import { afterEach, describe, expect, mock, spyOn, test } from "bun:test"
import fs from "fs/promises"
import path from "path"
import { pathToFileURL } from "node:url"
import {
  OpenCode,
  type EventSubscribeOutput,
  type FormInfo,
  type MessageListOutput,
  type OpenCodeClient,
  type PermissionRequest,
} from "@opencode-ai/client/promise"
import { createSessionTransport } from "../../src/mini/stream-v2.transport"
import type { StreamCommit } from "../../src/mini/types"
import { createFooterApiFixture } from "./fixture/footer-api"
import { canonicalToolPart } from "./fixture/tool-part"
import { tmpdir } from "../fixture/fixture"

type RunV2Event = EventSubscribeOutput

function feed() {
  const values: RunV2Event[] = []
  let closed = false
  let wake: (() => void) | undefined
  const stream = (async function* (): AsyncGenerator<RunV2Event, void, unknown> {
    while (!closed || values.length > 0) {
      if (values.length === 0) {
        await new Promise<void>((resolve) => {
          wake = resolve
        })
        continue
      }
      const value = values.shift()
      if (value) yield value
    }
  })()
  return {
    stream,
    push(value: RunV2Event) {
      values.push(value)
      wake?.()
      wake = undefined
    },
    close() {
      closed = true
      wake?.()
      wake = undefined
    },
  }
}

function ok<T>(data: T) {
  return Promise.resolve(data)
}

function defer<T = void>() {
  let resolve!: (value: T | PromiseLike<T>) => void
  const promise = new Promise<T>((done) => {
    resolve = done
  })
  return { promise, resolve }
}

function connected(id = "evt_connected") {
  return { id, type: "server.connected", data: {} } satisfies RunV2Event
}

function durable(sessionID: string, seq?: number): { aggregateID: string; seq: number; version: 1 }
function durable<const Version extends 1 | 2>(
  sessionID: string,
  seq: number,
  version: Version,
): { aggregateID: string; seq: number; version: Version }
function durable(sessionID: string, seq = 0, version: 1 | 2 = 1) {
  return { aggregateID: sessionID, seq, version }
}

function promptAdmission(input: Parameters<OpenCodeClient["session"]["prompt"]>[0], sessionID = "ses_1") {
  return {
    admittedSeq: 1,
    id: input.id ?? "msg_prompt",
    sessionID,
    type: "user" as const,
    data: {
      text: input.text,
      files: input.files,
      agents: input.agents,
      metadata: input.metadata,
    },
    delivery: input.delivery ?? ("steer" as const),
    timeCreated: 2,
  }
}

function footer() {
  return createFooterApiFixture()
}

type SessionMessages = MessageListOutput["data"]

function compaction(status: "running" | "completed", summary: string): SessionMessages[number] {
  const message = {
    id: "msg_compaction",
    type: "compaction" as const,
    reason: "auto" as const,
    summary,
    recent: "",
    time: { created: 1 },
  }
  if (status === "running") return { ...message, status }
  return { ...message, status }
}

function form(id: string, sessionID: string, title = id): FormInfo {
  return {
    id,
    sessionID,
    title,
    fields: [
      {
        key: "answer",
        type: "string",
        options: [{ value: "yes", label: "Yes" }],
        custom: true,
      },
    ],
  }
}

function eventForm(info: FormInfo): Extract<RunV2Event, { type: "form.created" }>["data"]["form"] {
  return info as Extract<RunV2Event, { type: "form.created" }>["data"]["form"]
}

function sdk(input: {
  streams: ReturnType<typeof feed>[]
  active?: () => Record<string, { type: "running" }>
  messages?: Record<string, SessionMessages>
  sessions?: Array<{ id: string; parentID?: string; title?: string; agent?: string; time: { updated: number } }>
  forms?: Record<string, FormInfo[]>
  globals?: FormInfo[]
  globalLocation?: { directory: string; workspaceID?: string }
  permissions?: Record<string, PermissionRequest[]>
  pending?: Record<string, Awaited<ReturnType<OpenCodeClient["session"]["pending"]["list"]>>>
  wait?: () => Promise<void>
}) {
  const client = OpenCode.make({ baseUrl: "https://opencode.test" })
  let subscription = 0
  spyOn(client.event, "subscribe").mockImplementation(() => input.streams[subscription++]?.stream ?? feed().stream)
  spyOn(client.message, "list").mockImplementation((request) =>
    ok({
      data: input.messages?.[request.sessionID] ?? [
        {
          id: "msg_old",
          type: "user" as const,
          text: "previous prompt",
          files: [],
          agents: [],
          time: { created: 1 },
        },
      ],
      cursor: {},
    }),
  )
  spyOn(client.permission, "list").mockImplementation((request) => ok(input.permissions?.[request.sessionID] ?? []))
  spyOn(client.form, "list").mockImplementation((request) => ok(input.forms?.[request.sessionID] ?? []))
  spyOn(client.form.request, "list").mockImplementation(() =>
    ok({
      location: {
        directory: input.globalLocation?.directory ?? "/tmp",
        workspaceID: input.globalLocation?.workspaceID,
        project: { id: "proj_1", directory: input.globalLocation?.directory ?? "/tmp" },
      },
      data: input.globals ?? [],
    }),
  )
  spyOn(client.session, "active").mockImplementation(() => ok(input.active?.() ?? {}))
  spyOn(client.session.pending, "list").mockImplementation((request) => ok(input.pending?.[request.sessionID] ?? []))
  spyOn(client.session, "wait").mockImplementation(() => input.wait?.() ?? ok(undefined))
  spyOn(client.session, "message").mockImplementation((request) => {
    const message = input.messages?.[request.sessionID]?.find((item) => item.id === request.messageID)
    return message ? (ok(message) as never) : Promise.reject(new Error(`message not found: ${request.messageID}`))
  })
  spyOn(client.session, "switchAgent").mockImplementation(() => ok(undefined))
  spyOn(client.session, "switchModel").mockImplementation(() => ok(undefined))
  // The generated methods have conditional return types for throwOnError; the
  // minimal shapes below are enough for family discovery and model fallback.
  spyOn(client.session, "list").mockImplementation((request) => {
    const parentID = request?.parentID
    return ok({
      location: { directory: "/tmp", project: { id: "proj_1", directory: "/tmp" } },
      data:
        input.sessions?.filter((session) =>
          parentID === undefined
            ? true
            : parentID === null
              ? session.parentID === undefined
              : session.parentID === parentID,
        ) ?? [],
    }) as never
  })
  spyOn(client.model, "default").mockImplementation(
    () =>
      ok({
        location: { directory: "/tmp", project: { id: "proj_1", directory: "/tmp" } },
        data: undefined,
      }) as never,
  )
  return client
}

afterEach(() => {
  mock.restore()
})

describe("V2 mini transport", () => {
  test("renders projected compactions as labeled transcript boundaries", async () => {
    const events = feed()
    events.push(connected())
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: sdk({
        streams: [events],
        messages: {
          ses_1: [compaction("completed", "## Transport")],
        },
      }),
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
    })

    expect(ui.commits).toMatchObject([
      { text: "Compaction", compaction: true, messageID: "msg_compaction" },
      { text: "## Transport", phase: "progress", messageID: "msg_compaction" },
      { text: "", phase: "final", messageID: "msg_compaction" },
    ])
    await transport.close()
  })

  test("shows an active compaction boundary before live summary output without history replay", async () => {
    const events = feed()
    events.push(connected())
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: sdk({
        streams: [events],
        active: () => ({ ses_1: { type: "running" } }),
        messages: {
          ses_1: [compaction("running", "")],
        },
      }),
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })

    events.push({
      id: "evt_compaction_delta",
      created: 2,
      type: "session.compaction.delta",
      data: { sessionID: "ses_1", text: "Transport" },
    })
    events.push({
      id: "evt_compaction_ended",
      created: 3,
      type: "session.compaction.ended",
      durable: durable("ses_1", 3),
      data: { sessionID: "ses_1", reason: "auto", text: "Transport", recent: "" },
    })

    while (!ui.commits.some((commit) => commit.phase === "final")) await Bun.sleep(0)
    expect(ui.commits).toMatchObject([
      { text: "Compaction", compaction: true, messageID: "msg_compaction" },
      { text: "Transport", phase: "progress", messageID: "msg_compaction" },
      { text: "", phase: "final", messageID: "msg_compaction" },
    ])
    await transport.close()
  })

  test("reports session title changes", async () => {
    const events = feed()
    events.push(connected())
    const titles: string[] = []
    const transport = await createSessionTransport({
      sdk: sdk({ streams: [events] }),
      sessionID: "ses_1",
      thinking: false,
      footer: footer().api,
      onSessionTitle: (title) => titles.push(title),
    })

    events.push({
      id: "evt_renamed",
      created: 1,
      type: "session.renamed",
      durable: durable("ses_1", 1),
      data: { sessionID: "ses_1", title: "Greeting" },
    })

    while (titles.length === 0) await Bun.sleep(0)
    expect(titles).toEqual(["Greeting"])
    await transport.close()
  })

  test("formats footer usage with compact tokens and context percentage", async () => {
    const events = feed()
    events.push(connected())
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: sdk({ streams: [events] }),
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
      contextLimit: (model) => (model.providerID === "test" && model.modelID === "model" ? 160_000 : undefined),
    })

    events.push({
      id: "evt_step_started",
      created: 1,
      type: "session.step.started",
      durable: durable("ses_1", 1),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        agent: "build",
        model: { providerID: "test", id: "model" },
      },
    })
    events.push({
      id: "evt_step_ended",
      created: 2,
      type: "session.step.ended",
      durable: durable("ses_1", 2),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        finish: "stop",
        cost: 0,
        tokens: { input: 7_000, output: 500, reasoning: 8, cache: { read: 0, write: 0 } },
      },
    })

    while (!ui.events.some((event) => event.type === "stream.patch" && event.patch.usage)) await Bun.sleep(0)
    expect(ui.events).toContainEqual({ type: "stream.patch", patch: { usage: "7.5K (5%)" } })
    await transport.close()
  })

  test("recursively hydrates blockers for direct and transitive descendants", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      sessions: [
        { id: "ses_child", parentID: "ses_1", title: "Child", time: { updated: 2 } },
        { id: "ses_grandchild", parentID: "ses_child", title: "Grandchild", time: { updated: 1 } },
      ],
      forms: {
        ses_child: [form("frm_child", "ses_child")],
        ses_grandchild: [form("frm_grandchild", "ses_grandchild")],
      },
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const snapshots = ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))

    expect(snapshots.at(-1)?.tabs.map((item) => item.sessionID)).toEqual(["ses_child", "ses_grandchild"])
    expect(snapshots.at(-1)?.forms.map((item) => item.id)).toEqual(["frm_child", "frm_grandchild"])
    expect(
      ui.events.find(
        (event) => event.type === "stream.view" && event.view.type === "form" && event.view.request.id === "frm_child",
      ),
    ).toMatchObject({
      type: "stream.view",
      view: { type: "form", request: { id: "frm_child", sessionID: "ses_child" } },
    })
    transport.settleForm?.("ses_child", "frm_child")
    expect(ui.events.at(-1)).toMatchObject({
      type: "stream.view",
      view: { type: "form", request: { id: "frm_grandchild", sessionID: "ses_grandchild" } },
    })
    await transport.close()
  })

