> ## Documentation Index
> Fetch the complete documentation index at: https://docs.devic.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Core concepts

> The eight things Devic is made of, and how they fit together.

Devic has a small number of building blocks. Everything else is a combination of them.

***

## The two things that do work

<Columns cols={2}>
  <Card title="Assistant" icon="comments">
    Converses. Someone — or something — sends a message and gets an answer, in a conversation that persists. Real-time, embeddable, the natural fit for support, sales and any interface a person uses.
  </Card>

  <Card title="Agent" icon="robot">
    Executes. It is given a task and works through it in a **thread**: planning, calling tools, pausing for approval, finishing. Long-running, autonomous, the natural fit for processes.
  </Card>
</Columns>

The dividing line is not the model or the tools — both have the same access to those. It is the shape of the work: a conversation with turns, or a task with a beginning and an end.

***

## The four things they use

| Block           | What it is                                                           | Page                                      |
| --------------- | -------------------------------------------------------------------- | ----------------------------------------- |
| **Tools**       | What an agent can *do*: MCP servers, built-in tools, connected apps. | [MCPs](/devic/mcps/index)                 |
| **Knowledge**   | What it can *read*: documents you write and files you upload.        | [Knowledge](/devic/knowledge/index)       |
| **Memory**      | What it *remembers* between conversations.                           | [Memory](/devic/memory/index)             |
| **Environment** | Where it *runs*: shared tools, variables and a real Linux sandbox.   | [Environments](/devic/environments/index) |

***

## The two things that organise it

<Columns cols={2}>
  <Card title="Project" icon="folder">
    How work is divided **inside** your account: access, cost and traceability follow the project. See [Projects](/devic/projects/index).
  </Card>

  <Card title="Tenant" icon="building">
    How work is divided **outside** it: your own customers, and the users inside them. See [Multi-tenant](/devic/multi-tenant/index).
  </Card>
</Columns>

<Note>
  These two are easy to confuse and are not the same axis. A project is your internal organisation — who on your team works on what. A tenant is your customer. A single project usually serves many tenants.
</Note>

***

## How they compose

A support assistant, embedded in your product:

<Steps>
  <Step title="An assistant">
    with a prompt and a model.
  </Step>

  <Step title="Knowledge">
    attached — return policy, product catalogue, tone of voice.
  </Step>

  <Step title="Tools">
    from a connected app, so it can look up a real order.
  </Step>

  <Step title="Memory">
    scoped by subtenant, so it remembers each customer and only that customer.
  </Step>

  <Step title="Embedded">
    with `@devicai/ui`, authenticated with a [tenant session](/devic/multi-tenant/tenant-sessions) so the customer's identity is proven rather than declared.
  </Step>
</Steps>

An overnight reconciliation process, instead:

<Steps>
  <Step title="An agent">
    with a plan and a schedule.
  </Step>

  <Step title="An environment">
    with the database CLI installed and the credentials as encrypted variables.
  </Step>

  <Step title="A sandbox snapshot">
    so each night starts where the last one left off.
  </Step>

  <Step title="Human in the loop">
    on the step that writes, so a person approves before anything moves.
  </Step>

  <Step title="A trigger">
    or a schedule, so nobody has to start it.
  </Step>
</Steps>

***

## Three ways to reach all of it

<Columns cols={3}>
  <Card title="Console" icon="window" href="/devic/quickstart">
    app.devic.ai — build, watch, review.
  </Card>

  <Card title="Public API" icon="code" href="/api-reference/introduction">
    Everything the console does, and what your product calls.
  </Card>

  <Card title="CLI and SDK" icon="rectangle-terminal" href="/devic/cli/index">
    The same API from a terminal or a Node backend.
  </Card>
</Columns>