oxc-project/oxc is a Rust collection of tools for parsing, transforming, resolving, linting, formatting, and minifying JavaScript and TypeScript. It is used to build and maintain JavaScript development and build toolchains. Catalogue add-ons provide workflows for using Oxc tools.
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.
npx agentmods add skills/oxc-project/oxc/migrate-oxfmtnpx skills add oxc-project/oxc --skill migrate-oxfmtgit clone --depth 1 https://github.com/oxc-project/oxcWrote 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.
[](https://agentmods.dev/skills/oxc-project/oxc/migrate-oxfmt)<a href="https://agentmods.dev/skills/oxc-project/oxc/migrate-oxfmt"><img src="https://agentmods.dev/badge/skills/oxc-project/oxc/migrate-oxfmt.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00053 | $0.02729 |
| Opus 5 | $0.00026 | $0.01365 |
| Sonnet 5 | $0.00011 | $0.00546 |
| Haiku 4.5 | $0.00005 | $0.00273 |
Grade A, and why
migrate-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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 228 lines — stays where its author put it; the contents beside it link to each section on GitHub.
This skill guides you through migrating a JavaScript/TypeScript project from Prettier or Biome to Oxfmt.
Overview
Oxfmt is a high-performance, Prettier-compatible code formatter. Most Prettier options are supported directly.
An automated migration tool is built into oxfmt, supporting both Prettier and Biome as migration sources.
Step 1: Run Automated Migration
First, decide whether the automated tool fits:
- Static root config (JSON/YAML, or a JS/TS config that just exports a plain object): use
--migratebelow. - Dynamic JS/TS config (logic such as environment branches or computed values):
--migratewrites only a resolved snapshot of the values — the logic does not survive. Migrate manually instead, porting the logic tooxfmt.config.tswith the option mappings in this guide. - Nested per-directory configs:
--migrateonly handles the config found from the current directory. Migrate the nested ones manually (see "Nested Config" in Step 2).
From Prettier
npx oxfmt@latest --migrate prettier
This will:
- Find and read your Prettier config (any format Prettier supports)
- Create
.oxfmtrc.jsonwith migrated options - Migrate
.prettierignorepatterns toignorePatterns - Migrate
prettier-plugin-tailwindcssoptions tosortTailwindcss - Migrate
prettier-plugin-svelteoptions tosvelte(svelteSortOrder→sortOrder,svelteAllowShorthand→allowShorthand,svelteIndentScriptAndStyle→indentScriptAndStyle) - Detect
prettier-plugin-packagejsonand enablesortPackageJson
From Biome
npx oxfmt@latest --migrate biome
This will:
- Find and read
biome.jsonorbiome.jsonc - Create
.oxfmtrc.jsonwith migrated options - Migrate negated patterns from
files.includestoignorePatterns - Map Biome's two-level config (
formatter.*andjavascript.formatter.*) to oxfmt options
Biome option mapping:
| Biome | oxfmt |
|---|---|
formatter.indentStyle ("tab"/"space") |
useTabs (true/false) |
formatter.indentWidth |
tabWidth |
formatter.lineWidth |
printWidth |
javascript.formatter.quoteStyle |
singleQuote |
javascript.formatter.jsxQuoteStyle |
jsxSingleQuote |
javascript.formatter.quoteProperties ("asNeeded") |
quoteProps ("as-needed") |
javascript.formatter.trailingCommas |
trailingComma |
javascript.formatter.semicolons ("always"/"asNeeded") |
semi (true/false) |
javascript.formatter.arrowParentheses ("asNeeded") |
arrowParens ("avoid") |
javascript.formatter.bracketSameLine |
bracketSameLine |
formatter.bracketSpacing |
bracketSpacing |
formatter.attributePosition ("multiline") |
singleAttributePerLine (true) |
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.
- 6d ago First seen · 228 lines · 53 tokens per session scan A 86afdda5fafc
migrate-oxfmt is a skill published in the GitHub repository oxc-project/oxc (22,642 stars, last pushed yesterday), licensed MIT. It adds 53 tokens to every session and 2,729 once invoked, about $0.0003 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 2026-08-30.
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