diff --git a/src/features/team-mode/team-state-store/resume.test.ts b/src/features/team-mode/team-state-store/resume.test.ts
new file mode 100644
index 000000000..959261f92
--- /dev/null
+++ b/src/features/team-mode/team-state-store/resume.test.ts
@@ -0,0 +1,388 @@
+/// <reference types="bun-types" />
+
+import { afterEach, describe, expect, mock, test } from "bun:test"
+import { randomUUID } from "node:crypto"
+import { mkdtemp, mkdir, readdir, rm, stat, utimes, writeFile } from "node:fs/promises"
+import { tmpdir } from "node:os"
+import path from "node:path"
+
+import { TeamModeConfigSchema } from "../../../config/schema/team-mode"
+import type { TeamModeConfig } from "../../../config/schema/team-mode"
+import type { ExecutorContext } from "../../../tools/delegate-task/executor-types"
+import { getInboxDir, resolveBaseDir } from "../team-registry/paths"
+import type { TeamSpec } from "../types"
+import { resumeAllTeams } from "./resume"
+import { createRuntimeState, loadRuntimeState, saveRuntimeState, transitionRuntimeState } from "./store"
+
+async function createTemporaryBaseDir(): Promise<string> {
+  return await mkdtemp(path.join(tmpdir(), "team-mode-resume-"))
+}
+
+function createConfig(baseDir: string): TeamModeConfig {
+  return TeamModeConfigSchema.parse({
+    base_dir: baseDir,
+    max_members: 6,
+    max_parallel_members: 3,
+    max_messages_per_run: 200,
+    max_wall_clock_minutes: 45,
+    max_member_turns: 50,
+  })
+}
+
+function createSpec(name = `team-${randomUUID().slice(0, 8)}`): TeamSpec {
+  return {
+    version: 1,
+    name,
+    createdAt: Date.now(),
+    leadAgentId: "lead",
+    members: [
+      {
+        kind: "subagent_type",
+        name: "lead",
+        subagent_type: "sisyphus",
+        backendType: "in-process",
+        isActive: true,
+        color: "red",
+      },
+      {
+        kind: "category",
+        name: "worker",
+        category: "deep",
+        prompt: "implement task",
+        backendType: "in-process",
+        isActive: true,
+        color: "blue",
+      },
+    ],
+  }
+}
+
+function createSpecWithTwoWorkers(name = `team-${randomUUID().slice(0, 8)}`): TeamSpec {
+  return {
+    version: 1,
+    name,
+    createdAt: Date.now(),
+    leadAgentId: "lead",
+    members: [
+      {
+        kind: "subagent_type",
+        name: "lead",
+        subagent_type: "sisyphus",
+        backendType: "in-process",
+        isActive: true,
+        color: "red",
+      },
+      {
+        kind: "category",
+        name: "worker-a",
+        category: "deep",
+        prompt: "implement task",
+        backendType: "in-process",
+        isActive: true,
+        color: "blue",
+      },
+      {
+        kind: "category",
+        name: "worker-b",
+        category: "deep",
+        prompt: "implement task",
+        backendType: "in-process",
+        isActive: true,
+        color: "green",
+      },
+    ],
+  }
+}
+
+type SessionGetMock = (input: { path: { id: string } }) => Promise<unknown>
+
+function createExecutorContext(
+  directory: string,
+  sessionGet: SessionGetMock = mock(async () => ({ data: null })),
+): ExecutorContext {
+  return {
+    client: {
+      session: {
+        get: sessionGet,
+      },
+    } as ExecutorContext["client"],
+    manager: {} as ExecutorContext["manager"],
+    directory,
+  }
+}
+
+describe("resumeAllTeams", () => {
+  const temporaryDirectories: string[] = []
+
+  afterEach(async () => {
+    await Promise.all(temporaryDirectories.splice(0).map(async (directoryPath) => {
+      await rm(directoryPath, { recursive: true, force: true })
+    }))
+    mock.restore()
+  })
+
+  test("marks stuck creating teams failed after reload recovery", async () => {
+    // given
+    const baseDir = await createTemporaryBaseDir()
+    temporaryDirectories.push(baseDir)
+    const config = createConfig(baseDir)
+    const runtimeState = await createRuntimeState(createSpec(), "ses_lead", "user", config)
