Plugin worker "${pluginId}" is not running for the duplex ch

Error message

Plugin worker "${pluginId}" is not running for the duplex channel.

What it means

Thrown by the plugin sandbox driver's openDuplexChannel when pluginWorkerManager.getWorker(pluginId) returns null — the lease names a plugin whose worker process is not currently running on the host. The duplex route must bind to the same worker session the sandbox runner streams through, so a stopped/crashed/never-started worker is a hard failure for the channel open.

Source

Thrown at server/src/services/environment-runtime.ts:2493

    async openDuplexChannel(input) {
      // Plugin-backed sandbox providers only: open the host-owned duplex route on
      // the plugin worker. The lease scope mirrors the sandbox execute path — the
      // provider driver key, the company, the environment, and the provider lease
      // id — so the route binds to the same worker session the runner streams.
      if (!input.lease.metadata?.sandboxProviderPlugin || !pluginWorkerManager) {
        throw new Error("Sandbox driver does not support duplex channels for this lease.");
      }
      const pluginId = readString(input.lease.metadata?.pluginId);
      const providerKey = readString(input.lease.metadata?.provider);
      const providerLeaseId = readString(input.lease.providerLeaseId);
      if (!pluginId || !providerKey || !providerLeaseId) {
        throw new Error(
          "Sandbox duplex channel needs a plugin id, a provider key, and a provider lease id on the lease.",
        );
      }
      const worker = pluginWorkerManager.getWorker(pluginId);
      if (!worker) {
        throw new Error(`Plugin worker "${pluginId}" is not running for the duplex channel.`);
      }
      const managerInput: WorkerManagerDuplexChannelOpenInput = {
        driverKey: providerKey,
        companyId: input.lease.companyId,
        environmentId: input.environment.id,
        providerLeaseId,
        command: input.command,
      };
      const session = await worker.openDuplexChannel(managerInput);
      return adaptDuplexChannelHostSession(session);
    },

    async effectiveSandboxCapabilities(input) {
      const metadata = input.lease.metadata ?? {};
      const providerKey =
        readString(metadata.provider) ??
        (input.environment.driver === "sandbox"
          ? readString((parseEnvironmentDriverConfig(input.environment).config as SandboxEnvironmentConfig).provider)

View on GitHub (pinned to a7e689b3c3)

Solutions

Check plugin worker status on the server (plugin registry/manager logs) for the named pluginId.
Restart or re-enable the plugin so its worker boots, then retry the channel open.
If the worker keeps dying, inspect the plugin worker logs for the crash cause and fix the plugin before retrying.
If the lease outlived a plugin upgrade, acquire a fresh sandbox lease from the current plugin version.

Defensive patterns

Strategy: retry

Validate before calling

const worker = pluginWorkerManager.getWorker(pluginId);
if (!worker) { await pluginWorkerManager.ensureWorkerStarted(pluginId); } // start the worker before opening the channel

Try / catch

try { return await driver.openDuplexChannel(input); } catch (err) { if (/is not running for the duplex channel/.test((err as Error).message)) { await restartPluginWorker(pluginId); return await driver.openDuplexChannel(input); } throw err; }

Prevention

Ensure plugin workers are started (or eagerly warmed) before agents begin duplex sessions.
Monitor plugin worker health and auto-restart crashed workers.
Acquire fresh leases after plugin upgrades rather than reusing leases bound to a dead worker session.

When it happens

Trigger: openDuplexChannel with valid lease metadata while the plugin's worker process is down: the plugin was disabled or failed to boot, the worker crashed earlier and was not restarted, or the channel open races worker startup right after server boot.

Common situations: Plugin worker crashed (OOM, unhandled error) leaving leases valid but workers dead; server restarted and lazy worker start has not happened yet for that plugin; plugin uninstalled/updated between lease creation and channel open.

Related errors

AI-assisted analysis of paperclipai/paperclip@a7e689b3c3 (2026-08-21). Data as JSON: /api/errors/60551e42af0b5de7. Report an issue: GitHub.