> For the complete documentation index, see [llms.txt](https://docs.drizz.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.drizz.dev/twins/reference/glossary.md). # Glossary The words you'll see in Drizz Twins, each in a sentence or two. The words used across these docs, each in a sentence or two. | Word | What it means | | ------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Twin** | a private, fake copy of a real product, such as Google Calendar or Gmail, that answers like the real one. Your agent calls it through the same operations it would call the real product with | | **World** | one private, seeded copy of the twins, with your data in it. Nothing you do there is seen anywhere else. Make one with `twin world create` or `twin start` | | **Seed file** | the plain-text file (`seed.md`) that says what is in a world when it starts: the events on the calendar, the mail in the inbox. See [Describe a world](/twins/using-twins/describe-a-world.md) | | **Folder** | where `twin world create` keeps a world's address and tokens (`handle.json`). Every other `twin world` command takes it | | **Handle** | a world as JSON, so another machine can pick it up with `twin world attach`. It holds the world's tokens | | **Clock** | the world's "now", pinned by `now:` in the seed file. Every day in the seed file is read against it. Your agent gets it in `TWIN_NOW` | | **Lease** | how long a world lives if nobody deletes it: 6 hours by default for `twin world create`. When it ends, the world deletes itself | | **Label** | a group name you give worlds (`--label`), so `twin world list` and `twin world cleanup` find them together | | **MCP** | the Model Context Protocol, the standard way AI agents call tools. Each twin is an MCP server | | **MCP address** | the URL your agent connects to, to reach one app in one world. A world with a calendar and a mailbox has one address for each | | **World token** | the token your agent sends with every call (`Authorization: Bearer `). It acts as one person inside one world. Also called a person token | | **API key** | the credential that makes, reads and deletes worlds. `twin login` mints one for your machine; Settings → API keys in the web console mints one for CI. Your agent never gets it | | **Organization** | your company's account. Its people, keys and worlds belong to it, and its world limit (25 by default) is shared by everyone in it | | **Role** | what a person may do in the organization: owner, admin or member. A role bounds the scopes of the keys a person may mint | | **Scope** | a permission an API key carries. Scopes are frozen when the key is minted | | **Record of calls** | the twin's own record of every call made in a world: the tool, how it ended, its arguments, and what it changed. Read it with `twin world calls`. Also called the trace | | **Trigger** | mail or events added to a running world, now, with `twin world trigger` | | **Fault** | a call the twin makes fail on purpose, so you can see how your agent copes. Set in a seed file's `## Faults`, with `TWIN_FAULTS`, or from the web console | | **Save** | a world written out as a seed file you can read and edit (`twin world save`) | | **Snapshot** | an exact copy of everything a world holds, as JSON, to make the same world again (`twin world snapshot`) | | **Scenario** | a twin's state kept by name in your organization's Library, to load into a twin later | | **Baseline** | the people and events a twin starts with in the web console: built-in ones, or your own | | **Environment** | several twins raised as one unit. Its members reset together, renew together and lapse together. See [Several twins as one unit](/twins/using-twins/several-twins.md) | | **Blueprint** | the description an environment is raised from: its instances, the links between them, its call budget and its principal | | **Instance** | one named twin inside an environment, such as `inbox` | | **Link** | a rule in a blueprint that a value in one twin must match a row in another | | **Budget** | the total calls an environment may spend. Zero means unbounded | | **Principal** | the identity a session acts as across an environment's instances | | **Emulated** | a twin served as a stateful replica of the product: deterministic, fast and free, and it never touches the real product. The worlds you make hold made-up data only | | **Live** | a twin served as a thin adapter over the real product's API, for the same operations against a real account | | **Web console** | the twins in a browser: make twins, connect an agent, and watch its calls live. See [Web console](/twins/using-twins/web-console.md) | ## Next * [Key concepts](/twins/getting-started/concepts.md): how the ideas fit together. * [CLI reference](/twins/reference/cli.md): every `twin` command. *** *Last updated: 27 October 2026*