opencode run -f mislabels local file attachments as text/plain #38952

Description

opencode run -f <path> (no --attach) always sets the attachment's mime to text/plain (or application/x-directory for a directory), regardless of the file's actual type. The correct mime is computed via FSUtil.mimeType() right above it but never used for this branch, and that call is also never awaited (it's an async function).

Effect: any non-text local attachment - an image, for example - gets sent to the model mislabeled as text/plain instead of e.g. image/png.

OpenCode version

1.18.5

Steps to reproduce

1. opencode run -m ollama/<vision-capable-model> --agent plan --print-logs --log-level DEBUG -f ./some-image.png -- "what does this image show?"
2. Check the logs: message=file mime=text/plain even though the attached file is a PNG.

Operating System

Linux