Official agent skill

Flags SDK

Set up and use feature flags and A/B tests with the Flags SDK (flags npm package) and Vercel Flags.

OfficialCustom licenceAuto-check: notesMarketing & SEO

Install Flags SDK

skills CLI

$ npx skills add vercel/vercel-plugin --skill flags-sdk -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install vercel/vercel-plugin flags-sdk --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/vercel/vercel-plugin.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/flags-sdk .claude/skills/flags-sdk && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "flags-sdk" agent skill from https://github.com/vercel/vercel-plugin/tree/main/skills/flags-sdk into .claude/skills/flags-sdk/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flags-sdk", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/vercel/vercel-plugin/tree/main/skills/flags-sdk

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add vercel/vercel-plugin --skill flags-sdk -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install vercel/vercel-plugin flags-sdk --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vercel/vercel-plugin.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/flags-sdk .agents/skills/flags-sdk && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "flags-sdk" agent skill from https://github.com/vercel/vercel-plugin/tree/main/skills/flags-sdk into .agents/skills/flags-sdk/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flags-sdk", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add vercel/vercel-plugin --skill flags-sdk -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install vercel/vercel-plugin flags-sdk --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vercel/vercel-plugin.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/flags-sdk .cursor/skills/flags-sdk && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "flags-sdk" agent skill from https://github.com/vercel/vercel-plugin/tree/main/skills/flags-sdk into .cursor/skills/flags-sdk/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flags-sdk", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/vercel/vercel-plugin.git --path skills/flags-sdk

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add vercel/vercel-plugin --skill flags-sdk -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install vercel/vercel-plugin flags-sdk --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vercel/vercel-plugin.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/flags-sdk .gemini/skills/flags-sdk && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "flags-sdk" agent skill from https://github.com/vercel/vercel-plugin/tree/main/skills/flags-sdk into .gemini/skills/flags-sdk/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flags-sdk", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install vercel/vercel-plugin flags-sdk

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add vercel/vercel-plugin --skill flags-sdk -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/vercel/vercel-plugin.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/flags-sdk .github/skills/flags-sdk && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "flags-sdk" agent skill from https://github.com/vercel/vercel-plugin/tree/main/skills/flags-sdk into .github/skills/flags-sdk/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flags-sdk", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add vercel/vercel-plugin --skill flags-sdk -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install vercel/vercel-plugin flags-sdk --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/vercel/vercel-plugin.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/flags-sdk .opencode/skills/flags-sdk && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "flags-sdk" agent skill from https://github.com/vercel/vercel-plugin/tree/main/skills/flags-sdk into .opencode/skills/flags-sdk/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "flags-sdk", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: flags-sdk
GitHub stars: 301
Token cost: ~6.9k tokens
SKILL.md length: 2,390 words
Files: 7 (incl. references)
Skills in repo: 38
Repo updated: Oct 8, 2026
First seen: Oct 7, 2026
Licence: Custom licence

At a glance

Set up and use feature flags and A/B tests with the Flags SDK (flags npm package) and Vercel Flags.

Works in 6 steps: Install packages (if not already in… → Link the project to Vercel (required for… → Pull environment variables: If… → …
Configuring the SDK
SKILL.md covers Core concepts, Set up the SDK, Pull environment variables and Create a flag, plus 10 more sections
Calls vercel, pnpm and npm; needs FLAGS_SECRET and VERCEL_OIDC_TOKEN

What it does

Flags SDK is an agent skill from vercel/vercel-plugin, published by the product's own GitHub organization. Set up and use feature flags and A/B tests with the Flags SDK (flags npm package) and Vercel Flags. Use when installing or configuring the SDK, adding a new or existing flag, wiring vercelAdapter (OIDC or SDK keys), declaring flags with flag(), using the vercel flags CLI (create, inspect, list, enable, disable, set, update, split, rollout, rules, segments, use-targeting, evaluations, versions, open, archive, unarchive, rm, sdk-keys, override, prepare), setting up providers/adapters (Vercel, Statsig, LaunchDarkly…

Its SKILL.md is about 6.9k tokens, which your agent loads only when the skill is triggered. The skill folder holds 7 other files, including reference files (for example `overlay.yaml`, `references/api.md` and `references/nextjs.md`).

It sits in Marketing & SEO, covering A/B testing and OAuth and OpenID Connect. It works with Vercel, Next.js, SvelteKit and npm. The repository describes itself as: Comprehensive Vercel ecosystem plugin — relational knowledge graph, skills for every major product, specialized agents, and Vercel conventions. Turns any AI agent into a Vercel…

When your agent uses it

Configuring the SDK
Wiring vercelAdapter (OIDC
Declaring flags with flag()
Using the vercel flags CLI (create

Example prompts

“/flags-sdk”

Requirements

Node.js
A credential in FLAGS_SECRET
A credential in VERCEL_OIDC_TOKEN

Workflow steps

6 steps, taken from the first numbered list in SKILL.md.

