oxfmt

A formatter for JavaScript and related files, including TypeScript, JSON, CSS, HTML, and Markdown. A formatter automatically rearranges code into a consistent style without changing its intended behavior.

In plain words
What is it for?
Use it to format files, check whether formatting is clean, configure formatting rules, or migrate settings from Prettier.
Why use it?
It reduces formatting disagreements and makes code-style checks faster in projects that use oxfmt.

Skill for Claude CodeCodex

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/delexw/claude-code-misc/oxfmt
Any agent
npx skills add delexw/claude-code-misc --skill oxfmt
Clone the repo
git clone --depth 1 https://github.com/delexw/claude-code-misc

Made for: Claude Code, Codex.

Per session 174 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,062 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 $0.00174 $0.02062
Opus 5 $0.00087 $0.01031
Sonnet 5 $0.00035 $0.00412
Haiku 4.5 $0.00017 $0.00206

Measured 2d ago against content hash 3afe763548cf, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

oxfmt 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 2d ago.

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/oxfmt/SKILL.md · 247 lines

How it starts

The opening of the file, as written. The whole thing — 247 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Oxfmt — The Oxc Formatter

Oxfmt is a Prettier-compatible formatter for the JavaScript ecosystem. It currently passes ~95% of Prettier's JS/TS test suite. It formats JavaScript, JSX, TypeScript, TSX, JSON, JSONC, JSON5, YAML, TOML, HTML, Angular, Vue, CSS, SCSS, Less, Markdown, MDX, GraphQL, Ember, and Handlebars.

When to use oxfmt

  • After modifying code in a project that has oxfmt installed
  • Setting up formatting in a new JS/TS project
  • Migrating from Prettier to oxfmt
  • Configuring formatting rules, editor integration, or CI checks

Quick reference

Installation

# Pick your package manager
npm add -D oxfmt
pnpm add -D oxfmt
yarn add -D oxfmt
bun add -D oxfmt

Add scripts to package.json:

{
  "scripts": {
    "fmt": "oxfmt",
    "fmt:check": "oxfmt --check"
  }
}

Running oxfmt with no arguments formats the current directory (like prettier --write .).

CLI flags

Flag Purpose
--check Check formatting without writing (exit 1 if unformatted)
--list-different List files that would change
--write Format and write in place (default)
--init Create .oxfmtrc.json with defaults
--migrate=prettier Convert .prettierrc to .oxfmtrc.json
--migrate=biome Convert Biome config to .oxfmtrc.json
-c PATH Use a specific config file
--ignore-path PATH Custom ignore file (repeatable)
--with-node-modules Include node_modules/ (skipped by default)
--no-error-on-unmatched-pattern Don't fail on unmatched globs
--stdin-filepath PATH Format stdin, using PATH to infer parser
--threads N Thread count (set to 1 for single core)
--lsp Start the LSP server (used by editors)

CLI does not support formatting options as flags (e.g., no --no-semi). Use the config file instead — this keeps formatting consistent across CLI, editors, and CI.

Configuration

Oxfmt looks for .oxfmtrc.json or .oxfmtrc.jsonc starting from the current directory, walking up.

Read the full file on GitHub · 247 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. 2d ago First seen · 247 lines · 174 tokens per session scan A 3afe763548cf

Subscribe to this mod's changes

oxfmt is a skill published in the GitHub repository delexw/claude-code-misc (1 stars, last pushed 5mo ago), licensed MIT. It adds 174 tokens to every session and 2,062 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.

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