nanocoai/nanoclaw · warning

Failed to append task run log

Error message

Failed to append task run log

What it means

A task_log message targeted a task thread but appendRunLog failed to write to the group's run log file. The log line is lost; the task itself continues.

Source

Thrown at src/delivery.ts:318

  const content = JSON.parse(msg.content);

  // System actions — handle internally (cli_request, etc.)
  if (msg.kind === 'system') {
    await handleSystemAction(content, session);
    return;
  }

  // Task-run log: the runner mirrors a run's final text here (one-door
  // delivery — final text never reaches a channel; the send_message tool is
  // the only delivery path from a task session). Append to the series log,
  // never deliver. The caller marks it delivered so it isn't retried.
  if (msg.kind === 'task_log') {
    if (session.messaging_group_id === null && isTaskThread(session.thread_id) && session.thread_id) {
      const series = session.thread_id.slice(`${TASKS_SYSTEM_THREAD_ID}:`.length);
      try {
        await appendRunLog(session.agent_group_id, series, typeof content.text === 'string' ? content.text : '');
      } catch (err) {
        log.warn('Failed to append task run log', { id: msg.id, sessionId: session.id, err });
      }
    } else {
      log.warn('task_log row outside a task session — ignoring', { id: msg.id, sessionId: session.id });
    }
    return;
  }

  // Agent-to-agent — route to target session via the agent-to-agent module.
  // Guarded by the channel_type check. If the module isn't installed the
  // `agent_destinations` table won't exist and `routeAgentMessage`'s permission
  // check will throw, which falls into the normal retry → mark-failed path.
  if (msg.channelType === 'agent') {
    if (!(await hasTable(getDb(), 'agent_destinations'))) {
      throw new Error(`agent-to-agent module not installed — cannot route message ${msg.id}`);
    }
    const { routeAgentMessage } = await import('./modules/agent-to-agent/agent-route.js');
    await routeAgentMessage(
      {

View on GitHub (pinned to 294ef2aee8)

Solutions

1. Check the group folder path exists and is writable by the host user
2. Free disk space if full
3. Verify task run-log destination via `ncl tasks get`
4. Task output is also in messages_out — regenerate the log if needed

import fs from 'node:fs';
fs.accessSync(groupDir, fs.constants.W_OK); // verify before task runs

try { await appendRunLog(...); } catch { /* keep task output in messages_out as source of truth */ }

When it happens

Trigger: appendRunLog throws — run-log file or its directory is unwritable/missing, disk full, or path issues in groups/<folder>/.

Common situations: Group folder perms changed, disk full, or the group directory was moved/deleted out from under the host.

Related errors

• invalid task id: ${series}
• Unknown provider: ${name}. Registered: ${known}
• engage_mode '${w.engage_mode}' can never engage on channel '
• MissingChannelAdapterError(channelType, instance)
• chat-sdk bridge instance ${JSON.stringify(config.instance)}

AI-assisted analysis of nanocoai/nanoclaw@294ef2aee8 (2026-08-28). Data as JSON: /api/errors/49d1beafe6cf05c5. Report an issue: GitHub.