deepseek-ai/deepseek-harness · error · Error

cannot change sandbox mode from "${currentMode}" to "${event

Error message

cannot change sandbox mode from "${currentMode}" to "${event.data.mode}" while persistent terminal sessions are open or being created; wait for creation to settle and close them first

What it means

Error "cannot change sandbox mode from "${currentMode}" to "${event.data.mode}" while persistent terminal sessions are open or being created; wait for creation to settle and close them first" thrown in deepseek-ai/deepseek-harness.

Source

Thrown at packages/terminal/terminal-bash/src/index.ts:50

const sandboxModeFences = new WeakMap<Agent, SandboxModeFenceState>()

function ensureSandboxModeFence(ctx: Context, owner: Agent): void {
  const existing = sandboxModeFences.get(owner)
  if (existing !== undefined) {
    existing.pty = ctx.terminals
    existing.sandboxPolicy = ctx.sandboxPolicy
    return
  }
  const state: SandboxModeFenceState = { pty: ctx.terminals, sandboxPolicy: ctx.sandboxPolicy }
  sandboxModeFences.set(owner, state)
  owner.ctx.on('internal/dispatch', (_mode, eventName, args) => {
    if (eventName !== 'session/event') return
    const [session, event] = args as [Session, SessionEvent]
    if (session !== owner.session || event.type !== 'sandbox/mode') return
    const currentMode = effectiveSandboxMode(session.events) ?? state.sandboxPolicy.defaultMode
    if (event.data.mode === currentMode || !state.pty.hasOwnerActivity(owner)) return
    throw new Error(
      `cannot change sandbox mode from "${currentMode}" to "${event.data.mode}" while persistent terminal sessions are open or being created; wait for creation to settle and close them first`,
    )
  }, { global: true })
}

function childEnvironment(spec: TerminalBackendSpawnSpec, dialect: ShellDialect): Record<string, string> {
  // The subprocess provider supplies its own scrubbed ambient base; these are
  // deliberate terminal-specific overrides layered after it.
  const common = {
    TERM: 'dumb',
    PAGER: 'cat',
    GIT_PAGER: 'cat',
    DSH_SHELL: '1',
    DSH_SESSION_ID: spec.owner.id,
    DSH_PTY_SESSION_ID: spec.sessionId,
  }
  if (dialect === 'pwsh') {
    // pwsh ignores PS1/PROMPT_COMMAND; its prompt is installed by the startup

View on GitHub (pinned to b150a551b8)

Solutions

1. Wait for terminal creation to settle, close all open persistent sessions, then change the sandbox mode.

When it happens

Trigger: Thrown at packages/terminal/terminal-bash/src/index.ts:50 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of deepseek-ai/deepseek-harness@b150a551b8 (2026-08-24). Data as JSON: /api/errors/a1f6df2712ef83d1. Report an issue: GitHub.