+    const worktreePath = path.join(baseDir, "worktrees", runtimeState.teamRunId, "worker")
+    await mkdir(worktreePath, { recursive: true })
+    await saveRuntimeState({
+      ...runtimeState,
+      createdAt: Date.now() - 40 * 60 * 1000,
+      members: runtimeState.members.map((member) => member.name === "worker"
+        ? { ...member, worktreePath }
+        : member),
+    }, config)
+
+    // when
+    const report = await resumeAllTeams(createExecutorContext(baseDir), config)
+    const persistedState = await loadRuntimeState(runtimeState.teamRunId, config)
+
+    // then
+    expect(persistedState.status).toBe("failed")
+    expect(report).toEqual({
+      resumed: 0,
+      marked_failed: 1,
+      marked_orphaned: 0,
+      cleaned: 0,
+      errors: [],
+    })
+    let statError: NodeJS.ErrnoException | null = null
+    try {
+      await stat(worktreePath)
+    } catch (error) {
+      statError = error as NodeJS.ErrnoException
+    }
+    expect(statError?.code).toBe("ENOENT")
+  })
+
+  test("marks active teams orphaned when lead session no longer exists", async () => {
+    // given
+    const baseDir = await createTemporaryBaseDir()
+    temporaryDirectories.push(baseDir)
+    const config = createConfig(baseDir)
+    const runtimeState = await createRuntimeState(createSpec(), "ses_dead", "project", config)
+    await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+      ...currentRuntimeState,
+      status: "active",
+    }), config)
+    const sessionGet = mock(async () => {
+      throw Object.assign(new Error("session not found"), { status: 404 })
+    })
+
+    // when
+    const report = await resumeAllTeams(createExecutorContext(baseDir, sessionGet), config)
+    const persistedState = await loadRuntimeState(runtimeState.teamRunId, config)
+
+    // then
+    expect(sessionGet).toHaveBeenCalledTimes(1)
+    expect(persistedState.status).toBe("orphaned")
+    expect(report).toEqual({
+      resumed: 0,
+      marked_failed: 0,
+      marked_orphaned: 1,
+      cleaned: 0,
+      errors: [],
+    })
+  })
+
+  test("preserves active teams when lead session is still alive", async () => {
+    // given
+    const baseDir = await createTemporaryBaseDir()
+    temporaryDirectories.push(baseDir)
+    const config = createConfig(baseDir)
+    const runtimeState = await createRuntimeState(createSpec(), "ses_alive", "user", config)
+    await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+      ...currentRuntimeState,
+      status: "active",
+    }), config)
+    const sessionGet = mock(async () => ({ data: { id: "ses_alive" } }))
+
+    // when
+    const report = await resumeAllTeams(createExecutorContext(baseDir, sessionGet), config)
+    const persistedState = await loadRuntimeState(runtimeState.teamRunId, config)
+
+    // then
+    expect(sessionGet).toHaveBeenCalledTimes(1)
+    expect(persistedState.status).toBe("active")
+    expect(report).toEqual({
+      resumed: 1,
+      marked_failed: 0,
+      marked_orphaned: 0,
+      cleaned: 0,
+      errors: [],
+    })
+  })
+
+  test("marks dead worker members errored while keeping the team active", async () => {
+    // given
+    const baseDir = await createTemporaryBaseDir()
+    temporaryDirectories.push(baseDir)
+    const config = createConfig(baseDir)
+    const runtimeState = await createRuntimeState(createSpecWithTwoWorkers(), "ses_alive_lead", "user", config)
+    await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+      ...currentRuntimeState,
+      status: "active",
+      leadSessionId: "ses_alive_lead",
+      members: currentRuntimeState.members.map((member) => {
+        if (member.name === "lead") return { ...member, sessionId: "ses_alive_lead", status: "running" as const }
+        if (member.name === "worker-a") return { ...member, sessionId: "ses_dead_a", status: "running" as const }
+        if (member.name === "worker-b") return { ...member, sessionId: "ses_alive_b", status: "running" as const }