Install packages (if not already in package.json)
Link the project to Vercel (required for vercel env pull and local OIDC token refresh)
Pull environment variables: If .env.local lacks VERCEL_OIDC_TOKEN=, follow Pull environment variables.
Set up the Vercel Toolbar (if not already present)
Ensure flags.ts exists: If missing, create flags.ts (or lib/flags.ts / src/flags.ts to match the project) with export {} so TypeScript…
Set up Flags Explorer (if not already present): Create app/.well-known/vercel/flags/route.ts — see Flags Explorer setup. Do this only…

What it can do on your machine

Read from SKILL.md and the folder at commit 2a1e58d. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
- vercel
- pnpm
- npm
- yarn
- bun
- npx
From the folder's file list and the shell code blocks in SKILL.md.
Network
Links to these hosts (documentation or services it may open):
- vercel.com
- flags-sdk.dev
- github.com
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names these keys or tokens, usually read from environment variables:
- FLAGS_SECRET
- VERCEL_OIDC_TOKEN
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Flags SDK loads about 6.9k tokens when it runs, and up to ~21k if it reads all its reference files. Until then it costs about 250 tokens; SKILL.md has 2,390 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~250
When it runs · the whole SKILL.md, loaded when a task matches: ~6.9k
With references · SKILL.md plus every file in references/, read only if the agent opens them: ~21k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check: notes

The automated check noted patterns worth knowing about, such as sudo or a known installer.

NoteMentions a .env fileSKILL.md:124

-sdk) (including `vercel env pull` when `.env.local` is missing). When they ask to create or add a flag, follow [Create

NoteMentions a .env fileSKILL.md:165

yet, or when Toolbar / Flags Explorer / `.env.local` are missing. Skip any step that is already done.

NoteMentions a .env fileSKILL.md:174

- Does `.env.local` contain `VERCEL_OIDC_TOKEN=` (or a `FLAGS=` SDK key)? → Env vars already pulled, skip step 3

NoteMentions a .env fileSKILL.md:191

3. **Pull environment variables**: If `.env.local` lacks `VERCEL_OIDC_TOKEN=`, follow [Pull environment variables](#pull

NoteMentions a .env fileSKILL.md:205

` writes the Development credentials to `.env.local`: the Vercel OIDC token that `vercelAdapter` uses locally (deploymen

NoteMentions a .env fileSKILL.md:207

- `.env.local` lacks `VERCEL_OIDC_TOKEN=` (or a `FLAGS=` SDK key)

NoteMentions a .env fileSKILL.md:219

he-sdk) first if packages, Vercel link, `.env.local`, Toolbar, `flags.ts`, or Flags Explorer are missing. Skip steps tha

NoteMentions a .env fileSKILL.md:220

- Does `.env.local` contain `VERCEL_OIDC_TOKEN=`? → Env vars already pulled; see [Pull environment variables](#pull-envi

NoteMentions a .env fileSKILL.md:260

3. **Pull environment variables**: If `.env.local` lacks `VERCEL_OIDC_TOKEN=`, follow [Pull environment variables](#pull

NoteMentions a .env fileSKILL.md:280

K packages, Toolbar, Flags Explorer, or `.env.local`. For a CLI-only request, skip app setup and code changes. Target th

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 2,390 words (~6,858 tokens).

“The Flags SDK (flags npm package) is a feature flags toolkit for Next.js and SvelteKit. It turns each feature flag into a callable function, works with any flag provider via adapters, and keeps pages static using the precompute pattern. Vercel…”

— opening of SKILL.md by vercel, Custom licence

name: flags-sdk
summary: Flags SDK guidance — declare flags with flag(), connect provider adapters, manage Vercel Flags via the vercel flags CLI, precompute static variants, and set…
metadata.priority: 6
metadata.docs: https://vercel.com/docs/flags, https://flags-sdk.dev
metadata.sitemap: https://vercel.com/sitemap.xml
metadata.pathPatterns: flags.ts, flags.tsx, lib/flags.ts, src/flags.ts, lib/flags/**, src/flags/**, .well-known/vercel/flags/**
metadata.importPatterns: flags/next, flags/sveltekit, flags/react, flags, @flags-sdk/*, @vercel/flags
metadata.bashPatterns: \bvercel\s+flags\b, \bvc\s+flags\b, \bnpm\s+(install|i|add)\s+[^\n]*\bflags\b, \bpnpm\s+(install|i|add)\s+[^\n]*\bflags\b…
retrieval.aliases: feature flags, feature toggles, vercel flags, flags sdk, a/b testing
retrieval.intents: add a feature flag, run an a/b test, gate a feature, roll out gradually, manage flags from cli
retrieval.entities: Flags SDK, Vercel Flags, Flags Explorer, vercelAdapter, precompute, FLAGS_SECRET

Outline of SKILL.md

Set up and use the Flags SDK
Core concepts
Flags as code
Server-side evaluation
Adapter pattern
Set up the SDK
Before you start
Steps
Pull environment variables
Create a flag
Before you start
Steps
Add a flag that already exists on Vercel
CLI-only flag management
Project targeting
Vercel Flags
Declaring flags
Basic flag
Flag with evaluation context
Flag with another adapter
Key parameters
Dedupe
Bulk evaluation
Flags Explorer setup
Next.js (App Router)
With external provider data
SvelteKit
FLAGS_SECRET
Precompute pattern
Custom adapters

Read the full SKILL.md on GitHub

Files

SKILL.md and 6 other files (references) in skills/flags-sdk of vercel/vercel-plugin.