  test("resolves a pre-existing child permission from its exact source message at startup", async () => {
    const events = feed()
    events.push(connected())
    const sourceMessage = {
      id: "msg_child_source",
      type: "assistant" as const,
      agent: "build",
      model: { providerID: "test", id: "model" },
      content: [
        canonicalToolPart(
          "shell",
          {
            status: "running" as const,
            input: { command: "git status --short" },
            metadata: {},
          },
          "call_child_source",
        ),
      ],
      time: { created: 1 },
    }
    const permission: PermissionRequest = {
      id: "per_child_startup",
      sessionID: "ses_child",
      action: "shell",
      resources: ["git status --short"],
      source: { type: "tool", messageID: "msg_child_source", callID: "call_child_source" },
    }
    const client = sdk({
      streams: [events],
      sessions: [{ id: "ses_child", parentID: "ses_1", title: "Child", time: { updated: 1 } }],
      permissions: { ses_child: [permission] },
      messages: {
        ses_child: [sourceMessage],
      },
    })
    const releaseSource = defer<void>()
    let sourceLookups = 0
    spyOn(client.session, "message").mockImplementation(async () => {
      sourceLookups++
      if (sourceLookups === 1) throw new Error("source temporarily unavailable")
      await releaseSource.promise
      return sourceMessage as never
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })

    while (sourceLookups < 2) await Bun.sleep(0)
    expect(
      ui.events.some(
        (event) =>
          event.type === "stream.view" && event.view.type === "permission" && event.view.request.id === permission.id,
      ),
    ).toBe(false)
    releaseSource.resolve()
    while (
      !ui.events.some(
        (event) =>
          event.type === "stream.view" && event.view.type === "permission" && event.view.request.id === permission.id,
      )
    )
      await Bun.sleep(0)

    expect(client.session.message).toHaveBeenCalledWith(
      { sessionID: "ses_child", messageID: "msg_child_source" },
      { signal: expect.any(AbortSignal) },
    )
    expect(
      ui.events.find(
        (event) =>
          event.type === "stream.view" && event.view.type === "permission" && event.view.request.id === permission.id,
      ),
    ).toMatchObject({
      view: {
        request: {
          tool: {
            id: "call_child_source",
            name: "shell",
            state: { status: "running", input: { command: "git status --short" } },
          },
        },
      },
    })
    expect(client.message.list).not.toHaveBeenCalledWith(
      expect.objectContaining({ sessionID: "ses_child" }),
      expect.anything(),
    )
    await transport.close()
  })

  test("reduces nested form owners idempotently and filters global events by complete location", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      sessions: [{ id: "ses_child", parentID: "ses_1", title: "Child", time: { updated: 1 } }],
      globalLocation: { directory: "/work", workspaceID: "wrk_1" },
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      location: { directory: "/work", workspaceID: "wrk_1" },
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const child = form("frm_child_live", "ses_child")
    events.push({ id: "evt_child_form", created: 1, type: "form.created", data: { form: eventForm(child) } })
    events.push({ id: "evt_child_form_retry", created: 2, type: "form.created", data: { form: eventForm(child) } })
    while (
      !ui.events.some(
        (event) => event.type === "stream.view" && event.view.type === "form" && event.view.request.id === child.id,
      )
    )
      await Bun.sleep(0)
    const childSnapshots = ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))
    expect(childSnapshots.at(-1)?.forms.filter((item) => item.id === child.id)).toHaveLength(1)

    events.push({
      id: "evt_child_form_done",
      created: 3,
      type: "form.replied",
      data: { id: child.id, sessionID: "ses_child", answer: { answer: "yes" } },
    })
    const global = form("frm_global_live", "global")
    events.push({
      id: "evt_global_wrong",
      created: 4,
      type: "form.created",
      location: { directory: "/work", workspaceID: "wrk_other" },
      data: { form: eventForm(global) },
    })
    await Bun.sleep(0)
    expect(
      ui.events.some(
        (event) => event.type === "stream.view" && event.view.type === "form" && event.view.request.id === global.id,
      ),
    ).toBe(false)
    events.push({
      id: "evt_global_right",
      created: 5,
      type: "form.created",
      location: { directory: "/work", workspaceID: "wrk_1" },
      data: { form: eventForm(global) },
    })
    while (
      !ui.events.some(
        (event) => event.type === "stream.view" && event.view.type === "form" && event.view.request.id === global.id,
      )
    )
      await Bun.sleep(0)
    expect(ui.events.at(-1)).toMatchObject({
      type: "stream.view",
      view: {
        type: "form",
        request: { id: "frm_global_live", location: { directory: "/work", workspaceID: "wrk_1" } },
      },
    })
    const beforeCancel = ui.events.filter((event) => event.type === "stream.view").length
    events.push({
      id: "evt_global_done",
      created: 6,
      type: "form.cancelled",
      location: { directory: "/work", workspaceID: "wrk_1" },
      data: { id: global.id, sessionID: "global" },
    })
    while (ui.events.filter((event) => event.type === "stream.view").length === beforeCancel) await Bun.sleep(0)
    expect(ui.events.filter((event) => event.type === "stream.view").at(-1)).toEqual({
      type: "stream.view",
      view: { type: "prompt" },
    })
    await transport.close()
  })

  test("waits authoritatively and reconciles the projected terminal suffix", async () => {
    const events = feed()
    events.push(connected())
    const settled = defer()
    const messages: SessionMessages = []
    const client = sdk({
      streams: [events],
      messages: { ses_1: messages },
      wait: () => settled.promise,
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })

    let admitted = false
    spyOn(client.session, "prompt").mockImplementation((request) => {
      admitted = true
      return ok({ data: promptAdmission(request) }) as never
    })

    const turn = transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: { messageID: "msg_prompt", text: "hello", parts: [] },
      files: [],
      includeFiles: true,
    })
    while (!admitted) await Bun.sleep(0)
    events.push({
      id: "evt_prompted",
      created: 0,
      type: "session.input.promoted",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        inputID: "msg_prompt",
      },
    })
    events.push({
      id: "evt_text",
      created: 0,
      type: "session.text.delta",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
        delta: "ans",
      },
    })
    events.push({
      id: "evt_settled",
      created: 0,
      type: "session.execution.succeeded",
      durable: durable("ses_1"),
      data: { sessionID: "ses_1" },
    })
    let done = false
    void turn.then(() => {
      done = true
    })
    await Bun.sleep(0)
    expect(done).toBe(false)
    messages.push(
      { id: "msg_prompt", type: "user", text: "hello", time: { created: 2 } },
      {
        id: "msg_assistant",
        type: "assistant",
        agent: "build",
        model: { providerID: "test", id: "model" },
        content: [{ type: "text", text: "answer" }],
        time: { created: 3, completed: 4 },
      },
    )
    settled.resolve()
    await turn

    expect(ui.commits.map((item) => item.text)).toEqual(["ans", "wer"])
    await transport.close()
  })

  test("shows durable pending delivery and appends queued input on promotion", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      pending: {
        ses_1: [
          {
            admittedSeq: 1,
            id: "msg_queued",
            sessionID: "ses_1",
            timeCreated: 1,
            type: "user",
            data: { text: "follow up" },
            delivery: "queue",
          },
        ],
      },
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const pending = () =>
      ui.events
        .findLast((item) => item.type === "queued.prompts")
        ?.prompts.map((item) => [item.messageID, item.delivery, item.admittedSeq])

    expect(pending()).toEqual([["msg_queued", "queue", 1]])
    events.push({
      id: "evt_promoted",
      created: 2,
      type: "session.input.promoted",
      durable: durable("ses_1", 2),
      data: { sessionID: "ses_1", inputID: "msg_queued" },
    })
    while (!ui.commits.some((item) => item.messageID === "msg_queued")) await Bun.sleep(0)

    expect(ui.commits).toContainEqual(
      expect.objectContaining({ kind: "user", messageID: "msg_queued", text: "follow up" }),
    )
    expect(pending()).toEqual([])
    const prompt = spyOn(client.session, "prompt").mockImplementation(
      (request) => ok({ ...promptAdmission(request), admittedSeq: 2 }) as never,
    )
    await transport.queuePromptTurn({
      agent: "review",
      model: undefined,
      variant: undefined,
      prompt: { messageID: "msg_next", text: "another", parts: [] },
      files: [],
      includeFiles: false,
    })
    expect(client.session.switchAgent).toHaveBeenCalledWith({ sessionID: "ses_1", agent: "review" }, expect.anything())
    expect(prompt).toHaveBeenCalledWith(expect.objectContaining({ delivery: "queue" }), expect.anything())
    events.push({
      id: "evt_earlier_admission",
      created: 3,
      type: "session.input.admitted",
      durable: durable("ses_1", 1),
      data: {
        sessionID: "ses_1",
        inputID: "msg_earlier",
        input: { type: "user", data: { text: "earlier" }, delivery: "steer" },
      },
    })
    while (true) {
      const pending = ui.events.findLast((item) => item.type === "queued.prompts")
      if (pending?.type === "queued.prompts" && pending.prompts.length >= 2) break
      await Bun.sleep(0)
    }
    expect(pending()).toEqual([
      ["msg_earlier", "steer", 1],
      ["msg_next", "queue", 2],
    ])
    await transport.close()
  })

  test("reports an observed execution failure before prompt promotion", async () => {
    const events = feed()
    events.push(connected())
    const idle = defer()
    const client = sdk({ streams: [events], messages: { ses_1: [] }, wait: () => idle.promise })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let admitted = false
    spyOn(client.session, "prompt").mockImplementation((request) => {
      admitted = true
      return ok(promptAdmission(request)) as never
    })

    const turn = transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: { messageID: "msg_prompt", text: "hello", parts: [] },
      files: [],
      includeFiles: false,
    })
    while (!admitted) await Bun.sleep(0)
    events.push({
      id: "evt_failed",
      created: 2,
      type: "session.execution.failed",
      durable: durable("ses_1", 2),
      data: { sessionID: "ses_1", error: { type: "unknown", message: "instructions unavailable" } },
    })
    await Bun.sleep(0)
    idle.resolve()

    await turn
    expect(ui.commits).toContainEqual(
      expect.objectContaining({ kind: "error", messageID: "msg_prompt", text: "instructions unavailable" }),
    )
    await transport.close()
  })

  test("attributes an execution-only failure to the latest promoted prompt", async () => {
    const events = feed()
    events.push(connected())
    const idle = defer()
    const messages: SessionMessages = []
    const client = sdk({ streams: [events], messages: { ses_1: messages }, wait: () => idle.promise })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let admitted = false
    spyOn(client.session, "prompt").mockImplementation((request) => {
      admitted = true
      return ok(promptAdmission(request)) as never
    })

    const turn = transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: { messageID: "msg_prompt", text: "hello", parts: [] },
      files: [],
      includeFiles: false,
    })
    while (!admitted) await Bun.sleep(0)
    events.push({
      id: "evt_prompt_promoted",
      created: 2,
      type: "session.input.promoted",
      durable: durable("ses_1", 2),
      data: { sessionID: "ses_1", inputID: "msg_prompt" },
    })
    await transport.queuePromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: { messageID: "msg_queued", text: "follow up", parts: [] },
      files: [],
      includeFiles: false,
    })
    events.push({
      id: "evt_queued_promoted",
      created: 3,
      type: "session.input.promoted",
      durable: durable("ses_1", 3),
      data: { sessionID: "ses_1", inputID: "msg_queued" },
    })
    events.push({
      id: "evt_failed",
      created: 4,
      type: "session.execution.failed",
      durable: durable("ses_1", 4),
      data: { sessionID: "ses_1", error: { type: "unknown", message: "model unavailable" } },
    })
    await Bun.sleep(0)
    messages.push(
      { id: "msg_prompt", type: "user", text: "hello", time: { created: 2 } },
      { id: "msg_queued", type: "user", text: "follow up", time: { created: 3 } },
    )
    idle.resolve()

    await turn
    expect(ui.commits).toContainEqual(
      expect.objectContaining({ kind: "error", messageID: "msg_queued", text: "model unavailable" }),
    )
    await transport.close()
  })

  test("sends local file and directory mentions as structured prompt files", async () => {
    await using tmp = await tmpdir()
    const filePath = path.join(tmp.path, "note.ts")
    const contextPath = path.join(tmp.path, "context.txt")
    const directoryPath = path.join(tmp.path, "docs")
    await Bun.write(filePath, "export const answer = 42\n")
    await Bun.write(contextPath, "context body")
    await fs.mkdir(directoryPath)
    await Bun.write(path.join(directoryPath, "README.md"), "# hello\n")