+        return member
+      }),
+    }), config)
+    const sessionGet = mock(async ({ path }: { path: { id: string } }) => {
+      if (path.id === "ses_alive_lead" || path.id === "ses_alive_b") return { data: { id: path.id } }
+      throw Object.assign(new Error("session not found"), { status: 404 })
+    })
+
+    // when
+    const report = await resumeAllTeams(createExecutorContext(baseDir, sessionGet), config)
+    const persistedState = await loadRuntimeState(runtimeState.teamRunId, config)
+
+    // then
+    expect(persistedState.status).toBe("active")
+    const workerA = persistedState.members.find((member) => member.name === "worker-a")
+    const workerB = persistedState.members.find((member) => member.name === "worker-b")
+    expect(workerA?.status).toBe("errored")
+    expect(workerA?.sessionId).toBeUndefined()
+    expect(workerB?.status).toBe("running")
+    expect(workerB?.sessionId).toBe("ses_alive_b")
+    expect(report.resumed).toBe(1)
+    expect(report.marked_orphaned).toBe(0)
+  })
+
+  test("reclaims stale .delivering-* reservations on resume of an active team", async () => {
+    // given
+    const baseDir = await createTemporaryBaseDir()
+    temporaryDirectories.push(baseDir)
+    const config = createConfig(baseDir)
+    const runtimeState = await createRuntimeState(createSpec(), "ses_alive", "user", config)
+    await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+      ...currentRuntimeState,
+      status: "active",
+    }), config)
+    const workerInbox = getInboxDir(resolveBaseDir(config), runtimeState.teamRunId, "worker")
+    await mkdir(workerInbox, { recursive: true, mode: 0o700 })
+    const strandedMessageId = randomUUID()
+    const strandedPath = path.join(workerInbox, `.delivering-${strandedMessageId}.json`)
+    await writeFile(strandedPath, JSON.stringify({
+      version: 1,
+      messageId: strandedMessageId,
+      from: "lead",
+      to: "worker",
+      kind: "message",
+      body: "stranded",
+      timestamp: Date.now(),
+    }))
+    const ancientMtime = new Date(Date.now() - 60 * 60 * 1000)
+    await utimes(strandedPath, ancientMtime, ancientMtime)
+    const sessionGet = mock(async () => ({ data: { id: "ses_alive" } }))
+
+    // when
+    await resumeAllTeams(createExecutorContext(baseDir, sessionGet), config)
+
+    // then
+    const entries = await readdir(workerInbox)
+    expect(entries).toContain(`${strandedMessageId}.json`)
+    expect(entries).not.toContain(`.delivering-${strandedMessageId}.json`)
+  })
+
+  test("leaves fresh .delivering-* reservations in place on resume", async () => {
+    // given
+    const baseDir = await createTemporaryBaseDir()
+    temporaryDirectories.push(baseDir)
+    const config = createConfig(baseDir)
+    const runtimeState = await createRuntimeState(createSpec(), "ses_alive", "user", config)
+    await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+      ...currentRuntimeState,
+      status: "active",
+    }), config)
+    const workerInbox = getInboxDir(resolveBaseDir(config), runtimeState.teamRunId, "worker")
+    await mkdir(workerInbox, { recursive: true, mode: 0o700 })
+    const freshMessageId = randomUUID()
+    const freshPath = path.join(workerInbox, `.delivering-${freshMessageId}.json`)
+    await writeFile(freshPath, "{}")
+    const sessionGet = mock(async () => ({ data: { id: "ses_alive" } }))
+
+    // when
+    await resumeAllTeams(createExecutorContext(baseDir, sessionGet), config)
+
+    // then
+    const entries = await readdir(workerInbox)
+    expect(entries).toContain(`.delivering-${freshMessageId}.json`)
+    expect(entries).not.toContain(`${freshMessageId}.json`)
+  })
+
+  test("orphans active teams when every worker session has died", async () => {
+    // given
+    const baseDir = await createTemporaryBaseDir()
+    temporaryDirectories.push(baseDir)
+    const config = createConfig(baseDir)
