[FEATURE] Enable media playback in Cowork artifact sandbox (video/audio/HLS)

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Current workaround is handing the HLS stream URL to the OS via vlc:// protocol or direct link, which opens playback in VLC or the default browser. Functional but defeats the purpose of inline playback within Cowork.

Proposed Solution

1. User asks Claude in Cowork: "Show me live news channels"
2. MCP plugin returns channel data (name, logo, HLS stream URL)
3. Claude generates an HTML artifact with a channel grid
4. User clicks a channel → video plays inline in the artifact
5. User asks "What else is on?" → Claude updates the artifact

Step 4 currently fails because the artifact sandbox blocks the <video> element from loading the HLS stream. Every other step works today.

Alternative Solutions

Tested on Cowork (Claude Desktop, macOS), April 2026. HTML artifacts only — React artifacts can't load CDN scripts like HLS.js.

Related issues: #22903, #12676, #29602

Priority

High - Significant impact on productivity

Feature Category

MCP server integration

Use Case Example

_No response_

Additional Context

_No response_