meta-skill

Create

moon runwasm moonbit-community/meta-skill new <dir>

Check

moon runwasm moonbit-community/meta-skill check [dir]

Shape

• Keep SKILL.md in the same semantic directory as the package that builds the .wasm artifact.
• Use moonbit-community/miniio for WASIp1 CLI args, stdout, stderr, and file I/O.
• Do not introduce moonbitlang/async or native filesystem APIs for the default portable CLI path.
• Use moonbitlang/x/path only for path manipulation when needed.
• Keep the skill body focused on instructions for AI agents, not general project documentation.

MiniIO Guidance

• 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 WASM executables.
• For @argparse CLIs, call cli.parse() and let argparse read the default argv. For hand-rolled parsers, read args with @miniio.args_get(); args[0] is the executable name, so command arguments start at args[1].
• Use @miniio.stdin, @miniio.stdout, and @miniio.stderr for stdio.
• Use @miniio.read_text_file and @miniio.write_text_file for UTF-8 text.
• Use @miniio.read_json_file and @miniio.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, @miniio.write_file, @miniio.open, @miniio.create, @miniio.readdir, and @miniio.rmdir for lower-level file work.
• Use @miniio.remove_file when the path must be a file, @miniio.rmdir when it must be a directory, and @miniio.remove only when accepting either is intentional.
• Use create_mode=@miniio.CreateMode::CreateOrTruncate, @miniio.CreateMode::OpenExisting, or @miniio.CreateMode::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

moon check
moon test
moon build --target wasm