[BUG] pptx/docx/xlsx skills fail with raw mcp__workspace__bash permission denial in Chat tab instead of a clear message (works fine in Cowork)

Environment

• Claude Desktop (macOS), enterprise managed Mac fleet (MDM profile pushed via a third party MDM provider, JumpCloud OIDC SSO for Desktop login)
• Both the Chat tab and Cowork tested
• Confirmed on multiple machines, admin and non-admin local accounts, and with the MDM profile present and removed

What happens
Asking Claude to build a PowerPoint file in the Chat tab triggers the built in pptx skill ("Ran skill: pptx"), which immediately attempts a Bash tool call (checking /sessions/, the skill's own plugin directory, and node -e "require('pptxgenjs')...") and fails with:

Permission to use mcp__workspace__bash has been denied.

No permission prompt is ever shown, so there's nothing to approve. The same request in the Cowork tab, on the same machine, with the same account, succeeds and produces a working .pptx file every time.

What we ruled out
We treated this as a permissions bug at first and spent a lot of time on it before concluding it's actually expected behavior:

• Not a managed-settings.json issue — there's no local settings file involved, and the denial is identical with the MDM profile present or completely removed.
• Not admin vs non-admin — fails identically for both.
• Not the Cowork-specific "install a helper tool" macOS prompt (a separate one-time setup step Cowork needs on first use) — Chat never shows that prompt at all, it fails outright every time regardless of whether that helper tool is already installed and working (confirmed Cowork works fine on the same machine).
• Other file types (CSV, PDF, plain text) build successfully in Chat with no issue. Only skills that need to run code (pptx, and presumably docx/xlsx, not individually re-tested) fail.

Likely root cause
Per the Code Execution Tool docs (https://platform.claude.com/docs/en/agents-and-tools/tool-use/code-execution-tool), supported platforms are Claude API, Claude on AWS, and Microsoft Foundry — Desktop's Chat surface isn't on that list. Cowork has its own execution environment and isn't subject to the same restriction. So this looks like the pptx/docx/xlsx/pdf skills are being offered in Chat even though Chat has no code execution backend to run them on, and the failure surfaces as a raw internal tool permission string instead of something that explains what's going on.

Expected behavior
Either:

1. Skills that require code execution shouldn't be offered/triggered in the Chat tab at all if Chat can't run them, or
2. If triggered anyway, the failure should be a clear, user facing message ("Building files like this needs Cowork") instead of Permission to use mcp__workspace__bash has been denied., which looks like a misconfiguration rather than an unsupported surface.

Impact
Confusing support burden for any team rolling out Claude Desktop at an organization: end users file this as "broken," IT spends time ruling out MDM/permissions/managed settings (as we did) before concluding it's an unsupported surface, not a bug on their end.