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Sweep 22 Sep 2026 · 17:19Z Build v2.1.280 501 read Stable v2.1.267 Latest v2.1.280 Next v2.1.280 Feeds RSS JSON llms.txt Unofficial
Claude Code v2.1.268 ·

Background monitor/watch tool gains a bounded, self-expiring mode

← All of v2.1.268 Home All releases

Behind an experimental flag, the monitor tool's watch timeout can now expire and require a manual re-arm instead of running indefinitely.

TierNothing to try yethow much it should matter to you
Useful5my rating, 1 to 5
Signal4worth watching, 1 to 5
AreaMonitor Toolwhat it touches
KindIn Developmentin v2.1.268,
Group of 2 Nothing to try yet Notable

Behind an experimental flag, the monitor tool's watch timeout can now expire and require a manual re-arm instead of running indefinitely.

What

  • The Monitor (background watch) tool's timeout behavior changed: behind an experimental flag, it now uses a bounded timeout schema with a capped, defaulted timeout_ms, instead of the previous unbounded schema.
  • When the bounded timeout expires, Claude Code now sends a specific notice that includes how much time elapsed and how many events were delivered (or none), and instructs the model to "re-arm" the watch rather than keep polling.
  • The system prompt text describing background monitors changes to match: instead of saying a monitor sends "one notification per occurrence... indefinitely", it now says "until the monitor expires (re-arm to continue)" when this flag is on.

Why An unbounded watch could run forever consuming resources; a bounded, self-expiring watch forces a periodic check-in ("re-arm") so long-running monitors don't run unattended indefinitely.

Read from
Names in the bundletimeout_ms
Feature flag
tengu_breezy_crescent Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: off · compiled default in v2.1.268: off

Read once, for one account on one subscription tier, against v2.1.268. It isn't a statement about your account. What a flag value here can and cannot tell you

Since it was published

The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.

Confirmed since Anthropic's documentation has since written up timeout_ms, on Agent SDK reference - TypeScript. timeout_ms: number; agent-sdk/typescript see the edit
What has happened since
Flag reading moved The flag server now returns on for tengu_breezy_crescent, read as this account. A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.

See this across every release →

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtWhether this bounded behavior is active for a given user depends on the tengu_breezy_crescent setting, which is currently off for this…
Anthropic's documentation agreesAnthropic's documentation has since written up timeout_ms, on Agent SDK reference - TypeScript.
The name it cites is new in this buildNew in this build: tengu_breezy_crescent

See this entry in the whole of v2.1.268 →

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