    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      readTextFile: (url) => fs.readFile(new URL(url), "utf8"),
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let request: Parameters<OpenCodeClient["session"]["prompt"]>[0] | undefined
    spyOn(client.session, "prompt").mockImplementation((input) => {
      request = input
      queueMicrotask(() => {
        events.push({
          id: "evt_prompted",
          created: 0,
          type: "session.input.promoted",
          durable: durable("ses_1"),
          data: {
            sessionID: "ses_1",
            inputID: "msg_prompt",
          },
        })
        events.push({
          id: "evt_settled",
          created: 0,
          type: "session.execution.succeeded",
          durable: durable("ses_1"),
          data: { sessionID: "ses_1" },
        })
      })
      return ok({ data: promptAdmission(input) }) as never
    })

    await transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: {
        messageID: "msg_prompt",
        text: "Review @note.ts and @docs",
        parts: [
          {
            type: "file",
            url: pathToFileURL(filePath).href,
            mime: "text/plain",
            filename: "note.ts",
            source: { type: "file", path: "note.ts", text: { start: 7, end: 15, value: "@note.ts" } },
          },
          {
            type: "file",
            url: pathToFileURL(`${directoryPath}${path.sep}`).href,
            mime: "application/x-directory",
            filename: "docs",
            source: { type: "file", path: "docs/", text: { start: 20, end: 25, value: "@docs" } },
          },
        ],
      },
      files: [
        { type: "file", url: pathToFileURL(contextPath).href, filename: "context.txt", mime: "text/plain" },
        { type: "file", url: "file:///tmp/image.png", filename: "image.png", mime: "image/png" },
      ],
      includeFiles: true,
    })

    expect(request?.text).toBe('Review @note.ts and @docs\n\n<file name="context.txt">\ncontext body\n</file>')
    expect(request?.files).toEqual([
      { uri: "file:///tmp/image.png", name: "image.png" },
      {
        uri: pathToFileURL(filePath).href,
        name: "note.ts",
        mention: { start: 7, end: 15, text: "@note.ts" },
      },
      {
        uri: pathToFileURL(`${directoryPath}${path.sep}`).href,
        name: "docs",
        mention: { start: 20, end: 25, text: "@docs" },
      },
    ])
    await transport.close()
  })

  test("sends attached file mentions as structured prompt files without reading them", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const remoteRead = spyOn(client.file, "read")
    const remoteList = spyOn(client.file, "list")
    const transport = await createSessionTransport({
      sdk: client,
      location: { directory: "/remote/project" },
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let request: Parameters<OpenCodeClient["session"]["prompt"]>[0] | undefined
    // The generated method has conditional return types for throwOnError; this mock represents the successful branch.
    // @ts-expect-error successful SDK response is valid for both modes at runtime
    spyOn(client.session, "prompt").mockImplementation((input) => {
      request = input
      queueMicrotask(() => {
        events.push({
          id: "evt_prompted",
          created: 0,
          type: "session.input.promoted",
          durable: durable("ses_1"),
          data: {
            sessionID: "ses_1",
            inputID: "msg_prompt",
          },
        })
        events.push({
          id: "evt_settled",
          created: 0,
          type: "session.execution.succeeded",
          durable: durable("ses_1"),
          data: { sessionID: "ses_1" },
        })
      })
      return ok({ data: promptAdmission(input) })
    })

    await transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: {
        messageID: "msg_prompt",
        text: "Review @note.ts and @docs",
        parts: [
          {
            type: "file",
            url: "file:///remote/project/note.ts",
            mime: "text/plain",
            filename: "note.ts",
            source: { type: "file", path: "note.ts", text: { start: 7, end: 15, value: "@note.ts" } },
          },
          {
            type: "file",
            url: "file:///remote/project/docs",
            mime: "application/x-directory",
            filename: "docs",
            source: { type: "file", path: "docs", text: { start: 20, end: 25, value: "@docs" } },
          },
        ],
      },
      files: [],
      includeFiles: true,
    })

    expect(remoteRead).not.toHaveBeenCalled()
    expect(remoteList).not.toHaveBeenCalled()
    expect(request?.text).toBe("Review @note.ts and @docs")
    expect(request?.files).toEqual([
      {
        uri: "file:///remote/project/note.ts",
        name: "note.ts",
        mention: { start: 7, end: 15, text: "@note.ts" },
      },
      {
        uri: "file:///remote/project/docs",
        name: "docs",
        mention: { start: 20, end: 25, text: "@docs" },
      },
    ])
    await transport.close()
  })

  test("sends local media mentions as structured prompt files", async () => {
    await using tmp = await tmpdir()
    const filePath = path.join(tmp.path, "diagram.png")
    await Bun.write(filePath, Uint8Array.of(0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00))

    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let request: Parameters<OpenCodeClient["session"]["prompt"]>[0] | undefined
    // The generated method has conditional return types for throwOnError; this mock represents the successful branch.
    // @ts-expect-error successful SDK response is valid for both modes at runtime
    spyOn(client.session, "prompt").mockImplementation((input) => {
      request = input
      queueMicrotask(() => {
        events.push({
          id: "evt_prompted",
          created: 0,
          type: "session.input.promoted",
          durable: durable("ses_1"),
          data: {
            sessionID: "ses_1",
            inputID: "msg_prompt",
          },
        })
        events.push({
          id: "evt_settled",
          created: 0,
          type: "session.execution.succeeded",
          durable: durable("ses_1"),
          data: { sessionID: "ses_1" },
        })
      })
      return ok({ data: promptAdmission(input) })
    })

    await transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: {
        messageID: "msg_prompt",
        text: "Review @diagram.png",
        parts: [
          {
            type: "file",
            url: pathToFileURL(filePath).href,
            mime: "text/plain",
            filename: "diagram.png",
            source: { type: "file", path: "diagram.png", text: { start: 7, end: 19, value: "@diagram.png" } },
          },
        ],
      },
      files: [],
      includeFiles: true,
    })

    expect(request?.text).toBe("Review @diagram.png")
    expect(request?.files).toEqual([
      {
        name: "diagram.png",
        uri: pathToFileURL(filePath).href,
        mention: { start: 7, end: 19, text: "@diagram.png" },
      },
    ])
    await transport.close()
  })

  test("shows V2 blockers and replies through the runtime-owned session API", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    events.push({
      id: "evt_permission",
      created: 0,
      type: "permission.asked",
      data: { id: "per_1", sessionID: "ses_1", action: "read", resources: ["/tmp/file"] },
    })

    await Bun.sleep(0)
    expect(ui.events).toContainEqual({
      type: "stream.view",
      view: {
        type: "permission",
        request: {
          id: "per_1",
          sessionID: "ses_1",
          action: "read",
          resources: ["/tmp/file"],
        },
      },
    })
    await transport.close()
  })

  test("reconnects and hydrates without completing before session.wait", async () => {
    const first = feed()
    const second = feed()
    first.push(connected("evt_connected_1"))
    second.push(connected("evt_connected_2"))
    const idle = defer()
    let running = true
    const client = sdk({
      streams: [first, second],
      active: () => {
        const active: Record<string, { type: "running" }> = {}
        if (running) active.ses_1 = { type: "running" }
        return active
      },
      wait: () => idle.promise,
    })
    let projected = false
    spyOn(client.message, "list").mockImplementation(() =>
      ok({
        data: projected
          ? [
              {
                id: "msg_prompt",
                type: "user",
                text: "hello",
                files: [],
                agents: [],
                time: { created: 2 },
              },
            ]
          : [],
        cursor: {},
      }),
    )
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let admitted = false
    // The generated method has conditional return types for throwOnError; this mock represents the successful branch.
    // @ts-expect-error successful SDK response is valid for both modes at runtime
    spyOn(client.session, "prompt").mockImplementation((request) => {
      admitted = true
      return ok({ data: promptAdmission(request) })
    })

    const turn = transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: { messageID: "msg_prompt", text: "hello", parts: [] },
      files: [],
      includeFiles: true,
    })
    while (!admitted) await Bun.sleep(0)
    projected = true
    running = false
    second.push({
      id: "evt_prior_failed",
      created: 1,
      type: "session.execution.failed",
      durable: durable("ses_1", 1),
      data: { sessionID: "ses_1", error: { type: "unknown", message: "prior execution failed" } },
    })
    second.push({
      id: "evt_prompted",
      created: 2,
      type: "session.input.promoted",
      durable: durable("ses_1", 2),
      data: { sessionID: "ses_1", inputID: "msg_prompt" },
    })
    first.close()
    while (!ui.events.some((event) => event.type === "stream.patch" && event.patch.status === "reconnecting"))
      await Bun.sleep(0)
    idle.resolve()
    await turn
    await transport.close()
  })

  test("does not duplicate the optimistic user row when reconnect hydration recovers a missed prompt", async () => {
    const first = feed()
    const second = feed()
    first.push(connected("evt_connected_1"))
    second.push(connected("evt_connected_2"))
    let running = true
    let projected = false
    const client = sdk({
      streams: [first, second],
      active: () => {
        const active: Record<string, { type: "running" }> = {}
        if (running) active.ses_1 = { type: "running" }
        return active
      },
    })
    spyOn(client.message, "list").mockImplementation(() =>
      ok({
        data: projected
          ? [
              {
                id: "msg_prompt",
                type: "user",
                text: "hello",
                files: [],
                agents: [],
                time: { created: 2 },
              },
            ]
          : [],
        cursor: {},
      }),
    )
    const ui = footer()
    ui.commits.push({ kind: "user", source: "system", text: "hello", phase: "start", messageID: "msg_prompt" })
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let admitted = false
    // The generated method has conditional return types for throwOnError; this mock represents the successful branch.
    // @ts-expect-error successful SDK response is valid for both modes at runtime
    spyOn(client.session, "prompt").mockImplementation((request) => {
      admitted = true
      return ok({ data: promptAdmission(request) })
    })

    const turn = transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: { messageID: "msg_prompt", text: "hello", parts: [] },
      files: [],
      includeFiles: true,
    })
    while (!admitted) await Bun.sleep(0)
    projected = true
    running = false
    first.close()
    await turn

    expect(ui.commits.filter((item) => item.kind === "user" && item.messageID === "msg_prompt")).toHaveLength(1)
    await transport.close()
  })

