Harness spec 2.0.0: background work is a job — commands and subagents alike, seen and steered

One registry per process, every job owned by a session: bash's background commands (and a command
still running at its timeout, which now goes to the background instead of being killed) and
subagents started with task background: true. job_list, job_output, job_stop (the former
bash_list, bash_output, bash_kill) and the new job_send and report; a finished job wakes the owning
session in every front end with its marked note. The TUI counts jobs, lists them (/jobs), opens a
command's output, enters a subagent and messages it, moves a command to the background (ctrl+b)
and asks before quitting with jobs running. The link gains the jobs capability. Subagents get a
session row of their own, the spec's preamble and agent texts, and their errors reach the report.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tests/headless-jobs.test.ts

@@ -0,0 +1,61 @@
+// `lembas run`: after the prompt the run waits for the jobs it started — their notes are turns of
+// their own — then stops what is left; --no-wait stops them at once (the spec's lifecycle: nobody
+// to ask). The terminal asker takes one question at a time.
+import { afterEach, expect, test } from "bun:test"
+import { mkdirSync, mkdtempSync, writeFileSync } from "node:fs"
+import { tmpdir } from "node:os"
+import { join } from "node:path"
+import { createApp } from "../src/app.ts"
+import type { AskReply } from "../src/bus/index.ts"
+import { paths } from "../src/config/paths.ts"
+import { settleJobs, terminalAsker } from "../src/headless.ts"
+import { MARKS } from "../src/jobs/note.ts"
+import { delta, fakeProvider, toolCall, type Fake } from "./fake-provider.ts"
+
+let fake: Fake | undefined
+afterEach(() => fake?.stop())
+
+function app(script: Parameters<typeof fakeProvider>[0]) {
+  fake = fakeProvider(script)
+  mkdirSync(paths.config, { recursive: true })
+  writeFileSync(join(paths.config, "connections.yaml"), `connections:\n  f:\n    dialect: openai-chat\n    base_url: ${fake.url}\n    models: { m: {} }\n`, { mode: 0o600 })
+  writeFileSync(join(paths.config, "config.yaml"), "model: f/m\n")
+  return createApp({ cwd: mkdtempSync(join(tmpdir(), "ph-hl-")), mode: "auto", store: false, snapshots: false, asker: { ask: async (): Promise<AskReply> => ({ kind: "once" }) } })
+}
+
+test("the run waits for the prompt's jobs and gets their notes as turns", async () => {
+  const a = app([
+    { chunks: [toolCall(0, "t1", "bash", JSON.stringify({ command: "sleep 0.4; echo late", background: true, description: "later" }))] },
+    { chunks: [delta({ content: "Running." })] },
+    { chunks: [delta({ content: "Seen late." })] },
+  ])
+  await a.turns.prompt("go")
+  expect(fake!.requests.length).toBe(2)
+  await settleJobs(a, true)
+  expect(fake!.requests.length).toBe(3)
+  expect(fake!.requests[2].messages.at(-1).content).toStartWith(MARKS.command)
+  expect(a.registry.running(a.jobsSessionId())).toEqual([])
+})
+
+test("--no-wait stops what runs instead", async () => {
+  const a = app([{ chunks: [toolCall(0, "t1", "bash", JSON.stringify({ command: "sleep 30", background: true, description: "server" }))] }, { chunks: [delta({ content: "Running." })] }])
+  await a.turns.prompt("go")
+  expect(a.registry.running(a.jobsSessionId())).toHaveLength(1)
+  await settleJobs(a, false)
+  const until = Date.now() + 3000
+  while (Date.now() < until && a.registry.running(a.jobsSessionId()).length) await Bun.sleep(20)
+  expect(a.registry.running(a.jobsSessionId())).toEqual([])
+  expect(fake!.requests.length).toBe(2)
+})
+
+test("the terminal asker answers one question at a time", async () => {
+  // --yes answers at once; the order of answers is the order of asks, not of whoever finished first.
+  const asker = terminalAsker({ yes: true })
+  const req = (n: string) => ({ tool: "bash", args: {}, request: { permission: "bash", class: "execute" as const, patterns: [n], command: n }, decision: { action: "ask" as const, reason: n, always: [] } })
+  const order: string[] = []
+  const a = asker.ask(req("one")).then((r) => (order.push("one"), r))
+  const b = asker.ask(req("two")).then((r) => (order.push("two"), r))
+  expect(await a).toEqual({ kind: "once" })
+  expect(await b).toEqual({ kind: "once" })
+  expect(order).toEqual(["one", "two"])
+})