SKILL.md
.vercel.approvers
overlay.yaml
references/api.md
references/nextjs.md
references/providers.md
references/sveltekit.md

Open the folder on GitHubat commit 2a1e58d

Compare with similar skills

Flags SDK next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Flags SDK compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Flags SDK this skillvercel/vercel-plugin	301	—	~6.9k	Automated safety check: Notes	Custom licence	today
Htmldropooiyeefei/ccc	494	—	~5.2k	Automated safety check: Warn	MIT	2 mo ago
Sandbox Benchvercel/next.js	143k	—	~4.1k	Automated safety check: Pass	MIT	today
Vercel Optimize Auditvercel-labs/agent-skills	32k	8 repos	~4.3k	Automated safety check: Pass	None	1 mo ago
AI SDKvercel-labs/ai-facts	168	20 repos	~1.2k	Automated safety check: Pass	None	5 mo ago
Vercel React Best Practicessanity-io/sanity	6.4k	129 repos	~1.6k	Automated safety check: Pass	MIT	today

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Questions about Flags SDK

What does Flags SDK do?

Set up and use feature flags and A/B tests with the Flags SDK (flags npm package) and Vercel Flags. Flags SDK is an agent skill from vercel/vercel-plugin, published by the product's own GitHub organization. Set up and use feature flags and A/B tests with the Flags SDK (flags npm package) and Vercel Flags.

When should I use Flags SDK?

Flags SDK fits situations like: configuring the SDK; wiring vercelAdapter (OIDC; declaring flags with flag(); using the vercel flags CLI (create.

How do I install Flags SDK in Claude Code?

Run `npx skills add vercel/vercel-plugin --skill flags-sdk -a claude-code`. Or copy the skill folder (skills/flags-sdk in vercel/vercel-plugin) into .claude/skills/flags-sdk in your project. Claude Code loads it when a task matches its description.

How do I install Flags SDK in Codex?

Run `npx skills add vercel/vercel-plugin --skill flags-sdk -a codex`. Or copy the skill folder (skills/flags-sdk in vercel/vercel-plugin) into .agents/skills/flags-sdk in your project. Codex loads it when a task matches its description.

Can I use Flags SDK in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add vercel/vercel-plugin --skill flags-sdk -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/flags-sdk, .gemini/skills/flags-sdk, .github/skills/flags-sdk and .opencode/skills/flags-sdk in your project.

What does Flags SDK need to run?

Going by SKILL.md and its folder, Flags SDK needs the command-line tools its instructions call (vercel, pnpm, npm, yarn, bun and npx) and credentials named FLAGS_SECRET and VERCEL_OIDC_TOKEN. Our summary lists: Node.js; A credential in FLAGS_SECRET; A credential in VERCEL_OIDC_TOKEN.

Does Flags SDK access the network?

SKILL.md names 3 domains. As links in the text: vercel.com, flags-sdk.dev and github.com. This is read from the text; nothing was executed.

Is Flags SDK safe to install?

Our automated static check of SKILL.md found notes only (mentions a .env file), nothing it rates as a warning. It is not a guarantee. Review the folder before installing.

What licence does Flags SDK use?

Flags SDK has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.

How many tokens does Flags SDK use?

About 6.9k tokens (SKILL.md is roughly 27k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 15k tokens, read only when the agent opens those files.

What are the alternatives to Flags SDK?

Skills that share tags, products or a category with Flags SDK: Htmldrop (ooiyeefei/ccc, 494 stars), Sandbox Bench (vercel/next.js, 143k stars), Vercel Optimize Audit (vercel-labs/agent-skills, 32k stars) and AI SDK (vercel-labs/ai-facts, 168 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Flags SDK?

vercel (a GitHub organization, an official publisher) maintains it in vercel/vercel-plugin, which has 301 GitHub stars. The repository holds 38 skills in this directory. The repository was last updated on October 8, 2026.

Source: vercel/vercel-plugin on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Flags SDK

Install Flags SDK

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Files

Compare with similar skills

Similar skills

Htmldrop

Sandbox Bench

Vercel Optimize Audit

AI SDK

Vercel React Best Practices

GSAP for React

More from vercel/vercel-plugin

Deployments Cicd

Plugin Audit

Vercel CLI

AI Gateway

Vercel Services

Access Protected Vercel Deployment

Questions about Flags SDK

Install Flags SDK

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Files

Compare with similar skills

Similar skills

More from vercel/vercel-plugin

Related

Questions about Flags SDK