Fern skills

Official Agent Skills for building with Fern. These teach coding agents — Claude Code, Cursor, Codex, Copilot, and others — how to work well in a Fern repository.

Install

npx skills add fern-api/skills

This lists the skills in this repo and installs the ones you pick into your agent's skills directory (.claude/skills/, .agents/skills/, .cursor/skills/, …). Common variants:

npx skills add fern-api/skills --skill fern-sdks        # one skill
npx skills add fern-api/skills --all                    # every skill, no prompt
npx skills add fern-api/skills -a claude-code -a cursor # pick the agents (repeat -a)
npx skills add fern-api/skills -g                       # user-level instead of this project
npx skills add fern-api/skills -l                       # just list what's available
npx skills ls                                           # what is installed here
npx skills update                                       # pull the latest versions

Requires Node 18+. Skills are plain Markdown, so you can also copy a skills/<name>/ folder into your agent's skills directory by hand.

Skills

Skill	Use for
fern-docs	Building Fern docs sites: docs.yml, navigation, pages, custom MDX, landing pages, changelog entries, and access control (authentication & RBAC).
fern-sdks	Generating and publishing SDKs: fern.config.json, generators.yml (groups, generators, outputs, GitHub modes), auth schemes and environments, .fernignore custom code, fern generate / fern check / fern generator upgrade, registry publishing, troubleshooting generated code.
fern-spec	Making OpenAPI/AsyncAPI specs Fern-friendly: operationId/schema hygiene, x-fern-* extensions (method names, pagination, examples, audiences, global headers, SDK variables), overlays vs overrides, auth and servers, spec sync.
fern-workflows	Running Fern in CI/CD: fern check on PRs, docs preview links and publishing, SDK release workflows and publishing modes, OpenAPI spec sync, FERN_TOKEN/registry secrets, runner-only failures.

Which one do I need?

You want to…	Skill
Add a docs page, change navigation, write a changelog entry, style the site	fern-docs
Add a language, change where an SDK is published, keep hand-written code across regenerations, debug fern generate	fern-sdks
Fix odd SDK method names, add pagination/examples/errors, decide between editing the spec, an overlay or an overrides file	fern-spec
Run fern check on pull requests, preview docs per PR, release an SDK from GitHub Actions, keep the spec in sync	fern-workflows

The skills cross-reference each other, so install the ones that match your repo (a docs repo wants fern-docs + fern-workflows; an SDK config repo wants fern-sdks + fern-spec + fern-workflows) or just install --all.

Using a skill

Once installed, your agent reads each skill's description and uses it when the task matches — nothing else to configure. For example:

• "Add a changelog entry for the new webhooks endpoint" → fern-docs
• "Publish our Python SDK to PyPI as acme-sdk" → fern-sdks
• "The SDK method is called postV1Users, make it users.create" → fern-spec
• "Add a GitHub Action that runs fern check on every PR" → fern-workflows

If the agent doesn't pick a skill up, name it: "use the fern-sdks skill to…" (Claude Code also accepts /fern-sdks). Each skill is an index (SKILL.md) plus references/*.md; the agent reads the index first and then only the reference that matches the task, so the skills stay cheap in context.

To try a skill without installing it:

npx skills use fern-api/skills@fern-sdks

What the skills assume

• The Fern CLI: npm install -g fern-api (or npx fern-api). fern check works offline; fern generate needs fern login or a FERN_TOKEN.
• A fern/ directory in your repo (fern init creates one). The skills tell the agent to run fern check after every config or spec change.
• Docs links in the skills point at https://buildwithfern.com/learn; append .md to any docs URL to fetch it as Markdown.

Repository layout

skills/
  <skill-name>/
    SKILL.md          # frontmatter (name, description) + index + rules
    references/*.md   # one file per task area, read on demand

Every generators.yml/OpenAPI example in the skills is checked with fern check, every GitHub Actions example with actionlint, and every docs link is checked to resolve. Contributions welcome: npx skills init <name> scaffolds a new skill; keep SKILL.md short and put detail in references/.