[BUG] Cowork: create_artifact / update_artifact / list_artifacts selectively removed from an otherwise fully healthy remote-devices bridge

Summary

Since approximately Aug 20, 2026, ~2:40 PM MST (last successful update_artifact call), the three artifact
tools on the desktop device bridge - create_artifact, update_artifact, list_artifacts - are ABSENT from
the tool list in every Cowork session. The rest of the same bridge is completely healthy in the same
sessions.

This is not the same failure as #76095 (where the whole device tool set is unavailable in new sessions) and
not the same as #51426 (where the sidebar entry point vanishes but the MCP tools still work). It is a
partial, selective removal of three tools from a server that is otherwise fully provisioned, which I
could not find described in any existing issue.

What still works, verified in the same sessions

• device_list_dir, device_bash, device_stage_files, device_commit_files - all fine
• project_memory_read / project_memory_write - fine
• computer_* tools - fine
• Artifact READ still works indirectly: device_stage_files accepts an artifact_ids parameter and

returns the artifact HTML. So the artifact subsystem is reachable; only create/update/list are gone.

What does not work

create_artifact, update_artifact, list_artifacts are not in the tool list at all. They are not erroring -
they are not present to call.

Reproduction / troubleshooting already done

1. Re-verified across multiple sessions Aug 20 through Aug 23.
2. Full Cmd+Q quit and relaunch of the desktop app - no change.
3. Explicit tool-list refresh - server responds and reports its tool count, artifact tools not among them.
4. New sessions and pre-existing sessions behave identically (unlike #76095, where that distinction is the

whole tell).

Environment

• Claude desktop app, macOS (darwin arm64), appVersion 1.34493.1, Electron 42.9.2
• Cowork sessions with a connected desktop device and connected folders

Impact

We run a persisted artifact as an always-on operations board, updated several times daily since mid-July.
It has been frozen at its Aug 20 state ever since, because no update path exists. The daily workaround is
rendering the same HTML to a file and re-sending it, which loses the persistence that made the artifact
useful in the first place.

Ask

Restore the three artifact tools to the desktop bridge - or, if they were intentionally removed, renamed, or
gated behind a new flag, please say so and document the supported replacement path. A selective removal with
no announcement and no error is very hard to distinguish from a bug on our end, and we spent several sessions
proving it was not.