Artifact publishing can copy files from other artifacts server-side, but it's off by default.
Artifact publishing can now copy files from another artifact instead of only using local files, via a copied list in the publish input with from_url/from_path entries, or a files entry shaped {artifact, path, ver?} that copies a published file server-side without downloading and re-uploading it. A separate copy_from action accepts from_url plus up to a capped number of asset_ids to copy assets between artifacts. Validation blocks copying an artifact's own index.html, blocks copying HTML/SVG/XML documents entirely, requires ver to be a valid version id, and caps the number of distinct source-artifact versions per publish.
This whole feature is off by default, gated by a remote flag (tengu_cobalt_plinth_samphire) that defaults to false. While off, any attempt to copy returns the fixed refusal "copying files from another artifact is not enabled for this account — nothing was published; publish with local files instead" and logs a tengu_artifact_publish event with reason copy_from_flag_off.
tengu_cobalt_plinth_samphire Off in both readingsThe flag server returned off for the account this site reads and for the anonymous baseline. A reading of off cannot rule out a rollout these two readings sit outside of.
This account: off · anonymous baseline: off · compiled default in v2.1.260: off
These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.
Read once, for one account on one subscription tier, against v2.1.260. It isn't a statement about your account. What a flag value here can and cannot tell you
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.
* With [feature-flag fetching off](/docs/en/env-vars#features-that-need-feature-flag-fetching), Claude Code stores a task you asked to keep across sessions in the project's `.claude/scheduled_tasks.json` file. When the `.claude` directory …scheduled-tasks see the edit
2. Pick the channel in the **Channel** field. Type a name to search public channels, or paste a channel ID or channel link copied from Slack. Private channels don't appear in the search results, so for a private channel, paste its ID from …claude-tag/admins/attach-to-scope see the edit
Anthropic's documentation has since written up copied, on Configure per-channel access.
New in this build: tengu_cobalt_plinth_samphire