  test("replaces the client for buffered hydration, descendants, turns, and interrupts", async () => {
    const firstEvents = feed()
    const secondEvents = feed()
    firstEvents.push(connected("evt_connected_1"))
    secondEvents.push(connected("evt_connected_2"))
    const first = sdk({ streams: [firstEvents] })
    const second = sdk({
      streams: [secondEvents],
      sessions: [{ id: "ses_child", parentID: "ses_1", title: "Child", time: { updated: 2 } }],
      forms: { ses_child: [form("frm_child", "ses_child")] },
    })
    const firstPrompt = spyOn(first.session, "prompt")
    const firstInterrupt = spyOn(first.session, "interrupt")
    spyOn(first.message, "list").mockImplementation(() =>
      ok({
        data: [
          {
            id: "msg_assistant",
            type: "assistant",
            agent: "build",
            model: { providerID: "test", id: "model" },
            content: [{ type: "text", text: "partial" }],
            time: { created: 1 },
          },
        ],
        cursor: {},
      }),
    )
    let releaseHydration!: () => void
    let replacementHydrating = false
    const hydration = new Promise<void>((resolve) => {
      releaseHydration = resolve
    })
    let releaseCatalog!: () => void
    let refreshes = 0
    const catalog = new Promise<void>((resolve) => {
      releaseCatalog = resolve
    })
    spyOn(second.message, "list").mockImplementation(async (request) => {
      if (request.sessionID !== "ses_1") return ok({ data: [], cursor: {} })
      replacementHydrating = true
      await hydration
      return ok({
        data: [
          {
            id: "msg_assistant",
            type: "assistant",
            agent: "build",
            model: { providerID: "test", id: "model" },
            content: [{ type: "text", text: "partial replacement" }],
            time: { created: 1 },
          },
        ],
        cursor: {},
      })
    })
    const current: OpenCodeClient[] = []
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: first,
      reconnect: async () => second,
      onClient: (client) => current.push(client),
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
      onCatalogRefresh: () => {
        refreshes++
        if (refreshes === 2) return catalog
      },
    })

    firstEvents.close()
    while (!replacementHydrating) await Bun.sleep(0)
    await expect(
      transport.runPromptTurn({
        agent: undefined,
        model: undefined,
        variant: undefined,
        prompt: { messageID: "msg_blocked", text: "blocked", parts: [] },
        files: [],
        includeFiles: true,
      }),
    ).rejects.toThrow("Event stream is reconnecting")
    secondEvents.push({
      id: "evt_buffered_text",
      created: 2,
      type: "session.text.delta",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
        delta: " replacement",
      },
    })
    let resized = false
    const resize = transport.replayOnResize({
      localRows: () => [],
      reset: async () => {
        resized = true
      },
    })
    releaseHydration()
    while (
      !ui.events.some(
        (event) => event.type === "stream.view" && event.view.type === "form" && event.view.request.id === "frm_child",
      )
    )
      await Bun.sleep(0)
    while (refreshes < 2) await Bun.sleep(0)
    await resize
    expect(resized).toBe(false)
    await expect(
      transport.runPromptTurn({
        agent: undefined,
        model: undefined,
        variant: undefined,
        prompt: { messageID: "msg_catalog_blocked", text: "blocked", parts: [] },
        files: [],
        includeFiles: true,
      }),
    ).rejects.toThrow("Event stream is reconnecting")
    releaseCatalog()
    await Bun.sleep(0)

    expect(current).toEqual([second])
    expect(first.event.subscribe).toHaveBeenCalledTimes(1)
    expect(second.event.subscribe).toHaveBeenCalledTimes(1)
    expect(second.session.list).toHaveBeenCalled()
    expect(second.form.list).toHaveBeenCalledWith({ sessionID: "ses_child" }, { signal: expect.any(AbortSignal) })
    expect(ui.commits.filter((commit) => commit.messageID === "msg_assistant").map((commit) => commit.text)).toEqual([
      "partial",
      " replacement",
    ])

    const prompt = spyOn(second.session, "prompt").mockImplementation((request) => {
      queueMicrotask(() => {
        secondEvents.push({
          id: "evt_replacement_prompt",
          created: 3,
          type: "session.input.promoted",
          durable: durable("ses_1", 1),
          data: { sessionID: "ses_1", inputID: "msg_replacement" },
        })
        secondEvents.push({
          id: "evt_replacement_settled",
          created: 4,
          type: "session.execution.succeeded",
          durable: durable("ses_1", 2),
          data: { sessionID: "ses_1" },
        })
      })
      return ok({ data: promptAdmission(request) }) as never
    })
    await transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: { messageID: "msg_replacement", text: "replacement prompt", parts: [] },
      files: [],
      includeFiles: true,
    })
    const interrupt = spyOn(second.session, "interrupt").mockImplementation(() => ok(undefined))
    await transport.interruptActiveTurn()

    expect(prompt).toHaveBeenCalled()
    expect(interrupt).toHaveBeenCalledWith({ sessionID: "ses_1" })
    expect(firstPrompt).not.toHaveBeenCalled()
    expect(firstInterrupt).not.toHaveBeenCalled()
    await transport.close()
  })

  test("reconciles buffered deltas already present in a resize snapshot", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
    })
    spyOn(client.message, "list").mockImplementation(() =>
      ok({
        data: [
          {
            id: "msg_assistant",
            type: "assistant",
            agent: "build",
            model: { providerID: "test", id: "model" },
            content: [{ type: "text", text: "the answer" }],
            time: { created: 2, completed: 3 },
          },
        ],
        cursor: {},
      }),
    )
    let reset!: () => void
    const resetting = new Promise<void>((resolve) => {
      reset = resolve
    })
    const replay = transport.replayOnResize({ localRows: () => [], reset: () => resetting })
    events.push({
      id: "evt_text_started",
      created: 0,
      type: "session.text.started",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
      },
    })
    events.push({
      id: "evt_text",
      created: 0,
      type: "session.text.delta",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
        delta: "answer",
      },
    })
    await Bun.sleep(0)
    reset()
    await replay

    expect(ui.commits.filter((item) => item.text === "the answer")).toHaveLength(1)
    expect(ui.commits.some((item) => item.text === "answer")).toBe(false)
    await transport.close()
  })

  test("replays live assistant text missing from the resize projection", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    spyOn(client.message, "list").mockImplementation(() =>
      ok({
        data: [
          {
            id: "msg_assistant",
            type: "assistant",
            agent: "build",
            model: { providerID: "test", id: "model" },
            content: [{ type: "text", text: "partial" }],
            time: { created: 2, completed: 3 },
          },
        ],
        cursor: {},
      }),
    )
    const ui = footer()
    const live: StreamCommit[] = []
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
      onCommit: (commit) => live.push(commit),
    })
    events.push({
      id: "evt_text",
      created: 0,
      type: "session.text.delta",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
        delta: " suffix",
      },
    })
    await Bun.sleep(0)
    expect(live.map((commit) => commit.text)).toEqual(["partial suffix"])

    await transport.replayOnResize({
      localRows: () => [
        { commit: live[0]! },
        {
          commit: {
            ...live[0]!,
            partID: "text:1",
            text: "entirely local",
          },
        },
      ],
      reset: async () => {},
    })

    expect(ui.commits.filter((commit) => commit.messageID === "msg_assistant").map((commit) => commit.text)).toEqual([
      "partial",
      " suffix",
      "partial",
      " suffix",
      "entirely local",
    ])
    await transport.close()
  })

  test("does not replay a resize-buffered suffix twice", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    spyOn(client.message, "list").mockImplementation(() =>
      ok({
        data: [
          {
            id: "msg_assistant",
            type: "assistant",
            agent: "build",
            model: { providerID: "test", id: "model" },
            content: [{ type: "text", text: "partial" }],
            time: { created: 2, completed: 3 },
          },
        ],
        cursor: {},
      }),
    )
    const ui = footer()
    const live: StreamCommit[] = []
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
      onCommit: (commit) => live.push(commit),
    })
    let reset!: () => void
    const resetting = new Promise<void>((resolve) => {
      reset = resolve
    })
    const replay = transport.replayOnResize({
      localRows: () => live.map((commit) => ({ commit })),
      reset: () => resetting,
    })
    events.push({
      id: "evt_text",
      created: 0,
      type: "session.text.delta",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
        delta: " suffix",
      },
    })
    await Bun.sleep(0)
    reset()
    await replay

    expect(ui.commits.filter((commit) => commit.messageID === "msg_assistant").map((commit) => commit.text)).toEqual([
      "partial",
      "partial",
      " suffix",
    ])
    expect(live.map((commit) => commit.text)).toEqual(["partial suffix"])
    await transport.close()
  })

  test("preserves active text and reasoning across resize before terminal projection", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    spyOn(client.message, "list").mockImplementation(() => ok({ data: [], cursor: {} }))
    const ui = footer()
    const live: StreamCommit[] = []
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: true,
      replay: true,
      footer: ui.api,
      onCommit: (commit) => live.push(commit),
    })
    events.push({
      id: "evt_text",
      created: 0,
      type: "session.text.delta",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
        delta: "hello",
      },
    })
    events.push({
      id: "evt_reasoning",
      created: 0,
      type: "session.reasoning.delta",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
        delta: "thought",
      },
    })
    await Bun.sleep(0)
    expect(live.map((commit) => commit.text)).toEqual(["hello", "Thinking: thought"])

    await transport.replayOnResize({
      localRows: () => live.map((commit) => ({ commit })),
      reset: async () => {},
    })

    expect(ui.commits.slice(-2).map((commit) => commit.text)).toEqual(["hello", "Thinking: thought"])
    await transport.close()
  })

  test("serializes and coalesces overlapping resize replays", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
    })
    let release!: () => void
    const blocked = new Promise<void>((resolve) => {
      release = resolve
    })
    const order: string[] = []
    const first = transport.replayOnResize({
      localRows: () => [],
      reset: async () => {
        order.push("first:start")
        await blocked
        order.push("first:end")
      },
    })
    await Bun.sleep(0)
    const second = transport.replayOnResize({
      localRows: () => [],
      reset: async () => {
        order.push("second")
      },
    })
    release()
    await Promise.all([first, second])

    expect(second).toBe(first)
    expect(order).toEqual(["first:start", "first:end", "second"])
    await transport.close()
  })

  test("restores local output and drains buffered events when resize hydration fails", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const live: StreamCommit[] = []
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
      onCommit: (commit) => live.push(commit),
    })
    events.push({
      id: "evt_text_1",
      created: 0,
      type: "session.text.delta",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
        delta: "hello",
      },
    })
    await Bun.sleep(0)
    spyOn(client.message, "list").mockImplementation(() => Promise.reject(new Error("projection failed")))

    const replay = transport.replayOnResize({
      localRows: () => live.map((commit) => ({ commit })),
      reset: async () => {},
    })
    events.push({
      id: "evt_text_2",
      created: 0,
      type: "session.text.delta",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
        delta: " world",
      },
    })
    await expect(replay).rejects.toThrow("projection failed")

    expect(ui.commits.slice(-2).map((commit) => commit.text)).toEqual(["hello", " world"])
    expect(live.at(-1)?.text).toBe("hello world")
    await transport.close()
  })

  test("dedupes a projected step failure from live redelivery", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    spyOn(client.message, "list").mockImplementation(() =>
      ok({
        data: [
          {
            id: "msg_assistant",
            type: "assistant",
            agent: "build",
            model: { providerID: "test", id: "model" },
            content: [],
            error: { type: "provider.transport", message: "provider failed" },
            time: { created: 2, completed: 3 },
          },
        ],
        cursor: {},
      }),
    )
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
    })
    events.push({
      id: "evt_step_failed",
      created: 2,
      type: "session.step.failed",
      durable: durable("ses_1", 1),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        error: { type: "provider.transport", message: "provider failed" },
      },
    })
    await Bun.sleep(0)

    expect(ui.commits.filter((commit) => commit.kind === "error" && commit.text === "provider failed")).toHaveLength(1)
    await transport.close()
  })

