--- title: "Glossary" description: "Every term you need for the first run — terminal, npm, provider, API key — explained without assuming a coding background." --- > Documentation Index > Fetch the complete documentation index at: https://colmugx.github.io/cetas/llms.txt > Use this file to discover all available pages before exploring further. # Glossary This page does one thing: explain, without a coding background, every term you meet on the way from install to your first message. Three groups, in the order you meet them. When a word is unfamiliar, look it up here and continue. ## Before installing ### Terminal The window where you talk by typing: on macOS it is called Terminal (search it in Spotlight), on Windows use PowerShell (search the Start menu), and on Linux you almost certainly have one. Cetas lives there. ### Node.js The runtime that makes Cetas go — think of it as the engine. You need version 24 or newer; if you have never installed it, download the LTS build from [nodejs.org](https://nodejs.org/) and follow the installer. Installing Node.js also gives you the `npm` command. ### npm The package manager that ships with Node.js — think an app store for developer tools. `npm install -g @posoco/cetas` means: install Cetas from that store, so it is available everywhere on this machine. ### Project directory (workspace) The **one folder** you want Cetas to work in. Reads, edits, and shell commands all happen inside that folder — which is why you enter it before starting. No project yet? A freshly created empty folder works fine. ### Repository A code or documentation folder under version control (usually git). If you do not have one yet, ignore this word: an empty folder is enough to start. ## Models and providers ### Provider The company that supplies the model, such as DeepSeek, OpenAI, or Kimi. Cetas does not ship a model of its own; it calls the provider you pick. First-time users need an account with one of them. ### API key A string the provider issues to you — think key and account in one: it proves the calls are yours and bills them to you. Create it on the provider's "API Keys" page. Cetas stores it only on your own machine. ### OAuth The other way to sign in: instead of copying a key, you approve once in the browser and the provider hands the credentials to Cetas directly. If `/login` offers a browser option, that is OAuth. ### Model The "brain" a provider supplies, such as `deepseek/deepseek-flash`. One provider usually offers several, differing in capability and price; `/model` picks between them. ### Reasoning effort How hard the same model thinks: higher effort is smarter, slower, and pricier. ### Decision model A separate small model that serves judgment calls (such as the permission gate), kept apart from the conversation model. You can ignore it on day one. ### Tokens and context Models meter and bill by tokens — roughly one Chinese character or half an English word each. The context is everything the model can "see" in one session; when it fills up, Cetas compacts it automatically. ## While using it ### Permission posture The session-level safety switch that decides whether the agent asks before it acts: `readonly` look only, `workspace_write` confirm before writing, `interactive` / `auto` / `yolo` progressively looser. `workspace_write` is the right setting for day one — see [Permissions](/cetas/en/configuration/permissions/). ### Session One full conversation with the agent, automatically journaled under `/.cetas/sessions/`. `/sessions` reopens an old one and `/rewind` walks it back to before a mistake — nothing needs "saving". ### Slash command A command starting with `/` (`/login`, `/model`, `/help`). It executes immediately, without going through the model. ### Cetas home (`/.cetas`) The single directory holding all durable state: configuration, credentials, sessions, caches. `` means your user directory — `%USERPROFILE%` on Windows, `/Users/you` or `/home/you` on macOS and Linux; a non-empty `CETAS_HOME` environment variable moves it elsewhere. Backing up means copying this directory — see [Cetas Home](/cetas/en/configuration/cetas-home/). ### MCP The protocol for attaching external tool servers (databases, ticket systems, internal APIs) to the agent; configured in `mcp.json`. Not needed on day one — see [MCP](/cetas/en/configuration/mcp/). ### ACP The Agent Client Protocol — how editors such as Zed talk to an agent. You only need it for the editor surface — see the [Editor](/cetas/en/editor/). ### Skill A folder with a `SKILL.md` holding instructions for one kind of work, loaded only when a task needs it — see [Skills](/cetas/en/configuration/skills/). ### Subagent A child agent the main session spins up for one bounded piece of work, with narrower tools and permissions than the parent — a read-only reviewer, for example. See [Subagents](/cetas/en/configuration/subagents/). Source: https://colmugx.github.io/cetas/en/getting-started/glossary/index.mdx