+    const runtimeState = await createRuntimeState(createSpec(), "ses_alive_lead", "user", config)
+    await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+      ...currentRuntimeState,
+      status: "active",
+      leadSessionId: "ses_alive_lead",
+      members: currentRuntimeState.members.map((member) => {
+        if (member.name === "lead") return { ...member, sessionId: "ses_alive_lead", status: "running" as const }
+        return { ...member, sessionId: "ses_dead_worker", status: "running" as const }
+      }),
+    }), config)
+    const sessionGet = mock(async ({ path }: { path: { id: string } }) => {
+      if (path.id === "ses_alive_lead") return { data: { id: path.id } }
+      throw Object.assign(new Error("session not found"), { status: 404 })
+    })
+
+    // when
+    const report = await resumeAllTeams(createExecutorContext(baseDir, sessionGet), config)
+    const persistedState = await loadRuntimeState(runtimeState.teamRunId, config)
+
+    // then
+    expect(persistedState.status).toBe("orphaned")
+    const worker = persistedState.members.find((member) => member.name === "worker")
+    expect(worker?.status).toBe("errored")
+    expect(worker?.sessionId).toBeUndefined()
+    expect(report.resumed).toBe(0)
+    expect(report.marked_orphaned).toBe(1)
+  })
+
+  test("orphans active teams on a second resume after one worker was already errored and the last live worker just died", async () => {
+    // given
+    const baseDir = await createTemporaryBaseDir()
+    temporaryDirectories.push(baseDir)
+    const config = createConfig(baseDir)
+    const runtimeState = await createRuntimeState(createSpecWithTwoWorkers(), "ses_alive_lead", "user", config)
+    await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+      ...currentRuntimeState,
+      status: "active",
+      leadSessionId: "ses_alive_lead",
+      members: currentRuntimeState.members.map((member) => {
+        if (member.name === "lead") return { ...member, sessionId: "ses_alive_lead", status: "running" as const }
+        if (member.name === "worker-a") return { ...member, sessionId: undefined, status: "errored" as const }
+        return { ...member, sessionId: "ses_dead_b", status: "running" as const }
+      }),
+    }), config)
+    const sessionGet = mock(async ({ path }: { path: { id: string } }) => {
+      if (path.id === "ses_alive_lead") return { data: { id: path.id } }
+      throw Object.assign(new Error("session not found"), { status: 404 })
+    })
+
+    // when
+    const report = await resumeAllTeams(createExecutorContext(baseDir, sessionGet), config)
+    const persistedState = await loadRuntimeState(runtimeState.teamRunId, config)
+
+    // then
+    expect(persistedState.status).toBe("orphaned")
+    const workerA = persistedState.members.find((member) => member.name === "worker-a")
+    const workerB = persistedState.members.find((member) => member.name === "worker-b")
+    expect(workerA?.status).toBe("errored")
+    expect(workerB?.status).toBe("errored")
+    expect(workerB?.sessionId).toBeUndefined()
+    expect(report.resumed).toBe(0)
+    expect(report.marked_orphaned).toBe(1)
+  })
+})
diff --git a/src/features/team-mode/team-state-store/resume.ts b/src/features/team-mode/team-state-store/resume.ts
new file mode 100644
index 000000000..96608bd4c
--- /dev/null
+++ b/src/features/team-mode/team-state-store/resume.ts
@@ -0,0 +1,245 @@
+import { rm, stat } from "node:fs/promises"
+
+import type { TeamModeConfig } from "../../../config/schema/team-mode"
+import { log } from "../../../shared/logger"
+import type { ExecutorContext } from "../../../tools/delegate-task/executor-types"
+import { reclaimStaleReservations } from "../team-mailbox/reservation"
+import { getRuntimeStateDir, resolveBaseDir } from "../team-registry/paths"
+import type { RuntimeState } from "../types"
+import { listActiveTeams, loadRuntimeState, transitionRuntimeState } from "./store"
+
+const CREATING_TIMEOUT_MS = 30 * 60 * 1000