  test("dedupes a retained live step failure from resize projection", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const live: StreamCommit[] = []
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
      onCommit: (commit) => live.push(commit),
    })
    events.push({
      id: "evt_step_failed",
      created: 2,
      type: "session.step.failed",
      durable: durable("ses_1", 1),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        error: { type: "provider.transport", message: "provider failed" },
      },
    })
    await Bun.sleep(0)
    expect(live[0]?.messageID).toBe("msg_assistant")
    spyOn(client.message, "list").mockImplementation(() =>
      ok({
        data: [
          {
            id: "msg_assistant",
            type: "assistant",
            agent: "build",
            model: { providerID: "test", id: "model" },
            content: [],
            error: { type: "provider.transport", message: "provider failed" },
            time: { created: 2, completed: 3 },
          },
        ],
        cursor: {},
      }),
    )

    await transport.replayOnResize({
      localRows: () => live.map((commit) => ({ commit })),
      reset: async () => {},
    })

    expect(ui.commits.filter((commit) => commit.kind === "error" && commit.text === "provider failed")).toHaveLength(2)
    await transport.close()
  })

  test("preserves an execution-only local error beside its projected prompt", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
    })
    spyOn(client.message, "list").mockImplementation(() =>
      ok({
        data: [
          {
            id: "msg_prompt",
            type: "user",
            text: "hello",
            files: [],
            agents: [],
            time: { created: 2 },
          },
        ],
        cursor: {},
      }),
    )

    await transport.replayOnResize({
      localRows: () => [
        {
          commit: {
            kind: "error",
            source: "system",
            text: "model unavailable",
            phase: "start",
            messageID: "msg_prompt",
          },
        },
      ],
      reset: async () => {},
    })

    expect(ui.commits.some((commit) => commit.kind === "error" && commit.text === "model unavailable")).toBe(true)
    await transport.close()
  })

  test("scopes text and reasoning ordinals by assistant message", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    spyOn(client.message, "list").mockImplementation(() =>
      ok({
        data: [
          {
            id: "msg_b",
            type: "assistant",
            agent: "build",
            model: { providerID: "test", id: "model" },
            content: [
              { type: "reasoning", text: "second thought" },
              { type: "text", text: "second answer" },
            ],
            time: { created: 4, completed: 5 },
          },
          {
            id: "msg_a",
            type: "assistant",
            agent: "build",
            model: { providerID: "test", id: "model" },
            content: [
              { type: "reasoning", text: "first thought" },
              { type: "text", text: "first answer" },
            ],
            time: { created: 2, completed: 3 },
          },
        ],
        cursor: {},
      }),
    )

    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: true,
      replay: true,
      footer: ui.api,
    })

    expect(ui.commits.map((item) => item.text)).toEqual([
      "Thinking: first thought",
      "first answer",
      "Thinking: second thought",
      "second answer",
    ])
    await transport.close()
  })

  test("renders full reasoning when only the ended event is observed", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: true,
      footer: ui.api,
    })
    events.push({
      id: "evt_reasoning",
      created: 0,
      type: "session.reasoning.ended",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_assistant",
        ordinal: 0,
        text: "considering",
      },
    })
    await Bun.sleep(0)

    expect(ui.commits.at(-1)?.text).toBe("Thinking: considering")
    await transport.close()
  })

  test("tracks repeated root call IDs independently across assistant messages", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })

    for (const [index, messageID] of ["msg_tool_one", "msg_tool_two"].entries()) {
      events.push({
        id: `evt_repeated_input_${index}`,
        created: index * 3 + 1,
        type: "session.tool.input.started",
        durable: durable("ses_1", index * 3),
        data: { sessionID: "ses_1", assistantMessageID: messageID, callID: "call_repeated", name: "read" },
      })
      events.push({
        id: `evt_repeated_called_${index}`,
        created: index * 3 + 2,
        type: "session.tool.called",
        durable: durable("ses_1", index * 3 + 1),
        data: {
          sessionID: "ses_1",
          assistantMessageID: messageID,
          callID: "call_repeated",
          input: { path: `${index + 1}.txt` },
          executed: true,
        },
      })
      events.push({
        id: `evt_repeated_success_${index}`,
        created: index * 3 + 3,
        type: "session.tool.success",
        durable: durable("ses_1", index * 3 + 2, 2),
        data: {
          sessionID: "ses_1",
          assistantMessageID: messageID,
          callID: "call_repeated",
          metadata: {},
          content: [{ type: "text", text: "" }],
          executed: true,
        },
      })
    }
    await Bun.sleep(0)

    const commits = ui.commits.filter((item) => item.part?.id === "call_repeated")
    expect(commits.map((item) => [item.messageID, item.phase])).toEqual([
      ["msg_tool_one", "start"],
      ["msg_tool_one", "final"],
      ["msg_tool_two", "start"],
      ["msg_tool_two", "final"],
    ])
    expect(
      commits
        .filter((item) => item.phase === "final")
        .map((item) => (item.part?.state.status === "streaming" ? undefined : item.part?.state.input)),
    ).toEqual([{ path: "1.txt" }, { path: "2.txt" }])
    await transport.close()
  })

  test("reduces root tool progress and preserves it on failure", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    events.push({
      id: "evt_progress_input",
      created: 1,
      type: "session.tool.input.started",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_progress",
        callID: "call_progress",
        name: "shell",
      },
    })
    events.push({
      id: "evt_progress_called",
      created: 2,
      type: "session.tool.called",
      durable: durable("ses_1", 1),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_progress",
        callID: "call_progress",
        input: { command: "printf partial && false" },
        executed: true,
      },
    })
    events.push({
      id: "evt_progress",
      created: 3,
      type: "session.tool.progress",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_progress",
        callID: "call_progress",
        metadata: { checkpoint: 1 },
      },
    })
    events.push({
      id: "evt_progress_failed",
      created: 4,
      type: "session.tool.failed",
      durable: durable("ses_1", 3, 2),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_progress",
        callID: "call_progress",
        error: { type: "unknown", message: "boom" },
        metadata: { checkpoint: 1 },
        content: [{ type: "text", text: "partial" }],
        executed: true,
      },
    })
    await Bun.sleep(0)

    const commits = ui.commits.filter((item) => item.part?.id === "call_progress")
    expect(commits.map((item) => [item.phase, item.text, item.toolState])).toEqual([
      ["start", "running shell", "running"],
      ["progress", "partial", "running"],
      ["final", "boom", "error"],
    ])
    expect(commits.at(-1)?.part?.state).toMatchObject({
      status: "error",
      metadata: { checkpoint: 1 },
      content: [{ type: "text", text: "partial" }],
    })
    await transport.close()
  })

  test("falls back to the default model when selecting a variant on a fresh session", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      location: { directory: "/project", workspaceID: "wrk_1" },
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    spyOn(client.session, "get").mockImplementation(() => ok({ model: undefined }) as never)
    const defaultModel = spyOn(client.model, "default").mockImplementation(
      () =>
        ok({
          location: { directory: "/tmp", project: { id: "proj_1", directory: "/tmp" } },
          data: { id: "gpt-5", providerID: "openai" },
        }) as never,
    )
    const switched = spyOn(client.session, "switchModel").mockImplementation(() => ok(undefined))
    let admitted = false
    // The generated method has conditional return types for throwOnError; this mock represents the successful branch.
    // @ts-expect-error successful SDK response is valid for both modes at runtime
    spyOn(client.session, "prompt").mockImplementation((request) => {
      admitted = true
      return ok({ data: promptAdmission(request) })
    })

    const turn = transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: "high",
      prompt: { messageID: "msg_prompt", text: "hello", parts: [] },
      files: [],
      includeFiles: true,
    })
    while (!admitted) await Bun.sleep(0)
    events.push({
      id: "evt_prompted",
      created: 0,
      type: "session.input.promoted",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        inputID: "msg_prompt",
      },
    })
    events.push({
      id: "evt_settled",
      created: 0,
      type: "session.execution.succeeded",
      durable: durable("ses_1"),
      data: { sessionID: "ses_1" },
    })
    await turn

    expect(switched).toHaveBeenCalledWith(
      { sessionID: "ses_1", model: { providerID: "openai", id: "gpt-5", variant: "high" } },
      { signal: undefined },
    )
    expect(defaultModel).toHaveBeenCalledWith(
      { location: { directory: "/project", workspace: "wrk_1" } },
      { signal: undefined },
    )
    await transport.close()
  })

  test("interrupts the current Session when an active turn is aborted", async () => {
    const events = feed()
    events.push(connected())
    const idle = defer()
    const client = sdk({ streams: [events], wait: () => idle.promise })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let admitted = false
    // The generated method has conditional return types for throwOnError; this mock represents the successful branch.
    // @ts-expect-error successful SDK response is valid for both modes at runtime
    spyOn(client.session, "prompt").mockImplementation((request) => {
      admitted = true
      return ok({ data: promptAdmission(request) })
    })
    const interrupted = spyOn(client.session, "interrupt").mockImplementation(() => ok(undefined))
    const controller = new AbortController()
    const turn = transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: { messageID: "msg_prompt", text: "hello", parts: [] },
      files: [],
      includeFiles: true,
      signal: controller.signal,
    })
    while (!admitted) await Bun.sleep(0)
    events.push({
      id: "evt_prompted",
      created: 0,
      type: "session.input.promoted",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        inputID: "msg_prompt",
      },
    })
    await Bun.sleep(0)
    controller.abort()
    idle.resolve()
    await turn

    expect(interrupted).toHaveBeenCalledWith({ sessionID: "ses_1" })
    await transport.close()
  })

  test("runs a shell turn through v2.session.shell and renders live output", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let request: Parameters<OpenCodeClient["session"]["shell"]>[0] | undefined
    spyOn(client.session, "shell").mockImplementation((input) => {
      request = input
      queueMicrotask(() => {
        events.push({
          id: input.id ?? "evt_missing",
          created: 0,
          type: "session.shell.started",
          durable: durable("ses_1"),
          data: {
            sessionID: "ses_1",
            shell: {
              id: "sh_shell",
              status: "running",
              command: "ls",
              cwd: "/tmp",
              shell: "/bin/sh",
              file: "/tmp/opencode-shell",
              metadata: {},
              time: { started: 0 },
            },
          },
        })
        events.push({
          id: "evt_shell_end",
          created: 0,
          type: "session.shell.ended",
          durable: durable("ses_1", 1),
          data: {
            sessionID: "ses_1",
            shell: {
              id: "sh_shell",
              status: "exited",
              command: "ls",
              cwd: "/tmp",
              shell: "/bin/sh",
              file: "/tmp/opencode-shell",
              exit: 0,
              metadata: {},
              time: { started: 0, completed: 1 },
            },
            output: { output: "file.txt", cursor: 8, size: 8, truncated: false },
          },
        })
      })
      return ok(undefined) as never
    })

    await transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: { text: "ls", parts: [], mode: "shell" },
      files: [],
      includeFiles: true,
    })

    expect(request).toMatchObject({ sessionID: "ses_1", command: "ls", id: expect.stringMatching(/^evt_/) })
    expect(ui.commits.filter((item) => item.shell)).toMatchObject([
      { phase: "start", partID: "shell:sh_shell", tool: "shell", toolState: "running", shell: { command: "ls" } },
      {
        phase: "progress",
        partID: "shell:sh_shell",
        text: "file.txt",
        toolState: "completed",
        shell: { command: "ls" },
      },
    ])
    expect(ui.events).toContainEqual({ type: "stream.patch", patch: { phase: "running", status: "running shell" } })
    await transport.close()
  })

  test("aborts an active shell turn without interrupting the session", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let started = false
    let aborted = false
    spyOn(client.session, "shell").mockImplementation(
      (_input, options) =>
        new Promise((_, reject) => {
          started = true
          options?.signal?.addEventListener("abort", () => {
            aborted = true
            reject(new Error("aborted"))
          })
        }) as never,
    )
    const interrupted = spyOn(client.session, "interrupt").mockImplementation(() => ok(undefined))

