Agent Skills: bun-file-io

Use this when

• Editing file I/O or scans in packages/opencode
• Handling directory operations or external tools

Bun file APIs (from Bun docs)

• Bun.file(path) is lazy; call text, json, stream, arrayBuffer, bytes, exists to read.
• Metadata: file.size, file.type, file.name.
• Bun.write(dest, input) writes strings, buffers, Blobs, Responses, or files.
• Bun.file(...).delete() deletes a file.
• file.writer() returns a FileSink for incremental writes.
• Bun.Glob + Array.fromAsync(glob.scan({ cwd, absolute, onlyFiles, dot })) for scans.
• Use Bun.which to find a binary, then Bun.spawn to run it.
• Bun.readableStreamToText/Bytes/JSON for stream output.

When to use node:fs

• Use node:fs/promises for directories (mkdir, readdir, recursive operations).

Repo patterns

• Prefer Bun APIs over Node fs for file access.
• Check Bun.file(...).exists() before reading.
• For binary/large files use arrayBuffer() and MIME checks via file.type.
• Use Bun.Glob + Array.fromAsync for scans.
• Decode tool stderr with Bun.readableStreamToText.
• For large writes, use Bun.write(Bun.file(path), text).

Quick checklist

• Use Bun APIs first.
• Use path.join/path.resolve for paths.
• Prefer promise .catch(...) over try/catch when possible.