+const STALE_RESERVATION_TTL_MS = 10 * 60 * 1000
+
+export interface ResumeReport {
+  resumed: number
+  marked_failed: number
+  marked_orphaned: number
+  cleaned: number
+  errors: Error[]
+}
+
+function toError(error: unknown): Error {
+  return error instanceof Error ? error : new Error(String(error))
+}
+
+function extractErrorMessage(error: unknown): string | undefined {
+  if (error instanceof Error) return error.message
+  if (typeof error === "string") return error
+  if (typeof error !== "object" || error === null || !("message" in error)) return undefined
+  return typeof error.message === "string" ? error.message : undefined
+}
+
+function extractErrorStatus(error: unknown): number | undefined {
+  if (typeof error !== "object" || error === null || !("status" in error)) return undefined
+  return typeof error.status === "number" ? error.status : undefined
+}
+
+function isSessionNotFoundError(error: unknown): boolean {
+  if (extractErrorStatus(error) === 404) return true
+  const message = extractErrorMessage(error)?.toLowerCase()
+  if (!message) return false
+  return message.includes("not found") || message.includes("missing")
+}
+
+async function runtimeDirectoryExists(teamRunId: string, config: TeamModeConfig): Promise<boolean> {
+  try {
+    await stat(getRuntimeStateDir(resolveBaseDir(config), teamRunId))
+    return true
+  } catch (error) {
+    const nodeError = error as NodeJS.ErrnoException
+    if (nodeError.code === "ENOENT") return false
+    throw error
+  }
+}
+
+async function removeRuntimeDirectory(teamRunId: string, config: TeamModeConfig): Promise<boolean> {
+  if (!(await runtimeDirectoryExists(teamRunId, config))) return false
+  await rm(getRuntimeStateDir(resolveBaseDir(config), teamRunId), { recursive: true, force: true })
+  return true
+}
+
+async function cleanupMemberWorktrees(runtimeState: RuntimeState): Promise<void> {
+  await Promise.all(runtimeState.members.map(async (member) => {
+    if (!member.worktreePath) return
+    await rm(member.worktreePath, { recursive: true, force: true })
+  }))
+}
+
+async function sessionExists(
+  ctx: ExecutorContext,
+  sessionId: string,
+): Promise<boolean> {
+  try {
+    const response = await ctx.client.session.get({ path: { id: sessionId } })
+
+    if (response.error != null) {
+      if (isSessionNotFoundError(response.error)) return false
+      throw toError(response.error)
+    }
+
+    return response.data != null
+  } catch (error) {
+    if (isSessionNotFoundError(error)) return false
+    throw error
+  }
+}
+
+function isCreatingStateStuck(runtimeState: RuntimeState, now: number): boolean {
+  return runtimeState.status === "creating" && now - runtimeState.createdAt > CREATING_TIMEOUT_MS
+}
+
+interface WorkerLiveness {
+  readonly name: string
+  readonly wasSpawned: boolean
+  readonly stillAlive: boolean
+}
+
+async function inspectWorkerMembers(
+  ctx: ExecutorContext,
+  runtimeState: RuntimeState,
+): Promise<WorkerLiveness[]> {
+  const workerMembers = runtimeState.members.filter((member) => member.agentType !== "leader")
+
+  return await Promise.all(workerMembers.map(async (member) => {
+    if (member.status === "errored") {
+      return { name: member.name, wasSpawned: true, stillAlive: false }
+    }
+
+    if (member.sessionId === undefined) {
+      return { name: member.name, wasSpawned: false, stillAlive: true }
+    }
+
+    const stillAlive = await sessionExists(ctx, member.sessionId)
+    return { name: member.name, wasSpawned: true, stillAlive }
+  }))
+}
+
+export async function resumeAllTeams(
+  ctx: ExecutorContext,
+  config: TeamModeConfig,
+): Promise<ResumeReport> {
+  const report: ResumeReport = {
+    resumed: 0,
+    marked_failed: 0,
+    marked_orphaned: 0,
+    cleaned: 0,
+    errors: [],
+  }
+  const now = Date.now()
+  const activeTeams = await listActiveTeams(config)
+
+  for (const activeTeam of activeTeams) {
+    try {