    const turn = transport.runPromptTurn({
      agent: undefined,
      model: undefined,
      variant: undefined,
      prompt: { text: "sleep 100", parts: [], mode: "shell" },
      files: [],
      includeFiles: true,
    })
    while (!started) await Bun.sleep(0)
    await transport.interruptActiveTurn()
    await turn

    expect(aborted).toBe(true)
    expect(interrupted).not.toHaveBeenCalled()
    await transport.close()
  })

  test("does not resolve an owned shell output wait from an unrelated shell", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let request: Parameters<OpenCodeClient["session"]["shell"]>[0] | undefined
    let complete!: () => void
    spyOn(client.session, "shell").mockImplementation((input) => {
      request = input
      return new Promise<void>((resolve) => {
        complete = resolve
      }) as never
    })

    let done = false
    const turn = transport
      .runPromptTurn({
        agent: undefined,
        model: undefined,
        variant: undefined,
        prompt: { text: "pwd", parts: [], mode: "shell" },
        files: [],
        includeFiles: true,
      })
      .then(() => {
        done = true
      })
    while (!request) await Bun.sleep(0)
    events.push({
      id: "evt_unrelated_shell",
      created: 0,
      type: "session.shell.started",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        shell: {
          id: "sh_unrelated",
          status: "running",
          command: "other",
          cwd: "/tmp",
          shell: "/bin/sh",
          file: "/tmp/unrelated",
          metadata: {},
          time: { started: 0 },
        },
      },
    })
    events.push({
      id: "evt_unrelated_end",
      created: 0,
      type: "session.shell.ended",
      durable: durable("ses_1", 1),
      data: {
        sessionID: "ses_1",
        shell: {
          id: "sh_unrelated",
          status: "exited",
          command: "other",
          cwd: "/tmp",
          shell: "/bin/sh",
          file: "/tmp/unrelated",
          exit: 0,
          metadata: {},
          time: { started: 0, completed: 1 },
        },
        output: { output: "wrong", cursor: 5, size: 5, truncated: false },
      },
    })
    await Bun.sleep(0)
    complete()
    await Bun.sleep(0)
    expect(done).toBe(false)

    events.push({
      id: request.id ?? "evt_missing",
      created: 0,
      type: "session.shell.started",
      durable: durable("ses_1", 2),
      data: {
        sessionID: "ses_1",
        shell: {
          id: "sh_owned",
          status: "running",
          command: "pwd",
          cwd: "/tmp",
          shell: "/bin/sh",
          file: "/tmp/owned",
          metadata: {},
          time: { started: 0 },
        },
      },
    })
    events.push({
      id: "evt_owned_end",
      created: 0,
      type: "session.shell.ended",
      durable: durable("ses_1", 3),
      data: {
        sessionID: "ses_1",
        shell: {
          id: "sh_owned",
          status: "exited",
          command: "pwd",
          cwd: "/tmp",
          shell: "/bin/sh",
          file: "/tmp/owned",
          exit: 0,
          metadata: {},
          time: { started: 0, completed: 1 },
        },
        output: { output: "/tmp", cursor: 4, size: 4, truncated: false },
      },
    })
    await turn

    expect(request.id).toMatch(/^evt_/)
    expect(ui.commits.some((item) => item.partID === "shell:sh_owned" && item.text === "/tmp")).toBe(true)
    await transport.close()
  })

  test("hydrates projected shell transcripts once and dedupes live redelivery", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      messages: {
        ses_1: [
          {
            id: "msg_shell",
            type: "shell" as const,
            shellID: "sh_1",
            status: "exited",
            command: "ls",
            exit: 0,
            output: { output: "file.txt", cursor: 8, size: 8, truncated: false },
            time: { created: 1, completed: 2 },
          },
        ],
      },
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
    })
    events.push({
      id: "evt_shell_end",
      created: 0,
      type: "session.shell.ended",
      durable: durable("ses_1", 1),
      data: {
        sessionID: "ses_1",
        shell: {
          id: "sh_1",
          status: "exited",
          command: "ls",
          cwd: "/tmp",
          shell: "/bin/sh",
          file: "/tmp/opencode-shell",
          exit: 0,
          metadata: {},
          time: { started: 0, completed: 1 },
        },
        output: { output: "file.txt", cursor: 8, size: 8, truncated: false },
      },
    })
    await Bun.sleep(0)
    await Bun.sleep(0)

    expect(ui.commits.filter((item) => item.shell)).toMatchObject([
      { phase: "start", partID: "shell:sh_1", shell: { command: "ls" } },
      { phase: "progress", partID: "shell:sh_1", text: "file.txt", toolState: "completed" },
    ])
    await transport.close()
  })

  test("renders failed projected shells as errors and marks truncated live output", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      messages: {
        ses_1: [
          {
            id: "msg_failed_shell",
            type: "shell" as const,
            shellID: "sh_failed",
            status: "exited",
            command: "false",
            exit: 7,
            output: { output: "failure output", cursor: 14, size: 14, truncated: false },
            time: { created: 1, completed: 2 },
          },
        ],
      },
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
    })
    events.push({
      id: "evt_truncated_start",
      created: 0,
      type: "session.shell.started",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        shell: {
          id: "sh_truncated",
          status: "running",
          command: "long",
          cwd: "/tmp",
          shell: "/bin/sh",
          file: "/tmp/truncated",
          metadata: {},
          time: { started: 0 },
        },
      },
    })
    events.push({
      id: "evt_truncated_end",
      created: 0,
      type: "session.shell.ended",
      durable: durable("ses_1", 1),
      data: {
        sessionID: "ses_1",
        shell: {
          id: "sh_truncated",
          status: "exited",
          command: "long",
          cwd: "/tmp",
          shell: "/bin/sh",
          file: "/tmp/truncated",
          exit: 0,
          metadata: {},
          time: { started: 0, completed: 1 },
        },
        output: { output: "partial", cursor: 7, size: 20, truncated: false },
      },
    })
    await Bun.sleep(0)

    expect(ui.commits).toContainEqual(
      expect.objectContaining({ toolState: "error", toolError: "Shell exited with code 7" }),
    )
    expect(ui.commits).toContainEqual(expect.objectContaining({ text: "partial\n[output truncated]" }))
    await transport.close()
  })

  test("routes command prompts through v2.session.command", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let request: Parameters<OpenCodeClient["session"]["command"]>[0] | undefined
    spyOn(client.session, "command").mockImplementation((input) => {
      request = input
      queueMicrotask(() => {
        events.push({
          id: "evt_prompted",
          created: 0,
          type: "session.input.promoted",
          durable: durable("ses_1"),
          data: {
            sessionID: "ses_1",
            inputID: "msg_cmd",
          },
        })
        events.push({
          id: "evt_settled",
          created: 0,
          type: "session.execution.succeeded",
          durable: durable("ses_1"),
          data: { sessionID: "ses_1" },
        })
      })
      return ok({
        admittedSeq: 1,
        id: input.id ?? "msg_cmd",
        sessionID: "ses_1",
        type: "user" as const,
        data: { text: "evaluated template" },
        delivery: "steer" as const,
        timeCreated: 2,
      })
    })

    await transport.runPromptTurn({
      agent: "build",
      model: { providerID: "test", modelID: "model" },
      variant: undefined,
      prompt: {
        messageID: "msg_cmd",
        text: "/deploy prod",
        parts: [
          {
            type: "file",
            url: "file:///tmp/mentioned.txt",
            filename: "mentioned.txt",
            source: { type: "file", text: { start: 8, end: 12, value: "prod" } },
          },
        ],
        command: { name: "deploy", arguments: "prod" },
      },
      files: [{ type: "file", url: "file:///tmp/context.txt", filename: "context.txt", mime: "text/plain" }],
      includeFiles: true,
    })

    expect(request).toMatchObject({
      sessionID: "ses_1",
      id: "msg_cmd",
      command: "deploy",
      arguments: "prod",
      agent: "build",
      model: { providerID: "test", id: "model" },
      files: [
        { uri: "file:///tmp/context.txt", name: "context.txt" },
        {
          uri: "file:///tmp/mentioned.txt",
          name: "mentioned.txt",
          mention: { start: 8, end: 12, text: "prod" },
        },
      ],
      delivery: "steer",
    })
    // Selection rides the command payload; no separate client-side switch.
    expect(client.session.switchAgent).not.toHaveBeenCalled()
    expect(client.session.switchModel).not.toHaveBeenCalled()
    await transport.close()
  })

  test("routes skill prompts through v2.session.skill and settles without promotion", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    let request: Parameters<OpenCodeClient["session"]["skill"]>[0] | undefined
    const command = spyOn(client.session, "command")
    const prompt = spyOn(client.session, "prompt")
    spyOn(client.session, "skill").mockImplementation((input) => {
      request = input
      queueMicrotask(() => {
        events.push({
          id: "evt_skill",
          created: 0,
          type: "session.skill.activated",
          durable: durable("ses_1"),
          data: {
            sessionID: "ses_1",
            id: input.skill ?? "tigerstyle",
            name: input.skill ?? "tigerstyle",
            text: "skill instructions",
          },
        })
        events.push({
          id: "evt_settled",
          created: 0,
          type: "session.execution.succeeded",
          durable: durable("ses_1"),
          data: { sessionID: "ses_1" },
        })
      })
      return ok(undefined) as never
    })

    await transport.runPromptTurn({
      agent: "review",
      model: undefined,
      variant: undefined,
      prompt: {
        messageID: "msg_skill",
        text: "/tigerstyle",
        parts: [],
        command: { name: "tigerstyle", arguments: "", source: "skill" },
      },
      files: [],
      includeFiles: true,
    })

    expect(client.session.switchAgent).toHaveBeenCalledWith({ sessionID: "ses_1", agent: "review" }, expect.anything())
    expect(request).toMatchObject({ sessionID: "ses_1", id: "msg_skill", skill: "tigerstyle" })
    expect(command).not.toHaveBeenCalled()
    expect(prompt).not.toHaveBeenCalled()
    expect(ui.commits).toContainEqual(
      expect.objectContaining({ kind: "system", text: '→ Skill "tigerstyle"', messageID: "msg_skill" }),
    )
    await transport.close()
  })

  test("refreshes catalogs on connection and location-scoped invalidations", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    const ui = footer()
    let refreshes = 0
    const transport = await createSessionTransport({
      sdk: client,
      location: {
        directory: "/project",
        workspaceID: "work-1",
      },
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
      onCatalogRefresh: () => refreshes++,
    })
    expect(refreshes).toBe(1)

    for (const type of [
      "catalog.updated",
      "integration.updated",
      "agent.updated",
      "command.updated",
      "skill.updated",
      "reference.updated",
    ] as const)
      events.push({
        id: `evt_${type}`,
        created: 0,
        type,
        location: { directory: "/project", workspaceID: "work-1" },
        data: {},
      })
    events.push({
      id: "evt_foreign_catalog",
      created: 0,
      type: "catalog.updated",
      location: { directory: "/other" },
      data: {},
    })
    events.push({
      id: "evt_foreign_workspace_catalog",
      created: 0,
      type: "catalog.updated",
      location: { directory: "/project", workspaceID: "work-2" },
      data: {},
    })
    while (refreshes < 7) await Bun.sleep(0)
    await Bun.sleep(0)

    expect(refreshes).toBe(7)
    await transport.close()
  })

