A tiny OpenClaw plugin that suppresses the Background task done: … notifications on the Telegram channel only.

When you spawn ACP or subagent background tasks bound to a Telegram thread (e.g. via openclaw acp spawn, thread bindings, or the built-in task registry), OpenClaw auto-delivers a terminal notification to the thread when each task finishes:

Background task done: kiro-identity-test4 (run 3970).
Background task blocked: …
Background task failed: …
…

These are noisy when you use ACP sessions heavily from Telegram. This plugin drops those specific outbound messages on the Telegram channel and only those.

• ✅ Intercepts the Telegram outbound via the message_sending hook and returns { cancel: true } for messages whose content starts with a known task-terminal prefix.
• ✅ Leaves every other Telegram message untouched (pass-through).
• ✅ Leaves the task registry untouched: tasks still run, still reach their terminal state, still update deliveryStatus, still dispatch in-session mirrors, still power openclaw tasks list. Only the Telegram notification line is swallowed.
• ❌ Does not modify ACPx, the task registry bundle, or any OpenClaw internals. No monkey-patching, no policy flipping, no cron.

The plugin drops outbound Telegram messages that start with any of:

• Background task done:
• Background task blocked:
• Background task failed:
• Background task timed out:
• Background task cancelled:
• Background task lost:
• Task needs follow-up:

These are the exact strings emitted by OpenClaw’s formatTaskTerminalMessage / formatTaskBlockedFollowupMessage (dist/task-registry-*.js).

git clone https://github.com/adagues/openclaw-telegram-task-silencer.git
openclaw plugins install ./openclaw-telegram-task-silencer
# restart the OpenClaw gateway for plugins to load

openclaw plugins uninstall telegram-task-silencer

OpenClaw exposes a message_sending hook (see dist/extensions/telegram/delivery-*.js) that runs right before each outbound Telegram message is delivered. The plugin registers a single handler:

api.on("message_sending", async (event, ctx) => {
  if (!isTelegramChannel(event, ctx)) return;           // wrong channel → pass-through
  if (!isTaskTerminalMessage(event?.content)) return;   // not a task notif → pass-through
  return { cancel: true };                              // drop this message only
});

That’s the whole plugin.

• Tested against OpenClaw 2026.4.29 / CLI 2026.4.22.
• Relies on the public plugin SDK (openclaw/plugin-sdk/plugin-entry) and the message_sending hook, both documented surfaces.
• If OpenClaw ever changes the terminal message wording, the prefix list in index.js needs an update.

MIT — see LICENSE.