miniio-portable-wasm

name	miniio-portable-wasm
description	Build portable MoonBit WASIp1 command-line executables and agent skill tools using moonbit-community/miniio as a normal dependency installed with moon add, including stdio, args/env, preopen-safe file I/O, and wasm run commands.

MiniIO Portable WASM

Use this when creating or revising a MoonBit executable for portable tools, Codex skills, or other agent workflows that should work outside this repository after moon add moonbit-community/miniio.

Start

• For a new tool, copy assets/miniio-cli/ and rename the module/package.
• For an existing tool, add the dependency with moon add moonbit-community/miniio.
• Keep the package target to WASM and make the package main-only:

import {
  "moonbit-community/miniio",
}

supported_targets = "wasm"

options(
  is_main: true,
)

Do not add explicit export-memory linker config. Current MoonBit toolchains add the needed memory export for is_main: true WASM executables.

I/O Rules

• Read args with @miniio.args_get(). args[0] is the executable name, so command arguments start at args[1].
• Use @miniio.stdin, stdout, and stderr for stdio.
• Use @miniio.read_text_file and write_text_file for UTF-8 text.
• Use @miniio.read_json_file and write_json_file for JSON config and manifest files.
• Use @miniio.copy_file when copying bytes from one guest path to another.
• Use @miniio.read_file, write_file, open, create, readdir, and rmdir for lower-level file work.
• Use remove_file when the path must be a file, rmdir when it must be a directory, and remove only when accepting either is intentional.
• Use create_mode=CreateOrTruncate, OpenExisting, or CreateNew instead of boolean creation flags.
• Treat every filesystem path as guest-visible. WASIp1 has no ambient cwd.
• moon run and moon test are useful development runners, but their WASI sandbox only exposes the working/project directory. Keep test fixtures under that tree when using Moon's runner.
• Document required preopens. For example, a program reading data/input.txt needs a run command such as:

wasmtime run --dir ./data::data _build/wasm/debug/build/<module>/<package>.wasm data/input.txt

Validate

Run these before handoff:

moon check
moon test
moon build

Prefer moon run <pkg> <args> for quick development tests.