Nothing to try yetTier: how much it should matter to you
3Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
ArtifactsArea: what it touches
In DevelopmentKind: in v2.1.267,
In DevelopmentSection of the release
What
When republishing an artifact (an update to something already published, sometimes called "hot" mode), the artifact tool's prompt now documents an optional deadline field. It accepts values like "now", "15m", "1h", "24h", "7d", or a specific ISO timestamp, and forces older running copies of the artifact to stop by that time. This is gated behind a schema flag (hotOn), and the field only applies to republishes, not ordinary edits, where it should be omitted.
Why
This gives control over how long an outdated running copy of a republished artifact is allowed to keep running before it's shut down, rather than leaving that unbounded.
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.
Added sinceA small documentation edit on Environment variables touched a line naming deadline after this was published.| `CLAUDE_CODE_WEBFETCH_DEADLINE_MS` | Upper bound in milliseconds on how long [WebFetch](/docs/en/tools-reference#webfetch-tool-behavior) waits for a page to download, including any redirects it follows. A download that hasn't completed b…env-varssee the edit
Confirmed sinceAnthropic's documentation has since written up deadline, on Claude Code changelog.* Fixed WebFetch hanging indefinitely on a server that keeps the response open without finishing; a fetch now fails after 300 seconds. Set `CLAUDE_CODE_WEBFETCH_DEADLINE_MS` to override the deadline (0 turns it off)changelogsee the edit
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up deadline, on Claude Code changelog.
