Claude Code mobile remote control silently drops image attachments (received on PC as text-only)

Summary

When sending an image attachment from the Claude Code mobile app via the "remote control" feature to a Claude Code session running on a Windows PC, the mobile UI shows the attachment uploaded successfully, but the PC-side Claude Code session receives only the text portion of the message — the image attachment is silently dropped and never appears in context.

Environment

• PC: Windows 11 Home China (10.0.26200)
• PC Claude Code CLI: v2.1.149 (at C:\Users\<user>\AppData\Roaming\Claude\claude-code\2.1.149\claude.exe, auto-bundled with Claude Desktop, last updated 2026-05-23)
• Mobile Claude Code app: version 1.260514.0 (build 26051400)
• Connection: Mobile remote control feature in the Claude Code mobile app, paired to the running Claude Code session on the PC

Reproduction

1. Start a Claude Code session on the PC.
2. Open the Claude Code mobile app on phone, use "remote control" to attach to the PC session.
3. Compose a message containing both text and an image attachment (any common format, e.g. PNG screenshot from phone or PC).
4. Send.

Expected

The PC-side Claude Code session receives the message and the image as a vision content block — the assistant can describe / reason about the image.

Actual

• Mobile UI shows the attachment uploaded successfully and the message sent.
• PC-side session receives the text part only.
• The image never appears in the assistant's context.
• The assistant correctly reports it did not receive any attachment.

Reproducibility

• 2 / 2 attempts via mobile remote control failed (100 % drop rate).
• Control: in the same PC session, an image sent via the Claude Desktop app (claude.ai chat client running on the same PC) was received correctly (1 / 1). So the issue is specific to the mobile remote control → PC session attachment delivery path, not the PC session's general ability to receive images.

Additional Context

• The user also operates a separate WhatsApp bot that invokes claude -p --system-prompt-file <sysprompt> --permission-mode bypassPermissions --disable-slash-commands with image paths included as @<local-path> mentions in the prompt — this does correctly trigger vision (full pixel-level descriptions returned). Confirms PC-side claude.exe has no issue with vision when given a proper image content block.
• Conclusion: the bug appears to live in the mobile-app → Anthropic relay → PC-session attachment delivery pipeline, not in claude.exe itself.

Severity

Medium — workaround exists (re-send via Claude Desktop on PC, or other channels). But it makes the mobile remote control feature unusable for any task that requires sharing a screenshot / chart / photo from phone (e.g. quick "look at this and tell me what's wrong" workflows that are the main reason to use a mobile companion).