# Flag

> Flag is a feature flag service your AI agent can drive, priced at cost: targeting rules, percentage rollouts, segments, prerequisites, approvals and scheduled changes for critical environments, flag history with restore, evaluation insights and stale-flag cleanup. A TypeScript SDK evaluates locally; any OpenFeature SDK works over OFREP. Agents connect to the MCP server; their production writes become change requests people approve. Invite-only beta; sign-ups are closed. Metered at cost per SDK request and event (billing is not switched on yet).

Everything is at https://flag.nightroll.app: the REST API (/api/v1), the SDK data plane (/sdk/v1, /ofrep/v1) and the MCP server (/mcp). Connecting an agent: https://flag.nightroll.app/quickstart. MCP tools: https://flag.nightroll.app/ai. Prices: https://flag.nightroll.app/pricing.

## Start

- [Overview](https://flag.nightroll.app/docs/index.md): What Flag is, its main ideas, and where to start: the dashboard, the TypeScript SDK, OFREP, the REST API and the MCP server.
- [Getting started](https://flag.nightroll.app/docs/getting-started.md): Accept your invite, create a flag, get an SDK key and read the flag from TypeScript or any OpenFeature SDK.

## Build

- [SDKs](https://flag.nightroll.app/docs/sdks.md): The TypeScript SDK (Node, Bun, Deno, browsers, React), its OpenFeature providers, and OFREP for any other OpenFeature SDK.
- [REST API](https://flag.nightroll.app/docs/api.md): The REST API at /api/v1 - authentication, errors, dry runs, semantic patch instructions, change requests, schedules and every endpoint group.

## Reference

- [Evaluation spec](https://flag.nightroll.app/docs/evaluation.md): How a flag is evaluated for a context: snapshots, rules, clauses, segments, bucketing and reasons. Every SDK implements it.
- [SDK protocol](https://flag.nightroll.app/docs/sdk-protocol.md): How SDKs talk to the data plane: keys, encrypted snapshots, change streams, remote evaluation, OFREP and events.

## Optional

- [Home page](https://flag.nightroll.app/): what Flag is, in plain words
- [Terms](https://flag.nightroll.app/legal/terms), [Privacy](https://flag.nightroll.app/legal/privacy), [Security](https://flag.nightroll.app/legal/security)