+      const runtimeState = await loadRuntimeState(activeTeam.teamRunId, config)
+
+      switch (runtimeState.status) {
+        case "creating": {
+          if (!isCreatingStateStuck(runtimeState, now)) break
+          await cleanupMemberWorktrees(runtimeState)
+          await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+            ...currentRuntimeState,
+            status: "failed",
+          }), config)
+          report.marked_failed += 1
+          break
+        }
+
+        case "active": {
+          if (!runtimeState.leadSessionId || !(await sessionExists(ctx, runtimeState.leadSessionId))) {
+            await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+              ...currentRuntimeState,
+              status: "orphaned",
+            }), config)
+            report.marked_orphaned += 1
+            break
+          }
+
+          await Promise.all(runtimeState.members.map(async (member) => {
+            try {
+              await reclaimStaleReservations(runtimeState.teamRunId, member.name, config, STALE_RESERVATION_TTL_MS)
+            } catch (reclaimError) {
+              log("team mailbox reservation reclaim failed", {
+                event: "team-mailbox-reclaim-failed",
+                teamRunId: runtimeState.teamRunId,
+                member: member.name,
+                error: reclaimError instanceof Error ? reclaimError.message : String(reclaimError),
+              })
+            }
+          }))
+
+          const workerCheckResults = await inspectWorkerMembers(ctx, runtimeState)
+          const deadWorkerNames = new Set(
+            workerCheckResults
+              .filter((result) => result.wasSpawned && !result.stillAlive)
+              .map((result) => result.name),
+          )
+          const hasAliveWorker = workerCheckResults.some((result) => result.stillAlive)
+          const hasAnyWorker = workerCheckResults.length > 0
+
+          const markDeadWorkersErrored = (currentRuntimeState: RuntimeState): RuntimeState => ({
+            ...currentRuntimeState,
+            members: currentRuntimeState.members.map((member) => (
+              deadWorkerNames.has(member.name)
+                ? { ...member, status: "errored" as const, sessionId: undefined }
+                : member
+            )),
+          })
+
+          if (hasAnyWorker && !hasAliveWorker) {
+            await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+              ...markDeadWorkersErrored(currentRuntimeState),
+              status: "orphaned",
+            }), config)
+            report.marked_orphaned += 1
+            break
+          }
+
+          if (deadWorkerNames.size > 0) {
+            await transitionRuntimeState(runtimeState.teamRunId, markDeadWorkersErrored, config)
+          }
+
+          report.resumed += 1
+          break
+        }
+
+        case "deleting": {
+          await cleanupMemberWorktrees(runtimeState)
+          await transitionRuntimeState(runtimeState.teamRunId, (currentRuntimeState) => ({
+            ...currentRuntimeState,
+            status: "deleted",
+          }), config)
+          if (await removeRuntimeDirectory(runtimeState.teamRunId, config)) {
+            report.cleaned += 1
+          }
+          break
+        }
+
+        case "deleted":
+        case "failed": {
+          if (await removeRuntimeDirectory(runtimeState.teamRunId, config)) {
+            report.cleaned += 1
+          }
+          break
+        }
+
+        case "shutdown_requested":
+        case "orphaned": {
+          break
+        }
+      }
+    } catch (error) {
+      const resumeError = toError(error)
+      report.errors.push(resumeError)
+      log("team runtime resume failed", {
+        event: "team-runtime-resume-failed",
+        teamRunId: activeTeam.teamRunId,
+        teamName: activeTeam.teamName,
+        status: activeTeam.status,
+        error: resumeError.message,
+      })
+    }
+  }
+
+  return report
+}