[FEATURE] Expose the Artifact tool and artifact-* skills in Remote Control (sdk-cli) sessions

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet (closest: #82682, a hang inside the skill, and #91883, the Artifact permission prompt in cloud routines — neither covers availability in Remote Control sessions)
• [x] This is a single feature request

Problem Statement

Sessions created from the mobile app's Code tab are spawned by the claude rc server as headless SDK sessions:

claude --print --sdk-url https://api.anthropic.com/v1/code/sessions/cse_… --session-id cse_… --input-format stream-json --output-format stream-json --replay-user-messages --resume=… --model …

They run with entrypoint: sdk-cli. In that entrypoint the built-in Artifact tool and the bundled artifact-design / artifact-diagramming / artifact-capabilities skills are not registered, while interactive cli and claude-desktop sessions on the same machine and the same version do have them. The Artifact tool's own prompt even carries a fallback text for "the artifact-design skill is not available in this session".

This is backwards for the mobile use case: on a phone, a published artifact (https://claude.ai/code/artifact/<id>) is the only native way to open and read a rendered document produced by the session. Today the only way to get one from the phone is to keep an interactive terminal session alive on the workstation (tmux/Ptyxis) so that it registers itself in Remote Control as a cli session, and use that one instead.

Reproduction (2.1.268 and 2.1.269, Linux/Fedora, native installer, claude rc running under a systemd user service with remoteControlAtStartup: true):

1. Open a new session from the mobile Code tab (served by claude rc).
2. Ask for an artifact, or check ToolSearch("select:Artifact") → nothing; /artifact-design is not in the skills list.
3. Open claude in a terminal on the same host (it also shows up in the mobile app via Remote Control) → Artifact and /artifact-design are available and publishing works.

Checked over the last 30 sessions in one project directory: every cli / claude-desktop session has the Artifact tool, no sdk-cli session has it. Permission mode is not the factor (the sessions that published artifacts also ran in auto mode).

Proposed Solution

Register the Artifact tool and the artifact-* skills for Remote Control sessions (sessions spawned by the rc bridge / attended sdk-cli sessions), or add an explicit opt-in — e.g. claude rc --enable-artifacts or a setting — so that a session created from the mobile app can publish artifacts exactly like an interactive one. Permission handling can stay under the session's normal permission mode.

Alternative Solutions

• Keeping a persistent interactive session (tmux) registered in Remote Control just to have artifacts on the phone.
• Asking an interactive peer session to publish on behalf of the mobile session (undesirable: cross-session permission laundering).
• Exporting to Google Drive / a local HTML file (loses the native "open document" experience on mobile, and the auto-mode classifier reasonably blocks uploads of internal content to third parties).

Priority

High – significant impact on productivity (mobile-first workflow with Remote Control).

Additional Context

• Claude Code 2.1.268 / 2.1.269, Linux (Fedora 44), native installer, Anthropic API / Max plan.
• The rc server keeps running the binary it started with (2.1.268) after an update to 2.1.269 until the service is restarted; not related to this request, mentioned only so versions are not confusing.