  test("hydrates skill activation messages once and dedupes live redelivery", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      messages: {
        ses_1: [
          {
            id: "msg_skill",
            type: "skill" as const,
            skill: "tigerstyle",
            name: "tigerstyle",
            text: "skill instructions",
            time: { created: 2 },
          },
        ],
      },
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      replay: true,
      footer: ui.api,
    })
    events.push({
      id: "evt_skill",
      created: 0,
      type: "session.skill.activated",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        id: "tigerstyle",
        name: "tigerstyle",
        text: "skill instructions",
      },
    })
    await Bun.sleep(0)
    await Bun.sleep(0)

    expect(ui.commits.filter((item) => item.text === '→ Skill "tigerstyle"')).toHaveLength(1)
    await transport.close()
  })

  test("discovers a subagent from its terminal failure snapshot", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events], messages: { ses_child_failed: [] } })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = () => ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))
    events.push({
      id: "evt_failed_subagent_input",
      created: 1,
      type: "session.tool.input.started",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_failed_subagent",
        callID: "call_failed_subagent",
        name: "subagent",
      },
    })
    events.push({
      id: "evt_failed_subagent_called",
      created: 2,
      type: "session.tool.called",
      durable: durable("ses_1", 1),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_failed_subagent",
        callID: "call_failed_subagent",
        input: { agent: "explore", description: "Inspect failure", prompt: "inspect" },
        executed: true,
      },
    })
    events.push({
      id: "evt_failed_subagent",
      created: 3,
      type: "session.tool.failed",
      durable: durable("ses_1", 2, 2),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_failed_subagent",
        callID: "call_failed_subagent",
        error: { type: "unknown", message: "subagent failed" },
        metadata: { sessionID: "ses_child_failed", status: "running" },
        executed: true,
      },
    })

    while (!states().some((state) => state.tabs.some((tab) => tab.sessionID === "ses_child_failed"))) await Bun.sleep(0)
    expect(states().at(-1)?.tabs).toMatchObject([
      {
        sessionID: "ses_child_failed",
        label: "Explore",
        description: "Inspect failure",
      },
    ])
    await transport.close()
  })

  test("discovers current subagents from progress and reduces descendant tool state", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events], messages: { ses_child_progress: [] } })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = () => ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))
    events.push({
      id: "evt_subagent_input",
      created: 1,
      type: "session.tool.input.started",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_subagent",
        callID: "call_subagent",
        name: "subagent",
      },
    })
    events.push({
      id: "evt_subagent_called",
      created: 2,
      type: "session.tool.called",
      durable: durable("ses_1", 1),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_subagent",
        callID: "call_subagent",
        input: { agent: "explore", description: "Inspect progress", prompt: "inspect" },
        executed: true,
      },
    })
    events.push({
      id: "evt_subagent_progress",
      created: 3,
      type: "session.tool.progress",
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_subagent",
        callID: "call_subagent",
        metadata: { sessionID: "ses_child_progress", status: "running" },
      },
    })
    while (!states().some((state) => state.tabs.some((tab) => tab.sessionID === "ses_child_progress")))
      await Bun.sleep(0)
    expect(states().at(-1)?.tabs).toMatchObject([
      {
        sessionID: "ses_child_progress",
        label: "Explore",
        description: "Inspect progress",
        status: "running",
        background: undefined,
      },
    ])

    transport.selectSubagent("ses_child_progress")
    while (!states().at(-1)?.details.ses_child_progress) await Bun.sleep(0)
    events.push({
      id: "evt_child_tool_input",
      created: 4,
      type: "session.tool.input.started",
      durable: durable("ses_child_progress"),
      data: {
        sessionID: "ses_child_progress",
        assistantMessageID: "msg_child_tool",
        callID: "call_child_shell",
        name: "shell",
      },
    })
    events.push({
      id: "evt_child_tool_called",
      created: 5,
      type: "session.tool.called",
      durable: durable("ses_child_progress", 1),
      data: {
        sessionID: "ses_child_progress",
        assistantMessageID: "msg_child_tool",
        callID: "call_child_shell",
        input: { command: "printf child && false" },
        executed: true,
      },
    })
    events.push({
      id: "evt_child_tool_progress",
      created: 6,
      type: "session.tool.progress",
      data: {
        sessionID: "ses_child_progress",
        assistantMessageID: "msg_child_tool",
        callID: "call_child_shell",
        metadata: { checkpoint: "child" },
      },
    })
    events.push({
      id: "evt_child_permission",
      created: 7,
      type: "permission.asked",
      data: {
        id: "per_child",
        sessionID: "ses_child_progress",
        action: "shell",
        resources: ["printf child && false"],
        source: { type: "tool", messageID: "msg_child_tool", callID: "call_child_shell" },
      },
    })
    events.push({
      id: "evt_child_tool_failed",
      created: 8,
      type: "session.tool.failed",
      durable: durable("ses_child_progress", 3, 2),
      data: {
        sessionID: "ses_child_progress",
        assistantMessageID: "msg_child_tool",
        callID: "call_child_shell",
        error: { type: "unknown", message: "child boom" },
        metadata: { checkpoint: "child" },
        content: [{ type: "text", text: "child partial" }],
        executed: true,
      },
    })
    while (
      !states()
        .at(-1)
        ?.details.ses_child_progress?.commits.some(
          (item) => item.part?.id === "call_child_shell" && item.toolState === "error",
        )
    )
      await Bun.sleep(0)

    const commits = states().at(-1)?.details.ses_child_progress?.commits ?? []
    expect(
      commits
        .filter((item) => item.part?.id === "call_child_shell")
        .map((item) => [item.phase, item.text, item.toolState]),
    ).toEqual([
      ["progress", "child partial", "running"],
      ["final", "child boom", "error"],
    ])
    expect(
      commits.find((item) => item.part?.id === "call_child_shell" && item.toolState === "error")?.part?.state,
    ).toMatchObject({
      status: "error",
      metadata: { checkpoint: "child" },
      content: [{ type: "text", text: "child partial" }],
    })
    expect(
      ui.events.find(
        (event) =>
          event.type === "stream.view" && event.view.type === "permission" && event.view.request.id === "per_child",
      ),
    ).toMatchObject({
      view: {
        request: {
          sessionID: "ses_child_progress",
          tool: { id: "call_child_shell", state: { input: { command: "printf child && false" } } },
        },
      },
    })
    await transport.close()
  })

  test("discovers a live child session and tracks its tab and selected detail", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      messages: {
        ses_child: [
          {
            id: "msg_task",
            type: "user" as const,
            text: "task prompt",
            files: [],
            agents: [],
            time: { created: 1 },
          },
          {
            id: "msg_child_a",
            type: "assistant" as const,
            agent: "explore",
            model: { providerID: "test", id: "model" },
            content: [{ type: "text" as const, text: "child answer" }],
            time: { created: 2 },
          },
        ],
      },
    })
    spyOn(client.session, "get").mockImplementation(
      () =>
        ok({
          id: "ses_child",
          parentID: "ses_1",
          projectID: "proj_1",
          agent: "explore",
          cost: 0,
          tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
          time: { created: 1, updated: 1 },
          title: "Find files",
          location: { directory: "/tmp" },
        }) as never,
    )
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = () => ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))
    transport.selectSubagent("ses_child")

    events.push({
      id: "evt_child_step",
      created: 0,
      type: "session.step.started",
      durable: durable("ses_child"),
      data: {
        sessionID: "ses_child",
        assistantMessageID: "msg_child_a",
        agent: "explore",
        model: { providerID: "test", id: "model" },
      },
    })
    while (!states().some((state) => state.details.ses_child?.commits.some((item) => item.text === "task prompt")))
      await Bun.sleep(0)
    expect(states().at(-1)?.tabs).toMatchObject([
      { sessionID: "ses_child", label: "Explore", title: "Find files", status: "running" },
    ])

    expect(
      states()
        .at(-1)
        ?.details.ses_child?.commits.filter((item) => item.text === "child answer"),
    ).toHaveLength(1)

    events.push({
      id: "evt_child_text_replayed",
      created: 0,
      type: "session.text.delta",
      data: {
        sessionID: "ses_child",
        assistantMessageID: "msg_child_a",
        ordinal: 0,
        delta: "answer",
      },
    })
    await Bun.sleep(0)
    expect(
      states()
        .at(-1)
        ?.details.ses_child?.commits.filter((item) => item.text === "child answer"),
    ).toHaveLength(1)

    events.push({
      id: "evt_child_text_suffix",
      created: 0,
      type: "session.text.delta",
      data: {
        sessionID: "ses_child",
        assistantMessageID: "msg_child_a",
        ordinal: 0,
        delta: " suffix",
      },
    })
    while (
      !states().some((state) => state.details.ses_child?.commits.some((item) => item.text === "child answer suffix"))
    )
      await Bun.sleep(0)

    events.push({
      id: "evt_child_settled",
      created: 0,
      type: "session.execution.succeeded",
      durable: durable("ses_child"),
      data: { sessionID: "ses_child" },
    })
    while (!states().some((state) => state.tabs.some((tab) => tab.status === "completed"))) await Bun.sleep(0)
    await transport.close()
  })

  test("reveals an admitted child prompt only when it is promoted after hydration", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      messages: { ses_child: [] },
      sessions: [{ id: "ses_child", parentID: "ses_1", time: { updated: 1 } }],
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = () => ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))
    transport.selectSubagent("ses_child")
    while (!states().some((state) => state.details.ses_child)) await Bun.sleep(0)

    events.push({
      id: "evt_child_admitted",
      created: 1,
      type: "session.input.admitted",
      durable: durable("ses_child"),
      data: {
        sessionID: "ses_child",
        inputID: "msg_child_prompt",
        input: { type: "user", data: { text: "actual child prompt" }, delivery: "steer" },
      },
    })
    await Bun.sleep(0)
    expect(
      states()
        .at(-1)
        ?.details.ses_child?.commits.some((item) => item.messageID === "msg_child_prompt"),
    ).toBe(false)

    events.push({
      id: "evt_child_promoted",
      created: 2,
      type: "session.input.promoted",
      durable: durable("ses_child", 1),
      data: { sessionID: "ses_child", inputID: "msg_child_prompt" },
    })
    while (
      !states()
        .at(-1)
        ?.details.ses_child?.commits.some(
          (item) => item.messageID === "msg_child_prompt" && item.text === "actual child prompt",
        )
    )
      await Bun.sleep(0)

    await transport.close()
  })

  test("preserves a pre-hydration admission promoted during stale hydration", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      sessions: [{ id: "ses_child", parentID: "ses_1", time: { updated: 1 } }],
    })
    let childHydrating = false
    let releaseHydration!: () => void
    const hydration = new Promise<void>((resolve) => {
      releaseHydration = resolve
    })
    spyOn(client.message, "list").mockImplementation(async (request) => {
      if (request.sessionID === "ses_child") {
        childHydrating = true
        await hydration
      }
      return ok({ data: [], cursor: {} })
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = () => ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))
    events.push({
      id: "evt_child_admitted_race",
      created: 1,
      type: "session.input.admitted",
      durable: durable("ses_child"),
      data: {
        sessionID: "ses_child",
        inputID: "msg_child_race",
        input: { type: "user", data: { text: "prompt admitted before hydration" }, delivery: "steer" },
      },
    })
    await Bun.sleep(0)
    transport.selectSubagent("ses_child")
    while (!childHydrating) await Bun.sleep(0)
    events.push({
      id: "evt_child_promoted_race",
      created: 2,
      type: "session.input.promoted",
      durable: durable("ses_child", 1),
      data: { sessionID: "ses_child", inputID: "msg_child_race" },
    })
    await Bun.sleep(0)
    releaseHydration()
    await Bun.sleep(0)
    await Bun.sleep(0)
    while (
      !states()
        .at(-1)
        ?.details.ses_child?.commits.some(
          (item) => item.messageID === "msg_child_race" && item.text === "prompt admitted before hydration",
        )
    )
      await Bun.sleep(0)

