[FEATURE] Device/Environment metadata in context

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

Claude has no awareness of the device, OS, app, or environment it's running in during a conversation (web, desktop, mobile, local vs. cloud deployment). This limits its ability to give context-appropriate help — e.g., troubleshooting "this isn't working on my tablet" requires the user to manually specify platform details that the client application already has access to.

Proposed Solution

Allow the client (web/desktop/mobile app) to optionally inject basic non-sensitive metadata into the system context at the start of a conversation — e.g., platform (iOS/Android/Windows/macOS/Linux), app type (web/desktop/mobile), and app version. This data is ALREADY collected by the platform for analytics/support purposes; making it visible to the model doesn't introduce new privacy exposure, but does let Claude tailor troubleshooting and formatting appropriately.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

User reports a bug or asks for help that depends on their platform ("this feature isn't showing up," "how do I do X here"). Currently Claude must ask what device/app they're using every time. With this metadata, Claude could respond immediately with platform-specific guidance.

Additional Context

_No response_