true },
+  )
+})
+
 function* listByProject(
   input: ListInput & {
     projectID: ProjectID

packages/opencode/src/tool/registry.ts

@@ -7,6 +7,7 @@ import { GlobTool } from "./glob"
 import { GrepTool } from "./grep"
 import { ReadTool } from "./read"
 import { TaskTool } from "./task"
+import { TaskStatusTool } from "./task_status"
 import { TodoWriteTool } from "./todo"
 import { WebFetchTool } from "./webfetch"
 import { WriteTool } from "./write"
@@ -50,6 +51,8 @@ import { Git } from "@/git"
 import { Skill } from "../skill"
 import { Permission } from "@/permission"
 import { Reference } from "@/reference/reference"
+import { BackgroundJob } from "@/background/job"
+import { SessionStatus } from "@/session/status"
 
 const log = Log.create({ service: "tool.registry" })
 
@@ -89,6 +92,8 @@ export const layer: Layer.Layer<
   | Agent.Service
   | Skill.Service
   | Session.Service
+  | SessionStatus.Service
+  | BackgroundJob.Service
   | Provider.Service
   | Git.Service
   | Reference.Service
@@ -112,6 +117,7 @@ export const layer: Layer.Layer<
 
     const invalid = yield* InvalidTool
     const task = yield* TaskTool
+    const taskStatus = yield* TaskStatusTool
     const read = yield* ReadTool
     const question = yield* QuestionTool
     const todo = yield* TodoWriteTool
@@ -219,6 +225,7 @@ export const layer: Layer.Layer<
           edit: Tool.init(edit),
           write: Tool.init(writetool),
           task: Tool.init(task),
+          task_status: Tool.init(taskStatus),
           fetch: Tool.init(webfetch),
           todo: Tool.init(todo),
           search: Tool.init(websearch),
@@ -243,6 +250,7 @@ export const layer: Layer.Layer<
             tool.edit,
             tool.write,
             tool.task,
+            ...(Flag.OPENCODE_EXPERIMENTAL_BACKGROUND_AGENTS ? [tool.task_status] : []),
             tool.fetch,
             tool.todo,
             tool.search,
@@ -366,6 +374,7 @@ export const defaultLayer = Layer.suspend(() =>
     Layer.provide(Skill.defaultLayer),
     Layer.provide(Agent.defaultLayer),
     Layer.provide(Session.defaultLayer),
+    Layer.provide(Layer.mergeAll(SessionStatus.defaultLayer, BackgroundJob.defaultLayer)),
     Layer.provide(Provider.defaultLayer),
     Layer.provide(Git.defaultLayer),
     Layer.provide(Reference.defaultLayer),