    await transport.close()
  })

  test("retries child hydration after a bounded live-event overflow", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      sessions: [{ id: "ses_child", parentID: "ses_1", time: { updated: 1 } }],
    })
    let childRequests = 0
    let releaseStale!: () => void
    let releaseRetry!: () => void
    const stale = new Promise<void>((resolve) => {
      releaseStale = resolve
    })
    const retry = new Promise<void>((resolve) => {
      releaseRetry = resolve
    })
    spyOn(client.message, "list").mockImplementation(async (request) => {
      if (request.sessionID !== "ses_child") return ok({ data: [], cursor: {} })
      childRequests++
      if (childRequests === 1) {
        await stale
        return ok({ data: [], cursor: {} })
      }
      await retry
      return ok({
        data: [
          {
            id: "msg_overflow_assistant",
            type: "assistant" as const,
            agent: "explore",
            model: { providerID: "test", id: "model" },
            content: [{ type: "text" as const, id: "txt_overflow_64", text: "live 64" }],
            time: { created: 2, completed: 3 },
          },
          {
            id: "msg_overflow_baseline",
            type: "user" as const,
            text: "baseline history",
            files: [],
            agents: [],
            time: { created: 1 },
          },
        ],
        cursor: {},
      })
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = () => ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))
    transport.selectSubagent("ses_child")
    while (childRequests < 1) await Bun.sleep(0)

    for (let index = 0; index < 65; index++)
      events.push({
        id: `evt_overflow_${index}`,
        created: index,
        type: "session.text.delta",
        data: {
          sessionID: "ses_child",
          assistantMessageID: "msg_overflow_assistant",
          ordinal: index,
          delta: `live ${index}`,
        },
      })
    while (
      !states()
        .at(-1)
        ?.details.ses_child?.commits.some((item) => item.text === "live 64")
    )
      await Bun.sleep(0)
    releaseStale()
    while (childRequests < 2) await Bun.sleep(0)
    expect(
      states()
        .at(-1)
        ?.details.ses_child?.commits.some((item) => item.text === "live 64"),
    ).toBe(true)

    releaseRetry()
    while (
      !states()
        .at(-1)
        ?.details.ses_child?.commits.some((item) => item.text === "baseline history")
    )
      await Bun.sleep(0)
    expect(
      states()
        .at(-1)
        ?.details.ses_child?.commits.some((item) => item.text === "live 64"),
    ).toBe(true)
    expect(childRequests).toBe(2)
    await transport.close()
  })

  test("reconciles pre-hydration tool metadata without downgrading projected completion", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      sessions: [{ id: "ses_child", parentID: "ses_1", time: { updated: 1 } }],
    })
    let childHydrating = false
    let releaseHydration!: () => void
    const hydration = new Promise<void>((resolve) => {
      releaseHydration = resolve
    })
    spyOn(client.message, "list").mockImplementation(async (request) => {
      if (request.sessionID !== "ses_child") return ok({ data: [], cursor: {} })
      childHydrating = true
      await hydration
      return ok({
        data: [
          {
            id: "msg_tool_projected",
            type: "assistant" as const,
            agent: "explore",
            model: { providerID: "test", id: "model" },
            content: [
              {
                type: "tool" as const,
                id: "call_overlap",
                name: "shell",
                state: {
                  status: "completed" as const,
                  input: { command: "projected" },
                  content: [{ type: "text" as const, text: "projected result" }],
                  metadata: {},
                },
                time: { created: 1, ran: 1, completed: 2 },
              },
            ],
            time: { created: 1, completed: 2 },
          },
        ],
        cursor: {},
      })
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = () => ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))
    const inputStarted = (callID: string, name: string, seq: number) =>
      events.push({
        id: `evt_started_${callID}`,
        created: seq,
        type: "session.tool.input.started",
        durable: durable("ses_child", seq),
        data: { sessionID: "ses_child", assistantMessageID: "msg_tool_projected", callID, name },
      })
    const called = (callID: string, input: Record<string, unknown>, seq: number) =>
      events.push({
        id: `evt_called_${callID}`,
        created: seq,
        type: "session.tool.called",
        durable: durable("ses_child", seq),
        data: {
          sessionID: "ses_child",
          assistantMessageID: "msg_tool_projected",
          callID,
          input,
          executed: true,
        },
      })

    inputStarted("call_terminal", "grep", 0)
    called("call_terminal", { pattern: "needle" }, 1)
    await Bun.sleep(0)
    transport.selectSubagent("ses_child")
    while (!childHydrating) await Bun.sleep(0)
    events.push({
      id: "evt_success_terminal",
      created: 2,
      type: "session.tool.success",
      durable: durable("ses_child", 2, 2),
      data: {
        sessionID: "ses_child",
        assistantMessageID: "msg_tool_projected",
        callID: "call_terminal",
        metadata: {},
        content: [{ type: "text", text: "found" }],
        executed: true,
      },
    })
    inputStarted("call_overlap", "shell", 3)
    called("call_overlap", { command: "stale" }, 4)
    await Bun.sleep(0)
    const beforeHydration = states().length
    releaseHydration()
    while (states().length === beforeHydration) await Bun.sleep(0)
    await Bun.sleep(0)

    const commits = states().at(-1)?.details.ses_child?.commits ?? []
    expect(commits.find((item) => item.partID === "prt_call_terminal")).toMatchObject({
      tool: "grep",
      toolState: "completed",
      part: { state: { input: { pattern: "needle" } } },
    })
    expect(commits.find((item) => item.partID === "prt_call_overlap")).toMatchObject({
      tool: "shell",
      toolState: "completed",
      part: { state: { input: { command: "projected" } } },
    })
    await transport.close()
  })

  test("keeps child terminal state observed during discovery", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    let resolveGet: (() => void) | undefined
    const gate = new Promise<void>((resolve) => {
      resolveGet = resolve
    })
    spyOn(client.session, "get").mockImplementation(async () => {
      await gate
      return ok({
        id: "ses_child",
        parentID: "ses_1",
        projectID: "proj_1",
        agent: "explore",
        cost: 0,
        tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
        time: { created: 1, updated: 1 },
        title: "Find files",
        location: { directory: "/tmp" },
      }) as never
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = () => ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))

    // Both events arrive while session.get is still in flight.
    events.push({
      id: "evt_child_step",
      created: 0,
      type: "session.step.started",
      durable: durable("ses_child"),
      data: {
        sessionID: "ses_child",
        assistantMessageID: "msg_child_a",
        agent: "explore",
        model: { providerID: "test", id: "model" },
      },
    })
    events.push({
      id: "evt_child_settled",
      created: 0,
      type: "session.execution.interrupted",
      durable: durable("ses_child"),
      data: { sessionID: "ses_child", reason: "user" },
    })
    await Bun.sleep(0)
    resolveGet?.()
    while (!states().some((state) => state.tabs.some((tab) => tab.status === "cancelled"))) await Bun.sleep(0)
    await transport.close()
  })

  test("does not resurrect a settled child from stale discovery buffer", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({ streams: [events] })
    let resolveGet: (() => void) | undefined
    const gate = new Promise<void>((resolve) => {
      resolveGet = resolve
    })
    spyOn(client.session, "get").mockImplementation(async () => {
      await gate
      return ok({
        id: "ses_child",
        parentID: "ses_1",
        projectID: "proj_1",
        agent: "explore",
        cost: 0,
        tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
        time: { created: 1, updated: 1 },
        title: "Find files",
        location: { directory: "/tmp" },
      }) as never
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = () => ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))

    // Child event arrives first and gets buffered behind the gated session.get.
    events.push({
      id: "evt_child_step",
      created: 0,
      type: "session.step.started",
      durable: durable("ses_child"),
      data: {
        sessionID: "ses_child",
        assistantMessageID: "msg_child_a",
        agent: "explore",
        model: { providerID: "test", id: "model" },
      },
    })
    // Parent's background subagent tool.success adopts the child mid-discovery.
    events.push({
      id: "evt_parent_input",
      created: 0,
      type: "session.tool.input.started",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_parent_a",
        callID: "call_sub",
        name: "subagent",
      },
    })
    events.push({
      id: "evt_parent_call",
      created: 0,
      type: "session.tool.called",
      durable: durable("ses_1"),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_parent_a",
        callID: "call_sub",
        input: { agent: "explore", description: "Find things", prompt: "go", background: true },
        executed: true,
      },
    })
    events.push({
      id: "evt_parent_success",
      created: 0,
      type: "session.tool.success",
      durable: durable("ses_1", 1, 2),
      data: {
        sessionID: "ses_1",
        assistantMessageID: "msg_parent_a",
        callID: "call_sub",
        metadata: { sessionID: "ses_child", status: "running", output: "" },
        content: [{ type: "text", text: "" }],
        executed: true,
      },
    })
    // The settled event arrives after adoption, so it applies directly.
    events.push({
      id: "evt_child_settled",
      created: 0,
      type: "session.execution.interrupted",
      durable: durable("ses_child"),
      data: { sessionID: "ses_child", reason: "shutdown" },
    })
    while (!states().some((state) => state.tabs.some((tab) => tab.status === "cancelled"))) await Bun.sleep(0)

    // Resolving discovery must not replay the buffered step.started over the
    // terminal status.
    const before = states().length
    resolveGet?.()
    while (states().length === before) await Bun.sleep(0)
    await Bun.sleep(0)
    await Bun.sleep(0)
    expect(states().at(-1)?.tabs).toMatchObject([{ sessionID: "ses_child", status: "cancelled" }])
    await transport.close()
  })

  test("adopts historical children from the session family list", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      sessions: [
        { id: "ses_child_old", parentID: "ses_1", title: "Earlier subagent", agent: "explore", time: { updated: 9 } },
        { id: "ses_unrelated", title: "Different session", time: { updated: 5 } },
        { id: "ses_sibling", parentID: "ses_2", title: "Someone else's child", time: { updated: 4 } },
      ],
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))
    expect(client.session.list).toHaveBeenCalledWith(
      { parentID: "ses_1", limit: 100, order: "desc" },
      { signal: expect.any(AbortSignal) },
    )
    expect(states.at(-1)?.tabs).toMatchObject([
      {
        sessionID: "ses_child_old",
        label: "Explore",
        title: "Earlier subagent",
        status: "completed",
      },
    ])
    await transport.close()
  })

  test("hydrates completed subagent children from projected tool output", async () => {
    const events = feed()
    events.push(connected())
    const client = sdk({
      streams: [events],
      messages: {
        ses_1: [
          {
            id: "msg_parent",
            type: "assistant" as const,
            agent: "build",
            model: { providerID: "test", id: "model" },
            time: { created: 1, completed: 3 },
            content: [
              {
                type: "tool" as const,
                id: "call_sub",
                name: "subagent",
                state: {
                  status: "completed" as const,
                  input: { agent: "explore", description: "Find things", prompt: "go" },
                  content: [{ type: "text" as const, text: "done" }],
                  metadata: { sessionID: "ses_child", status: "completed", output: "done" },
                },
                time: { created: 1, ran: 1, completed: 2 },
              },
            ],
          },
        ],
      },
    })
    const ui = footer()
    const transport = await createSessionTransport({
      sdk: client,
      sessionID: "ses_1",
      thinking: false,
      footer: ui.api,
    })
    const states = ui.events.flatMap((event) => (event.type === "stream.subagent" ? [event.state] : []))
    expect(states.at(-1)?.tabs).toMatchObject([
      {
        sessionID: "ses_child",
        label: "Explore",
        description: "Find things",
        status: "completed",
      },
    ])
    await transport.close()
  })
})