moonbit-toolchain

moonbit-toolchain is a skill for Claude Code, Codex from hyfdev/moonbit-agent-skills. It costs 188 tokens per session (1,567 once invoked), scanned A, original, MIT.

A verified reference for using the MoonBit programming language and its command-line tools. It covers creating modules, managing packages and dependencies, checking, building, running, testing, formatting, documentation, coverage, benchmarks, and multiple compilation targets.

In plain words
What is it for?
Use it when starting or maintaining a MoonBit project, configuring packages, running tests, building for WebAssembly, JavaScript, or native targets, or checking coverage and benchmarks. It also explains how to re-test important commands when versions differ.
Why use it?
MoonBit commands and configuration can change between releases, so the guide records a tested version and requires checking the locally installed version before relying on its examples. It helps avoid copying commands that no longer match the toolchain.

Skill for Claude CodeCodex

Written for Claude Code and Codex: user-invocable in frontmatter, but also agents/openai.yaml present.

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/hyfdev/moonbit-agent-skills/moonbit-toolchain
Any agent
npx skills add hyfdev/moonbit-agent-skills --skill moonbit-toolchain
Clone the repo
git clone --depth 1 https://github.com/hyfdev/moonbit-agent-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for moonbit-toolchain

README.md
[![agentmods](https://agentmods.dev/badge/skills/hyfdev/moonbit-agent-skills/moonbit-toolchain.svg)](https://agentmods.dev/skills/hyfdev/moonbit-agent-skills/moonbit-toolchain)
Your own site
<a href="https://agentmods.dev/skills/hyfdev/moonbit-agent-skills/moonbit-toolchain"><img src="https://agentmods.dev/badge/skills/hyfdev/moonbit-agent-skills/moonbit-toolchain.svg" alt="Measured on agentmods" height="20"></a>
Per session 188 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,567 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00188 $0.01567
Opus 5 $0.00094 $0.00783
Sonnet 5 $0.00038 $0.00313
Haiku 4.5 $0.00019 $0.00157

Measured 6d ago against content hash 6431de6524b9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

moonbit-toolchain scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/env_report.ts), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/moonbit-toolchain/SKILL.md · 61 lines

How it starts

The opening of the file, as written. The whole thing — 61 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MoonBit toolchain

Verification contract

Every command and configuration shape in this skill was executed for real against moon 0.1.20260803 / moonrun 0.1.20260803 (MoonBit release 0.10.6, build 2026-08-03) on 2026-08-07, Linux x86_64, exercising targets wasm-gc, wasm, js, native. MoonBit ships install channels (latest, nightly, pre-release), not pinned historical versions, so re-check the installed version before relying on a cached skill copy.

Before relying on this skill, run moon version --all (or node scripts/env_report.ts, which also checks native-backend prerequisites). If versions differ from the pin:

  1. Prefer moon help <subcommand> and moon <subcommand> --help output over this skill for exact flags.
  2. Re-run any load-bearing command in a scratch module (moon new probe --user tmp) before promising its behavior.
  3. Compare against the official latest version manifest and current documentation; do not wait for a matching monthly Updates article.
  4. State the version difference in your answer.

Non-negotiable working rules

  • Run commands, don't recall them. Flags and defaults changed repeatedly (build dir is _build now, not target; moon ide exists; moon explain exists). If you cannot execute, quote --help output or mark the answer unverified.
  • Config formats are mid-migration. The current formats are the non-JSON moon.mod / moon.pkg DSL; moon.mod.json / moon.pkg.json are deprecated and no longer accepted by every subcommand (moon doc rejects them at this pin). Never create new JSON configs; never mix advice between the two formats without labeling which is which. See references/project-layout-and-config.md.
  • Don't guess package or API availability. Use moon ide doc '<query>' for installed APIs and the mooncakes registry for packages; a familiar name from npm/crates is not evidence a MoonBit package exists.
  • Prefer the narrowest verifying command and show it: moon check after config edits, targeted moon test <path> for test questions, moon info to prove API-surface claims.
  • Never run destructive or account-level commands unprompted: moon publish, moon register, moon login, moon upgrade, moon clean --dep-cache, and moon clean --build-cache change global or remote state — describe them instead, and only run them on explicit request.

Read the full file on GitHub · 61 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 61 lines · 188 tokens per session scan A 6431de6524b9

Subscribe to this mod's changes

moonbit-toolchain is a skill published in the GitHub repository hyfdev/moonbit-agent-skills (6 stars, last pushed 29d ago), licensed MIT. It adds 188 tokens to every session and 1,567 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.