Monitor Tool / Claude Code v2.1.98

What

A new built-in tool that streams events from background scripts as live notifications in the conversation.

Usage

# Inside a Claude Code session, Claude can use the Monitor tool to:
# - Tail logs for errors
# - Watch for file changes
# - Poll GitHub for new PR comments
# - Stream events from WebSocket listeners

Details

Each stdout line from the script becomes a notification in the conversation
Events arriving within 200ms are batched into a single notification
Supports persistent: true mode for session-length watches (PR monitoring, log tails)
Supports timeout_ms for time-limited monitoring
Monitors that produce too many events are automatically stopped with guidance to restart using tighter filters
Use TaskStop to cancel a running monitor
Distinct from Bash with run_in_background — Monitor is for the streaming case ("tell me every time X happens"), while background Bash is for one-shot "wait until done"

Evidence

MonitorTool definition (search for "stream events from a background script as live notifications")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.