macOS Finder file copy pastes a PNG file icon into remote Codex instead of the image (0.9.0) #3975

Is this a reproducible bug?

• I confirm this is a reproducible bug, not a feature request, idea, question, contribution proposal, or direction check.
• I reproduced this bug on the version and environment reported below using the exact steps provided.

Current behavior

Copying an image file in Finder and pressing Ctrl+V in Codex on a connected remote machine attaches a generic PNG file icon instead of the image. The source image showed a purple anime character; the received file is a valid 1024×1024 PNG showing only the generic file icon. We opened the staged file directly on the remote host to verify this is its actual content, not a Codex display placeholder.

Remote server log for the paste (path shortened):

2026-09-11T22:07:44.140407Z INFO herdr::server::headless: staged client clipboard image client_id=62 bytes=70970 path=/tmp/herdr-clipboard-images-1000/client-62-clipboard-1789164464140319697-0.png

Expected behavior

The remote Codex session receives the contents of the image file copied in Finder, not its file icon.

Reproduction

1. Run Herdr in Kitty on macOS and connect to a Linux machine through the 0.9 remote machines integration.
2. Open Codex in a pane on that remote machine.
3. Select an image file in Finder and press Cmd+C (copy the file, not pixels from an image viewer).
4. Focus the remote Codex input and press Ctrl+V.
5. Submit the attachment. It contains the generic PNG icon rather than the original image.

Impact

I cannot reliably share Finder-copied images with the remote coding agent: the paste succeeds but silently attaches the wrong image.

Environment

• Herdr version: 0.9.0 on both macOS client and Linux remote
• Update channel: stable
• Operating system: macOS 26.6.2 (25G83), Apple Silicon; remote Linux aarch64, kernel 6.12.100-125.179.amzn2023.aarch64
• Terminal: Kitty 0.48.2 on macOS
• Shell: zsh
• Agent: codex-cli 0.154.0 on the remote
• Relevant workflow: remote machines integration; Finder Cmd+C followed by Ctrl+V in remote Codex. This is a single-file clipboard paste, not the multi-file drag-and-drop behavior in macOS --remote multi-image Finder drops paste local paths instead of staging images #1238.